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EXECUTIVE SUMMARY

The Animal and Plant Health Inspection Service (APHIS) of the United States (U.S.) 

Department of Agriculture (USDA) has responsibility under the Plant Protection Act (Title IV 

Pub. L. 106-224, 114 Stat. 438, 7 U.S.C. § 7701-7772) to prevent the introduction and 

dissemination of plant pests into the U.S. 

APHIS regulation 7 CFR § 340.6 provides that an applicant may petition APHIS to evaluate 

submitted data to determine that a particular regulated article does not present a plant pest risk 

and no longer should be regulated. If APHIS determines that the regulated article does not 

present a plant pest risk, the petition is granted, thereby allowing unrestricted introduction of the 

article.

Monsanto Company is submitting this request to APHIS for a determination of nonregulated 

status for the new biotechnology-derived maize product, MON 87429, any progeny derived from 

crosses between MON 87429 and conventional maize, and any progeny derived from crosses of 

MON 87429 with biotechnology-derived maize that have previously been granted nonregulated 

status under 7 CFR Part 340.

Product Description

Monsanto Company has developed herbicide tolerant MON 87429 maize, which is tolerant to the 

herbicides dicamba, glufosinate, aryloxyphenoxypropionate (AOPP) acetyl coenzyme A 

carboxylase (ACCase) inhibitors (so called “FOPs” herbicides such as quizalofop) and

2,4-dichlorophenoxyacetic acid (2,4-D). In addition, it provides tissue-specific glyphosate 

tolerance to facilitate the production of hybrid maize seeds. MON 87429 contains a demethylase 

gene from Stenotrophomonas maltophilia that expresses a dicamba mono-oxygenase (DMO) 

protein to confer tolerance to dicamba herbicide, the phosphinothricin-N-acetyltransferase (pat) 

gene from Streptomyces viridochromogenes that expresses the PAT protein to confer tolerance to 

glufosinate herbicide and the ft_t gene, a modified version of the

R-2,4-dichlorophenoxypropionate dioxygenase (Rdpa) gene from Sphingobium herbicidovorans,

that expresses a FOPs and 2,4-D dioxygenase protein (FT_T) that confers tolerance to quizalofop

and 2,4-D herbicides. MON 87429 maize also produces the 5-enolpyruvylshikimate-3-phosphate 

synthase protein from Agrobacterium sp. strain CP4 (CP4 EPSPS) to confer tolerance to 

glyphosate for use in hybrid seed production. MON 87429 maize utilizes an endogenous maize

regulatory element to target CP4 EPSPS mRNA for degradation in tassel tissues, resulting in

reduced CP4 EPSPS protein expression in pollen. Appropriately timed glyphosate applications

produce a non-viable pollen phenotype and allow for desirable cross pollinations to be made in

maize without using mechanical or manual detasseling methods to control self-pollination in 

female inbred parents.

Tissue-specific expression of CP4 EPSPS protein in MON 87429, allowing for glyphosate 

induced non-viable pollen phenotype, is the second generation of Monsanto’s Roundup®

Hybridization System (RHS) for hybrid seed production. The first-generation RHS event, 

MON 87427 maize, was deregulated in 2013 (USDA-APHIS Petition #10-281-01p). The 

second-generation RHS trait in MON 87429 allows inbred MON 87429 lines, treated with 

glyphosate at the appropriate timings, to serve as a female parent in the production of hybrid 
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seed. Female inbred MON 87429 lines receive two glyphosate applications at vegetative growth 

stages ranging from V8 to V13 that correspond to the time when immature male reproductive

tissues are forming. Treatment with glyphosate at these stages results in the intended non-viable 

pollen phenotype in MON 87429 inbred lines due to tissue-specific glyphosate sensitivity in the 

immature male reproductive tissue. In hybrid maize production systems, treatment of female 

inbred MON 87429 plants with glyphosate during the time immature male reproductive tissue is

developing will inhibit self-pollination. MON 87429 female inbreds instead will be pollinated by 

a desired male pollen donor inbred grown in close proximity that contains a deregulated 

glyphosate tolerance trait, such as NK603. This cross-pollination results in hybrid offspring 

(e.g., MON 87429 × NK603) with full plant tolerance to glyphosate, both in vegetative and 

reproductive tissues, as well as tolerance to dicamba, glufosinate, quizalofop, and 2,4-D 

herbicides. 

The RHS trait in MON 87429 maize offers the same benefits to hybrid maize seed production as 

the RHS trait in MON 87427, described in detail in USDA-APHIS Petition #10-281-01p. 

Briefly, these benefits include enabling hybrid seed producers to discontinue the practice of 

manually or mechanically detasseling female inbred plants in their production field, which must 

occur during a critical 3-4 day time period of maize tassel development, which can be influenced 

by changes in weather (e.g., extreme heat). The ability to treat MON 87429 maize female inbreds 

with glyphosate (between V8 to V13), in place of detasseling, provides flexibility to hybrid 

maize seed producers as well as reduces the cost of hybrid seed production by removing the 

reliance on costly, labor intensive manual/mechanical detasseling. An additional benefit of 

including the RHS trait in MON 87429 maize, along with dicamba-, glufosinate-, and 

quizalofop- and 2,4-D-tolerance traits, is the reduction in the number of trait loci that would 

otherwise need to be managed and combined, via traditional breeding methods.

The MON 87429 event confers glyphosate tolerance in specific plant tissues (i.e., not in tassels) 

and will be used to facilitate the production of hybrid seed. MON 87429 is not intended to be 

offered for commercial use as a stand-alone product, but will be combined, through traditional 

breeding methods, with other deregulated events that confer full-plant glyphosate tolerance (e.g., 

NK603). MON 87429 maize combined with the glyphosate-tolerant maize system through 

traditional breeding will provide growers: 1) an opportunity for an efficient, effective weed 

management system for hard-to-control and herbicide-resistant weeds; 2) a flexible system with 

multiple herbicide sites-of-action for in-crop application in current maize production systems; 

3) an opportunity to delay selection for further resistance to glyphosate and other herbicides that 

are important in crop production; 4) excellent crop tolerance to dicamba, glufosinate, quizalofop, 

2,4-D and glyphosate; and 5) additional weed management tools to enhance weed management 

systems necessary to maintain or improve maize yield and quality to meet the growing needs of 

the food, feed, and industrial markets.

MON 87429 maize will offer growers multiple choices for effective weed management including 

tough-to-control and herbicide-resistant broadleaf and grass weeds. The flexibility to use 

combinations of dicamba, glufosinate, 2,4-D, quizalofop and glyphosate herbicides representing 

multiple sites-of-action provides an effective weed management system for maize production. 

Dicamba provides effective control of over 95 annual and biennial broadleaf weed species, 

approximately 50 perennial broadleaf species and control or suppression of over 50 woody plant 

species. Glufosinate, a broad-spectrum contact herbicide, provides effective control of 
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approximately 70 annual broadleaf weed species, over 30 grass weeds and control or suppression 

of over 30 biennial and perennial grass and broadleaf weed species. Quizalofop, a selective 

postemergence herbicide, provides effective control of approximately 35 annual and perennial 

grass weeds including glyphosate-resistant grasses. 2,4-D provides effective control of over 70 

annual broadleaf weed species, and approximately 30 perennial broadleaf species. Glyphosate 

provides control of approximately 100 annual weed species (grass and broadleaf), over 60 

perennial weed species (grass and broadleaf) and control or suppression of approximately 65 

woody brush, trees and vines. Additionally, dicamba, glufosinate, and 2,4-D individually or in 

certain combinations provide control of herbicide-resistant weeds, including glyphosate-resistant 

biotypes of Palmer amaranth (Amaranthus palmeri), marestail (Conyza canadensis), common 

ragweed (Ambrosia artemisiifolia), giant ragweed (Ambrosia trifida) and waterhemp 

(Amaranthus tuberculatus).

Data and Information Presented Confirms the Lack of Plant Pest Potential and the Food 

and Feed Safety of MON 87429 Compared to Conventional Maize

The data and information presented in this petition demonstrate MON 87429 is agronomically

and phenotypically comparable to commercially cultivated maize, with the exception of the 

introduced traits. Moreover, the data and information presented demonstrate MON 87429 is not 

expected to pose an increased plant pest risk, including weediness, compared to commercially 

cultivated maize. The food, feed, and environmental safety of MON 87429 was confirmed based 

on multiple, well-established lines of evidence: 

• Maize is a familiar crop that does not possess any of the attributes commonly associated 

with weeds and has a history of safe consumption. The conventional control used for the 

transformation process was included in studies to serve as an appropriate basis of 

comparison for MON 87429.

• A detailed molecular characterization of the inserted DNA demonstrates a single, intact 

copy of the T-DNA insert in a single locus within the maize genome.

• Extensive evaluation of the FT_T protein and previous assessments of the DMO, PAT 

and CP4 EPSPS proteins expressed in MON 87429, confirm they are unlikely to be 

toxins or allergens. 

• An extensive evaluation of MON 87429 phenotypic and agronomic characteristics and 

environmental interactions demonstrates MON 87429 has no increased plant pest risk 

compared to conventional maize.

• An assessment of potential impact to non-target organisms (NTOs) including organisms 

beneficial to agriculture and endangered species indicates that MON 87429 is not 

expected to have an adverse effect on other organisms compared to conventional maize

under normal agricultural practices.

• Evaluation of the agronomic and phenotypic characteristics of MON 87429, using current 

cultivation and management practices, leads to the conclusion that deregulation of 

MON 87429 is not expected to have an adverse effect on maize agronomic practices.
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Maize is a Familiar Crop Lacking Weedy Characteristics 

Maize is grown extensively throughout the world and is the largest cultivated grain crop 

followed by wheat (Triticum sp.) and rice (Oryza sativa L.) in total global production. In the 

U.S., maize is grown in almost all states and is the largest crop grown in terms of net value. 

Maize has been studied extensively, and the initial steps in its domestication can be traced back 

to approximately 9,000 years ago in southern Mexico. Although grown extensively throughout 

the world, maize is not considered a threat to invade natural or agricultural ecosystems because it 

does not establish self-sustaining populations outside of cultivation. This lack of weediness may 

reflect its poor competitive ability, lack of seed dormancy, and barriers to seed dispersal, as 

maize cobs retain seed and are covered in a husk. Several other characteristics common in 

weeds, such as rapid flowering following emergence, are lacking in maize. Traits often 

associated with weediness are typically not selected for during domestication and subsequent 

breeding and selection, and similarly, the history of maize breeding and production in the U.S. 

does not indicate there are any changes in the characteristics of maize that would increase the 

weediness of the crop. Although maize seed can overwinter in a rotation with soybeans or other 

crops, mechanical and chemical measures are routinely used to control maize volunteers. Maize 

is not sexually compatible with plant species occurring in the U.S. other than teosinte, an 

introduced wild relative. However, gene introgression from maize into teosinte is unlikely in the 

U.S. due to barriers to crossing, including morphological and developmental differences and 

limited geographical distribution of teosinte populations. 

Conventional Maize LH244 is an Appropriate Comparator to MON 87429

Conventional control materials developed for use as comparators in safety assessment studies 

were based on the type of study conducted and the genetic background of the test material. The 

conventional control materials included the original transformation line (LH244) and LH244 

crossed to a conventional line (HCL617) to create F1 starting control materials. LH244 was used 

as the control in molecular characterization studies. LH244 × HCL617 was used as the control in 

compositional analysis studies and in phenotypic, agronomic and environmental interactions 

assessments. Where appropriate, commercial hybrid maize materials (reference hybrids) were 

also used to establish a range of variability or responses representative of commercial maize in 

the U.S.

Molecular Characterization Verified the Integrity and Stability of the Inserted DNA in 

MON 87429

MON 87429 was produced by Agrobacterium mediated-transformation of maize tissue using the 

T-DNA transformation vector PV-ZMHT519224. This plasmid vector contains a single transfer 

DNA (T-DNA), that is delineated by Right and Left Border regions. The T-DNA contains the 

pat, dmo, ft_t, and cp4 epsps expression cassettes. Following transformation, traditional 

breeding, segregation, selection and screening were used to isolate those plants that contain the

pat, dmo, ft_t, and cp4 epsps expression cassettes and do not contain any plasmid backbone 

sequences.

Characterization of the DNA insert in MON 87429 was conducted using a combination of 

sequencing, polymerase chain reaction (PCR), and bioinformatics. The results of this 
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characterization demonstrate that MON 87429 contains one copy of the intended T-DNA 

containing the pat, dmo, ft_t, and cp4 epsps expression cassettes that is stably inherited over 

multiple generations and segregates according to Mendelian principles. These conclusions are 

based on several lines of evidence: 

• Molecular characterization of MON 87429 by Next Generation Sequencing (NGS) 

demonstrated that MON 87429 contains a single intended DNA insert. These wholegenome analyses provided a comprehensive assessment of MON 87429 to determine 

the presence and identity of sequences derived from PV-ZMHT519224 and 

demonstrated that MON 87429 contains a single T-DNA insert with no detectable 

plasmid backbone sequences.

• Directed sequencing (locus-specific PCR, DNA sequencing and analyses) performed 

on MON 87429 was used to determine the complete sequence of the single DNA 

insert from PV-ZMHT519224, the adjacent flanking genomic DNA, and the 5' and 3' 

insert-to-flank junctions. This analysis confirmed that the sequence and organization 

of the DNA is identical to the corresponding region in the PV-ZMHT519224 T-DNA. 

Furthermore, the genomic organization at the insertion site in MON 87429 was 

assessed by comparing the sequences flanking the T-DNA insert in MON 87429 to 

the sequence of the insertion site in conventional maize. This analysis determined that 

54 bases were deleted upon T-DNA integration. There also was a 29 base insertion in 

the MON 87429 5′ flanking sequence and a 31 base insertion in the MON 87429 

3′ flanking sequence.

• Generational stability analysis by Next Generation Sequencing (NGS) demonstrated 

that the single PV-ZMHT519224 T-DNA insert in MON 87429 has been maintained 

through five breeding generations, thereby confirming the stability of the T-DNA in 

MON 87429.

• Segregation analysis corroborates the insert stability demonstrated by NGS and 

independently establishes the nature of the T-DNA as a single chromosomal locus 

that shows an expected pattern of inheritance.

Taken together, the characterization of the genetic modification in MON 87429 demonstrates 

that a single copy of the intended T-DNA was stably integrated at a single locus of the maize 

genome and that no plasmid backbone sequences are present in MON 87429.

In addition, MON 87429 maize utilizes an endogenous maize regulatory element (a target 

sequence for endogenous small interfering RNAs (siRNAs)) to target CP4 EPSPS mRNA for 

degradation in tassel tissues. A focused study on the MON 87429 siRNA Target Sequence 

demonstrated the absence of unintended effects on endogenous gene regulation.
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Data Confirm DMO, PAT, CP4 EPSPS and FT_T Protein Safety

MON 87429 contains a dmo expression cassette that expresses a single MON 87429 DMO 

precursor protein that is post-translationally processed during the chloroplast targeting process 

into two forms of the DMO protein; referred to as MON 87429 DMO+1 and MON 87429 

DMO+0. MON 87429 DMO+1 is identical to MON 87429 DMO+0 with the exception that it 

contains an additional amino acid on the N-terminus, a cysteine residue, derived from the 

alternative processing of the chloroplast transit peptide APG6. Given this degree of similarity,

the term MON 87429 DMO protein will be used hereafter to refer to both forms of the protein 

collectively and distinctions will only be made where necessary. DMO proteins highly similar to 

those produced in MON 87429 are also present in MON 88701 cotton, MON 87708 soybean and 

MON 87419 maize which were deregulated by USDA-APHIS in 2015, 2015 and 2016,

respectively. MON 88701 cotton, MON 87708 soybean and MON 87419 maize also completed 

FDA consultation in 2013, 2011 and 2016, respectively, where it was demonstrated that food and 

feed derived from these crops are not materially different than the respective conventional crops. 

Data, demonstrating the safety of DMO, were reviewed by U.S. agencies in accordance with the 

review responsibilities under the Coordinated Framework, resulting in full authorization of these 

products in the U.S. The safety of DMO protein has been favorably assessed following 

extensive reviews by regulatory agencies in at least 12 different countries. Although there are 

minor differences in amino acid sequence, the DMO proteins expressed in MON 87429 are 

identical to previously reviewed DMO proteins in terms of structure of the catalytic site, 

function, immunoreactivity, and substrate specificity. Thus, prior safety assessments of DMO 

proteins are applicable to the DMO protein expressed in MON 87429.

The PAT protein in MON 87429 has the same sequence as PAT protein produced in several 

other commercially available crops that have been reviewed by USDA and previously 

deregulated (e.g., T25, DAS-59122-7 and TC1507 maize and A2704-12 and A5547-127 

soybean). The safety of PAT proteins has been confirmed following extensive reviews by 

regulatory agencies in at least 15 different countries for more than 30 biotechnology-derived 

events in several different crop species (e.g., maize, soybean, cotton, canola and sugar beet). The 

lack of any documented reports of adverse effects of PAT-containing crops since their 

commercial introduction further confirms the safety of the PAT protein. The amino acid 

sequence of the PAT protein expressed in MON 87429 is identical to the wild type PAT protein 

encoded by S. viridochromogenes except for the first methionine, which is removed due to cotranslational processing in MON 87429. N-terminal methionine cleavage is common and 

naturally occurs in the vast majority of proteins. Thus, prior safety assessments of PAT proteins 

are applicable to the PAT protein expressed in MON 87429.

The CP4 EPSPS protein in MON 87429 has the same sequence as CP4 EPSPS proteins produced 

in several other commercially available crops that have been reviewed by USDA and previously 

deregulated (e.g., 40-3-2 and MON 89788 soybean, NK603, MON 87427 and MON 88017 

maize, RT73 canola, H7-1 sugar beet, 1445 and MON 88913 cotton, and J101 and J163 alfalfa). 

The safety and mode-of-action of CP4 EPSPS proteins is well documented and is the subject of 

numerous publications. Additionally, in 1996 the U.S. EPA established an exemption from the 

requirement of a tolerance for residues of the plant pesticide inert ingredient CP4 EPSPS and the 

genetic material necessary for its production in all plants (40 CFR § 174.523, redesignated from 

§ 180.1174, effective April 25, 2007). The safety of the CP4 EPSPS protein as expressed in 
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MON 88017 and MON 87427 maize has also been reviewed and approved in at least 12 

countries. Thus, prior safety assessments of CP4 EPSPS protein are applicable to the CP4 

EPSPS protein expressed in MON 87429.

A multistep approach was used to characterize and assess the safety of the FT_T protein

expressed in MON 87429 resulting from the genetic modification. The expression level of the 

FT_T protein in selected tissues of MON 87429 was determined and potential for exposure to 

humans and animals was assessed. In addition, the donor species for the FT_T protein coding 

sequences, Sphingobium species, are ubiquitous in the environment and are not commonly 

known for human or animal pathogenicity or allergenicity. Bioinformatics analysis determined 

that the FT_T protein lacks structural similarity to known allergens, gliadins, glutenins, or 

protein toxins. The FT_T protein is rapidly digested in pepsin and pancreatin and demonstrates 

no acute oral toxicity in mice at a dose level that far exceeds anticipated exposure by humans and 

animals. Hence, the consumption of the FT_T protein from MON 87429 or its progeny poses no 

meaningful risk to human and animal health.

MON 87429 is Compositionally Equivalent to Conventional Maize 

Safety assessments of biotechnology-derived crops follow the comparative safety assessment 

process in which the composition of grain and/or other raw agricultural commodities of the 

biotechnology-derived crop are compared to the appropriate conventional control that has a 

history of safe use. Maize is not known to have any endogenous toxicants or antinutrients 

associated with overall plant pest potential. For MON 87429, the introduced proteins, DMO, 

PAT, CP4 EPSPS and FT_T, confer herbicide tolerance and lack catalytic activity that is 

intended to or expected to affect the plant’s metabolism. Given the nature of these introduced 

traits and the overall lack of meaningful unintended compositional characteristics observed for 

biotechnology-derived products characterized to date, compositional changes that would affect 

the levels of nutritional components in MON 87429 maize were not expected.

Monsanto is currently in consultation with the Food and Drug Administration following their 

policy, “Foods Derived from New Plant Varieties,” on the food and feed safety of MON 87429 

maize (Submitted 05-Feb-2019). Composition data for 25 components including major nutrients 

in grain and forage and anti-nutrients in grain was submitted to FDA as part of the voluntary 

food/feed safety and nutritional assessment for MON 87429 maize. The results of the 

compositional assessment found that there were no biologically meaningful differences between 

MON 87429 and conventional control and support the conclusion that MON 87429 maize is 

compositionally equivalent to the conventional control.

MON 87429 Does Not Change Maize Plant Pest Potential or Environmental Interactions

Plant pest potential of a biotechnology-derived crop is assessed from the basis of familiarity that 

the USDA recognizes as an important underlying concept in risk assessment. The concept of 

familiarity is based on the fact that the biotechnology-derived plant is developed from a 

conventional plant hybrid or variety whose biological properties and plant pest potential are well 

known. Familiarity considers the biology of the plant, the introduced trait, the receiving 

environment, and the interactions among these factors. This provides a basis for comparative 

risk assessment between a biotechnology-derived plant and the conventional control. Thus, the 
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phenotypic, agronomic, and environmental interactions assessment of MON 87429 included the 

genetically similar conventional control as a comparator. This evaluation used a weight of 

evidence approach and considered statistical differences between MON 87429 and the 

conventional control with respect to reproducibility, magnitude, and directionality. Comparison

to a range of commercial references grown concurrently established the range of natural 

variability for maize and provided a context from which to further evaluate any statistical 

differences. Assessments included seed germination and dormancy characteristics and pollen 

characteristics in the laboratory as well as phenotypic and agronomic characteristics and plant 

responses to abiotic stressors, diseases, and arthropod pests in the field. Results from the 

phenotypic, agronomic, and environmental interactions assessment indicated that MON 87429 

does not possess enhanced weediness characteristics, increased susceptibility or tolerance to 

specific abiotic stressors, diseases, or arthropod pests, or characteristics that would confer an 

increased plant pest risk compared to conventional maize.

MON 87429 Will Not Negatively Affect Non-Target Organisms (NTOs) Including Those 

Beneficial to Agriculture 

An evaluation of the impacts of MON 87429 on non-target organisms (NTOs) is a component of 

the plant pest risk assessment. Because MON 87429 does not possess pesticidal activity, all 

organisms that interact with MON 87429 are considered to be NTOs. Data from the 2017 U.S. 

phenotypic and agronomic studies, including observational data on plant response to abiotic 

stressors, diseases, and arthropod pests, were collected for MON 87429 and conventional 

controls. Results from these studies support conclusions that MON 87429 is unlikely to 

adversely affect NTOs. 

The DMO, PAT, and CP4 EPSPS proteins have been assessed in multiple products by 

USDA-APHIS and U.S. FDA in the past years. DMO protein is produced in both MON 87708 

soybean, MON 88701 cotton and MON 87419 maize that were granted nonregulated status by 

USDA-APHIS. Starting in 1996 with Bayer’s T25 maize, numerous glufosinate tolerant crops 

(canola, cotton, maize, soybean, sugar beet) containing PAT proteins have been granted 

nonregulated status by USDA-APHIS. CP4 EPSPS protein is also produced in numerous other 

glyphosate tolerant crops (soybean, maize, cotton, sugar beet, canola, and alfalfa) that have been 

granted nonregulated status by USDA-APHIS. Assessment of the FT_T proteins non-toxic 

mode-of-action (MOA), lack of acute oral toxicity, and lack of impact on plant pest potential

supports a conclusion that the FT_T protein will not have adverse impacts to NTOs. In addition, 

after either extensive testing and/or wide scale commercial cultivation, in no instance have 

adverse impacts to NTOs been associated with exposure to DMO, PAT, or CP4 EPSPS proteins 

from these biotechnology-derived crops. 

The biochemical information and experimental data for evaluation of MON 87429 included 

mode of action, molecular characterization, DMO, PAT, CP4 EPSPS and FT_T protein safety 

assessment, establishment of compositional equivalence to conventional maize, data from the 

environmental interactions assessment, and demonstration of agronomic and phenotypic 

equivalence to conventional maize. Taken together, these data support the conclusion that 

MON 87429 has no plausible mechanism for harm to NTOs, nor does it pose an additional risk 

to organisms beneficial to agriculture or threatened and endangered species compared to 

conventional maize.
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Deregulation of MON 87429 is Not Expected to Have Effects on Maize Agronomic 

Practices

An assessment of current maize agronomic practices was conducted to determine whether the 

cultivation of MON 87429 has the potential to impact current maize agronomic practices. Maize 

fields are typically highly managed areas that are dedicated to grain and/or forage production. 

MON 87429 has been developed to offer maize growers multiple choices for effective weed 

management including tough to control and herbicide resistant broadleaf and grass weeds. The 

combination of dicamba, glufosinate, quizalofop and 2,4-D tolerance offers multiple herbicide 

sites-of-actions and provides an effective weed management system for maize production in the 

U.S. Dicamba, glufosinate, quizalofop, and 2,4-D herbicides are currently labeled for preplant 

and postemergence applications in maize. In support of Monsanto’s third generation herbicide 

tolerant MON 87419 maize, deregulated by USDA in 2016, Monsanto requested that EPA allow 

the 0.5 lb a.e./ac postemergence application window for dicamba to be extended from V5 to V8 

growth stage or 36-inch height of maize, whichever occurs first, without reducing the application 

rate of dicamba (U.S. EPA, 2019). The combined (pre- and post-emergence) maximum annual 

application rate of dicamba in MON 87419 maize would be 2.0 lbs. a.e. dicamba per acre per 

year, increased from the current maximum annual application rate of 0.75 lbs. a.e. in 

conventional maize. Pending approval of the expanded label at EPA, the dicamba use pattern for 

MON 87429 would be no different than that of MON 87419. Glufosinate, quizalofop and 2,4-D, 

are currently labeled for preplant applications on conventional and herbicide-tolerant maize 

hybrids and for in-crop postemergence applications on herbicide-tolerant hybrids. Use of 

glufosinate, quizalofop and 2,4-D over the top of MON 87429 will follow the current labeled use

patterns of these individual herbicides. The MON 87429 event confers glyphosate tolerance in 

specific plant tissues (i.e., not in tassels) and will be used to facilitate the production of hybrid 

seed. MON 87429 is not intended to be offered for commercial use as a stand-alone product, but 

will be combined, through traditional breeding methods, with other deregulated events that 

confer full-plant glyphosate tolerance (e.g., NK603). The introduction of MON 87429 stacked 

with a deregulated glyphosate tolerance trait will follow the current labeled use patterns of 

glyphosate herbicide. The introduction of MON 87429 maize is not expected to have adverse 

impacts on current agronomic, cultivation and management practices for maize. No meaningful 

changes are anticipated in crop rotations, tillage practices, planting practices, fertility 

management, weed and disease management, and volunteer management from the introduction 

of MON 87429.

Conclusion

Based on the data and information presented in this petition, it is concluded that MON 87429 is 

unlikely to pose a plant pest risk. Therefore, Monsanto Company requests a determination from 

USDA-APHIS that MON 87429 and any progeny derived from crosses between MON 87429 

and conventional maize or deregulated biotechnology-derived maize be granted nonregulated 

status under 7 CFR Part 340.
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TABLE OF CONTENTS

I. RATIONALE FOR THE DEVELOPMENT OF MON 87429......................................25

I.A. Basis for the Request for a Determination of Nonregulated Status under 

7 CFR § 340.6 ...............................................................................................................25

I.B. Rationale for the Development of Herbicide Tolerant Maize MON 87429...........25

I.C. Submissions to Other Regulatory Agencies...........................................................28

I.C.1. Submission to FDA......................................................................................28

I.C.2. Related Submissions to U.S. EPA ...............................................................28

I.C.3. Submissions to Foreign Government Agencies...........................................29

II. THE BIOLOGY OF MAIZE ........................................................................................30

II.A. Maize as a Crop ....................................................................................................30

II.B. Characteristics of the Recipient Plant ...................................................................31

II.C. Maize as a Test System in Product Safety Assessment ........................................32

III. DESCRIPTION OF THE GENETIC MODIFICATION ............................................33

III.A. Description of Transformation Plasmid PV-ZMHT519224................................33

III.B. Description of the Transformation System..........................................................34

III.C. The pat Coding Sequence and PAT Protein ........................................................41

III.D. The dmo Coding Sequence and DMO Protein ....................................................42

III.E. The ft_t Coding Sequence and FT_T Protein ......................................................43

III.F. The cp4 epsps Coding Sequence and CP4 EPSPS Protein ..................................43

III.G. Regulatory Sequences .........................................................................................44

III.H. T-DNA Border Regions ......................................................................................45

III.I. Genetic Elements Outside the T-DNA Border Regions .......................................45

IV. CHARACTERIZATION OF THE GENETIC MODIFICATION..............................47

IV.A. Description of Methodology Used to Characterize MON 87429 .......................47

IV.B. Characterization of the DNA Insert in MON 87429 ...........................................51

IV.B.1. Next Generation Sequencing for MON 87429 and Conventional Control 

Genomic DNA .......................................................................................................51

IV.B.2. Selection of Sequence Reads Containing Sequence of the 

PV-ZMHT519224..................................................................................................58

IV.B.3. Determination of T-DNA Copy Number and Presence or Absence of 

Plasmid Vector Backbone......................................................................................58
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IV.C. Organization and Sequence of the Insert and Adjacent DNA in MON 87429 ...62

IV.D. Sequencing of the MON 87429 Insertion Site ....................................................64

IV.E. Determination of Insert Stability over Multiple Generations of MON 87429 ....66

IV.F. Inheritance of the Genetic Insert in MON 87429 ................................................67

IV.G. MON 87429 RHS Mechanism of Action............................................................70

IV.H. Absence of Unintended Effects due to the MON 87429 RHS Mechanism of 

Action ............................................................................................................................73

IV.H.1. Lack of Secondary siRNA from CP4 EPSPS mRNA Suppression..........73

IV.I. Characterization of the Genetic Modification Summary and Conclusion............76

V. CHARACTERIZATION AND SAFETY ASSESSMENT OF THE DMO, PAT, CP4 

EPSPS AND FT_T PROTEINS PRODUCED IN MON 87429 .......................................78

V.A. DMO Protein Safety Assessment Summary.........................................................78

V.B. PAT Protein Safety Assessment Summary...........................................................81

V.C. CP4 EPSPS Protein Safety Assessment Summary ...............................................83

V.D. FT_T Protein Characterization and Safety Assessment .......................................85

V.D.1. Identity and Function of the FT_T protein from MON 87429...................85

V.D.2. Characterization and Equivalence of FT_T protein from MON 87429.....87

V.D.3. FT_T Protein Donor Organism and History of Safe Use...........................88

V.D.4. FT_T Protein Catalyzes a Specific Enzyme Reaction ...............................88

V.D.5. FT_T Protein in MON 87429 is Not Homologous to Known Allergens or 

Toxins ....................................................................................................................92

V.D.6. FT_T Protein in MON 87429 is Susceptible to Degradation in in vitro

Digestion Assay .....................................................................................................92

V.D.7. FT_T Protein in MON 87429 is Not Acutely Toxic..................................93

V.D.8. Assessment of Potential Allergenicity of the FT_T Protein ......................93

V.D.9. Human and Animal Exposure to the FT_T Protein ...................................94

V.E. Expression Levels of DMO, PAT, CP4 EPSPS and FT_T Proteins Produced in 

MON 87429...................................................................................................................94

V.E.1. Expression Level of DMO Protein .............................................................94

V.E.2. Expression Level of PAT Protein...............................................................95

V.E.3. Expression Level of CP4 EPSPS Protein ...................................................96

V.E.4. Expression Level of FT_T Protein .............................................................98
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VI. COMPOSITIONAL ASSESSMENT OF MON 87429.............................................100

VI.A. Compositional Equivalence of MON 87429 Grain and Forage to Conventional 

Maize ...........................................................................................................................100

VII. PHENOTYPIC, AGRONOMIC, AND ENVIRONMENTAL INTERACTIONS 

ASSESSMENT................................................................................................................110

VII.A. Characteristics Measured for Assessment .......................................................110

VII.B. Data Interpretation ...........................................................................................113

VII.B.1. Interpretation of Phenotypic and Agronomic Data................................113

VII.B.2. Interpretation of Environmental Interactions Data ................................115

VII.C. Comparative Assessments of the Phenotypic, Agronomic, and Environmental 

Interactions Characteristics of MON 87429................................................................115

VII.C.1. Seed Germination and Dormancy Characteristics.................................115

VII.C.2. Field Phenotypic, Agronomic and Environmental Interactions 

Characteristics......................................................................................................117

VII.C.3. Pollen Characteristics ............................................................................121

VII.D. Conclusions for Phenotypic, Agronomic, and Environmental Interactions 

Evaluation....................................................................................................................122

VIII. U.S. AGRONOMIC PRACTICES .........................................................................123

VIII.A. Introduction ....................................................................................................123

VIII.B. Overview of U.S. Maize Production...............................................................125

VIII.B.1. Maize Grain Production .......................................................................125

VIII.B.2. Maize Seed Production.........................................................................126

VIII.C. Production Management Considerations........................................................128

VIII.D. Management of Insect Pests...........................................................................129

VIII.E. Management of Diseases and Other Pests ......................................................129

VIII.F. Weed Management..........................................................................................130

VIII.F.1. Methods of Weed Control in Maize .....................................................130

VIII.F.2. Herbicide Resistant Weeds in Maize ....................................................143

VIII.F.3. Impact of MON 87429 Maize Introduction on Weed Management 

Practices...............................................................................................................145

VIII.F.4. MON 87429 Maize as a Component in Weed Resistance Management148

VIII.F.5. Weed Management Conclusion............................................................149
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VIII.G. Crop Rotation Practices in Maize...................................................................149

VIII.H. Maize Volunteer Management .......................................................................151

VIII.I. Stewardship of MON 87429 Maize .................................................................154

VIII.J. Summary and Conclusion: Impact of the Introduction of MON 87429 Maize on 

Agricultural Practices..................................................................................................155

IX. PLANT PEST ASSESSMENT .................................................................................156

IX.A. Introduction .......................................................................................................156

IX.B. Plant Pest Assessment of MON 87429 and Expressed Protein.........................156

IX.B.1. Characteristics of the Genetic Insert and Expressed Protein ..................156

IX.B.2. Compositional Characteristics ................................................................159

IX.B.3. Phenotypic, Agronomic, and Environmental Interaction Characteristics159

IX.C. Weediness Potential of MON 87429.................................................................162

IX.D. Potential for Pollen Mediated Gene Flow and Introgression ............................162

IX.D.1. Hybridization with Cultivated Maize .....................................................162

IX.D.2. Hybridization with Teosinte ...................................................................167

IX.D.3. Hybridization with Tripsacum................................................................167

IX.D.4. Transfer of Genetic Information to Species with which Maize Cannot 

Interbreed (Horizontal Gene Flow)......................................................................168

IX.E. Potential Impact on Maize Agronomic Practices ..............................................168

IX.F. Conventional Breeding with Other Biotechnology-derived or Conventional 

Maize ...........................................................................................................................168

IX.G. Summary of Plant Pest Assessments.................................................................169

X. ADVERSE CONSEQUENCES OF INTRODUCTION ............................................171

Appendix A : USDA Notifications and Permits.............................................................192

Appendix B : Overview, Materials, Methods and Supplementary Results for Molecular 

Analyses of MON 87429 .................................................................................................196

Appendix C : MON 87429 RHS Mechanism of Action.................................................204

Appendix D : Characterization of FT_T Protein Produced in MON 87429...................208

Appendix E : Specificity of the MON 87429 Dicamba Mono-Oxygenase (DMO) 

Enzyme Using o-Anisic Acid as a Substrate ...................................................................232

Appendix F : Materials and Methods Used for the Analysis of the Levels of DMO, PAT, 

CP4 EPSPS and FT_T Proteins Expressed in MON 87429 ............................................238
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Appendix G : Mode of Action and Specificity of MON 87429 FT_T Protein...............241

Appendix H : Materials and Methods for Seed Germination and Dormancy Assessment 

of MON 87429.................................................................................................................246

Appendix I : Material and Methods for Phenotypic, Agronomic, and Environmental 

Interaction Assessment of MON 87429 under Field Conditions.....................................250

Appendix J : Materials and Methods for Pollen Morphology and Viability Assessment259

Appendix K : Herbicide Resistance................................................................................264

Appendix L : MON 87429 Exogenous Substrate Specificity.........................................294

Appendix M : Materials and Methods for Compositional Analysis of Maize MON 87429 

Grain and Forage..............................................................................................................296

Appendix N : Digestive Fate of the FT_T Protein..........................................................303
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LIST OF TABLES

Table III-1. Summary of Genetic Elements in PV-ZMHT519224 ...................................37

Table IV-1. Summary of Genetic Elements in MON 87429 ............................................52

Table IV-2. Unique Junction Sequence Class Results......................................................59

Table IV-3. Junction Sequence Classes Detected.............................................................66

Table IV-4. Segregation of the Expression Cassette During the Development of 

MON 87429 .......................................................................................................................69

Table V-1. In Vitro FT_T Enzymatic Activity Assay Compound List.............................89

Table V-2. Summary of DMO Protein Levels in Maize Tissues Collected 

from MON 87429 Produced in United States Field Trials During 2017...........................95

Table V-3. Summary of PAT Protein Levels in Maize Tissues Collected 

from MON 87429 Produced in United States Field Trials During 2017...........................96

Table V-4. Summary of CP4 EPSPS Protein Levels in Maize Tissues Collected 

from MON 87429 Produced in United States Field Trials During 2017...........................97

Table V-5. Summary of CP4 EPSPS Protein Levels in Maize Pollen Tissue Collected 

from MON 87429 Produced in United States Field Trials During 2017...........................97

Table V-6. Summary of FT_T Protein Levels in Maize Tissues Collected 

from MON 87429 Produced in United States Field Trials During 2017...........................98

Table VI-1. Summary of Maize Grain Proximates, Linoleic Acid, Carbohydrates by 

Calculation and Fiber for MON 87429 and Conventional Control .................................103

Table VI-2. Summary of Maize Grain Essential Amino Acids for MON 87429 and 

Conventional Control.......................................................................................................105

Table VI-3. Summary of Maize Grain Anti-Nutrients for MON 87429 and Conventional 

Control .............................................................................................................................107

Table VI-4. Summary of Maize Forage Proximates, Carbohydrates by Calculation and 

Fiber for MON 87429 and Conventional Control............................................................108

Table VI-5. Literature and ILSI-CCDB Database Ranges for Components in Maize 

Grain and Forage..............................................................................................................109

Table VII-1. Phenotypic, Agronomic, and Environmental Interactions Characteristics 

Evaluated in U.S. Field Trials and Laboratory Studies ...................................................111

Table VII-2. Germination and Dormancy Characteristics of MON 87429 and the 

Conventional Control.......................................................................................................117

Table VII-3. Phenotypic and agronomic and Environmental Interactions Sites for 

MON 87429 during 2017.................................................................................................118
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Table VII-4. Combined-Site Analysis of Phenotypic and Agronomic Characteristics of 

MON 87429 Compared to the Conventional Control in 2017 U.S. Field Trials.............119

Table VII-5. Summary of Qualitative Environmental Interactions Assessments for 

MON 87429 during 2017.................................................................................................120

Table VII-6. Viability and Diameter of Pollen Collected from MON 87429, the 

Conventional Control, and the Reference Materials........................................................121

Table VIII-1. Field Maize Production in the U.S., 2007-20181......................................126

Table VIII-2. Troublesome Weeds in Maize Production1..............................................133

Table VIII-3. Herbicide Applications in Maize in 2018 in the U.S.1.............................134

Table VIII-4. Crop Tolerance and Grass Weed Responses to Herbicides Applied in 

Maize Production.............................................................................................................137

Table VIII-5. Broadleaf Weed Responses to Herbicides Applied in Maize Production 140

Table VIII-6. Common Weeds in Maize and Their Resistance to Herbicide Sites-ofaction in the U.S.1

............................................................................................................144

Table VIII-7. Anticipated Weed Management Recommendations for MON 87429 Maize 

Combined with Glyphosate-Tolerant Maize Systems1....................................................147

Table VIII-8. Rotational Crops in the U.S. Following Maize Production......................150

Table VIII-9. Herbicides Labeled for Control of Volunteer Maize in Labeled Rotational 

Crops1...............................................................................................................................153

Table IX-1. Summary of Published Literature on Maize Cross Pollination...................164

Table A-1. USDA Notifications and Permits Approved for MON 87429 and Status of 

Trials Planted under These Notifications.........................................................................192

Table B-1. Sequencing (NGS) Conducted for the Control and Test Substance .............200

Table B-2. Summary of NGS Data for the Conventional Control DNA Sample Spiked 

with PV-ZMHT519224....................................................................................................201

Table C-1. Primers and probes used in this study...........................................................205

Table D-1. Summary of MON 87429 FT_T Protein Identity and Equivalence .............209

Table D-2. Summary of the Tryptic Masses Identified for the MON 87429-Produced 

FT_T Using Nano LC-MS/MS ........................................................................................212

Table D-3. Summary of the Tryptic Masses Identified for E. coli-produced FT_T Using 

MALDI-TOF MS1...........................................................................................................214

Table D-4. Immunoreactivity of the MON 87429-Produced and E. coli-Produced FT_T 

Proteins ............................................................................................................................218
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Table D-5. Apparent Molecular Weight and Purity Analysis of the 

MON 87429-Produced FT_T Protein ..............................................................................220

Table D-6. Apparent Molecular Weight Comparison Between the MON 87429-Produced 

FT_T and E. coli-Produced FT_T Proteins......................................................................220

Table D-7. Functional Activity of MON 87429-Produced and E. Coli-Produced FT_T 

Protein..............................................................................................................................223

Table D-8. Individual Assay Data and 95% Prediction Interval Generated for the 

Apparent MW of FT_T Protein for One Future Assay....................................................229

Table D-9. Individual Assay Data and 95% Prediction Interval Generated for the 

Functional Activity of the FT_T Protein for One Future Assay......................................230

Table E-1. Compounds Used in Specificity In Vitro Enzyme Assays ...........................233

Table F-1. DMO, PAT, FT_T and CP4 EPSPS Extraction Parameter...........................238

Table G-1. Characterization of FT_T Enzyme ...............................................................242

Table H-1. Starting Seed for Germination and Dormancy Assessment of MON 87429248

Table I-1. Starting Seed for Phenotypic, Agronomic, and Environmental Interactions 

Assessment of MON 87429.............................................................................................251

Table I-2. Field Information for Phenotypic, Agronomic, and Environmental Interactions 

Assessment of MON 87429.............................................................................................252

Table I-3. Summary of Abiotic Stressor Response Evaluations for MON 87429 and the 

Conventional Control in 2017 U.S. Field Trials..............................................................255

Table I-4. Summary of Disease Damage Evaluations for MON 87429 and the 

Conventional Control in 2017 U.S. Field Trials..............................................................256

Table I-5. Summary of Arthropod Damage Evaluations for MON 87429 and the 

Conventional Control in 2017 U.S. Field Trials..............................................................257

Table J-1. Starting Seed for Pollen Morphology and Viability Assessment ..................261

Table K-1. Representative Management Recommendations for Control of Common 

Weeds in Maize with Biotypes Resistant to Herbicide(s) Tolerated by MON 87429 and to 

Glyphosate .......................................................................................................................278

Table L-1 Induced Herbicide Injury to MON 87429 and Control...................................295

Table M-1. Re-expression Formulas for Statistical Analysis of Composition Data.......300
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LIST OF FIGURES

Figure III-1. Schematic of the Development of MON 87429...........................................35

Figure III-2. Circular Map of PV-ZMHT519224 .............................................................36

Figure III-3. Deduced Amino Acid Sequence of the PAT Protein ...................................41

Figure III-4. Deduced Amino Acid Sequence of APG6 Chloroplast Targeting Sequence 

and the DMO Protein.........................................................................................................42

Figure III-5. Deduced Amino Acid Sequence of MDH Chloroplast Targeting Sequence 

and the FT_T Protein .........................................................................................................43

Figure III-6. Deduced Amino Acid Sequence of the CP4 EPSPS Protein .......................44

Figure IV-1. Molecular Characterization using Sequencing and Bioinformatics.............48

Figure IV-2. Five Types of NGS Reads............................................................................50

Figure IV-3. Schematic Representation of the Insert and Flanking Sequences in 

MON 87429 .......................................................................................................................56

Figure IV-4. Breeding History of MON 87429 ................................................................57

Figure IV-5. Read Mapping of Conventional Maize LH244 Versus PV-ZMHT519224.60

Figure IV-6. Read Mapping of MON 87429 (R3) Versus PV-ZMHT519224.................61

Figure IV-7. Overlapping PCR Analysis across the Insert in MON 87429......................63

Figure IV-8. PCR Amplification of the MON 87429 Insertion Site.................................65

Figure IV-9. Breeding Path for Generating Segregation Data for MON 87429...............68

Figure IV-10. Schematic Diagram of cp4 epsps Gene Cassette, CP4 EPSPS mRNA and 

CP4 EPSPS Protein............................................................................................................71

Figure IV-11. MON 87429 CP4 EPSPS siRNA Target Sequence Molecular Mechanism 

of Action ............................................................................................................................72

Figure IV-12. Absence of CP4 EPSPS Derived Secondary siRNAs................................74

Figure IV-13. Expression of Endogenous Genes with Sequence Homology to the siRNA 

Target Sequence in Tassels................................................................................................75

Figure V-1. Forms of DMO Protein and Their Relation to the Wild-Type DMO Protein80

Figure V-2 Deduced Amino Acid Sequence of the FT_T Protein....................................86

Figure V-3. Substrate and Metabolites of FT_T Protein Reaction with Quizalofop (left) 

and 2,4-D (right) ................................................................................................................87

Figure VII-1. Interpretation of Statistical Differences....................................................114

Figure VIII-1. U.S. Maize Acreage by County in 2017..................................................126
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Figure VIII-2. Hybrid maize seed planted, and grain produced in the U.S. from 2000-

2018..................................................................................................................................128

Figure C-1. Transgenic elements in the T-DNA for generating plants containing 

MON 87429 .....................................................................................................................204

Figure D-1. N-Terminal Sequence of the MON 87429-Produced FT_T Protein...........210

Figure D-2. Peptide Map of the MON 87429-Produced FT_T and E. coli-Produced FT_T215

Figure D-3. Western Blot Analysis and Immunoreactivity of MON 87429-Produced and 

E. coli-Produced FT_T Proteins ......................................................................................217

Figure D-4. Purity and Apparent Molecular Weight Analysis of the 

MON 87429-Produced FT_T Protein ..............................................................................219

Figure D-5. Glycosylation Analysis of the MON 87429-Produced and E. coli-Produced 

FT_T Proteins ..................................................................................................................222

Figure E-1. Representative Assay Results for o-Anisic Acid.........................................235

Figure E-2. Representative Assay Results for Dicamba.................................................236

Figure J-1. General Morphology of Pollen from MON 87429, the Conventional Control, 

and Commercially Available Conventional Reference Materials under 200X 

Magnification...................................................................................................................262

Figure K-1. Global Weed Resistance to Various Herbicide Families............................269

Figure N-1. SDS-PAGE Analysis of the Degradation of FT_T Protein by Pepsin ........305

Figure N-2. Western Blot Analysis of the Degradation of FT_T Protein by Pepsin ......307

Figure N-3. Western Blot Analysis of the Degradation of FT_T Protein by Pancreatin309

Figure N-4. SDS-PAGE and Western Blot Analysis of the Degradation of FT_T Protein 

by Sequential Digestion ...................................................................................................311
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ABBREVIATIONS AND DEFINITIONS2

αKG alpha-ketoglutarate

2,4-D 2,4-Dichlorophenoxyacetic Acid

ACCase Acetyl Coenzyme A Carboxylase

APHIS Animal and Plant Health Inspection Service

aroA 5-enolpyruvylshikimate-3-phosphate synthetase gene from 

Agrobacterium sp. strain CP4

CAB Chlorophyll a/b-Binding

CaMV Cauliflower Mosaic Virus 

CFR Code of Federal Regulations

CP4 EPSPS Agrobacterium tumefaciens strain CP4, 5-enolpyruvlshikimate-3-

phosphate synthase protein 

CTP Chloroplast Transit Peptide

CTAB Hexadecyltrimethylammonium Bromide

CV Column Volume

BIO Biotechnology Industry Organization

BRS Biotechnology Regulatory Service

DAP Days After Planting

DCSA 3,6-Dichlorosalycilic Acid

DMO Dicamba Mono-Oxygenase

DNA Deoxyribonucleic Acid

dw Dry Weight

E. coli Escherichia coli

EDTA Ethylenediaminetetraacetic acid

ELN Electronic Lab Notebook

EPA Environmental Protection Agency

E-score Expectation Score

ETS Excellence Through Stewardship

FDA Food and Drug Administration (U.S.)

FIFRA Federal Insecticide, Fungicide and Rodenticide Act

FOIA Freedom of Information Act

FOPs aryloxyphenoxypropionate acetyl coenzyme A carboxylase 

inhibitor herbicides such as quizalofop

FT_T FOPs and 2,4-D Dioxygenase Protein 

GLP Good Laboratory Practice

IAC Immunoaffinity Chromatography

IAM Iodoacetamide

kb Kilobase

LOQ Limit of Quantitation

 

2 Alred, G.J., C.T. Brusaw, and W.E. Oliu. 2003. Handbook of Technical Writing, 7th edn., pp. 2-7. Bedford/St. 

Martin's, Boston, MA.
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ABBREVIATIONS AND DEFINITIONS (continued)

MBu Million bushels

Mdh malate dehydrogenase gene from Arabidopsis thaliana

MOA Mode of Action

mRNA Messenger RNA

mts-siRNA Male Tissue Specific Small Interfering RNA

MW Molecular Weight

NGS Next Generation Sequencing

OECD Organization for Economic Co-operation and Development

OPA o-phthalaldehyde

ORF Open Reading Frame

OSL Over Season Leaf

PAT Phosphinothricin N–Acetyltransferase

PCR Polymerase Chain Reaction 

RdpA R-2,4-Dichlorophenoxypropionate Dioxygenase

RHS Roundup® Hybridization System 

S3P Shikimate-3phoshate

SDS-PAGE Sodium Dodecyl Sulfate–Polyacrylamide Gel Electrophoresis

SE Standard Error 

ShkG 5-enolpyruvylshikimate-3-phosphate synthase from 

Arabidopsis thaliana

siRNA Small Interfering RNA

SOA Site-of-action

SOP Standard Operating Procedure

μg/g Microgram per Gram

USDA United States Department of Agriculture

WT Wildtype
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I. RATIONALE FOR THE DEVELOPMENT OF MON 87429

I.A. Basis for the Request for a Determination of Nonregulated Status under 

7 CFR § 340.6

The Animal and Plant Health Inspection Service (APHIS) of the United States (U.S.) 

Department of Agriculture (USDA) has responsibility, under the Plant Protection Act 

(Title IV Pub. L. 106-2a24, 114 Stat. 438, 7 U.S.C. § 7701-7772) to prevent the 

introduction and dissemination of plant pests into the U.S. APHIS regulation 

7 CFR § 340.6 provides that an applicant may petition APHIS to evaluate submitted data 

to determine that a particular regulated article does not present a plant pest risk and no 

longer should be regulated. If APHIS determines that the regulated article does not 

present a plant pest risk, the petition is granted, thereby allowing unrestricted introduction 

of the article. 

Monsanto Company is submitting this request to APHIS for a determination of 

nonregulated status for the new biotechnology-derived maize product, MON 87429, any 

progeny derived from crosses between MON 87429 and conventional maize, and any 

progeny derived from crosses of MON 87429 with biotechnology-derived maize that 

have previously been granted nonregulated status under 7 CFR Part 340.

I.B. Rationale for the Development of Herbicide Tolerant Maize MON 87429 

Maize (Zea mays L.) is the largest crop grown in the U.S. in terms of acreage planted and 

net value. Planted maize acres in the U.S. have ranged between 88 to 94 million acres 

from 2015 to 2018 (USDA-NASS, 2018a). Annual and perennial weeds are considered 

to be the greatest pest problem in corn production (Aref and Pike, 1998). Weeds compete 

with maize for water, nutrients, and light resulting in substantial yield losses when left 

uncontrolled. Weed species in maize vary from region to region and from state to state. 

Economic thresholds for controlling weeds in maize require some form of weed 

management practice on all maize acreage. Weed management practices include 

mechanical tillage, crop rotations, cultural practices, and herbicide application. 

Numerous selective herbicides are available for preplant, preemergence, and 

postemergence control of annual and perennial weeds in maize. Approximately 98% of 

the maize acreage in the U.S. receives an herbicide application (USDA-NASS, 2019b). 

MON 87429 maize will offer growers multiple choices for effective weed management 

including tough-to-control and herbicide-resistant broadleaf and grass weeds. The 

flexibility to use dicamba, glufosinate, quizalofop, 2,4-D and glyphosate and/or 

combinations of these five herbicides representing multiple sites-of-action will provide an 

effective weed management system for maize production. Dicamba provides effective 

control of over 95 annual and biennial broadleaf weed species, approximately 50 

perennial broadleaf species and control or suppression of over 50 woody plant species. 

Glufosinate, a broad-spectrum contact herbicide, provides effective control of 

approximately 70 annual broadleaf weed species and over 30 grass weed species and 

control or suppression of over 30 biennial and perennial grass and broadleaf weed 
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species. Quizalofop, a selective postemergence herbicide, provides effective control of 

approximately 35 annual and perennial grass weed species including glyphosate-resistant 

grasses. 2,4-D provides effective control of over 70 annual and biennial broadleaf weed 

species, and approximately 30 perennial broadleaf weed species. Glyphosate provides 

control of approximately 100 annual weed species (grass and broadleaf), over 60

perennial weed species (grass and broadleaf) and control or suppression of approximately 

65 woody brush, trees and vines. Additionally, dicamba, glufosinate, and 2,4-D 

individually or in certain combinations provide control of herbicide-resistant weeds, 

including glyphosate-resistant biotypes of Palmer amaranth (Amaranthus palmeri), 

marestail (Conyza canadensis), common ragweed (Ambrosia artemisiifolia), giant 

ragweed (Ambrosia trifida), johnson grass (Sorghum halepense) and waterhemp 

(Amaranthus tuberculatus).

The MON 87429 event confers glyphosate tolerance in specific plant tissues (i.e., not in 

tassels) and will be used to facilitate the production of hybrid seed. MON 87429 is not 

intended to be offered for commercial use as a stand-alone product, but will be combined, 

through traditional breeding methods, with other deregulated events that confer full-plant 

glyphosate tolerance (e.g., NK603). MON 87429 maize combined with 

glyphosate-tolerant maize through traditional breeding will provide: 1) an opportunity for 

an efficient, effective weed management system for hard-to-control and 

herbicide-resistant weeds; 2) a flexible system with multiple herbicide sites-of-action for 

in-crop application in current maize production systems; 3) an opportunity to delay 

selection for further resistance to glyphosate and other herbicides that are important in 

crop production; and 4) excellent crop tolerance to dicamba, glufosinate, quizalofop, 

2,4-D and glyphosate. These enhanced weed management tools will maintain or improve 

maize yield and quality to meet the growing needs of the food, feed, and industrial 

markets.

Maize differs from other major U.S. crops, such as soybean or cotton, in that it is 

typically planted as a hybrid, and maize hybrids are utilized on nearly all maize 

production acres currently planted in the U.S. The seed supply used to plant the U.S. 

maize acreage is produced via hybrid seed production. The volume of seed planted in the 

U.S., to produce hybrid maize seed, has increased from 22.45 million bushels (MBu) 

planted in 2000 to 30.90 MBu planted in 2018 (USDA-ERS, 2018a). Hybrid seed 

production is accomplished through the combining of genetic material from one inbred 

parent with that of the other inbred parent. Specifically, pollen from the tassel (male 

flower) of the male parent is used to fertilize the ear (female flower) of the female parent. 

One challenge inherent to the production of hybrid maize seed is that the female parent 

produces pollen at the same time as the male parent. Therefore, pollen from the female 

parent must be removed or eliminated in order to assure uni-directional transfer of 

genetic material, via pollen, only from the male parent to the female parent. In the past,

removal or elimination of the pollen from the female parent required deployment of 

costly, labor intensive and time-critical methods such as manual or mechanical 

detasseling, or maintenance of Cytoplasmic Male Sterile lines, to ensure quality hybrid 

seed was produced. These hybrid seed production methods are further detailed in 

MON 87427 USDA-APHIS Petition #10-281-01p (p. 128), Monsanto’s first-generation 
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Roundup® Hybridization System (RHS) for hybrid seed production, which was assessed 

and deregulated by USDA-APHIS in 2013. 

Tissue-specific expression of CP4 EPSPS protein in MON 87429, allowing for 

glyphosate induced non-viable pollen phenotype, is the second-generation of Monsanto’s 

Roundup® Hybridization System (RHS) for hybrid seed production. The first-generation 

RHS event, MON 87427 maize, was assessed by USDA-APHIS and deregulated in 2013

(USDA-APHIS Petition #10-281-01p). The second-generation RHS trait in MON 87429 

allows inbred MON 87429 lines, treated with glyphosate at the appropriate timings, to 

serve as a female parent in the production of hybrid seed, similar to previously 

deregulated MON 87427 maize. Female inbred MON 87429 lines receive two 

glyphosate applications at vegetative growth stages ranging from V8 to V13, that 

correspond to the time when immature male tissues are forming. Treatment with 

glyphosate during this time period, when male tissue is forming, results in the intended 

non-viable pollen phenotype due to tissue-specific glyphosate sensitivity in the immature 

male tissue (See Section IV.G). 

To produce commercial hybrid maize seed with whole plant glyphosate tolerance using 

the RHS hybrid seed production system, female inbred MON 87429 plants treated with 

glyphosate during immature male tissue development will be pollinated by pollen donor 

plants (male inbred) that contain a deregulated glyphosate tolerance trait (e.g., NK603). 

The male inbred plants will be cultivated in proximity to the female inbred MON 87429 

plants and will not be impacted by the RHS-required glyphosate applications, due to full 

glyphosate tolerance in all tissues. This cross-pollination results in hybrid offspring (e.g., 

MON 87429 × NK603) with full tolerance to glyphosate in both vegetative and 

reproductive tissues, as well as tolerance to dicamba, glufosinate, quizalofop, and 2,4-D 

herbicides. For weed control in hybrid seed production fields with MON 87429 maize 

inbred used as female parent, in-crop applications of glyphosate may be made at the same 

rates and timings as directed on glyphosate agricultural product labels for other 

glyphosate tolerant maize events.

The RHS trait in MON 87429 maize offers the same benefits to hybrid maize seed 

production as the RHS trait in MON 87427, described in detail in USDA-APHIS Petition 

#10-281-01p (p. 5). Briefly, these benefits include enabling hybrid seed producers to 

discontinue the practice of manually or mechanically detasseling female inbred plants in 

their production field, which must occur during a critical 3-4 day time period of maize 

tassel development, which can be influenced by changes in weather (e.g., extreme heat). 

The ability to treat MON 87429 maize female inbreds with glyphosate (between V8 to 

V13), in place of detasseling, provides flexibility to hybrid maize seed producers as well 

as reduces the cost of hybrid seed production by removing the reliance on costly, labor 

intensive manual/mechanical detasseling. An additional benefit of including the RHS trait 

in MON 87429 maize, along with dicamba-, glufosinate-, and quizalofop- and 2,4-Dtolerance traits, is the reduction in the number of trait loci that would otherwise need to 

be managed and combined, via traditional breeding methods.
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I.C. Submissions to Other Regulatory Agencies

Under the Coordinated Framework for Regulation of Biotechnology (CFR) (USDAAPHIS, 1986), the responsibility for regulatory oversight of biotechnology-derived crops 

falls primarily on three U.S. agencies: U.S. Food and Drug Administration (FDA), the 

United States Department of Agriculture (USDA), and in the case of plant incorporated 

protectants (PIPs), the Environmental Protection Agency (EPA). Deregulation of

MON 87429 by USDA constitutes only one component of the overall regulatory 

oversight and review of this product. As a practical matter, MON 87429 cannot be 

released and marketed until FDA and USDA have completed their reviews and 

assessments under their respective jurisdictions. As MON 87429 does not contain a PIP, 

no submission on MON 87429 will be made to the EPA. 

I.C.1. Submission to FDA

MON 87429 falls within the scope of the 1992 FDA policy statement concerning 

regulation of products derived from new plant varieties, including those developed 

through biotechnology (U.S. FDA, 1992). In compliance with this policy, Monsanto has 

initiated a consultation with the FDA, identified under BNF No. 000173. A food/feed 

safety and nutritional assessment summary document was submitted to the FDA in 

February 2019.

I.C.2. Related Submissions to U.S. EPA

Substances that are pesticides, as defined under the Federal Insecticide, Fungicide and 

Rodenticide Act (FIFRA; 7 U.S.C. §136(u)), are subject to regulation by U.S. EPA.

When registering the use of herbicides, U.S. EPA performs a thorough risk assessment 

including acute, chronic, and aggregate risks for the U.S. population, including setting 

safe limits for pesticide residues including parent molecules and metabolites. In each 

case a determination of safety is made that no harm will result to the general population 

or to infants and children from the aggregate exposure of the herbicide. 

MON 87429 provides improved crop tolerance to dicamba, and the ability to extend use 

of dicamba through the V8 growth stage will provide more effective preemergence and 

postemergence control of problem weed species compared to currently labeled 

applications of dicamba in conventional maize hybrids. In support of Monsanto’s third 

generation herbicide tolerant product MON 87419 maize, Monsanto requested that EPA 

allow the 0.5 lb a.e./ac postemergence application window for dicamba to be extended 

from V5 to V8 growth stage or 36-inch height of maize, whichever occurs first (U.S. 

EPA, 2019). The combined (pre- and post-emergence) maximum annual application rate 

of dicamba in MON 87419 maize would be 2.0 lbs. a.e. dicamba per acre per year, 

increased from the current maximum annual application rate of 0.75 lbs. a.e. in 

conventional maize. Pending approval of the expanded label at EPA, the dicamba use 

pattern for MON 87429 would be no different than that of MON 87419. 
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Glufosinate use over the top of MON 87429 will not change from current approved use

pattern of glufosinate3. Glufosinate is labeled for preplant applications on conventional 

and herbicide-tolerant maize hybrids and for in-crop postemergence applications on 

glufosinate-tolerant hybrids only. 

U.S. EPA has registered the use of 2,4-D on maize4up to 1 lb. preemergence and one to 

two applications of up to 1 lb. between emergence and V8 or 30 inches whichever occurs 

first. Monsanto, or a partner at our behest, will request the U.S. EPA to register the same 

already approved use pattern in maize for use on MON 87429 maize.

U. S. EPA has registered the use of quizalofop5on maize up to 0.083 lb from V2 to V6 

stage of development. Monsanto will request the U.S. EPA to register the same already 

approve use pattern in maize for use on MON 87429 maize.

Glyphosate use over the top of MON 87429 will follow the current approved use pattern 

of glyphosate6. Glyphosate is labeled for preplant applications on conventional and 

herbicide-tolerant maize hybrids and for in-crop postemergence applications on 

glyphosate-tolerant hybrids only.

I.C.3. Submissions to Foreign Government Agencies

Consistent with our commitments to the Biotechnology Industry Organization (BIO) and 

Excellence Through Stewardship® (ETS)7, Monsanto will meet applicable regulatory 

requirements for MON 87429 in the country of intended production and for major import 

countries, as identified in the trade assessment process that have functioning regulatory

systems to assure global compliance and support the flow of international trade. 

Monsanto will continue to monitor other countries that are key importers of maize from 

the U.S., for the development of formal biotechnology approval processes. If new 

functioning regulatory processes are developed, Monsanto will re-evaluate its 

stewardship plans and make appropriate modifications to minimize the potential for trade 

disruption.

 

3 Federal Register, 77 FR 59106-59113, Glufosinate Ammonium, Pesticide Tolerances

4 Federal Register, 82 FR 9523-9529, 2,4-D; Pesticide Tolerances

5 Federal Register, 83 FR 7111-7115, Quizalofop ethyl; Pesticide Tolerances

6 Federal Register, 76 FR 27268-27271, Glyphosate; Pesticide Tolerances

® Excellence Through Stewardship is a registered trademark of Excellence Through Stewardship, 

Washington, DC.

7 http://www.excellencethroughstewardship.org/.
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II. THE BIOLOGY OF MAIZE

The biology of maize has been well documented (Anderson and de Vicente, 2010; 

Farnham et al., 2003; OGTR, 2008). In addition to the wealth of information on maize 

biology, the Organisation for Economic Co-operation and Development authored a 

Consensus Document (OECD, 2003) on the biology of maize. This document provides 

key information regarding:

• general description of maize biology, including taxonomy and morphology and 

use of maize as a crop plant

• agronomic practices in maize cultivation

• geographic centers of origin

• reproductive biology

• cultivated maize as a volunteer weed

• inter-species/genus introgression into relatives and interactions with other 

organisms

• summary of the ecology of maize

Additional information on the biology and uses of maize can also be found on the 

Australian Government Department of Health and Ageing (Office of the Gene 

Technology Regulator) web site (OGTR, 2008), and in the USDA-ARS GRIN database 

(USDA-ARS, 2015). The taxonomic information for maize is available in the USDA’s 

PLANTS Profile (USDA-NRCS, 2019).

To support the evaluation of the plant pest potential of MON 87429 relative to 

conventional maize, additional information regarding several aspects of maize biology 

can be found elsewhere in this petition. This includes: agronomic practices for maize in 

Section VIII; volunteer management of maize in Section VIII.H; and inter-species/genus 

introgression potential in Section IX.D.

II.A. Maize as a Crop

Maize is widely grown in nearly all areas of the world and is the largest grain crop in the 

world, ahead of both wheat (Triticum sp.) and rice (Oryza sativa L.), in total metric ton 

production (FAOSTAT, 2019). In the 2016/2017 marketing year, world maize area was 

approximately 194 million hectares (ha) with a total grain production of approximately 

1,122 million metric tons (MMT) (USDA-FAS, 2018). The top five production regions 

were: USA (385 MMT), China (264 MMT), Brazil (99 MMT), the European Union (62 

MMT), and Argentina (41 MMT) (USDA-FAS, 2018). In the U.S., maize is grown in 

most states and in 2017, its production value of over $49 billion was the highest of any 

crop (USDA-NASS, 2019a).

In industrialized countries maize has two major uses: (1) as animal feed in the form of 

grain, forage or silage; and (2) as a raw material for wet- or dry-milled processed 

products such as high fructose maize syrup, oil, starch, glucose, dextrose and ethanol. 

By-products of the wet- and dry- mill processes are also used as animal feed. These 
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processed products are used as ingredients in many industrial applications and in human 

food products. Most maize produced in industrialized countries is used as animal feed or 

for industrial purposes, but maize remains an important food staple in many developing 

regions, especially sub-Saharan Africa and Central America, where it is frequently the 

mainstay of human diets (Morris, 1998).

Maize is a familiar plant that has been rigorously studied due to its use as a staple 

food/feed and the economic opportunity it brings to growers. Archeological and genetic 

evidence suggests that maize domestication began in southern Mexico approximately 

9,000 years ago, and that it was derived from Balsas teosinte, Zea mays subsp. 

parviglumis (Kistler et al., 2018; Matsuoka et al., 2002; Piperno et al., 2009). Although 

grown extensively throughout the world, maize is not considered a threat to invade 

natural or agricultural ecosystems. Maize does not establish self-sustaining populations 

outside of cultivation (Crawley et al., 2001; OECD, 2003; Raybould et al., 2012). This

lack of weediness may reflect its poor competitive ability (Olson and Sander, 1988), lack 

of seed dormancy, and barriers to seed dispersal, as maize cobs retain seed and are 

covered in a husk (Wilkes, 1972). A number of other characteristics common in weeds, 

such as rapid flowering following emergence, are lacking in maize (Keeler, 1989). 

Today, the majority of U.S. maize acreage is planted to hybrids, a practice that started in 

the 1920s (Wych, 1988). Maize hybrids have advantages in yield and plant vigor 

associated with heterosis, also known as hybrid vigor (Duvick, 1999).

Conventional plant breeding results in selection of desirable characteristics in a plant 

through the generation of unique combinations of genes obtained by intra- and 

inter-specific crossing, mutation breeding or utilization of other traditional breeding 

methodologies. However, there is a limit to the genetic diversity that is available for use 

and selection with conventional plant breeding. Biotechnology, as an additional tool to 

conventional breeding, offers access to greater genetic diversity than conventional 

breeding alone, resulting in expression of traits that are highly desirable to growers and 

downstream crop users.

II.B. Characteristics of the Recipient Plant

The MON 87429 transformation was conducted with inbred maize line LH244, a 

patented maize line assigned to Holden’s Foundation Seeds LLC in 2001 (U.S. Patent 

#6,252,148). LH244 is a medium season yellow dent maize line of Stiff Stalk 

background that is best adapted to the central regions of the U.S. corn belt. 

Following transformation of immature LH244 embryos, a single transformed plant was 

selected and self-pollinated to increase seed supplies. An inbred line homozygous for 

MON 87429 was selected and then used to produce other MON 87429 materials for 

product testing, safety assessment studies, and commercial hybrid development. The 

non-transformed LH244 was used to produce conventional maize comparators (hereafter 

referred to as conventional controls) in the safety assessment of MON 87429.
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II.C. Maize as a Test System in Product Safety Assessment

In studies utilizing hybrid maize, the test is a hybrid of LH244 (MON 87429 expressing 

DMO, PAT, FT_T and CP4 EPSPS proteins) × HCL617 unless otherwise noted (Figure 

IV-4). LH244 × HCL617 was used as near isogenic, conventional control for this 

submission (hereafter referred to as conventional control). LH244 was used as the 

conventional control in molecular characterization studies. LH244 × HCL617 was used 

as the conventional control in compositional analysis and in phenotypic, agronomic and 

environmental interactions assessments. Where appropriate conventional commercial 

maize hybrids (hereafter referred to as reference hybrids) were used to establish ranges of 

natural variability or responses representative of commercial maize hybrids. Reference 

hybrids used at each field trial location were selected based on their availability and 

agronomic fit for the respective geographic regions. 

To conduct the studies reported in this petition, appropriate MON 87429 test materials 

were generated for the molecular characterization (Sections III and IV), protein 

characterization and expression analysis (Section V), compositional analysis (Section 

VI), and phenotypic, agronomic and environmental interactions assessment (Section VII). 

The full molecular characterization studies and initiation of commercial breeding efforts 

were conducted with the R3 generation (Figure IV-4). Protein characterization and 

expression analysis, composition analysis, and phenotypic, agronomic and environmental 

interactions assessment were conducted with MON 87429 breeding generation R3F1.
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III. DESCRIPTION OF THE GENETIC MODIFICATION 

This section provides a description of the transformation process and plasmid vector used 

in the development of MON 87429 (Figure III-1 and Figure III-2). Molecular analyses 

are an integral part of the characterization of maize products with new traits introduced 

by methods of biotechnology. Vectors and methods are selected for transformation to 

achieve high probability of obtaining the trait of interest and integration of the introduced 

DNA into a single locus in the plant genome. This helps ensure that only the intended 

DNA encoding the desired trait(s) is integrated into the plant genome and facilitates the 

molecular characterization of the product. Information provided here allows for the 

identification of the genetic material present in the transformation vector delivered to the 

host plant and for an analysis of the data supporting the characterization of the DNA 

inserted in the plant found in Section IV. 

III.A. Description of Transformation Plasmid PV-ZMHT519224

Plasmid vector PV-ZMHT519224 was used in the transformation of maize to produce 

MON 87429 and its plasmid map is shown in Figure III-2. A detailed description of the 

genetic elements and their prefixes (e.g., B, P, L, I, TS, CS, T, and OR) in 

PVZMHT519224 is provided in Table III-1. Plasmid vector PV-ZMHT519224 is 

approximately 17.8 kb in length and contains a single T-DNA that is delineated by Right 

and Left Border regions. The T-DNA contains the pat, dmo, ft_t, and cp4 epsps

expression cassettes. During transformation, the T-DNA was inserted into the maize 

genome. Following transformation, traditional breeding, segregation, selection and 

screening were used to isolate those plants that contained the pat, dmo, ft_t, and cp4 

epsps expression cassettes and did not contain the backbone sequences.

The pat expression cassette contains the following genetic elements: promoter, 5' UTR, 

and intron sequences for a ubiquitin gene (Ubq) from Erianthus ravennae (plume grass),

the pat gene from Streptomyces viridochromogenes, and the 3' UTR sequence of the 

fructose-bisphosphate aldolase (Fba) gene from Setaria italica (foxtail millet). The dmo

expression cassette contains the following genetic elements: Promoter, 5' UTR, and 

intron sequences for a ubiquitin gene (Ubq) from Coix lacryma-jobi (adlay millet), 

chloroplast-targeting sequence of the Albino and pale green 6 (Apg6) gene from 

Arabidopsis thaliana, the dmo gene from Stenotrophomonas maltophilia, and the 3' UTR 

sequence of the OsMt gene from Oryza sativa (rice). The ft_t expression cassette 

contains the following genetic elements: promoter, 5' UTR, and intron sequences for a 

ubiquitin gene (Ubq) from Arundo donax (giant reed), chloroplast-targeting sequence 

malate dehydrogenase (Mdh) gene from Arabidopsis thaliana, the ft_t gene from 

Sphingobium herbicidovorans, and the 3' UTR sequence from the gene coding for a no 

apical meristem (Nam) protein domain from Oryza sativa (rice). The cp4 epsps

expression cassette contains the following genetic elements: promoter and leader 

sequence from the 35S RNA of cauliflower mosaic virus (CaMV), 5' UTR leader 

sequence from the gene coding for chlorophyll a/b-binding (CAB) protein of 

Triticum aestivum (wheat), intron and flanking UTR sequence of the act1 gene from 

Oryza sativa (rice), chloroplast-targeting sequence of the 5-enolpyruvylshikimate-3-
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phosphate synthase (ShkG) gene from Arabidopsis thaliana, the cp4 epsps gene from 

Agrobacterium sp. strain CP4, and 3' UTR sequence of Zea mays cDNA (Genbank 

Accession: EU974548) that contains male tissue specific siRNA target sequence, and 3' 

UTR sequence of the glycine-rich RNA binding protein (Grp3) gene from Oryza sativa

(rice).

The backbone region of PV-ZMHT519224 contains two origins of replication for 

maintenance of the plasmid vector in bacteria (ori V, ori pBR322), and a bacterial 

selectable marker gene (aadA).

III.B. Description of the Transformation System 

MON 87429 was developed through Agrobacterium tumefaciens mediated transformation 

of immature maize embryos based on the method described by (Sidorov and Duncan, 

2009) utilizing PV-ZMHT519224. Immature embryos were excised from a 

post-pollinated maize ear of LH244. After co-culturing the excised immature embryos 

with Agrobacterium carrying the plasmid vector, the immature embryos were placed on 

selection medium containing glyphosate and carbenicillin disodium salt in order to inhibit 

the growth of untransformed plant cells and excess Agrobacterium, respectively. Once 

transformed callus developed, the callus was placed on media conducive to shoot and 

root development. The rooted plants (R0) with normal phenotypic characteristics were 

selected and transferred to soil for growth and further assessment. As demonstrated in 

this petition (Section VII), the use of disarmed Agrobacterium tumefaciens strain ABI, a 

designated plant pest, as the transformation vector has not imparted plant pest 

characteristics to MON 87429. 

The R0 plants generated through the transformation process described above had already 

been exposed to glyphosate in the selection medium and demonstrated glyphosate 

tolerance. The R0 plants were self-pollinated to produce R1 seed. Subsequently, the R1 

population was screened for the presence of T-DNA and absence of vector backbone 

sequences by construct-level PCR assay and Southern blot analysis. Only plants that 

were homozygous positive for T-DNA and negative for vector backbone were selected 

for further development and their progenies were subjected to further molecular and 

phenotypic assessments. As is typical of a commercial event production and selection 

process, hundreds of different transformation events (regenerants) were generated in the 

laboratory using PV-ZMHT519224. After careful selection and evaluation of these 

events in the laboratory, greenhouse and field, MON 87429 was selected as the lead event 

based on superior trait efficacy, agronomic, phenotypic, and molecular characteristics 

(Prado et al., 2014). Studies on MON 87429 were initiated to further characterize the 

genetic insertion and the expressed product, and to establish the food, feed, and 

environmental safety relative to conventional maize. The major steps involved in the 

development of MON 87429 are depicted in Figure III-1. The result of this process was 

the production of MON 87429 maize with the pat, dmo, ft_t and cp4 epsps expression 

cassettes.
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Figure III-1. Schematic of the Development of MON 87429

Transformed LH244 (a maize line for more efficient transformation) 

immature embryos with PV-ZMHT519224 in Agrobacterium 

tumefaciens

Selected transformants (R0 Plants) containing the selectable marker 

(cp4 epsps expression cassette) and generated rooted shoots from the 

transformed callus tissues

Identified MON 87429 as lead event and further evaluated its progeny 

in laboratory and field assessments for T-DNA insert integrity, 

dicamba-, glufosinate-, quizalofop-, 2,4-D-, and tissue-specific 

glyphosate-tolerance, absence of all other vector DNA, and 

agronomic/phenotypic characteristics

Evaluated R1 Plants by PCR and selected the transformed plants for the 

homozygous presence of the T-DNA

Evaluated plants (subsequent generations) for insert integrity using 

molecular analyses

Assembled Agrobacterium binary plasmid vector PV-ZMHT519224 and 

transferred to Agrobacterium tumefaciens strain ABI
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Figure III-2. Circular Map of PV-ZMHT519224

A circular map of PV-ZMHT519224 used to develop MON 87429 is shown. PV-ZMHT519224 

contains one T–DNA. Genetic elements are shown on the exterior of the map.

17776 bp
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Table III-1. Summary of Genetic Elements in PV-ZMHT519224

Genetic Element Location in 

Plasmid Vector

Function (Reference)

T-DNA

B1-Left Border 

Region

1-442 DNA region from 

Agrobacterium tumefaciens containing 

the left border sequence used for transfer 

of the T–DNA (Barker et al., 1983)

Intervening Sequence 443-513 Sequence used in DNA cloning

P

2

-Ea.Ubq 514-2695 Promoter, 5' UTR, and intron sequences 

for a ubiquitin gene (Ubq) from 

Erianthus ravennae (plume grass) that 

directs transcription in plant cells 

(Cornejo et al., 1993)

Intervening Sequence 2696-2700 Sequence used in DNA cloning

CS3-pat 2701-3252 Coding sequence for the 

phosphinothricin N–acetyltransferase 

(PAT) protein of 

Streptomyces viridochromogenes that 

confers tolerance to glufosinate 

(Wehrmann et al., 1996; Wohlleben et 

al., 1988)

T4-Fba 3253-3629 3' UTR sequence of the fructosebisphosphate aldolase (Fba) gene from 

Setaria italica (foxtail millet) that directs 

polyadenylation of mRNA (Hunt, 1994)

Intervening Sequence 3630-3691 Sequence used in DNA cloning

P-Clj.Ubq 3692-5617 Promoter, 5' UTR, and intron sequences 

for a ubiquitin gene (Ubq) from Coix 

lacryma-jobi (adlay millet) that directs 

transcription in plant cells (Cornejo et al., 

1993)

Intervening Sequence 5618-5627 Sequence used in DNA cloning
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Table III-1. Summary of Genetic Elements in PV-ZMHT519224 (continued)

TS5-APG6 5628-5831 Codon optimized targeting sequence of 

the Albino and pale green 6 (Apg6) gene 

from Arabidopsis thaliana encoding a 

chloroplast-targeted Hsp101 homologue 

transit peptide region that directs the 

protein to the chloroplast (GenBank 

Accession: NM_121549)

CS-dmo 5832-6854 Codon optimized coding sequence for the 

dicamba mono–oxygenase (DMO) 

protein of Stenotrophomonas maltophilia

that confers dicamba resistance (Herman 

et al., 2005; Wang et al., 1997)

Intervening Sequence 6855-6862 Sequence used in DNA cloning

T-Mt 6863-7162 3' UTR sequence of the OsMt gene from 

Oryza sativa (rice) encoding 

metallothionein-like protein that directs 

polyadenylation of mRNA (Hunt, 1994)

Intervening Sequence 7163-7170 Sequence used in DNA cloning

P-Ad.Ubq 7171-9127 Promoter, 5' UTR, and intron sequences 

for a ubiquitin gene (Ubq) from Arundo 

donax (giant reed) that directs 

transcription in plant cells (Cornejo et al., 

1993)

Intervening Sequence 9128-9140 Sequence used in DNA cloning

TS-MDH 9141-9383 Targeting sequence from 

Arabidopsis thaliana Mdh gene encoding 

the malate dehydrogenase transit peptide 

region that directs the protein to the 

chloroplast (GenBank Accession: 

BT000621)

CS-ft_t 9384-10271 Modified version of R-2,4-

dichlorophenoxypropionate

dioxygenase (Rdpa) gene from 

Sphingobium herbicidovorans that

expresses a FOPs and 2,4-D dioxygenase 

protein (FT_T) that confers tolerance to 

quizalofop and 2,4-D herbicides (Müller 

et al., 2006)
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Table III-1. Summary of Genetic Elements in PV-ZMHT519224 (continued)

Intervening Sequence 10272-10286 Sequence used in DNA cloning

T-Nam 10287-10803 3' UTR sequence from the gene coding for

a no apical meristem (Nam) protein 

domain containing

protein from Oryza sativa (rice) (Hunt, 

1994)

Intervening Sequence 10804-10809 Sequence used in DNA cloning

P-35S 10810-11133 Promoter and leader from the 35S RNA 

of cauliflower mosaic virus (CaMV) 

(Odell et al., 1985) that directs 

transcription in plant cells

Intervening Sequence 11134-11155 Sequence used in DNA cloning

L6-Cab 11156-11216 5' UTR leader sequence from the gene 

coding for chlorophyll a/b-binding (CAB) 

protein of Triticum aestivum (wheat) that 

is involved in regulating gene expression 

(Lamppa et al., 1985)

Intervening Sequence 11217-11232 Sequence used in DNA cloning

I

7

-Ract1 11233-11712 Intron and flanking UTR sequence of the 

act1 gene from Oryza sativa (rice) 

encoding rice Actin 1 protein (McElroy 

et al., 1990) that is involved in regulating 

gene expression.

Intervening Sequence 11713-11721 Sequence used in DNA cloning

TS-CTP2 11722-11949 Targeting sequence of the ShkG gene 

from Arabidopsis thaliana encoding the 

EPSPS transit peptide region that directs 

transport of the protein to the chloroplast 

(Herrmann, 1995; Klee et al., 1987)

CS-cp4 epsps 11950-13317 Codon optimized coding sequence of 

the 5-enolpyruvylshikimate-3-phosphate 

synthetase (aroA) gene from 

the Agrobacterium sp. strain CP4 

encoding the CP4 EPSPS protein that 

provides glyphosate tolerance (Barry et 

al., 2001; Padgette et al., 1996)

Intervening Sequence 13318-13323 Sequence used in DNA cloning

siRNA Target 

Sequence

13324-13524 Modified partial 3' UTR sequence of Zea 

mays cDNA (Genbank Accession: 

EU974548) that contains male tissue 

specific siRNA target sequence 

(Brodersen and Voinnet, 2006)
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Table III-1. Summary of Genetic Elements in PV-ZMHT519224 (continued)

1 B, Border

2 P, Promoter

3 CS, Coding Sequence

4 T, Transcription Termination Sequence

5 TS, Targeting Sequence

6 L, Leader

7

I, Intron 

8 OR, Origin of Replication

Intervening Sequence 13525-13532 Sequence used in DNA cloning

T-Grp3 13533-14143 3' UTR sequence of the glycine-rich 

RNA binding- protein (Grp3) gene from 

Oryza sativa (rice) encoding the GRP3 

protein that directs polyadenylation of 

mRNA (Hunt, 1994)

Intervening Sequence 14144-14184 Sequence used in DNA cloning

B-Right Border 

Region

14185-14515 DNA region from

Agrobacterium tumefaciens containing 

the right border sequence used for 

transfer of the T–DNA (Depicker et al., 

1982; Zambryski et al., 1982)

Vector Backbone

Intervening Sequence 14516-14659 Sequence used in DNA cloning

aadA 14660-15548 Bacterial promoter, coding sequence, and 

3' UTR for an aminoglycoside-modifying 

enzyme, 3''(9) –O–nucleotidyltransferase 

from the transposon Tn7 (Fling et al., 

1985) that confers spectinomycin and 

streptomycin resistance

Intervening Sequence 15549-16082 Sequence used in DNA cloning

OR8-ori-pBR322 16083-16671 Origin of replication from plasmid 

pBR322 for maintenance of plasmid in 

E. coli (Sutcliffe, 1979)

Intervening Sequence 16672-17293 Sequence used in DNA cloning

OR-ori V 17294-17690 Origin of replication from the broad host 

range plasmid RK2 for maintenance of 

plasmid in Agrobacterium (Stalker et al., 

1981)

Intervening Sequence 17691-17776 Sequence used in DNA cloning
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III.C. The pat Coding Sequence and PAT Protein

The pat expression cassette contains the pat gene encoding a protein of 183 amino acids

(Figure III-3). MON 87429 expresses a 25.5 kDa PAT protein, which consists of a single 

polypeptide of 182 amino acids after the removal of the lead methionine that is cleaved 

during a co-translational process (Wehrmann et al., 1996; Wohlleben et al., 1988). The 

pat open reading frame in the expression cassette includes sequence from S. 

viridochromogenes that encodes the PAT protein. The expression of PAT protein confers 

glufosinate tolerance.

1 MSPERRPVEI RPATAADMAA VCDIVNHYIE TSTVNFRTEP QTPQEWIDDL

51 ERLQDRYPWL VAEVEGVVAG IAYAGPWKAR NAYDWTVEST VYVSHRHQRL

101 GLGSTLYTHL LKSMEAQGFK SVVAVIGLPN DPSVRLHEAL GYTARGTLRA

151 AGYKHGGWHD VGFWQRDFEL PAPPRPVRPV TQI

Figure III-3. Deduced Amino Acid Sequence of the PAT Protein

The amino acid sequence of the MON 87429 PAT protein was deduced from the full-length 

coding nucleotide sequence present in PV-ZMHT519224 (See Table III-1 for more detail). The 

lead methionine (boxed with solid line) of the PAT protein produced in MON 87429 is cleaved 

during a co-translational process in MON 87429.
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III.D. The dmo Coding Sequence and DMO Protein

The dmo expression cassette contains the dmo gene. The dmo expression cassette

encodes a precursor protein of 408 amino acids (340 amino acids encoded by the dmo 

gene and 68 amino acids encoded by the APG6 gene for targeting the DMO protein into 

chloroplasts) (Figure III-4). MON 87429 expresses two forms of mature DMO protein 

due to alternative processing of the chloroplast transit peptide (CTP). One form consists 

of 341 amino acids, which includes 340 amino acids encoded by the dmo gene and 1 

amino acid (cysteine) encoded by the APG6 gene. The other form of the DMO protein 

consists of 340 amino acids encoded by the dmo gene. The two forms of mature DMO 

protein expressed in MON 87429 are indistinguishable by Coomassie stain of SDSPAGE and western blot analysis because the difference in molecular weight between 

these two forms is very small. Therefore, only a ~38.4 kDa DMO protein band is 

observed by Coomassie stain of SDS-PAGE and western blot analysis. The dmo open 

reading frame in the expression cassette includes a codon optimized sequence from S. 

maltophilia that encodes the DMO protein (Herman et al., 2005; Wang et al., 1997). The 

expression of the DMO protein confers tolerance to dicamba herbicide.

1 MATATTTATA AFSGVVSVGT ETRRIYSFSH LQPSAAFPAK PSSFKSLKLK

51 QSARLTRRLD HRPFVVRCML TFVRNAWYVA ALPEELSEKP LGRTILDTPL

101 ALYRQPDGVV AALLDICPHR FAPLSDGILV NGHLQCPYHG LEFDGGGQCV

151 HNPHGNGARP ASLNVRSFPV VERDALIWIW PGDPALADPG AIPDFGCRVD

201 PAYRTVGGYG HVDCNYKLLV DNLMDLGHAQ YVHRANAQTD AFDRLEREVI

251 VGDGEIQALM KIPGGTPSVL MAKFLRGANT PVDAWNDIRW NKVSAMLNFI

301 AVAPEGTPKE QSIHSRGTHI LTPETEASCH YFFGSSRNFG IDDPEMDGVL

351 RSWQAQALVK EDKVVVEAIE RRRAYVEANG IRPAMLSCDE AAVRVSREIE

401 KLEQLEAA

Figure III-4. Deduced Amino Acid Sequence of APG6 Chloroplast Targeting 

Sequence and the DMO Protein

The amino acid sequence of the MON 87429 DMO precursor protein was deduced from the fulllength coding nucleotide sequence present in PV-ZMHT519224 (See Table III-1 for more detail). 

The first 68 amino acids of the precursor protein (underlined) are the CTP from APG6 gene. The 

CTP targets MON 87429 DMO precursor protein to the chloroplast and is partially cleaved in the 

chloroplast producing the mature 341 amino acid and 340 amino acid DMO proteins that begin 

with the cysteine at position 68 and methionine at position 69, respectively. The double underline 

shows the cysteine amino acid from APG6.
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III.E. The ft_t Coding Sequence and FT_T Protein

The ft_t expression cassette contains the ft_t gene. The ft_t expression cassette encodes a 

precursor protein of 376 amino acids (295 amino acids encoded by the ft_t gene and 81 

amino acids encoded by the MDH gene for targeting the FT_T protein into chloroplasts)

(Figure III-5). MON 87429 expresses a ~36 kDa mature FT_T protein, which consists of 

a single polypeptide of 296 amino acids, 295 amino acids are encoded by the ft_t gene 

and 1 amino acid (alanine) is encoded by MDH gene due to the processing of the 

chloroplast transit peptide (CTP). The ft_t open reading frame in the expression cassette 

is the modified version of R-2,4-dichlorophenoxypropionate dioxygenase (Rdpa) gene 

from Sphingobium herbicidovorans that encodes a FOPs and 2,4-D dioxygenase protein 

(FT_T) (Müller et al., 2006). The expression of FT_T protein confers tolerance to 

quizalofop and 2,4-D herbicides.

1 MATATSASLF STVSSSYSKA SSIPHSRLQS VKFNSVPSFT GLKSTSLISG 

51 SDSSSLAKTL RGSVTKAQTS DKKPYGFKIN AMHAALTPLT NKYRFIDVQP 

101 LTGVLGAEIT GVDLREPLDD STWNEILDAF HTYQVIYFPG QAITNEQHIA 

151 FSRRFGPVDP VPILKSIEGY PEVQMIRREA NESSRFIGDD WHTDSTFLDA

201 PPAAVVMRAI EVPEYGGDTG FLSMYSAWET LSPTMQATIE GLNVVHSATK 

251 VFGSLYQATN WRFSNTSVKV MDVDAGDRET VHPLVVTHPV TGRRALYCNQ 

301 VYCQKIQGMT DAESKSLLQF LYEHATKFDF TCRVRWKKDQ VLVWDNLCTM 

351 HRAVPDYAGK FRYLTRTTVA GDKPSR

Figure III-5. Deduced Amino Acid Sequence of MDH Chloroplast Targeting 

Sequence and the FT_T Protein

The amino acid sequence of the MON 87429 FT_T precursor protein was deduced from the fulllength coding nucleotide sequence present in PV-ZMHT519224 (See Table III-1 for more detail). 

The first 81 amino acids of the precursor protein (underlined) are the CTP from MDH gene. 

MDH targets FT_T protein to the chloroplast and is cleaved in the chloroplast producing the 

mature 296 amino acid FT_T protein that begins with the alanine at position 81. The double 

underline shows the alanine amino acid from MDH that is the N-terminus of the mature FT_T 

protein.

III.F. The cp4 epsps Coding Sequence and CP4 EPSPS Protein

The cp4 epsps expression cassette contains the cp4 epsps gene. The cp4 epsps expression 

cassette encodes a precursor protein of 531 amino acids (455 amino acids encoded by the 

cp4 epsps gene and 76 amino acids encoded by the CTP2 gene for targeting the CP4 

EPSPS protein into chloroplasts) (Figure III-6). MON 87429 expresses a 44 kDa CP4 

EPSPS protein, consisting of a single polypeptide of 455 amino acids starting at the 

methionine position 77 (Padgette et al., 1996) after a complete cleavage of the chloroplast 

transit peptide (CTP2). The cp4 epsps coding sequence is the codon optimized coding 

sequence of the aroA gene from Agrobacterium sp. strain CP4 encoding CP4 EPSPS 
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(Barry et al., 2001; Padgette et al., 1996). The CP4 EPSPS protein is similar and 

functionally equivalent to endogenous plant EPSPS enzymes, but has a much-reduced 

affinity for glyphosate, the active ingredient in Roundup agricultural herbicides, relative 

to endogenous plant EPSPS (Barry et al., 2001; Padgette et al., 1996). The presence of 

this protein renders the plant tolerant to glyphosate.

1 MLHGASSRPA TARKSSGLSG TVRIPGDKSI SHRSFMFGGL ASGETRITGL

51 LEGEDVINTG KAMQAMGARI RKEGDTWIID GVGNGGLLAP EAPLDFGNAA

101 TGCRLTMGLV GVYDFDSTFI GDASLTKRPM GRVLNPLREM GVQVKSEDGD

151 RLPVTLRGPK TPTPITYRVP MASAQVKSAV LLAGLNTPGI TTVIEPIMTR

201 DHTEKMLQGF GANLTVETDA DGVRTIRLEG RGKLTGQVID VPGDPSSTAF

251 PLVAALLVPG SDVTILNVLM NPTRTGLILT LQEMGADIEV INPRLAGGED

301 VADLRVRSST LKGVTVPEDR APSMIDEYPI LAVAAAFAEG ATVMNGLEEL

351 RVKESDRLSA VANGLKLNGV DCDEGETSLV VRGRPDGKGL GNASGAAVAT

401 HLDHRIAMSF LVMGLVSENP VTVDDATMIA TSFPEFMDLM AGLGAKIELS

451 DTKAA

Figure III-6. Deduced Amino Acid Sequence of the CP4 EPSPS Protein

The amino acid sequence of the MON 87429 CP4 EPSPS protein was deduced from the 

full-length coding nucleotide sequence present in PV-ZMHT519224 (See Table III-1 for more 

detail). Another mature form of CP4 EPSPS protein containing 454 amino acids, resulting from 

the cleavage of the lead methionine (boxed with dash line) was also observed.

III.G. Regulatory Sequences 

The pat coding sequence in MON 87429 is under the regulation of the promoter, 5' 

untranslated region (UTR) and intron for a ubiquitin gene (Ubq) from Erianthus

ravennae (plume grass) that direct transcription in plant cells (Cornejo et al., 1993). The 

pat coding sequence also utilizes the 3′ UTR sequence of the fructose-bisphosphate 

aldolase (Fba) gene from Setaria italica (foxtail millet) that directs polyadenylation of 

mRNA (Hunt, 1994).

The dmo coding sequence in MON 87429 is under the regulation of the promoter, 5' UTR 

and intron for a ubiquitin gene (Ubq) from Coix lacryma-jobi (adlay millet) that direct 

transcription in plant cells (Cornejo et al., 1993). The dmo coding sequence utilizes a 

codon optimized targeting sequence of the Albino and pale green 6 (Apg6) gene from 

Arabidopsis thaliana encoding a chloroplast-targeted Hsp101 homologue transit peptide 

region that directs transport of the DMO protein to the chloroplast (GenBank Accession: 

NM_121549). The dmo coding sequence also utilizes the 3' UTR sequence of the OsMt

gene from Oryza sativa (rice) encoding metallothionein-like protein that directs 

polyadenylation of mRNA (Hunt, 1994).
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The ft_t coding sequence in MON 87429 is under the regulation of the promoter, 5' UTR, 

and intron for a ubiquitin gene (Ubq) from Arundo donax (giant reed) that directs 

transcription in plant cells (Cornejo et al., 1993). The ft_t coding sequence utilizes a 

chloroplast targeting sequence from Arabidopsis thaliana Mdh gene encoding the malate 

dehydrogenase transit peptide region that directs transport of the FT_T protein to the 

chloroplast (GenBank Accession: BT000621). The ft_t coding sequence also utilizes the 

3' UTR sequence from the gene coding for a no apical meristem (Nam) protein domain 

containing protein from Oryza sativa (rice) that directs polyadenylation of mRNA (Hunt, 

1994).

The cp4 epsps coding sequence in MON 87429 is under the regulation of the promoter 

and leader from the 35S RNA of cauliflower mosaic virus (CaMV) (Odell et al., 1985)

that direct transcription in plant cells. The cp4 epsps coding sequence also utilizes the 5' 

UTR leader sequence from the gene coding for chlorophyll a/b-binding (CAB) protein of 

Triticum aestivum (wheat) that is involved in regulating gene expression (Lamppa et al., 

1985), and the intron and flanking UTR sequence of the act1 gene from Oryza sativa

(rice) encoding rice Actin 1 (Ract1) protein that is also involved in regulating gene 

expression (McElroy et al., 1990). The cp4 epsps coding sequence utilizes a chloroplast 

targeting sequence of the ShkG gene from Arabidopsis thaliana encoding the EPSPS 

transit peptide region that directs transport of the CP4 EPSPS protein to the chloroplast 

(Herrmann, 1995; Klee et al., 1987). The cp4 epsps coding sequence is regulated by a 

modified partial 3' UTR sequence of Zea mays cDNA (Genbank Accession: EU974548) 

that contains a target sequence recognized by endogenous male tissue specific siRNAs 

(Brodersen and Voinnet, 2006), which suppresses cp4 epsps gene expression in maize 

male tissue (Yang et al., 2018). The cp4 epsps coding sequence also utilizes a 3' UTR 

sequence of the glycine-rich RNA-binding protein (Grp3) gene from Oryza sativa (rice) 

encoding the GRP3 protein that directs polyadenylation of mRNA (Hunt, 1994).

III.H. T-DNA Border Regions

PV-ZMHT519224 contains Left and Right Border regions (Figure III-2 and Table III-1) 

that were derived from A. tumefaciens plasmids. The border regions each contain a nick 

site that is the site of DNA exchange during transformation (Barker et al., 1983; Depicker 

et al., 1982; Zambryski et al., 1982). The border regions separate the T-DNA from the 

plasmid backbone region and are involved in the efficient transfer of T-DNA into the 

maize genome. As demonstrated in this petition (Section VII), the use of genetic elements 

from A. tumefaciens, a designated plant pest, has not imparted plant pest characteristics to 

MON 87429.

III.I. Genetic Elements Outside the T-DNA Border Regions 

Genetic elements that exist outside of the T-DNA border regions are those that are 

essential for the maintenance or selection of PV-ZMHT519224 in bacteria and are 

referred to as plasmid backbone. The selectable marker, aadA is the coding sequence for 

an aminoglycoside-modifying enzyme, 3''(9) –O–nucleotidyltransferase from the 

transposon Tn7 (Fling et al., 1985) that confers spectinomycin and streptomycin 

resistance in E. coli and Agrobacterium for use in molecular cloning. The origin of 
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replication, ori-pBR322, is required for the maintenance of the plasmid in E. coli and is 

derived from the plasmid vector pBR322 (Sutcliffe, 1979). The origin of replication, 

ori V, is required for the maintenance of the plasmid in Agrobacterium and is derived 

from the broad host range plasmid RK2 from Agrobacterium (Stalker et al., 1981). 

Because these elements are outside the T-DNA border regions, they are not expected to 

be transferred into the maize genome. The absence of the backbone and other unintended 

plasmid sequence in MON 87429 was confirmed by sequencing and bioinformatic 

analyses (Section IV).

 
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IV. CHARACTERIZATION OF THE GENETIC MODIFICATION

This section describes the methods and results of a comprehensive molecular 

characterization of the genetic modification present in MON 87429. It provides 

information on the DNA insertion(s) into the plant genome of MON 87429, and 

additional information regarding the arrangement and stability of the introduced genetic 

material. The information provided in this section addresses the relevant factors in 

Codex Plant Guidelines, Section 4, paragraphs 30, 31, 32, and 33 (Codex Alimentarius, 

2009).

IV.A. Description of Methodology Used to Characterize MON 87429

A schematic representation of the next generation sequencing (NGS) methodology and 

the basis of the characterization using NGS and PCR sequencing are illustrated in Figure 

IV-1 below. Appendix B defines the test, control and reference substances, and provides 

an additional overview of these techniques, their use in DNA characterization in maize 

plants and the materials and methods.
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Figure IV-1. Molecular Characterization using Sequencing and Bioinformatics

Genomic DNA from MON 87429 (Test) and the conventional control was sequenced using 

technology that produces a set of short, randomly distributed sequence reads that 

comprehensively cover test and control genomes (Step 1). Utilizing these genomic sequence 

reads, bioinformatics searches are conducted to identify all sequence reads that are significantly 

similar to the transformation plasmid (Step 2). These identified captured reads are then mapped 

and analyzed to determine the presence/absence of transformation plasmid backbone sequences, 

identify insert junctions, and to determine the insert and copy number (Step 3). Using directed 

sequencing, overlapping PCR products are also produced which span any insert and the wild type 

insertion locus (Step 4 and Step 5 respectively); these overlapping PCR products are sequenced to 

allow for detailed characterization of the inserted DNA and insertion site.

Step 1: Next Generation Sequencing (NGS) of 

genomic DNA samples. A collection of read 

sequences are generated which comprehensively 

cover the test and control sample genomes

Step 2: Selection of the reads containing 

sequence significantly similar to that of the 

transformation plasmid

Step 3: Bioinformatic analysis to detect and 

characterize all read sequences originating from 

the transgenic insertion(s)

1. Presence or absence of backbone insertions:

No unintended backbone or T-DNA

sequences detected (Read Mapping)

2. Insert and copy number determined:

Junctions located and characterized

Step 4: Directed sequencing across the insertion 

from the 5’ flank to the 3’ flank

Step 5: Directed sequencing across the wild type 

insertion site

3. Exact sequence of insert(s)

4. Organization and intactness of genetic 

elements in the insert sequence is confirmed

5. Integrity and organization of insertion site(s)

Experimental Stage Resultant Molecular Characterization

NGS

Directed 

Sequencing
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The NGS method was used to characterize the genomic DNA from MON 87429 and the 

conventional control by generating short (~150 bp) randomly distributed sequence 

fragments (sequencing reads) generated in sufficient number to ensure comprehensive 

coverage of the sample genomes. It has been previously demonstrated that whole 

genome sequencing at 75× depth of coverage is adequate to provide comprehensive 

coverage and ensure detection of inserted DNA (Kovalic et al., 2012). To confirm 

sufficient sequence coverage of the genome, the 150 bp sequence reads are analyzed to 

determine the coverage of a known single-copy endogenous maize gene. This establishes 

the depth of coverage (the median number of times each base of the genome is 

independently sequenced). The level of sensitivity of this method was demonstrated by 

detection of a positive control plasmid DNA spiked at 1 and 1/10th copy-per-genome 

equivalent. This confirms the method’s ability to detect any sequences derived from the 

transformation plasmid. Bioinformatics analysis was then used to select sequencing 

reads that contained sequences similar to the transformation plasmid, and these were 

analyzed in depth to determine the number of DNA inserts. NGS was run on five 

breeding generations of MON 87429 and the appropriate conventional controls. Results 

of NGS are shown in Sections IV.B and IV.E.

The DNA inserts of MON 87429 were characterized by mapping of sequencing reads to 

the transformation plasmid and identifying junctions and unpaired read mappings 

adjacent to the junctions. Examples of five types of NGS reads are shown in Figure IV-2. 

The junctions of the DNA insert and the flanking DNA are unique for each insertion 

(Kovalic et al., 2012). Therefore, insertion sites can be recognized by analyzing for 

sequence reads containing such junctions. 

Directed sequencing (locus-specific PCR and DNA sequencing analyses, Figure IV-1, 

Step 4) complements the NGS method. It assesses the sequence identity of the insert 

relative to the corresponding sequence from the T-DNA in PV-ZMHT519224, and 

demonstrates that each genetic element in the insert was intact without rearrangement. It 

also characterizes the flank sequence beyond the insert corresponding to the genomic 

DNA of MON 87429. Directed sequencing results are described in Sections IV.B, IV.C

and IV.D; methods are presented in Appendix B. 

The stability of the T-DNA present in MON 87429 across multiple breeding generations 

was evaluated by NGS as described above by determining the number and identity of the 

DNA inserts in each generation. For a single copy T-DNA insert, two junction sequence 

classes are expected. In the case of an event where a single insertion locus is stably 

inherited over multiple breeding generations, two identical junction sequence classes 

would be detected in all the breeding generations tested. Results are described in 

Section IV.E; methods are presented in Appendix B.

Segregation analysis of the T-DNA was conducted to determine the inheritance and 

generational stability of the insert in maize. Segregation analysis corroborates the insert 

stability demonstrated by NGS and independently establishes the genetic behavior of the 

T-DNA. Results are described in Section IV.F. 
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Figure IV-2. Five Types of NGS Reads 

NGS yields data in the form of read pairs where sequence from each end of a size selected DNA 

fragment is returned. Depicted above are five types of sequencing reads/read pairs generated by 

NGS sequencing which can be found spanning or outside of junction points. Sequence boxes are 

filled red or black if it matches with plasmid sequence, and empty if it matches with genomic 

sequence. Grey highlighting indicates sequence reads spanning the junction. Junctions are 

detected by examining the NGS data for reads having portions of plasmid sequences that span 

less than the full read, as well as reads mapping adjacent to the junction points where their mate 

pair does not map to the plasmid sequence. The five types of sequencing reads/read pairs being 

(1) Paired and unpaired reads mapping to genomic sequence outside of the insert, greater than 

99.999% of collected reads fall into this category and are not evaluated in this analysis, (2) Paired 

reads mapping entirely to the transformation plasmid sequence, such reads reveal the presence of 

transformation related sequence in planta, (3) Paired reads where one read maps entirely within 

the inserted DNA and the other read maps partially to the insert (indicating a junction point), (4) 

Single read mapping partially to the transformation plasmid DNA sequence (indicating a junction 

point) where its mate maps entirely to the genomic flanking sequence and (5) Single read 

mapping entirely to the transformation plasmid DNA sequence where its mate maps entirely to 

genomic flanking sequence, such reads are part of the junction signature.
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IV.B. Characterization of the DNA Insert in MON 87429

The number of inserted DNA sequences from PV-ZMHT519224 in MON 87429 was 

assessed by generating a comprehensive collection of reads via NGS of MON 87429 

genomic DNA using the R3 generation. A plasmid map of PV-ZMHT519224 is shown in 

Figure III-2. Table IV-1 provides descriptions of the genetic elements present in 

MON 87429. A schematic representation of the insert and flanking sequences in 

MON 87429 is shown in Figure IV-3. For full details on materials and methods see 

Appendix B.

IV.B.1. Next Generation Sequencing for MON 87429 and Conventional Control 

Genomic DNA 

Genomic DNA from five breeding generations of MON 87429 (Figure IV-4) and 

conventional controls were isolated from seed and prepared for sequencing. For material 

and method details see Appendix B. These genomic DNA libraries were used to generate 

short (~150 bp) randomly distributed sequencing reads of the maize genome (Figure 

IV-1, Step 1). 

To demonstrate sufficient sequence coverage the 150 bp sequence reads were analyzed 

by mapping all reads to a known single copy endogenous gene (Zea mays pyruvate 

decarboxylase (pdc3), GenBank Accession: AF370006.2) in each of the five breeding 

generations. The analysis of sequence coverage plots showed that the depth of coverage 

(i.e., the median number of times any base of the genome is expected to be independently 

sequenced) was 86× or greater for the five generations of MON 87429 (R3, R3F1, R4, 

R4F1, and R5) and the conventional control (Appendix B, Table B-1). It has been 

previously demonstrated that whole genome sequencing at 75× depth of coverage 

provides comprehensive coverage and ensures detection of inserted DNA (Kovalic et al., 

2012). 

To demonstrate the method’s ability to detect any sequences derived from the 

PV-ZMHT519224 transformation plasmid, a sample of conventional control genomic 

DNA spiked with PV-ZMHT519224 DNA was analyzed by NGS and bioinformatics. 

The level of sensitivity of this method was demonstrated to a level of one genome 

equivalent and 1/10th genome equivalent, 100% nucleotide identity was observed over 

100% of PV-ZMHT519224 (Appendix B, Table B-2). This result demonstrates that all 

nucleotides of PV-ZMHT519224 are observed by the sequencing and bioinformatic 

assessments performed and that a detection level of at least 1/10th genome equivalent 

was achieved for the plasmid DNA sequence assessment.
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Table IV-1. Summary of Genetic Elements in MON 87429

Genetic Element1 Location in 

Sequence2

Function (Reference)

5' Flanking DNA 1-1029 DNA sequence flanking the 5' end of the 

insert

B3-Left Border

Regionr1

1030-1288 DNA region from 

Agrobacterium tumefaciens containing 

the left border sequence used for transfer 

of the T–DNA (Barker et al., 1983)

Intervening Sequence 1289-1359 Sequence used in DNA cloning

P

4

-Ea.Ubq 1360-3541 Promoter, 5' UTR, and intron sequences 

for a ubiquitin gene (Ubq) from 

Erianthus ravennae (plume grass) that 

directs transcription in plant cells 

(Cornejo et al., 1993)

Intervening Sequence 3542-3546 Sequence used in DNA cloning

CS5-pat 3547-4098 Coding sequence for the phosphinothricin 

N–acetyltransferase (PAT) protein of 

Streptomyces viridochromogenes that 

confers tolerance to glufosinate 

(Wehrmann et al., 1996; Wohlleben et al., 

1988)

T6-Fba 4099-4475 3' UTR sequence of the fructosebisphosphate aldolase (Fba) gene from 

Setaria italica (foxtail millet) that directs 

polyadenylation of mRNA (Hunt, 1994)

Intervening Sequence 4476-4537 Sequence used in DNA cloning

P-Clj.Ubq 4538-6463 Promoter, 5' UTR, and intron sequences 

for a ubiquitin gene (Ubq) from Coix 

lacryma-jobi (adlay millet) that directs 

transcription in plant cells (Cornejo et al., 

1993)

Intervening Sequence 6464-6473 Sequence used in DNA cloning

TS7-APG6 6474-6677 Codon optimized targeting sequence of 

the Albino and pale green 6 (Apg6) gene 

from Arabidopsis thaliana encoding a 

chloroplast-targeted Hsp101 homologue 

transit peptide region that directs the 

protein to the chloroplast (GenBank 

Accession: NM_121549)
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Table IV-1. Summary of Genetic Elements in MON 87429 (continued)

CS-dmo 6678-7700 Codon optimized coding sequence for the 

dicamba mono–oxygenase (DMO) 

protein of Stenotrophomonas maltophilia

that confers dicamba resistance (Herman 

et al., 2005; Wang et al., 1997)

Intervening Sequence 7701-7708 Sequence used in DNA cloning

T-Mt 7709-8008 3' UTR sequence of the OsMt gene from 

Oryza sativa (rice) encoding 

metallothionein-like protein that directs 

polyadenylation of mRNA (Hunt, 1994)

Intervening Sequence 8009-8016 Sequence used in DNA cloning

P-Ad.Ubq 8017-9973 Promoter, 5' UTR, and intron sequences 

for a ubiquitin gene (Ubq) from Arundo 

donax (giant reed) that directs 

transcription in plant cells (Cornejo et al., 

1993)

Intervening Sequence 9974-9986 Sequence used in DNA cloning

TS-MDH 9987-10229 Targeting sequence from 

Arabidopsis thaliana Mdh gene encoding 

the malate dehydrogenase transit peptide 

region that directs the protein to the 

chloroplast (GenBank Accession: 

BT000621)

CS-ft_t 10230-11117 Modified version of 

R-2,4-dichlorophenoxypropionate

dioxygenase (Rdpa) gene from 

Sphingobium herbicidovorans that 

expresses a FOPs and 2,4-D dioxygenase 

protein (FT_T) that confers tolerance to 

quizalofop and 2,4-D herbicides (Müller 

et al., 2006)

Intervening Sequence 11118-11132 Sequence used in DNA cloning

T-Nam 11133-11649 3' UTR sequence from the gene coding 

for a no apical meristem (Nam) protein 

domain containing protein from 

Oryza sativa (rice) (Hunt, 1994)

Intervening Sequence 11650-11655 Sequence used in DNA cloning
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Table IV-1. Summary of Genetic Elements in MON 87429 (continued)

P-35S 11656-11979 Promoter and leader from the 35S RNA 

of cauliflower mosaic virus (CaMV) 

(Odell et al., 1985) that directs 

transcription in plant cells

Intervening Sequence 11980-12001 Sequence used in DNA cloning

L8-Cab 12002-12062 5' UTR leader sequence from the gene 

coding for chlorophyll a/b-binding (CAB) 

protein of Triticum aestivum (wheat) that 

is involved in regulating gene expression 

(Lamppa et al., 1985)

Intervening Sequence 12063-12078 Sequence used in DNA cloning

I

9

-Ract1 12079-12558 Intron and flanking UTR sequence of the 

act1 gene from Oryza sativa (rice) 

encoding rice Actin 1 protein (McElroy et 

al., 1990) that is involved in regulating 

gene expression.

Intervening Sequence 12559-12567 Sequence used in DNA cloning

TS-CTP2 12568-12795 Targeting sequence of the ShkG gene 

from Arabidopsis thaliana encoding the 

EPSPS transit peptide region that directs 

transport of the protein to the chloroplast 

(Herrmann, 1995; Klee et al., 1987)

CS-cp4 epsps 12796-14163 Codon optimized coding sequence of 

the 5-enolpyruvylshikimate-3-phosphate 

synthetase (aroA) gene from 

the Agrobacterium sp. strain CP4 

encoding the CP4 EPSPS protein that 

provides glyphosate tolerance (Barry et 

al., 2001; Padgette et al., 1996)

Intervening Sequence 14164-14169 Sequence used in DNA cloning

siRNA Target 

Sequence

14170-14370 Modified partial 3' UTR sequence of Zea 

mays cDNA (Genbank Accession: 

EU974548) that contains male tissue 

specific siRNA Target Sequence 

(Brodersen and Voinnet, 2006)

Intervening Sequence 14371-14378 Sequence used in DNA cloning

T-Grp3 14379-14989 3' UTR sequence of the glycine-rich 

RNA binding- protein (Grp3) gene from 

Oryza sativa (rice) encoding the GRP3 

protein that directs polyadenylation of 

mRNA (Hunt, 1994)
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Table IV-1. Summary of Genetic Elements in MON 87429 (continued)

Intervening Sequence 14990-15030 Sequence used in DNA cloning

B-Right Border 

Regionr1

15031-15037 DNA region from

Agrobacterium tumefaciens containing 

the right border sequence used for 

transfer of the T–DNA (Depicker et al., 

1982; Zambryski et al., 1982)

3' Flanking DNA 15038-16068 Flanking DNA

1 Although flanking sequences and intervening sequences are not functional genetic elements, 

they comprise a portion of the sequence.

2 Numbering refers to the sequence of the insert in MON 87429 and adjacent DNA

3 B, Border 

4 P, Promoter

5 CS, Coding Sequence

6 T, Transcription Termination Sequence

7 TS, Targeting Sequence 

8 L, Leader

9

I, Intron

r1 Superscript in Left and Right Border Regions indicate that the sequence in MON 87429 was 

truncated compared to the sequences in PV-ZMHT519224
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Figure IV-3. Schematic Representation of the Insert and Flanking Sequences in MON 87429

DNA derived from T-DNA of PV-ZMHT519224 integrated in MON 87429. Right-angled arrows indicate the ends of the integrated T-DNA and 

the beginning of the flanking sequence. Identified on the map are genetic elements within the insert. This schematic diagram may not be drawn to 

scale.

r1 Superscript in Left and Right Border Regions indicate that the sequence in MON 87429 was truncated compared to the sequences in 

PV-ZMHT519224.
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Figure IV-4. Breeding History of MON 87429

The generations used for molecular characterization and insert stability analyses are indicated in 

bold text. R0 (LH244) corresponds to the transformed plant,  designates self-pollination.

1Generations used to confirm insert stability 

2 Generation used for molecular characterization

3 Generation used for commercial development of MON 87429

R0

R1

R2

R31, 2, 3

R41

R51

R3F11

R4F11

 HCL617

 L7126Z
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IV.B.2. Selection of Sequence Reads Containing Sequence of the PV-ZMHT519224

The transformation plasmid, PV-ZMHT519224 was transformed into the parental variety 

LH244 to produce MON 87429. Consequently, any DNA inserted into MON 87429 will 

consist of sequences that are similar to the PV-ZMHT519224 DNA sequence. Therefore, 

to fully characterize the DNA from PV-ZMHT519224 inserted in MON 87429, it is 

sufficient to analyze only the sequence reads that have significant similarity to 

PV-ZMHT519224 (Figure IV-1, Step 2). 

Using established criteria (described in the materials and methods, Appendix B), 

sequence reads similar to PV-ZMHT519224 were selected from MON 87429 sequence 

datasets and were then used as input data for bioinformatic junction sequence analysis. 

PV-ZMHT519224 sequences were also compared against the conventional control 

sequence dataset.

IV.B.3. Determination of T-DNA Copy Number and Presence or Absence of 

Plasmid Vector Backbone

By mapping sequence reads to the transformation plasmid sequence and identifying 

junction signatures, the presence or absence of backbone sequence and the number of 

T-DNA insertions can be determined. For a single copy T-DNA insert sequence at a 

single genomic locus, a single junction signature pair and few if any reads aligning with 

the transformation plasmid backbone sequences are expected.

When reads from conventional maize LH244 were aligned with the transformation 

plasmid sequence, a number of reads mapped to the T-DNA element siRNA Target 

Sequence (Figure IV-5, see Panels 1 and 2; Panel 3 illustrates the read depth). The 

sequence alignments were expected since the siRNA Target Sequence in the T-DNA is 

derived from endogenous maize genomic sequence. Notably, the sequence alignment is 

isolated to that element alone and does not cross the element boundaries. No other 

sequence reads from LH244 conventional maize mapped to the transformation plasmid. 

Additional conventional controls (LH244 × HCL617 was the control for R3F1, and 

LH244 × L7126Z was the control for R4F1) evaluated in the generational stability 

analysis (see Table IV-3) produced comparable read maps. 

When reads from the MON 87429 (R3) dataset were aligned with the transformation 

plasmid sequence, large numbers of reads mapped to T-DNA, and no reads were 

identified which aligned to the transformation plasmid backbone (Figure IV-6). 

The mapping of a large number of sequencing reads from the MON 87429 (R3) dataset to 

the T-DNA was expected and fully consistent with the presence of the inserted DNA 

MON 87429. Since these sequences are identical, the mapped read mate pairs were used 

to distinguish their true mapping location. Also, no reads in the MON 87429 (R3) 

generation dataset were identified that align with the plasmid backbone. As a result, it is 

concluded that MON 87429 (R3) does not contain inserted sequence from the 

transformation plasmid backbone.
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To determine the insert number in MON 87429 (R3), selected reads mapping to T-DNA 

as described above were analyzed to identify junctions. This bioinformatic analysis is 

used to find and classify partially matched reads characteristic of the ends of insertions. 

The number of unique junctions determined by this analysis are shown in Table IV-2. 

Table IV-2. Unique Junction Sequence Class Results

Sample Junctions Detected

MON 87429 (R3) 2

LH244 0

LH244 × HCL617 0

LH244 × L7126Z 0

Detailed mapping information of the junction sequences is shown in Figure IV-6. The 

location and orientation of the junction sequences relative to the T-DNA insert 

determined for MON 87429 are illustrated in Figure IV-6, panels 1 and 2. As shown in 

the figure, there are two junctions identified in MON 87429. Both junctions contain the 

T-DNA border sequence joined to flanking genomic sequence, indicating that they 

represent the sequences at the junctions of the intended T-DNA insert and the maize 

genome. As described earlier, no junctions were detected in any of the conventional 

maize control samples. 

Considered together, the absence of plasmid backbone and the presence of two junctions 

(joining T-DNA borders and flanking sequences) indicate a single intended T-DNA at a 

single locus in the genome of MON 87429. Both of these junctions originate from the 

same locus of the MON 87429 genome and are linked by contiguous, known and 

expected DNA sequence. This is demonstrated by complete coverage of the sequenced 

reads spanning the interval between the junctions and the directed sequencing of 

overlapping PCR products described in Section IV.C. 

Based on the comprehensive NGS and junction identification it is concluded that 

MON 87429 contains one copy of the T-DNA inserted into a single locus. This 

conclusion is confirmed by the sequencing and analysis of overlapping PCR products 

from this locus as described below.
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Figure IV-5. Read Mapping of Conventional Maize LH244 Versus 

PV-ZMHT519224 

Panel 1 shows the location of unpaired mapped reads, Panel 2 shows paired mapped reads, and 

Panel 3 shows a representation of combined read depth for unpaired and paired reads. Vertical 

lines, in green, show genetic element boundaries. Comparable results were observed when read 

mapping LH244 × HCL617 versus PV-ZMHT519224, or read mapping LH244 × L7126Z versus 

PV-ZMHT519224. These additional conventional controls were used for the generational 

stability analysis (see Table IV-3).
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Figure IV-6. Read Mapping of MON 87429 (R3) Versus PV-ZMHT519224

Panel 1 shows the location of unpaired mapped reads. Panel 2 shows paired mapped reads and 

Panel 3 shows a representation of combined read depth for unpaired and paired reads. Vertical 

lines, in green, show genetic element boundaries. The region of flank junction sequences that 

aligns with transformation plasmid is shown in red. Comparable results were observed when read 

mapping the R3F1, R4, R4F1, and R5 generations of MON 87429 versus PV-ZMHT519224 (see 

Table IV-3 for the generational stability analysis). 
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IV.C. Organization and Sequence of the Insert and Adjacent DNA in MON 87429

The organization of the elements within the DNA insert and the adjacent genomic DNA 

was assessed using directed DNA sequence analysis (refer to Figure IV-1, Step 4). PCR 

primers were designed to amplify two overlapping regions of the MON 87429 genomic 

DNA that span the entire length of the insert and the adjacent DNA flanking the insert 

(Figure IV-7). The amplified PCR products were subjected to DNA sequencing analyses. 

The results of this analysis confirm that the MON 87429 insert is 14,008 bp and that each 

genetic element within the T-DNA is intact compared to PV-ZMHT519224. The border 

regions both contain small terminal deletions with the remainder of the inserted border 

regions being identical to the sequence in PV-ZMHT519224. The sequence and 

organization of the insert was also shown to be identical to the corresponding T-DNA of 

PV-ZMHT519224 as intended. This analysis also shows that only T-DNA elements 

(described in Table IV-1) were present within the inserted DNA. In addition, 1,029 base 

pairs flanking the 5′ end of the MON 87429 insert (Table IV-1, bases 1-1029) and 

1031 base pairs flanking the 3′ end of the MON 87429 insert (Table IV-1, bases 

15038-16068) were determined. 
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Figure IV-7. Overlapping PCR Analysis across the Insert in MON 87429

PCR was performed on both conventional control genomic DNA and genomic DNA of the R3 

generation of MON 87429 using two pairs of primers to generate overlapping PCR fragments 

from MON 87429 for sequencing analysis. To verify size and specificity of the PCR products, 

12 μl of each of the PCR reactions was loaded on the gel. The expected product size for each 

amplicon is provided in the illustration of the insert in MON 87429 that appears at the bottom of 

the figure. This figure is a representative of the data generated in the study. Lane designations 

are as follows:

Lane

1 1 Kb Plus DNA Ladder

2 No template control

3 LH244 Conventional Control 

4 MON 87429

5 No template control

6 LH244 Conventional Control 

7 MON 87429

8 1 Kb Plus DNA Ladder

Arrows on the agarose gel photograph denote the size of the DNA, in kilobase pairs, obtained 

from the 1 Kb Plus DNA Ladder (Invitrogen) on the ethidium bromide stained gel.

r1 Superscript in Left and Right Border Regions indicate that the sequence in MON 87429 was 

truncated compared to the sequences in PV-ZMHT519224

1

8.0

9.0

2 3 4 5 6 7 8

12

1.0

0.5

2.0

3.0

8.0

9.0

12

1.0

0.5

2.0

3.0

Product A Product B
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IV.D. Sequencing of the MON 87429 Insertion Site

PCR and sequence analysis were performed on genomic DNA extracted from the 

conventional control to examine the insertion site in conventional maize (see Figure IV-1, 

Step 5). The PCR was performed with one primer specific to the genomic DNA 

sequence flanking the 5' end of the MON 87429 insert paired with a second primer 

specific to the genomic DNA sequence flanking the 3' end of the insert (Figure IV-8). A 

sequence comparison between the PCR product generated from the conventional control 

and the sequence generated from the 5' and 3' flanking sequences of MON 87429 

indicates that 54 bases of maize genomic DNA were deleted during integration of the 

T-DNA. There also was a 29 base insertion in the MON 87429 5′ flanking sequence and 

a 31 base insertion in the MON 87429 3' flanking sequence. Such changes are common 

during plant transformation (Anderson et al., 2016) and these changes presumably 

resulted from DNA repair mechanisms in the plant during Agrobacterium-mediated 

transformation processes (Salomon and Puchta, 1998). 
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Figure IV-8. PCR Amplification of the MON 87429 Insertion Site

PCR analysis was performed to evaluate the insertion site. PCR was performed on conventional 

control genomic DNA using Primer A, specific to the 5′ flanking sequence, and Primer B, 

specific to the 3′ flanking sequence of the insert in MON 87429. The DNA generated from the 

conventional control PCR was used for sequencing analysis. This illustration depicts the 

MON 87429 insertion site in the conventional control (upper panel) and the MON 87429 insert 

(lower panel). Approximately 5 μl of each of the PCR reactions was loaded on the gel. This 

figure is representative of the data generated in the study. Lane designations are as follows:

Lane

1 1 Kb Plus DNA Ladder

2 No template control 

3 LH244 Conventional Control

4 1 Kb Plus DNA Ladder

Arrows on the agarose gel photograph denote the size of the DNA, in kilobase pairs, obtained 

from the 1 Kb Plus DNA Ladder (Invitrogen) on the ethidium bromide stained gel.

r1 Superscript in Left and Right Border Regions indicate that the sequence in MON 87429 was 

truncated compared to the sequences in PV-ZMHT519224.

1 2 3 4

0.3

12.0

0.4

0.3

12.0

0.4

1.0

2.0

3.0

1.0

2.0

3.0
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IV.E. Determination of Insert Stability over Multiple Generations of MON 87429

In order to demonstrate the genetic stability of the T-DNA present in MON 87429 

through multiple breeding generations, NGS reads from five breeding generations of 

MON 87429 were mapped to the transformation plasmid for junction identification. The 

breeding history of MON 87429 is presented in Figure IV-4, and the specific generations 

tested are indicated in the figure legend. The MON 87429 (R3) generation was used for 

the molecular characterization analyses discussed in Sections IV.B-IV.D and shown in 

Figure IV-4. To assess stability, four additional generations were evaluated by NGS as 

previously described in Section IV.B, and compared to the fully characterized 

MON 87429 R3 generation. The conventional controls used for the generational stability 

analysis included LH244, LH244 × HCL617 and LH244 × L7126Z which represent 

similar background genetics to each of the analyzed MON 87429 breeding generations. 

Genomic DNA isolated from each of the selected generations of MON 87429 and 

conventional controls were used for mapping and subsequent junction identification 

(Table IV-3). 

To determine the insert number in the MON 87429 samples, the sequences generated and 

selected as described above in Section IV.B.2 were analyzed to identify junctions. The 

number of any resultant unique junctions containing the PV-ZMHT519224 DNA 

sequence determined by this analysis is shown in the table below.

Table IV-3. Junction Sequence Classes Detected

Sample

Junction Sequences 

Detected

MON 87429 (R3) 2

MON 87429 (R3F1) 2

MON 87429 (R4) 2

MON 87429 (R4F1) 2

MON 87429 (R5) 2

LH244 0

LH244 × HCL617 0

LH244 × L7126Z 0

As shown by alignment to the full flank/insert sequence obtained from directed 

sequencing, a single conserved pair of junctions linked by contiguous known and 

expected DNA sequence is present in MON 87429 (R3). Two identical junctions are 

found in each of the breeding generations (R3, R3F1, R4, R4F1, and R5), confirming the 

insertion of a single copy of PV-ZMHT519224 T-DNA at a single locus in the genome of 

MON 87429, and the consistency of these junctions in the mapping data across all 

generations tested demonstrates that this single locus is stably maintained throughout the 

MON 87429 breeding process.

These results demonstrate that the single locus of integration characterized in the R3 

generation of MON 87429 is found in five breeding generations of MON 87429, 
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confirming the stability of the insert. This comprehensive NGS and bioinformatic 

analysis of NGS data from multiple generations supports the conclusion that MON 87429 

contains a single, stable, inserted T-DNA.

IV.F. Inheritance of the Genetic Insert in MON 87429

The MON 87429 T-DNA resides at a single locus within the maize genome and therefore 

should be inherited according to Mendelian principles of inheritance. During 

development of lines containing MON 87429, phenotypic and genotypic segregation data 

were recorded to assess the inheritance and stability of the MON 87429 T-DNA using 

Chi square (χ2) analysis over several generations. The χ2analysis is based on comparing 

the observed segregation ratio to the expected segregation ratio according to Mendelian 

principles. 

The MON 87429 breeding path for generating segregation data is described in Figure 

IV-9. The transformed R0 plant was self-pollinated to generate R1 seed. An individual 

plant homozygous for the MON 87429 T-DNA was identified in the R1 segregating 

population via a Real-Time TaqMan® PCR assay. 

The homozygous positive R1 plant was self-pollinated to give rise to R2 seed. The R2 

plants were self-pollinated to produce R3 seed. R3 plants homozygous for the 

MON 87429 T-DNA were crossed via traditional breeding techniques to a Monsanto 

proprietary elite inbred parent that did not contain the dmo, pat, ft_t, or cp4 epsps coding 

sequences to produce hemizygous R3F1 seed. The R3F1 plants were crossed again with 

a Monsanto proprietary elite inbred parent to produce BC1 seed. The BC1 generation 

was tested for the presence of the MON 87429 T-DNA by Real-Time TaqMan® PCR 

assay to select for hemizygous MON 87429 plants. At the BC1 generation, the 

MON 87429 T-DNA was predicted to segregate at a 1:1 ratio 

(hemizygous positive: homozygous negative) according to Mendelian inheritance 

principles.

Selection of hemizygous BC1 plants, followed by crossing with the Monsanto proprietary 

elite inbred parent, followed by testing for the presence of the T-DNA was repeated for 

two additional generations, to produce hemizygous BC2 seed and hemizygous BC3 seed, 

each at a predicted 1:1 (hemizygous positive: homozygous negative) segregation ratio 

according to Mendelian inheritance principles.

A Pearson’s chi-square (χ2) analysis was used to compare the observed segregation ratios 

of the MON 87429 T-DNA to the expected ratios. The χ2analysis was performed using 

the statistical program R Version 3.3.1 (2016-06-21).

The Chi-square was calculated as: 

χ 2 = ∑ (( | o – e | )2/ e)
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where o = observed frequency of the genotype or phenotype and e = expected frequency 

of the genotype or phenotype. The level of statistical significance was predetermined to 

be 5% (α = 0.05).

The results of the χ2 analysis of the segregating progeny of MON 87429 are presented in 

Table IV-4. The χ2 value in the BC1, BC2, and BC3 generations indicated no statistically 

significant difference between the observed and expected segregation ratios of 

MON 87429 T-DNA. These results support the conclusion that the MON 87429 T-DNA 

resides at a single locus within the maize genome and is inherited according to Mendelian 

principles. These results are also consistent with the molecular characterization data 

indicating that MON 87429 contains a single intact copy of the T-DNA inserted at a 

single locus in the maize genome (Section IV.B-IV.E).

Figure IV-9. Breeding Path for Generating Segregation Data for MON 87429

*Chi-square analysis was conducted on segregation data from BC1, BC2, and BC3 generations 

(bolded text).

: Self-Pollinated

BC: Back Cross
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Table IV-4. Segregation of the Expression Cassette During the Development of MON 87429

1:1 Segregation

Generation Total 

Plants

Observed # 

Plant

Positive

Observed # 

Plant 

Negative

Expected # 

Plant Positive

Expected # 

Plant Negative χ 2 Probability

BC1 309 148 161 154.50 154.50 0.55 0.460

BC2 236 112 124 118.00 118.00 0.61 0.435

BC3 216 97 119 108.00 108.00 2.24 0.134
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IV.G. MON 87429 RHS Mechanism of Action

MON 87429 maize produces the 5-enolpyruvylshikimate-3-phosphate synthase protein 

from Agrobacterium sp. strain CP4 (CP4 EPSPS) to provide maize lines with 

tissue-specific glyphosate tolerance to facilitate the production of hybrid maize seed. 

MON 87429 maize utilizes an endogenous maize regulatory element to target CP4 

EPSPS mRNA for degradation in tassel tissues, resulting in reduced CP4 EPSPS protein 

expression in pollen (Table V-5). Specifically-timed glyphosate applications will 

produce a non-viable pollen phenotype through male tissue-specific glyphosate 

sensitivity in MON 87429 maize. Glyphosate is a systemic herbicide that is readily 

translocated via the phloem in plants (Devine et al., 1993). Once glyphosate is in the 

phloem, it moves to areas of high meristematic activity, following a typical source to sink 

distribution (Devine et al., 1993). Pollen development in a maize plant takes 

approximately four weeks to complete (Ma et al., 2008). Early tassel development begins 

at approximately V9 growth stage (Ritchie et al., 1997), therefore glyphosate applications 

made at around this time will allow maximum translocation of glyphosate to the male 

reproductive tissues, and selectively cause cell death only in those cells that are not 

tolerant to glyphosate (e.g., pollen cells).

The first-generation RHS product, MON 87427 maize, utilizes a specific promoter and 

intron combination (e35S-hsp70) to drive CP4 EPSPS expression in vegetative and 

female reproductive tissues. This specific promoter and intron combination in 

MON 87427 results in limited or no production of CP4 EPSPS protein in key male 

reproductive tissues; resulting in the non-viable pollen phenotype following late 

applications of glyphosate (USDA-APHIS Petition #10-281-01p p. 26). While the RHS 

trait in MON 87429 maize results in the same tissue-specific CP4 EPSPS expression seen 

in MON 87427, the mechanism by which this is achieved is enhanced in MON 87429.

Expression of CP4 EPSPS in MON 87429 plants is driven by the CaMV 35S promoter, a 

known constitutive promoter (Holtorf et al., 1995; Terada and Shimamoto, 1990). In 

maize and other monocot plants, CaMV 35S has been shown to drive weak gene 

expression in pollen tissue (Hamilton et al., 1992; Heck et al., 2005). Additionally, 

MON 87429 maize utilizes an endogenous maize regulatory element to target CP4 

EPSPS mRNA for degradation specifically in tassel tissues, resulting in reduced CP4 

EPSPS protein expression in pollen.

RNA interference (RNAi) is a natural process in eukaryotic organisms for the regulation 

of endogenous gene expression (Fire et al., 1998; Jones-Rhoades et al., 2006). Both 

microRNAs (miRNAs) and small interfering RNAs (siRNAs) can trigger the RNAi

pathway (Carthew and Sontheimer, 2009). Endogenous maize male tissue specific small 

interfering RNAs (mts-siRNA) described in Yang et al. (2018), are expected to be 

involved in regulation of endogenous gene expression in male tissue such as the tassel. 

MON 87429 takes advantage of endogenous mts-siRNAs to degrade the CP4 EPSPS 

mRNA in male tissue. MON 87429 CP4 EPSPS mRNA contains a 201 bp siRNA Target 

Sequence in the 3' UTR (Figure IV-10) which is recognized by the endogenous 

mts-siRNAs resulting in degradation of the CP4 EPSPS mRNA, and reduced expression 

of CP4 EPSPS protein in male tissue. 
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Figure IV-10. Schematic Diagram of cp4 epsps Gene Cassette, CP4 EPSPS mRNA 

and CP4 EPSPS Protein

The identification, cloning and testing of the 201 bp siRNA Target Sequence in 

MON 87429 is described in detail in Yang et al. (2018). The process is summarized as 

follows: 1) Identification of male tissue specific small interfering RNAs (mts-siRNA) 

primarily expressed in tassel, 2) Identification of Target Sequences corresponding to 

these endogenous mts-siRNAs present in maize, 3) Identification and selection of the 

target gene, EU974548, based on the 3' UTR region of this gene containing clustered, 

overlapping alignments of multiple siRNA Target Sequences, 4) Confirmation that the 

endogenous target, EU974548, is conserved across a wide range of maize germplasms, 5) 

Selection of the 201 bp siRNA Target Sequence, derived from EU974548, based on the 

intended non-viable pollen phenotype. 

The model representing the mechanism of action by which mts-siRNAs trigger 

degradation of the CP4 EPSPS mRNA in MON 87429 tassel tissue is summarized below 

and shown in Figure IV-11. The first five steps represent the endogenous mts-siRNA 

pathway in conventional maize, based on current knowledge of siRNA driven RNAi 

systems (Gorski et al., 2017): 

• Step 1: mts-siRNA precursor(s) RNA is produced from endogenous mtssiRNA gene. 

• Step 2: The mts-siRNA precursor RNA is cleaved by the Dicer (DCL4) 

complex to produce mts-siRNAs.

• Step 3: Independently, endogenous target genes are transcribed that contain 

siRNA Target Sequences (shown as red line in the endogenous target gene 

double helix). 

• Step 4: The resulting mts-siRNA molecules, from step 2, are then 

incorporated into multiprotein RNA-induced silencing complexes (RISC), 

which facilitate siRNA Target Sequence recognition and mRNA cleavage 

which leads to specific suppression of the target mRNA. 

• Step 5: It is expected that endogenous mRNAs containing siRNA Target 

Sequences are cleaved by the RISC complex and then subjected to further 

degradation by 3'-5' and 5'-3' exoribonucleases due to the lack of a 3' poly 

adenine tail or a 5' cap structure at the cleavage site, inhibiting mRNA 

translation into protein. 
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The following three steps occur only in MON 87429 male tassel tissue as MON 87429 

uses the endogenous siRNA machinery to specifically target CP4 EPSPS mRNA for 

degradation:

• Step 6: Upon CP4 EPSPS mRNA transcription, endogenous mts-siRNAs 

trigger cleavage of CP4 EPSPS mRNA via recognition of the 201bp siRNA 

Target Sequence in the 3' UTR of the CP4 EPSPS mRNA. 

• Step 7: The CP4 EPSPS mRNA cleavage products are then subjected to 

degradation by 3'-5' and 5'-3' exoribonucleases due to the lack of a 3' poly 

adenine tail or a 5' cap structure at the cleavage site. 

• Step 8: As a result of above processes, CP4 EPSPS mRNA is reduced, 

resulting in reduction in translation. Thus, little to no CP4 EPSPS protein is 

expressed in male tissue resulting in glyphosate sensitivity.

The same CP4 EPSPS mRNA is expressed throughout MON 87429 maize tissue (e.g., 

root, leaf, ear and tassel), however due to the male tissue specific expression of the 

mts-siRNAs, the CP4 EPSPS mRNA is only targeted for degradation in tassel tissue 

resulting in little to no expression of CP4 EPSPS protein in pollen (Table V-5).

Figure IV-11. MON 87429 CP4 EPSPS siRNA Target Sequence Molecular 

Mechanism of Action 
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IV.H. Absence of Unintended Effects due to the MON 87429 RHS Mechanism of 

Action

IV.H.1. Lack of Secondary siRNA from CP4 EPSPS mRNA Suppression

In plants, primary mRNA degradation products, produced via siRNA mediated 

degradation, may be used as an RNA template for the generation of secondary siRNAs.

These secondary siRNAs could initiate suppression of genes other than the intended 

target of the primary siRNA. Additionally, it has been reported that secondary siRNAs 

can move short distances (cell-to-cell) or long distances (between organs) from the site of 

origin and potentially silence genes with complementary sequence (Borges and 

Martienssen, 2015) resulting in the suppression of mRNAs other than the intended 

primary target. To determine whether secondary siRNAs are derived from the CP4 

EPSPS transcript in MON 87429 plants, low molecular weight RNA Northern blotting 

was conducted (Figure IV-12). The upper panel shows high quality and equal loading of 

total RNA samples from various MON 87429 and conventional wildtype (WT) tissues. 

The RNA molecules were then transferred onto a membrane and hybridized with three 

probes that cover the entire CP4 EPSPS transcript except for the siRNA Target Sequence. 

The siRNA Target Sequence was intentionally excluded from the probes to avoid cross 

hybridization with the endogenous mts-siRNAs (Appendix C).

An in vitro synthesized 25-nt RNA oligo with a sequence identical to a portion of the 

CP4 EPSPS mRNA was detected as a positive control (Figure IV-12, middle left), 

indicating that the probes worked, and hybridization and visualization were successful. 

No hybridizing small RNAs were observed in any samples tested (including leaves, roots, 

tassels at different developmental stages, and ears) for either MON 87429 or the WT 

plants (Figure IV-12, middle), demonstrating that no secondary siRNAs were generated 

from the CP4 EPSPS transcripts in plants containing MON 87429. After stripping off the 

CP4 EPSPS probes, the blot was reprobed with a DNA oligo complementary to 

Zm-miRNA159, which is expressed in all maize tissues (Zhang et al., 2009) and used as a 

positive control here. Zm-miRNA159 was detected in all samples (Figure IV-12, 

bottom), indicating separation and electroblotting of small RNAs were successful (Yang 

et al., 2018).
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Figure IV-12. Absence of CP4 EPSPS Derived Secondary siRNAs. 

Total RNA from various tissues of WT (LH244 conventional control; left side of blot) or 

MON 87429 maize (right side of blot), respectively, was used for Northern blotting. The upper 

panel shows equal loading and quality of the RNA samples by sharp, distinct RNA bands. M: a 

mix of the 1kb RNA ladder (1 μg) and a synthetic 25-nt CP4 EPSPS RNA oligo (1 ng) as a 

positive control; T1: V6 tassel; T2: V8 tassel; T3: V10 tassel; T4: V12 tassel; E: VT ear; L: V6 

leaf; R: VE root; S: VE shoot; C: synthetic DIG-labeled 20- and 25-nt RNAs as small size 

markers. The middle panel is the low molecular weight RNA blot that was hybridized with three 

DIG-labeled probes covering the whole CP4 EPSPS transcript except the 201-bp target region. 

The lower panel is the same small RNA blot that was reprobed for miR159 after stripping off the 

CP4 EPSPS probes to demonstrate the quality of small RNA in the samples. 

IV.H.1.1. Expression of Endogenous Genes with Sequence Homology to the siRNA 

Target Sequence

Bioinformatic analysis identified seven putative endogenous genes in the maize genome 

that contain sequences with at least 90% identity with the siRNA Target Sequence

present in the CP4 EPSPS mRNA 3’ UTR. All these putative genes are located in one 

region on chromosome 6. This is consistent with reports demonstrating that the maize 

genome is clustered with 60-80% highly repetitive sequences that are often 

non-functional pseudogenes and long terminal repeat (LTR) retrotransposons (Meyers et 

al., 2001; SanMiguel et al., 1996; Whitelaw et al., 2003). These putative genes share 

amino acid sequence homology with putative membrane proteins resembling serine 

incorporators that facilitate the synthesis of two serine-derived lipids, phosphatidylserine 

and sphingolipids (Yang et al., 2018). To confirm that the inclusion of the 201 bp siRNA 

Target Sequence in the cp4 epsps expression cassette did not impact the regulation of 

these seven putative endogenous genes, the expression levels of the putative gene 

transcripts in tassels were assessed.

Two quantitative reverse transcription PCR assays were developed: a TaqMan assay 

designed for detecting transcripts from two of the seven putative genes and a SYBR 

Green assay designed for six of the seven putative genes in the gene family (expression 
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of one putative gene can be detected by both assays) (Appendix C). Due to low transcript 

abundance and high sequence similarities between these seven putative genes, assays 

targeted to the individual transcripts could not be developed. Overall, these putative 

genes were expressed at very low levels in both transgenic MON 87429 and conventional

wildtype (WT) control tassels. Furthermore, the expression levels of the putative 

endogenous genes in MON 87429 plants were comparable to those in WT control plants, 

and there were no significant differences in transcript expression between MON 87429 

and WT control plants (Figure IV-13). Four additional representative conventional maize 

lines (Lines 1-4) were included to assess the natural variability in expression of these 

putative genes across conventional maize lines. The natural variability in expression of 

these putative genes proved to be greater than the difference between MON 87429 and 

WT control plants. These data demonstrate there is no impact to the regulation of the 

seven putative genes that share sequence homology with the siRNA Target Sequence in 

MON 87429. Furthermore, there were no observed off-type phenotypes in MON 87429 

maize plants (e.g. flowering, pollen characteristics or grain yield) that would be 

indicative of adverse unintended effects (Section VII). 

Figure IV-13. Expression of Endogenous Genes with Sequence Homology to the 

siRNA Target Sequence in Tassels

(A) Expression levels of two endogenous genes as determined by a TaqMan assay. (B) 

Expression levels of six endogenous genes as determined by a SYBR Green assay. Plants 

containing MON 87429 (test) and WT (LH244 conventional control) and additional four

conventional maize lines (reference) were grown in a randomized complete block design with 

100 replications for the test and control materials, and 25 replications for each reference material 

in a greenhouse. Each replication included three technical replicates (subsamples) per material. 

Real-time PCR was conducted in triplicate for each subsample. The statistical analysis using a 

linear mixed model for a randomized complete block design reveals there are no significant 

differences between test and WT control at the 5% level. Large dots: mean relative expression 

level; small dots: upper or lower 95% confidence interval, respectively.
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IV.I. Characterization of the Genetic Modification Summary and Conclusion 

As described above, characterization of the genetic modification in MON 87429 was 

conducted using a combination of sequencing, PCR, and bioinformatics. The results of 

this characterization demonstrate that MON 87429 contains a single copy of the intended 

T-DNA containing the pat, dmo, ft_t, and cp4 epsps expression cassettes that is stably 

integrated at a single locus and is inherited according to Mendelian principles over 

multiple generations. These conclusions are based on the following: 

• Molecular characterization of MON 87429 by Next Generation Sequencing 

(NGS) demonstrated that MON 87429 contains a single intended DNA insert. 

These whole-genome analyses provided a comprehensive assessment of 

MON 87429 to determine the presence and identity of sequences derived from 

PV-ZMHT519224 and demonstrated that MON 87429 contains a single 

T-DNA insert with no detectable plasmid backbone sequences.

• Directed sequencing (locus-specific PCR, DNA sequencing and analyses) 

performed on MON 87429 was used to determine the complete sequence of 

the single DNA insert from PV-ZMHT519224, the adjacent flanking genomic 

DNA, and the 5' and 3' insert-to-flank junctions. This analysis confirmed that 

the sequence and organization of the DNA is identical to the corresponding 

region in the PV-ZMHT519224 T-DNA. Furthermore, the genomic 

organization at the insertion site in MON 87429 was assessed by comparing 

the sequences flanking the T-DNA insert in MON 87429 to the sequence of 

the insertion site in conventional maize. This analysis determined that 54 

bases were deleted upon T-DNA integration. There also was a 29 base 

insertion in the MON 87429 5′ flanking sequence and a 31 base insertion in 

the MON 87429 3′ flanking sequence.

• Generational stability analysis by Next Generation Sequencing (NGS) 

demonstrated that the single PV-ZMHT519224 T-DNA insert in MON 87429 

has been maintained through five breeding generations, thereby confirming 

the stability of the T-DNA in MON 87429.

• Segregation analysis corroborates the insert stability demonstrated by NGS 

and independently establishes the nature of the T-DNA as a single 

chromosomal locus that shows an expected pattern of inheritance.

• MON 87429 maize utilizes an endogenous maize regulatory element to target 

CP4 EPSPS mRNA for degradation in tassel tissues, resulting in reduced CP4 

EPSPS protein expression in pollen with no impact on endogenous plant gene 

expression. 

Taken together, the characterization of the genetic modification in MON 87429 

demonstrates that a single copy of the intended T-DNA was stably integrated at a single 
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locus of the maize genome and that no plasmid backbone sequences are present in 

MON 87429.

In addition, MON 87429 maize utilizes an endogenous maize regulatory element (an 

siRNA Target Sequence) to target CP4 EPSPS mRNA for degradation in tassel tissues. 

A focused study on the MON 87429 siRNA Target Sequence demonstrated the absence 

of unintended effects on endogenous gene regulation.
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V. CHARACTERIZATION AND SAFETY ASSESSMENT OF THE DMO, 

PAT, CP4 EPSPS AND FT_T PROTEINS PRODUCED IN MON 87429 

Characterization of the introduced protein(s) in a biotechnology-derived crop is important 

to establishing food, feed, and environmental safety. As described in Section IV, 

MON 87429 contains dmo, pat, cp4 epsps and ft_t expression cassettes that, when 

transcribed and translated, result in the expression of the DMO, PAT, CP4 EPSPS and 

FT_T proteins, respectively. Based on the previous characterizations and safety 

assessments, as well as the history of safe use for the DMO, PAT and CP4 EPSPS 

proteins, information pertaining to the characterization, equivalence, allergenicity and 

toxicity of these proteins will not be discussed in detail in this petition. Summaries of 

safety assessments for DMO, PAT, and CP4 EPSPS proteins that have been previously 

evaluated by the USDA-APHIS are found in Sections V.A., V.B. and V.C. The 

characterization and safety assessment of the FT_T protein is found in section V.D. 

These assessments support a conclusion that the DMO, PAT, CP4 EPSPS, and FT_T 

proteins produced in MON 87429 are safe for human and animal consumption and do not 

impact the plant pest risk of MON 87429 maize.

V.A. DMO Protein Safety Assessment Summary

MON 87429 maize contains a demethylase gene from Stenotrophomonas maltophilia that 

expresses a dicamba mono-oxygenase (DMO) protein. As a mono-oxygenase protein, the 

DMO protein is part of a the larger oxygenase family of enzymes that incorporate one or 

two oxygen atoms into substrates and are widely distributed in many universal metabolic 

pathways (Harayama et al., 1992). In MON 87429 maize, the DMO protein 

enzymatically catalyzes the demethylation of the broadleaf herbicide dicamba to the 

non-herbicidal compound 3,6-dichlorosalicylic acid (DCSA) and formaldehyde, thus 

conferring dicamba resistance (Chakraborty et al., 2005). Expression of the DMO protein 

in MON 87429 is targeted to the chloroplast by a chloroplast transit peptide (CTP), which 

facilitates its co-localization with the endogenous reductase and ferredoxin enzymes 

required to supply electrons for the DMO demethylation reaction (Behrens et al., 2007). 

The DCSA product of the reaction catalyzed by the DMO protein is a known metabolite 

of dicamba in conventional cotton, soybean, soil, and livestock, and its safety has been 

evaluated by the FAO-WHO and EPA (FAO-WHO, 2011a; U.S. EPA, 2009). The other 

reaction product, formaldehyde, is found naturally in many plants and edible fungi at 

levels up to several hundred ppm (Adrian-Romero et al., 1999; Tashkov, 1996).

In the construction of the plasmid vector used in the development of MON 87429, 

PV-ZMHT519224, the Albino and pale green 6 chloroplast transit peptide (CTP) coding 

sequence from Arabidopsis thaliana (APG6, Table IV-1) was joined to the dmo coding 

sequence, resulting in the production of a precursor protein consisting of the DMO 

protein and an N-terminal 68 amino acid chloroplast transit peptide APG6, which is used 

to target the precursor protein to the chloroplast (Herrmann, 1995; Klee et al., 1987). 

Typically, transit peptides are precisely removed from the precursor protein following 

delivery to the targeted plastid (della-Cioppa et al., 1986) resulting in the full length 

protein. However, there are examples in the literature of alternatively processed forms of 
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a protein targeted to a plant’s chloroplast (Behrens et al., 2007; Clark and Lamppa, 1992). 

Data from N-terminal sequencing analysis of the MON 87429-produced DMO indicate 

that processing of the DMO precursor protein expressed in MON 87429 produced two 

isoforms of the mature MON 87429 DMO protein that differ by a single, additional 

amino acid at the N-terminus that is derived from the CTP. The single amino difference 

between the two isoforms of the DMO protein expressed in MON 87429 (designated 

DMO+1 and DMO+0) results in the presence of two polypeptide chains of 341 and 340 

amino acids, respectively, with an apparent molecular weight ~38 kDa, as the two forms 

are indistinguishable by Coomassie stain and western blot analysis of SDS-PAGE gels. 

Thus, MON 87429 DMO protein will be used to refer to both forms of the protein 

collectively in this petition, except where stated otherwise.

The MON 87429 DMO protein shares a high level of sequence identity with DMO 

proteins previously assessed and present in biotechnology-derived crops that were 

deregulated by USDA-APHIS (MON 87708 soybean, USDA-APHIS Petition #10-188-

01p, MON 88701 cotton, USDA-APHIS Petition #12-185-01p and MON 87419 maize, 

USDA-APHIS Petition #15-113-01p). Additionally, these biotechnology-derived crops 

expressing DMO proteins completed consultation with U.S. FDA (MON 87708 soybean, 

BNF 000125, MON 88701 cotton, BNF 000135 and MON 87419 maize, BNF 000135), 

where it was demonstrated that food and feed derived from these events are not 

materially different than the respective conventional crops. The minor amino acid 

substitutions between the wild-type DMO protein from the DI-6 strain of S. maltophilia, 

the MON 87429 DMO protein and the DMO proteins expressed in these other 

biotechnology-derived crops are localized to the N-terminus of the proteins and at 

position 112 of the amino acid sequences (Herman et al., 2005) (Figure V-1). 

Additionally, based upon the crystal structure of the wild-type DMO proteins, these 

amino acid substitutions are structurally distant from the active site and are not expected 

to impact catalytic site coordination, functional activity, immunoreactivity or specificity 

(D'Ordine et al., 2009; Dumitru et al., 2009; Wang et al., 2016). Thus, prior safety 

assessments of the DMO protein expressed in other biotechnology-derived crops are 

directly applicable to the DMO protein expressed in MON 87429.
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Figure V-1. Forms of DMO Protein and Their Relation to the Wild-Type DMO 

Protein

The diagram represents the various DMO forms discussed in this section. Position refers to 

amino acid residues as wild-type DMO and the N-terminal boxed region indicates residues from 

CTPs. The blue regions indicate regions of 100% amino acid identity. The wild-type DMO form 

isolated from S. maltophilia was the first form sequenced (Herman et al., 2005). The 

MON 87429 DMO proteins are identical to wild-type DMO, except for the insertion of a leucine 

at position 2 and an addition of 1 amino acid encoded by the AGP6 gene at the N-terminus for 

MON 87429 DMO+1. The MON 87419 DMO proteins are identical to wild-type DMO, except 

for the insertion of a leucine at position 2 and the amino acids derived from the C-terminal transit 

peptides at the N-terminus, which are 12 and 7 amino acids encoded by the CTP4 gene at the Nterminus for MON 87419 DMO+12 and MON 87419 DMO+7, respectively. The MON 88701 

DMO protein is identical to wild-type DMO, except for an insertion of a leucine at position 2, and 

an addition of 9 amino acids encoded by the CTP2 gene at the N-terminus. The MON 87708 

DMO proteins are identical to wild-type DMO, except for the insertion of an alanine at position 2, 

a single amino acid change at position 112 (tryptophan to cysteine) and an additional 27 amino 

acids encoded by the RbcS gene at the N-terminus for MON 87708 DMO+27. The MON 87708 

DMO (fully processed) protein additionally lacks a lead methionine residue. 

The DMO protein is specific for the oxidative demethylation of dicamba, forming DCSA. 

Dicamba interacts with amino acids in the catalytic site of DMO through both the 

carboxylate moiety and the chlorine atoms of dicamba, which are primarily involved in 

orienting the substrate in the catalytic site. These chlorine atoms are required for 

catalysis (D'Ordine et al., 2009; Dumitru et al., 2009). Given the limited existence of 

chlorinated compounds with structures similar to dicamba in plants and other eukaryotes 

(Wishart, 2010; Wishart et al., 2009), it is unlikely that MON 87429 DMO will catalyze 

the conversion of endogenous compounds. In order to confirm the specificity of the 

MON 87429 DMO protein for dicamba, and to demonstrate that the minor differences in 

amino acid sequences present in the MON 87429 DMO protein relative to the DMO 

proteins expressed in previous biotechnology-derived crops protein do not impact the 

activity or selectivity for dicamba herbicide as compared to potential endogenous 

substrates, the potential for MON 87429 DMO to catabolize dicamba and o-anisic acid 

was evaluated using the same qualitative assay used to evaluate the selectivity of 
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MON 87708 DMO (USDA-APHIS Petition #10-188-01p p. 76). Although o-anisic acid 

is not known to be present in corn, this substance was chosen for this confirmatory 

experiment since, among the five substrates used in the original study, which included 

ferulic acid, o-anisic acid, sinapic acid, syringic acid, and vanillic acid, o-anisic acid is 

the substrate that is most structurally similar to dicamba. The results from this 

assessment were similar to the previously reported results for MON 87708 DMO in that 

the DCSA product was observed using dicamba as the substrate whereas no demethylated 

products were observed with o-anisic acid as the substrate (Appendix E), confirming that 

the MON 87429 DMO did not catabolize o-anisic acid. Thus, MON 87429 DMO is 

active and has a high specificity for dicamba as a substrate.

The data and information summarized in this section confirm that the molecular 

mechanism of the MON 87429 DMO protein that confers dicamba tolerance is well 

understood, that the MON 87429 DMO protein is structurally and functionally 

homologous to the DMO proteins present in biotechnology-derived crops that have been 

deregulated by USDA-APHIS and demonstrated to not be materially different than the 

respective conventional crops in consultation with the US FDA, and that the MON 87429 

DMO protein is specific for dicamba. Thus, prior environmental and safety assessments 

for the DMO protein demonstrating the lack of impact on plant pest potential, the lack of 

homology to known protein toxins or allergens, digestibility in in vitro digestion assays 

and lack of acute oral toxicity are directly applicable to the MON 87429 DMO protein 

and are not detailed further herein.

V.B. PAT Protein Safety Assessment Summary

MON 87429 maize contains an acetyltransferase gene from Streptomyces 

viridochromogenes that expresses phosphinothricin N-acetyltransferase (PAT) protein. 

The molecular mechanism of the PAT protein, which acetylates glufosinate in the 

presence of acetyl CoA to form N-acetyl glufosinate, is well understood (Thompson et al., 

1987). Glufosinate is a racemic mixture of the D- and L-forms of the amino acid 

phosphinothricin. The herbicidal activity of glufosinate results from the binding of 

L-phosphinothricin to glutamine synthetase (OECD, 1999; 2002a). Expression of the 

PAT protein in MON 87429 maize results in the ability to covert L-phosphinothricin to 

the non-herbicidal N-acetyl glufosinate, thus conferring glufosinate resistance to the crop.

Phosphinothricin N-acetyltransferase (PAT) proteins have been isolated from two 

separate species of Streptomyces, S. hygroscopicus (Thompson et al., 1987) and S. 

viridochromogenes (Wohlleben et al., 1988). The PAT protein isolated from S. 

hygroscopicus is encoded by the bar gene, and the PAT protein isolated from S. 

viridochromogenes is encoded by the pat gene. These PAT proteins are made up of 183 

amino acids with 85% identity to each other at the amino acid level (Wohlleben et al., 

1988). Based on previous studies (Wehrmann et al., 1996) that have extensively 

characterized PAT proteins produced from bar and pat genes, OECD recognizes both 

proteins to be equivalent with regard to function and safety (OECD, 1999). Expression 

of the pat gene in MON 87429 results in a single polypeptide of 182 amino acids with an 

apparent molecular weight of ~25 kDa. Data from N-terminal sequencing analysis of the 

MON 87429-produced PAT protein indicate that it is identical to the wild type PAT 
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protein encoded by S. viridochromogenes and to the PAT proteins produced in several 

commercially available glufosinate tolerant crops, including events T25, TC1507,

A2704-12, A5547-127 and DAS-59122-7 (USDA-APHIS Petitions #94-357-01p, #00-

136-01p, #96-068-01p, #98-014-1p, #03-353-01p respectively) (Hérouet et al., 2005; 

ILSI-CERA, 2011), except for the first methionine that is removed due to cotranslational processing in MON 87429. N-terminal methionine cleavage is common and 

naturally occurs in the vast majority of proteins (Meinnel and Giglione, 2008).

Numerous glufosinate-tolerant crops including maize, canola, soybean, sugar beet, rice 

and cotton have been deregulated by USDA-APHIS (USDA-APHIS Petitions 

#94-357-01p, #00-136-01p, #03-353-01p and #15-113-01p maize; #98-278-01p and 01-

206-01p canola, #98-014-01p, #12-215-01p, #11-234-01p and #09-349-01p soybean; 

#97-336-01p sugar beet, #98-329-01p rice; and #12-185-01p, #13-262-01p and #08-340-

01p cotton) and completed consultations with US FDA (U.S. FDA, 1995b; a; 1996; 1997; 

1998a; b; 1999; 2002), where it was demonstrated that food and feed derived from these 

crops are not materially different than the respective conventional crops. The safety of 

PAT proteins has been confirmed following extensive reviews by regulatory agencies in 

at least 15 different countries for more than 30 biotechnology-derived events in several 

different crop species (e.g., maize, soybean, cotton, canola and sugar beet). Additionally, 

the EPA has issued a tolerance exemption for PAT protein (U.S. EPA, 1997). Prior 

safety assessments of the PAT proteins expressed in these other biotechnology-derived 

crops are directly applicable to the MON 87429 PAT protein because the amino acid 

sequence of the MON 87429 PAT protein is identical to the PAT proteins in these

biotechnology-derived crops that are derived from the pat gene and because the PAT 

proteins produced from the bar and pat genes are equivalent in terms of function and 

safety. The PAT proteins have a robust history of safe consumption and safe use in 

agriculture that is supported by the lack of any documented reports of adverse human or 

animal affects since the introduction of biotechnology-derived crops expressing PAT 

proteins in 1995 (Duke, 2005).

The PAT protein expressed in MON 87429 is highly specific for glufosinate. Enzyme 

assays have demonstrated that the PAT protein is unable to acetylate other common 

L-amino acids that are structurally similar to L-phosphinothricin, and substrate 

competition assays showed no inhibition of glufosinate acetylation in the presence of 

high concentrations of L-amino acids that are structurally similar to L-phosphinothricin 

(including the glufosinate analog L-glutamate) (Wehrmann et al., 1996). Recent 

metabolic profiling reported non-specific PAT (bar) mediated acetylation of two amino 

acids (aminoadipate and tryptophan) in senescent leaf extracts from A. thaliana, however 

this observation has not been reported in maize (Christ et al., 2017). Thus, the PAT 

protein has high substrate specificity for L-phosphinothricin, the herbicidal component of 

glufosinate, and it has been shown in other PAT-expressing maize products (e.g., T25, 

TC1507, MON 87419 and DAS-59122-7) that PAT does not affect maize metabolism.

The data and information summarized in this section confirm that the molecular 

mechanism of the MON 87429 PAT protein that confers glufosinate tolerance is well 

understood, that the MON 87429 PAT protein is identical to the PAT proteins present in 

biotechnology-derived crops that have been deregulated by USDA-APHIS and 
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demonstrated to not be materially different than the respective conventional crops in 

consultation with the US FDA, that the MON 87429 PAT protein is highly specific for 

glufosinate and that the PAT protein does not affect maize metabolism. Thus, prior 

environmental and safety assessments for the PAT protein demonstrating lack of impact 

on plant pest potential, lack of homology to known protein toxins or allergens, 

digestibility in in vitro digestion assays and lack of acute oral toxicity are directly 

applicable to the MON 87429 PAT protein and are not detailed further herein.

V.C. CP4 EPSPS Protein Safety Assessment Summary

MON 87429 contains a 5-enolpyruvulshikimate-3-phosphate synthase (EPSPS) gene 

from Agrobacterium sp. strain CP4 (cp4 epsps) that expresses a EPSPS protein. EPSPS is 

a key enzyme involved in aromatic amino acid biosynthesis and catalyzes a reaction 

where the enolpyruvyl group from phosphoenol pyruvate (PEP) is transferred to the 5-

hydroxyl of shikimate-3-phosphate (S3P) to form 5-enolpyruvylshikimate-3-phosphate 

(EPSP) and inorganic phosphate (Alibhai and Stallings, 2001). Shikimic acid is a 

substrate for the biosynthesis of aromatic amino acids (phenylalanine, tryptophan and 

tyrosine) and other aromatic molecules that are necessary for plant growth. The shikimic 

acid pathway and EPSPS enzymes are ubiquitous to plants and microorganisms, but are

absent in mammals, fish, birds, reptiles, and insects (Alibhai and Stallings, 2001). The 

CP4 EPSPS protein expressed in MON 87429 is structurally similar and functionally 

identical to endogenous plant EPSPS enzymes, but has a much reduced affinity for 

glyphosate, the active ingredient in Roundup agricultural herbicides, relative to 

endogenous plant EPSPS (Sikorski and Gruys, 1997). In conventional plants, glyphosate 

blocks the biosynthesis of EPSP, thereby depriving plants of essential amino acids 

(Haslam, 1993; Steinrücken and Amrhein, 1980). In Roundup Ready® plants, which are 

tolerant to Roundup® agricultural herbicides, requirements for aromatic amino acids and 

other metabolites are met by the continued action of the CP4 EPSPS enzyme in the 

presence of glyphosate (Padgette et al., 1996).

The cp4 epsps expression cassette in MON 87429 encodes a precursor protein of 531 

amino acids (455 amino acids encoded by the cp4 epsps gene and 76 amino acids 

encoded by the CTP2 gene for targeting the CP4 EPSPS protein into chloroplasts). 

Expression of the cp4 epsps gene in MON 87429 results in a single polypeptide chain of 

455 amino acids with an apparent molecular weight of ~44 kDa. Data from N-terminal 

sequencing analysis of the MON 87429-produced CP4 EPSPS protein indicate that the 

polypeptide chain starts at methionine position 77 after complete cleavage of the 

chloroplast transit peptide (CTP2) (Padgette et al., 1996). The CP4 EPSPS protein 

expressed in MON 87429 is identical in structure and function to the CP4 EPSPS protein 

expressed in Roundup Ready® products across several crops, including soybeans, maize, 

canola, cotton, sugar beet, and alfalfa. 

The safety and mode-of-action of CP4 EPSPS protein is well documented and is the 

subject of many publications (Harrison et al., 1996; Hoff et al., 2007; ILSI-CERA, 2010; 

U.S. EPA, 1996a). Numerous glyphosate-tolerant, commercially available CP4 EPSPS 

containing crops have been deregulated by USDA-APHIS (USDA-APHIS Petitions 

#10-281-01p and 04-125-01p maize; 11-188-01p and 98-216-01p canola; 04-110-01p 
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alfalfa; 06-178-01p and 93-258-01p soybean) and have completed consultations with the 

FDA (e.g., MON 87427 BNF 000126 in 2012 and MON 88017 BNF 000097 in 2005), 

where it was demonstrated that food and feed derived from these crops are not materially 

different than the respective conventional crops. The safety of the CP4 EPSPS protein 

has been reviewed by regulatory agencies around the world (ILSI-CERA, 2011; OECD, 

1999; 2002a). Additionally, in 1996 the U.S. EPA established an exemption from the 

requirement of a tolerance for residues of the plant pesticide inert ingredient CP4 EPSPS 

and the genetic material necessary for its production in all plants (40 CFR § 174.523, 

redesignated from § 180.1174, effective April 25, 2007). Prior safety assessments of the 

CP4 EPSPS protein expressed in these other biotechnology-derived crops are directly 

applicable to the MON 87429 CP4 EPSPS protein because the amino acid sequence and 

function of the MON 87429 CP4 EPSPS protein is identical to the CP4 EPSPS proteins 

in these biotechnology-derived crops. The CP4 EPSPS protein has a robust history of safe 

consumption and safe use in agriculture that is supported by the lack of any documented 

reports of adverse human or animal effects since the introduction of biotechnologyderived crops expressing CP4 EPSPS protein.

EPSPS enzymes, including the MON 87429 CP4 EPSPS protein, are highly specific for 

their substrates. The only known substrates of any biological significance for EPSPS 

enzymes are S3P and PEP. Glyphosate is not enzymatically modified by EPSPS. 

Shikimic acid was shown to be a very poor substrate for EPSPS enzyme, requiring much 

higher concentrations to observe turnover by the enzyme than for S3P (Gruys et al., 

1992). Methyl shikimate, quinic acid, and dihydroshikimic acid do not serve as 

substrates for the EPSPS enzyme (Franz et al., 1997). As with most physiological 

pathways, there is tight regulation of metabolic flux through the shikimic acid pathway. 

Pathway flux is regulated both transcriptionally and post-transcriptionally (Maeda and 

Dudareva, 2012; Tzin et al., 2012). The first enzyme in the pathway, 3-deoxy-D-arabinoheptulosonate 7-phosphate synthase (DAHPS), has been identified as the key regulatory 

checkpoint for the flux through the pathway, with possible secondary checkpoints at 

shikimate kinase and chorismate synthase (Maeda and Dudareva, 2012; Tzin et al., 2012). 

Thus, plants, have mechanisms to regulate flux through the shikimate pathway 

irrespective of EPSPS synthase activity levels. Due to both the high substrate specificity 

of EPSPS enzymes and lack of a role as a regulatory enzyme in the shikimic acid 

pathway, there is no plausible mechanism for the modification of endogenous plant 

constituents due to the expression of CP4 EPSPS.

The data and information summarized in this section confirm that the molecular 

mechanism of the MON 87429 CP4 EPSPS protein that confers glyphosate tolerance is 

well understood, that the MON 87429 CP4 EPSPS protein is identical to the CP4 EPSPS 

proteins present in biotechnology-derived crops that have been deregulated by USDAAPHIS and demonstrated to not be materially different than the respective conventional 

crops in consultation with the US FDA, that the MON 87429 CP4 EPSPS protein is 

selective for glyphosate and that the CP4 EPSPS protein does not affect maize 

metabolism. Thus, prior environmental and safety assessments for the CP4 EPSPS 

protein demonstrating a lack of impact on plant pest potential, lack of homology to 

known protein toxins or allergens, digestibility in in vitro digestion assays and lack of 
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acute oral toxicity are directly applicable to the MON 87429 CP4 EPSPS protein and are 

not detailed further herein.

V.D. FT_T Protein Characterization and Safety Assessment 

A multistep approach to the safety assessment of the MON 87429 FT_T proteins was 

conducted according to guidance established by the Codex Alimentarius Commission 

(Codex Alimentarius, 2009) and OECD, which embody the principles and guidance of 

the FDA’s 1992 policy on foods from new plant varieties. The assessment includes: 1) 

documenting the history of safe consumption of the expressed protein or its structural and 

functional homology to proteins that lack adverse effects on human or animal health; 2) 

characterization of the physicochemical and functional properties of each expressed 

protein; 3) quantification of each expressed proteins’ expression in plant tissues; 4) 

examination of the similarity of each expressed protein to known allergens, toxins or 

other biologically active proteins known to have adverse effects on humans and animals; 

5) evaluation of the susceptibility of each expressed protein to the digestive enzymes 

pepsin and pancreatin; 6) a confirmatory evaluation of potential animal toxicity through 

an animal assay. The safety assessment supports the conclusion that exposure to the 

FT_T protein derived from MON 87429 would not pose any meaningful risk to human or 

animal health or the environment.

V.D.1. Identity and Function of the FT_T protein from MON 87429

The FT_T protein produced in MON 87429 is encoded by the ft_t gene that provides 

tolerance to aryloxyalkanoate herbicides. Aryloxyalkanoate herbicides include the 

aryloxyphenoxypropionate acetyl coenzyme A carboxylase (ACCase) inhibitors (so 

called “FOPs” herbicides such as quizalofop) and some synthetic auxins, such as 2,4-D. 

The ft_t gene in MON 87429 is a modified version of the R-2,4-

dichlorophenoxypropionate dioxygenase (Rdpa) gene from the soil bacteria Sphingobium

herbicidovorans. The amino acid sequence of the FT_T protein shares ~ 89% sequence 

identity with wild type RdpA (Figure V-2). A total of 30 amino acid substitutions 

throughout the protein sequence resulted in FT_T displaying improved enzyme kinetics 

(increased Vmax) and substrate affinity (reduced Km) for 2,4-D, relative to RdpA 

(Appendix G, Table G-1). The amino acid modifications also resulted in FT_T protein 

displaying retained activity at temperatures experienced during the summer months in 

maize growing areas compared to RdpA protein (Appendix G, Table G-1). 
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1 AMHAALTPLT NKYRFIDVQP LTGVLGAEIT GVDLREPLDD STWNEILDAF

51 HTYQVIYFPG QAITNEQHIA FSRRFGPVDP VPILKSIEGY PEVQMIRREA

101 NESSRFIGDD WHTDSTFLDA PPAAVVMRAI EVPEYGGDTG FLSMYSAWET

151 LSPTMQATIE GLNVVHSATK VFGSLYQATN WRFSNTSVKV MDVDAGDRET

201 VHPLVVTHPV TGRRALYCNQ VYCQKIQGMT DAESKSLLQF LYEHATKFDF

251 TCRVRWKKDQ VLVWDNLCTM HRAVPDYAGK FRYLTRTTVA GDKPSR

Figure V-2 Deduced Amino Acid Sequence of the FT_T Protein

The amino acid sequence of the MON 87429 FT_T protein was deduced from the full-length 

coding nucleotide sequence present in PV-ZMHT519224 (See Table III-1 for more detail). The 

double underline shows the alanine amino acid from the CTP MDH that is the N-terminus of the 

mature FT_T protein. The single underline shows the 30 amino acid substitutions in FT_T. The 

number counts start from methionine corresponding to start codon. The substitutions are S6T, 

S9T, Q10N, R11K, F12Y, E13R, R14F, A16D, L82I, G103S, V105F, D130E, H134Y, T145S, 

R169K, Q178T, R180W, G209V, S210T, K213R, G214A, V217C, R224K, E226Q, P235S, 

R246K, G289A, V291D, R292K, and A294S, where the first letter denotes the original amino 

acids followed by the position and the new amino acid.

RdpA protein is an alpha-ketoglutarate-dependent non-heme iron dioxygenase (Müller et 

al., 2006), and given their structural similarity, the FT_T protein is also an alphaketoglutarate-dependent non-heme iron dioxygenase. Alpha-ketoglutarate-dependent 

non-heme iron dioxygenases belong to a diverse superfamily of Fe(II)/alphaketoglutarate dependent hydroxylases that catalyze a range of oxygenation reactions in 

synthesis and decomposition reactions that include hydroxylation reactions, 

desaturations, demethylations, ring expansions, ring formations and other oxidative 

reactions (Hausinger, 2004). This protein superfamily is broadly distributed across the 

plant, animal and bacterial kingdoms, therefore environmental exposure to 

Fe(II)/alpha-ketoglutarate dependent hydroxylases is ubiquitous. Members of this 

superfamily share a common double-stranded, beta-helix protein fold with three metalbinding ligands found in a His1-X-Asp/Glu-Xn-His2 motif (Hausinger, 2004). In 

oxygenation reactions, alpha-ketoglutarate (αKG) chelates Fe(II) using its C1 carboxylate 

and C2-ketone. Decarboxylation of αKG results in the formation of succinate and carbon 

dioxide, which leads to the generation of an Fe(IV)-oxo or other activated oxygen species 

that subsequently hydroxylate the primary substrate, e.g., quizalofop (Bugg, 2003; 

Carolis and Luca, 1994; Hausinger, 2004). Thus, the FT_T protein catalyzes a 

dioxygenase reaction in the presence of αKG and oxygen to metabolize quizalofop, a 

FOP herbicide, into the herbicidally-inactive quizalofop phenol and pyruvate (Figure 

V-3). The FT_T protein also catalyzes the dioxygenase reaction that degrades 2,4-

dichlorophenoxyacetic acid (2,4-D), a synthetic auxin herbicide, into herbicidallyinactive 2,4-dichlorophenol (2,4-DCP) and glyoxylic acid in the presence of alphaketoglutarate and oxygen. Succinate and carbon dioxide are released as products of this 

reaction (Figure V-3). The safety of 2,4-D, quizalofop, and their relevant metabolites 
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have been assessed by US EPA. US EPA concluded that there is a reasonable certainty 

that no harm will result to the general population, or to infants and children from 

aggregate exposure to 2,4-D (U.S. EPA, 2017a) or quizalofop (U.S. EPA, 2018) residues 

or their metabolites.

Figure V-3. Substrate and Metabolites of FT_T Protein Reaction with Quizalofop 

(left) and 2,4-D (right)

V.D.2. Characterization and Equivalence of FT_T protein from MON 87429

The safety assessment of crops derived through biotechnology includes characterization 

of the physicochemical and functional properties of the introduced protein(s) produced 

from the inserted DNA and accompanied by various assessments to confirm the safety of 

the protein(s). For safety data generated using E. coli-produced protein(s) to be applied 

to plant-produced protein(s), the equivalence of the plant- and E. coli-produced proteins 

must be assessed. 

The MON 87429-produced FT_T protein purified from grain of MON 87429 was 

characterized and the equivalence of the physicochemical and functional properties 

between the MON 87429-produced FT_T and E. coli-produced MON 87429 FT_T 

proteins was established using a panel of analytical tests: 1) N-terminal sequence 

analysis of MON 87429-produced FT_T determined the expected N-terminal sequence; 

2) Nanoscale liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis 

yielded peptide masses consistent with the expected peptide masses from the theoretical 

trypsin digest of the MON 87429-produced FT_T sequence; 3) western blot analysis with 

an antibody specific for FT_T protein demonstrated that the immunoreactive properties 

of the MON 87429-produced FT_T and E. coli-produced MON 87429 FT_T were 

equivalent; 4) SDS-PAGE analysis showed that the electrophoretic mobility and apparent 

molecular weight of the MON 87429-produced FT_T and E. coli-produced MON 87429 

FT_T proteins were equivalent; 5) MON 87429-produced FT_T and E. coli-produced 

MON 87429 FT_T proteins were both determined to be non-glycosylated; and 6) 

functional activity analysis demonstrated that MON 87429-produced FT_T and 
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E. coli-produced MON 87429 FT_T proteins had equivalent enzymatic activity (See 

Appendix D).

Taken together, these data provide a detailed and thorough characterization of the 

MON 87429-produced FT_T protein and establish its equivalence to E. coli-produced 

MON 87429 FT_T protein. This equivalence justifies the use of the E. coli-produced 

MON 87429 FT_T protein in studies to assess the safety of the FT_T protein expressed in 

MON 87429.

V.D.3. FT_T Protein Donor Organism and History of Safe Use

MON 87429 contains the ft_t gene, a modified version of the Rdpa gene from 

Sphingobium herbicidovorans, that expresses the FT_T protein. FT_T is a modified 

version of the R-2,4-dichlorophenoxypropionate dioxygenase (RdpA) protein (Müller et 

al., 2006). S. herbicidovorans is a common gram-negative, rod-shaped, non-motile, nonspore-forming soil bacterium (Takeuchi et al., 2001; Zipper et al., 1996), which is strictly 

aerobic and chemo-organotrophic, and not known to be associated with human disease. 

The taxonomy of S. herbicidovorans is:

Kingdom: Bacteria

Phylum: Proteobacteria

Class: Alphaproteobacteria

Order: Sphingomonadales

Family: Sphingomonadaceae

Genus: Sphingobium

Members of the genus Sphingobium have been isolated from a wide variety of habitats 

including soil and freshwater (Chaudhary et al., 2017). Sphingobium species have also 

been isolated from foods such as corn (Rijavec et al., 2007), papaya (Thomas et al., 2007)

and tomato (Enya et al., 2006). Thus, there is wide-spread human and animal exposure to 

the Sphingobium species in the environment without any known adverse safety or 

allergenicity reports.

As noted in Section V.D.1, the FT_T protein shares the common high order structure of 

alpha-ketoglutarate-dependent dioxygenases that contains a classical dioxygenase active 

pocket including an iron atom coordinated by two histidine residues and one aspartic acid 

or glutamate residue (Hausinger, 2004). These alpha-ketoglutarate-dependent 

dioxygenases have been identified in a broad range of organisms including bacteria, 

fungi, plants, and vertebrates, which have been extensively consumed by both humans 

and animals (Hausinger, 2004; Kundu, 2012) without any reports of adverse effects.

V.D.4. FT_T Protein Catalyzes a Specific Enzyme Reaction

Whereas the amino acid modifications described in Section V.D.1 present in the FT_T 

protein, relative to wild type RdpA from S. herbicidovorans, improved enzymatic 

activity, substrate affinity and retained activity at increased temperatures, they did not 

alter the specificity of the FT_T protein for its substrate. To confirm FT_T protein 

substrate specificity was not impacted by the optimization, an endogenous substrate 
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specificity assessment was conducted. Endogenous plant small molecules with similar 

structures to known FT_T substrates, which are compatible with the FT_T enzymatic 

active site, were investigated as potential substrates. 

The screening approach, detailed in Appendix G, utilized a three-step process: Step 1, the 

NAPRALERT8database, which includes plant specific small molecule datasets collected 

from several crop plant species including corn (Bisson et al., 2016), was utilized to 

identify small molecules with structural similarity to dichlorprop, a synthetic auxin

herbicide that has the most basic structure of the herbicidal aryloxyalkanoate compounds. 

In Step 2, selected compounds were then subjected to in silico protein-small molecule 

docking simulations using the structure of the coordinated FT_T active site that was 

determined by crystallography. This step resulted in the identification of 38 compounds 

that showed potential docking to the FT_T active site in silico. In Step 3, 32

commercially available compounds out of the 38 compounds identified in Step 2, 11 

herbicide control compounds and cinnamate (a compound identified as a marginal 

substrate in a similar enzyme family (Griffin et al., 2013)) were screened as potential 

substrates in vitro by measuring the functional response of purified FT_T protein. The 

list of compounds assayed, and results can be found in Table V-1.

Table V-1. In Vitro FT_T Enzymatic Activity Assay Compound List

Pub

Chem ID1 Chemical Name1

Common

Name1 Tag2

Rel. 

Activity3

5484172

(2R)-2-[4-[(6-chloro-2-

quinoxalinyl)oxy]phenoxy]propanoic acid Quizalofop-P Herbicide 100%

185588

(2R)-2-(4-chloro-2-

methylphenoxy)propanoic acid Mecoprop-P Herbicide 69%

91701

2-[4-[[5-(trifluoromethyl)-2-

pyridinyl]oxy]phenoxy]propanoic acid Fluazifop Herbicide 53%

15118048

(2R)-2-[4-(4-cyano-2-

fluorophenoxy)phenoxy]propanoic acid Cyhalofop Herbicide 35%

8427 2-(2,4-dichlorophenoxy)propanoic acid Dichlorprop Herbicide 21%

1486 2-(2,4-dichlorophenoxy)acetic acid 2,4-D Herbicide 19%

50895

2-[4-[[3-chloro-5-(trifluoromethyl)-2-

pyridinyl]oxy]phenoxy]propanoic acid Haloxyfop Herbicide 19%

86134

2-[4-[(6-chloro-1,3-benzoxazol-2-

yl)oxy]phenoxy]propanoic acid Fenoxaprop Herbicide 15%

7204 2-(4-chloro-2-methylphenoxy)acetic acid MCPA Herbicide 15%

 

8 https://napralert.org/
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Pub

Chem ID1 Chemical Name1

Common

Name1 Tag2

Rel. 

Activity3

50465

2-[(4-amino-3,5-dichloro-6-fluoro-2-

pyridinyl)oxy]acetic acid Fluroxypyr Herbicide 8%

41428

2-[(3,5,6-trichloro-2-pyridinyl)oxy]acetic 

acid Triclopyr Herbicide 3%

4947 3,4,5-trihydroxybenzoic acid propyl ester Propyl gallate Endogenous 1%

637775

(E)-3-(4-hydroxy-3,5-dimethoxyphenyl)-2-

propenoic acid Sinapate Endogenous < 1%

7127 1,2-dimethoxy-4-prop-2-enylbenzene Methyl Eugenol Endogenous < 1%

1548883

(Z)-3-(4-hydroxy-3-methoxyphenyl)-2-

propenoic acid Ferulic acid Endogenous < 1%

21685 2,6-di(butan-2-yl)phenol N/A Endogenous < 1%

445858

(E)-3-(4-hydroxy-3-methoxyphenyl)-2-

propenoic acid Ferulic acid Endogenous < 1%

75318 2-ethoxycarbonylbenzoic acid Monoethylphalate Endogenous < 1%

5281166

2-[(1R,2R)-3-oxo-2-[(Z)-pent-2-

enyl]cyclopentyl]acetic acid Jasmonic acid Endogenous < 1%

13988328

8-Hydroxy-2-oxo-1,2-dihydroquinoline-4-

carboxylic acid

2,8-dihydroxy-4-

quinolinecarboxyl

ic acid Endogenous < 1%

6140 (2S)-2-amino-3-phenylpropanoic acid Phenylalanine Endogenous < 1%

736186

(E)-3-(3-hydroxy-4-methoxyphenyl)-2-

propenoic acid Isoferulic acid Endogenous < 1%

10742 4-hydroxy-3,5-dimethoxybenzoic acid Syringic acid Endogenous < 1%

802 2-(1H-indol-3-yl)acetic acid

Indole-3-acetic 

acid Endogenous < 1%

637542 (E)-3-(4-hydroxyphenyl)-2-propenoic acid

4-

Hydroxycinnamic 

acid Endogenous < 1%

730037 4-(1H-indol-3-yl)-4-oxobutanoic acid N/A Endogenous < 1%

325 (4-propan-2-ylphenyl)methanol

4-

Isopropylbenzyl 

alcohol Endogenous < 1%

8554

benzene-1,2-dicarboxylic acid dimethyl 

ester

Dimethyl 

phthalate Endogenous < 1%

60961

(2R,3R,4S,5R)-2-(6-aminopurin-9-yl)-5-

(hydroxymethyl)oxolane-3,4-diol Adenosine Endogenous < 1%
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Pub

Chem ID1 Chemical Name1

Common

Name1 Tag2

Rel. 

Activity3

12474015 3-ethyl-5-methoxy-1H-indole N/A Endogenous < 1%

896

N-[2-(5-methoxy-1H-indol-3-

yl)ethyl]acetamide Melatonin Endogenous < 1%

13067 2-(1H-indol-3-yl)acetic acid ethyl ester

Ethyl 3-

indoleacetate Endogenous < 1%

637758 (E)-3-phenyl-2-propenoic acid ethyl ester Ethyl cinnamate Endogenous < 1%

6781 benzene-1,2-dicarboxylic acid diethyl ester Diethyl phthalate Endogenous < 1%

17355 4-phenyl-2-butanone Benzylacetone Endogenous < 1%

3314 2-methoxy-4-prop-2-enylphenol Eugenol Endogenous < 1%

62428 2-(1-naphthalenyl)acetic acid ethyl ester

Ethyl 1-

naphthaleneacetat

e Endogenous < 1%

6057

(2S)-2-amino-3-(4-

hydroxyphenyl)propanoic acid Tyrosine Endogenous < 1%

10364 2-methyl-5-propan-2-ylphenol Carvacrol Endogenous < 1%

6305

(2S)-2-amino-3-(1H-indol-3-yl)propanoic 

acid Tryptophan Endogenous < 1%

444539 (E)-3-phenylprop-2-enoic acid Trans-cinnamate Literature < 1%

77021 2,7-dimethoxynaphthalene N/A Endogenous < 1%

689043

(E)-3-(3,4-dihydroxyphenyl)-2-propenoic 

acid Caffeic acid Endogenous < 1%

3080590 2-(2-oxo-1,3-dihydroindol-3-yl)acetic acid

2-oxoindole-3-

acetate Endogenous < 1%

1 The PubChem ID, Chemical Name, Common Name (if available) and Tag are provided (N/A is not 

available). https://pubchem.ncbi.nlm.nih.gov/.

2 The column “Tag” indicates which compounds are herbicides (Herbicide), endogenous compound 

(Endogenous) or literature reported (Literature).

3The activity of triplicate assays (each with 3 replicates; n= 9) for FT_T activity reported as relative activity,

which is the observed activity of the compound relative to quizalofop-P reported as a percentage. Initial 

velocities were first normalized in each test set against 2,4-D (positive control in each assay) and then 

across experiments against quizalofop-P.
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Eleven herbicide controls were included in the assay. As expected, FT_T protein activity 

was detected in the presence of the 11 herbicide control compounds. The measured 

FT_T activity for all 32 endogenous plant compounds and cinnamate was ≤ 1% relative 

to quizalofop. These data suggest that FT_T protein is specific to substrate molecules 

with the following structural features: (1) existence of phenoxy group (2) presence of 

terminal carboxylate, and (3) available site for oxidation between the phenoxy group and 

terminal carboxylate. Endogenous plant small molecules with all three features did not 

exist in the NAPRALERT database, including the six compounds identified in the in 

silico Step 2 above that were not commercially available to test in vitro. Therefore, the 

FT_T enzyme is unlikely to metabolize endogenous small molecules in maize plants at 

biologically relevant activity levels.

V.D.5. FT_T Protein in MON 87429 is Not Homologous to Known Allergens or 

Toxins

Bioinformatics analyses were performed to assess the potential for allergenicity, toxicity, 

or biological activity of FT_T protein. The allergen bioinformatic results demonstrated 

there were no biologically relevant sequence similarities to allergens when the FT_T 

protein sequence was used as a query for a FASTA search of the publicly available 

allergen (AD_2018) database. Furthermore, no short (eight amino acid) polypeptide 

matches were shared between the FT_T protein sequence and proteins in the allergen 

database. These data show that FT_T protein sequence lacks both structurally and 

immunologically relevant similarities to known allergens, gliadins, and glutenins. 

FASTA bioinformatic alignment searches using the FT_T amino acid sequence were 

performed with a toxin database to identify possible homology with proteins that may be 

harmful to human and animal health. The toxin database, TOX_2018, is a subset of 

sequences derived from the PRT_2018 database, that was selected using a keyword 

search and filtered to remove likely non-toxin proteins. The TOX_2018 database 

contains 28,344 sequences. The results of the bioinformatic analyses demonstrated that 

no structurally relevant similarity exists between the FT_T protein and any sequence in 

the TOX_2018 database.

These analyses demonstrated that FT_T protein does not share amino acid sequence 

similarities with known allergens, gliadins, glutenins, or protein toxins which could have 

adverse effects on human or animal health.

V.D.6. FT_T Protein in MON 87429 is Susceptible to Degradation in in vitro

Digestion Assay

The susceptibility to degradation by pepsin and pancreatin of MON 87429-produced 

FT_T was assessed using the E. coli-produced MON 87429 FT_T, which was shown to 

be equivalent to the MON 87429-produced FT_T (see Appendix D). The results 

indicated that the full-length, E. coli-produced FT_T protein is readily degraded by 

pepsin and pancreatin. Transient peptide fragments of ~4 kDa that were resistant (i.e., 

present over the course of the 60 min digestive reaction) to pepsin degradation were 

observed. To better understand the fate of the transiently-stable peptide fragments, 

sequential degradation of the FT_T protein in pepsin followed by pancreatin was 
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conducted. The results indicated that the transient fragments are readily degraded by 

sequential digestion (see Appendix N). Thus, evidence supports the conclusion that 

gastrointestinal digestion is sufficient to degrade the intact FT_T protein and any 

fragments thereof making it highly unlikely that intact or large peptide fragments of 

FT_T protein would be absorbed in the small intestine and have the potential to impact 

human or animal health.

V.D.7. FT_T Protein in MON 87429 is Not Acutely Toxic

An acute oral toxicology study with FT_T protein was conducted to provide further 

confirmation of the safety of this protein. There was no evidence of acute toxicity in 

mice when dosed orally at 2000 mg/kg body weight with FT_T protein. Based on an 

absence of toxicity in the acute oral toxicity study with the FT_T protein and the 

relatively low dietary exposure to the protein (i.e., low expression levels of FT_T protein 

present in MON 87429 grain (Section V.E.4 Table V-6), the risks to humans and animals 

following dietary exposure to the FT_T protein from consumption of food or feeds 

derived from MON 87429 is very low.

V.D.8. Assessment of Potential Allergenicity of the FT_T Protein

The allergenic potential of an introduced protein is assessed by comparing the 

biochemical characteristics of the introduced protein to biochemical characteristics of 

known allergens (Codex Alimentarius, 2009). Using a weight of evidence approach, a 

protein is not likely to be associated with allergenicity if: 1) the protein is from a 

non-allergenic source; 2) the protein represents a small portion of the total plant protein; 

3) the protein does not share structural similarities to known allergens based on the amino 

acid sequence; and 4) the protein shows susceptibility to pepsin and pancreatin 

treatments. 

The FT_T protein has been assessed for its potential allergenicity according to these 

safety assessment guidelines.

1) FT_T protein originates from S. herbicidovorans, an organism that has not been 

reported to be a source of known allergens. 

2) FT_T protein represents a small portion of the total protein in the grain that could 

be consumed from MON 87429 maize due to very low expression in grain.

3) Bioinformatics analyses demonstrated that FT_T protein does not share amino 

acid sequence similarities with known allergens and, therefore, is highly unlikely to 

contain immunologically cross-reactive allergenic epitopes. 

4) Finally, in vitro experiments conducted with the FT_T protein demonstrated that 

the protein is rapidly digested by proteases found in the human gastrointestinal tract 

(pepsin and pancreatin) under physiological conditions. 

Taken together, these data support the conclusion that FT_T protein produced in 

MON 87429 does not pose a significant allergenic risk to humans or animals.
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V.D.9. Human and Animal Exposure to the FT_T Protein

Based on the non-toxic mode-of-action of the FT_T protein, its susceptibility to the 

digestive enzymes pepsin and pancreatin, the relatively low dietary exposure to the 

protein (i.e., low expression levels of FT_T protein present in MON 87429 grain), and 

based on an absence of toxicity in a confirmatory acute oral toxicity study, it is unlikely 

that exposure to the FT_T protein in food and feed products derived from MON 87429 

pose a risk to human and animal health.

V.E. Expression Levels of DMO, PAT, CP4 EPSPS and FT_T Proteins Produced in 

MON 87429

The protein expression levels determined in MON 87429 are used to assess exposure to 

the introduced proteins via food or feed ingestion and potential environmental 

exposure. The most appropriate tissues to evaluate DMO, PAT, CP4 EPSPS and FT_T 

protein levels are forage, leaf, root and grain tissue samples. Levels of the introduced 

proteins were determined in forage, leaf, root and grain tissue and were used as 

appropriate to evaluate potential food, feed and environmental exposures.

MON 87429 DMO, PAT, CP4 EPSPS and FT_T protein levels in various tissues of 

MON 87429 relevant to the characterization and risk assessment were determined using a 

multiplexed immunoassay. In addition, to further support the MON 87429 RHS trait 

mode-of-action (MOA), levels of CP4 EPSPS expression in pollen tissue was determined 

to demonstrate the differential expression between vegetative and pollen tissue. Tissues 

of MON 87429 were collected from four replicate plots planted in a randomized 

complete block design during the 2017 growing season at five field sites in the U.S. The 

field sites were representative of maize-producing regions suitable for commercial 

production. Forage, leaf, root, grain and pollen tissue samples were collected from plants 

at each replicated plot at all field sites treated with dicamba, glufosinate, quizalofop and 

2,4-D herbicides (Appendix F).

V.E.1. Expression Level of DMO Protein

MON 87429 DMO protein levels were determined in forage, leaf, root and grain tissues. 

The results obtained from the multiplexed immunoassay are summarized in Table V-2

and the details of the materials and methods are described in Appendix F. The mean 

DMO protein level in MON 87429 across all sites was highest in leaf at 35 μg/g dw and 

lowest in root at 2.3 μg/g dw. The mean DMO protein level in MON 87429 grain was 

2.4 μg/g dw.
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Table V-2. Summary of DMO Protein Levels in Maize Tissues Collected 

from MON 87429 Produced in United States Field Trials During 2017

Tissue

Type

Development

Stage

Mean (SE)

Range

(μg/g dw)1

LOQ2

(μg/g dw)

Forage R5 21 (1.6)

9.1-32

0.14

Leaf V2-V4 35 (2.3)

16-55 

0.14

Grain R6 2.4 (0.15)

1.3-3.6 

0.14

Root V2-V4 2.3 (0.27)

1.0-5.2 

0.14

1Protein levels are expressed as the arithmetic mean and standard error (SE) as microgram (μg) of 

protein per gram (g) of tissue on a dry weight basis (dw). The means, SE, and ranges (minimum 

and maximum values) were calculated for each tissue across all sites (n=20). 

2 LOQ=limit of quantitation.

V.E.2. Expression Level of PAT Protein

PAT protein levels were determined in forage, leaf, root and grain tissues. The results 

obtained from the multiplexed immunoassay are summarized in Table V-3 and the details 

of the materials and methods are described in Appendix F. The mean PAT protein level 

in MON 87429 across all sites was highest in leaf at 5.8 μg/g dw and lowest in grain at 

0.84 μg/g dw. 
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Table V-3. Summary of PAT Protein Levels in Maize Tissues Collected 

from MON 87429 Produced in United States Field Trials During 2017

Tissue

Type

Development

Stage

Mean (SE)

Range

(μg/g dw)1

LOQ2

(μg/g dw)

Forage R5 1.3 (0.067)

0.71-1.8

0.03

Leaf V2-V4 5.8 (0.40)

2.9-9.8

0.03

Grain R6 0.84 (0.066)

0.32-1.5

0.03

Root V2-V4 2.0 (0.15)

0.40-3.1 0.03

1Protein levels are expressed as the arithmetic mean and standard error (SE) as microgram (μg) of 

protein per gram (g) of tissue on a dry weight basis (dw). The means, SE, and ranges (minimum 

and maximum values) were calculated for each tissue across all sites (n=20). 

2 LOQ=limit of quantitation.

V.E.3. Expression Level of CP4 EPSPS Protein

CP4 EPSPS protein levels were determined in forage, leaf, root and grain tissues. The 

results obtained from the multiplexed immunoassay are summarized in Table V-4. CP4 

EPSPS protein levels were also determined in pollen to further demonstrate the 

differential expression between vegetative and pollen tissue resultant from the 

MON 87429 RHS trait mode-of-action (MOA). The results obtained from the 

multiplexed immunoassay are summarized in Table V-5. The details of the materials and 

methods for these analyses are described in Appendix F. The mean CP4 EPSPS protein 

level in MON 87429 across all sites was the highest in leaf at 54 μg/g dw and lowest in 

grain at 0.63 μg/g dw. The mean CP4 EPSPS protein level in MON 87429 pollen across 

all sites was below the limit of quantitation (<LOQ).
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Table V-4. Summary of CP4 EPSPS Protein Levels in Maize Tissues Collected 

from MON 87429 Produced in United States Field Trials During 2017

Tissue

Type

Development

Stage

Mean (SE)

Range

(μg/g dw)1

LOQ2

(μg/g dw)

Forage R5 7.6 (0.50)

4.0 - 11 0.30

Leaf V2-V4 54 (3.2)

30- 82 

0.11

Grain R6 0.63 (0.028)

0.41- 0.85 

0.34

Root V2-V4 10 (1.7)

3.4 - 29 

0.11

1Protein levels are expressed as the arithmetic mean and standard error (SE) as microgram (μg) of 

protein per gram (g) of tissue on a dry weight basis (dw). The means, SE, and ranges (minimum 

and maximum values) were calculated for each tissue across all sites (n=20).

2 LOQ=limit of quantitation.

Table V-5. Summary of CP4 EPSPS Protein Levels in Maize Pollen Tissue 

Collected from MON 87429 Produced in United States Field Trials During 2017

Tissue

Type

Development

Stage

Mean (SE)

Range

(μg/g dw)1

LOQ2

(μg/g dw)

Pollen R1 <LOQ 0.11

1Protein levels are expressed as the arithmetic mean and standard error (SE) as microgram (μg) of 

protein per gram (g) of tissue on a dry weight basis (dw). The means, SE, and ranges (minimum 

and maximum values) were calculated for each tissue across all sites (n=20). Over 50% of the 

samples (12 of 20) were <LOQ and so < LOQ is reported here. 

2LOQ=limit of quantitation.
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V.E.4. Expression Level of FT_T Protein

FT_T protein levels were determined in forage, leaf, root and grain tissues. The results 

obtained from the multiplexed immunoassay are summarized in Table V-6 and the details 

of the materials and methods are described in Appendix F. The mean FT_T protein level 

in MON 87429 across all sites was the highest in leaf at 440 μg/g dw and lowest in 

root at 41 μg/g dw. The mean FT_T protein level in MON 87429 grain was 47 μg/g dw.

Table V-6. Summary of FT_T Protein Levels in Maize Tissues Collected 

from MON 87429 Produced in United States Field Trials During 2017

Tissue

Type

Development

Stage

Mean (SE)

Range

(μg/g dw)1

LOQ2

(μg/g dw)

Forage R5 97 (5.2)

56 - 140 0.036

Leaf V2-V4 440 (25)

210 - 670 0.036

Grain R6 47 (3.6)

19 - 79 0.036

Root V2-V4 41 (4.1)

7.2 - 82 0.036

1Protein levels are expressed as the arithmetic mean and standard error (SE) as microgram (μg) of 

protein per gram (g) of tissue on a dry weight basis (dw). The means, SE, and ranges (minimum 

and maximum values) were calculated for each tissue across all sites (n=20). 

2 LOQ=limit of quantitation.

V.F. MON 87429 DMO, PAT, CP4 EPSPS and FT_T Proteins Characterization and 

Safety Conclusion

MON 87429 DMO is an enzyme that catalyzes the demethylation of dicamba to the 

non-herbicidal compound 3,6-dichlorosalicylic acid (DCSA) and formaldehyde. DMO 

proteins have been previously characterized, and the safety of these proteins and crops 

expressing these proteins has been well established. Expression studies using 

immunoassay demonstrated that DMO was expressed at low levels in grain. Taken 

together, the evidence indicates that the consumption of the DMO protein from 

MON 87429 or its progeny is safe for humans and animals.

PAT protein is an acetyltransferase that catalyzes the acetylation of the herbicide 

glufosinate. PAT proteins, including the PAT protein isolated from MON 87429, have 

been previously characterized, and the safety of these proteins and crops expressing these 

proteins has been well established. Expression studies using immunoassay demonstrated 
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that PAT was expressed at low levels in grain. Taken together, the evidence indicates 

that the consumption of the PAT protein from MON 87429 or its progeny is safe for 

humans and animals.

Members of the EPSPS protein family, including CP4 EPSPS, are enzymes which 

catalyze a key step in aromatic amino acid biosynthesis and catalyzes the reaction where 

the enolpyruvyl group from phosphoenol pyruvate (PEP) is transferred to the 5-hydroxyl 

of shikimate-3-phosphate to form 5-enolpyruvylshikimate-3-phosphate (EPSP) and 

inorganic phosphate. CP4 EPSPS proteins, including the CP4 EPSPS protein isolation 

from MON 87429, have been previously characterized, and the safety of these proteins 

and crops expressing these proteins has been well established. Expression studies using 

immunoassay demonstrated that CP4 EPSPS was expressed at low levels in grain. Taken 

together, the evidence indicates that the consumption of the CP4 EPSPS protein from 

MON 87429 or its progeny is safe for humans and animals.

The FT_T protein is an alpha-ketoglutarate-dependent non-heme iron dioxygenase that 

catalyzes a dioxygenase reaction in the presence of alpha-ketoglutarate (αKG) and 

oxygen by incorporating oxygen into quizalofop, thus degrading it into the herbicidallyinactive quizalofop phenol and pyruvate, while maintaining specificity for its substrate. 

The physicochemical characteristics of the MON 87429-produced FT_T protein were 

determined and equivalence between MON 87429-produced FT_T and E. coli-produced 

FT_T proteins was demonstrated. This equivalence justifies the use of the E. 

coli-produced FT_T as a test substance in the protein safety studies (acute oral toxicity 

and digestibility). Expression studies using immunoassay demonstrated that FT_T was 

expressed at low levels in grain. The FT_T protein lacks structural similarity to 

allergens, toxins or other proteins known to produce adverse effects in mammals. In 

addition, the ubiquitous presence of Sphingobium species in the environment has resulted 

in widespread human and animal exposure and is not commonly known for allergenicity 

and human or animal pathogenicity. The FT_T protein is rapidly digested by proteases 

found in the human gastrointestinal tract (pepsin and pancreatin) and demonstrated no 

acute oral toxicity in mice at the high dose tested. Based on the above information, the 

consumption of the FT_T protein in foods derived from MON 87429 or its progeny is 

considered safe for humans and animals.

The protein safety data presented herein support the conclusion that food and feed 

products containing MON 87429 or derived from MON 87429 are as safe for human and 

animal consumption as maize currently on the market and expression of the DMO, PAT, 

CP4 EPSPS and FT_T proteins in MON 87429 does not impact the weediness or plant 

pest risk of MON 87429 maize.
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VI. COMPOSITIONAL ASSESSMENT OF MON 87429

Food and feed safety assessments of biotechnology-derived crops follow the comparative 

safety assessment process (Codex Alimentarius, 2009) in which the composition of grain 

and/or other raw agricultural commodities of the biotechnology-derived crop are 

compared to the appropriate conventional control that has a history of safe use. Maize is 

not known to have any endogenous toxicants or antinutrients associated with overall plant 

pest potential (OECD, 2002b). For MON 87429, the introduced proteins, DMO, PAT, 

CP4 EPSPS and FT_T, confer herbicide tolerance and lack catalytic activity that is 

intended to or expected to affect the plant’s metabolism. Given the nature of these 

introduced traits and the overall lack of meaningful unintended compositional 

characteristics observed for biotechnology-derived products characterized to date 

(Herman and Price, 2013; Venkatesh et al., 2015), compositional changes that would 

affect the levels of components in MON 87429 maize were not expected. 

Monsanto is currently in consultation with the Food and Drug Administration following 

their policy, “Foods Derived from New Plant Varieties,” on the food and feed safety of 

MON 87429 maize (Submitted 05-Feb-2019). Samples were collected from 5 field sites 

grown in 2017 that were representative of U.S. maize growing regions. Composition data 

for 25 components including major nutrients in grain (protein, amino acids, total fat, 

linoleic acid, carbohydrates, acid detergent fiber, neutral detergent fiber and ash), major 

nutrients in forage (protein, total fat, carbohydrates, acid detergent fiber, neutral detergent 

fiber and ash) and anti-nutrients in grain (phytic acid and raffinose) were submitted to 

FDA as part of the voluntary food/feed safety and nutritional assessment for MON 87429 

maize. The results of the compositional assessment found that there were no biologically 

meaningful differences between MON 87429 and conventional control and support the 

conclusion that MON 87429 maize is compositionally equivalent to the conventional 

control.

This section provides analyses of concentrations of key nutrients and anti-nutrients in 

grain and forage of MON 87429 compared to that of a conventional control maize hybrid 

grown and harvested under similar conditions. The production of materials for 

compositional analyses used a sufficient variety of field trial sites, reflecting a range of 

environmental conditions under which MON 87429 is expected to be grown and robust 

field designs (randomized complete block design with four replicates). Samples were 

subjected to sensitive analytical methods that allow quantitative and accurate 

measurements of key components. See Appendix M for details on composition methods. 

VI.A. Compositional Equivalence of MON 87429 Grain and Forage to Conventional 

Maize

Grain and forage samples were harvested from MON 87429 and a conventional control 

grown at five sites in the United States during 2017. The field sites were planted in a 

randomized complete block design with four replicates per site. MON 87429 and the 

conventional control were grown under agronomic field conditions typical for each of the 

different growing regions. MON 87429 plots were treated with dicamba, glufosinate, 
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quizalofop and 2,4-D to generate samples under conditions of the intended use of the 

product.

The compositional analysis provided a comprehensive comparative assessment of the 

levels of key nutrients and anti-nutrients in grain and forage of MON 87429 and the 

conventional control. 

Compositional analyses of grain and forage samples are reported for a subset of 

components listed in the maize OECD consensus document (OECD, 2002b). Harvested 

grain samples were assessed for moisture and levels of key nutrients including 

proximates (protein, total fat and ash), essential amino acids (10 components), linoleic 

acid (essential fatty acid), carbohydrates by calculation and fiber (acid detergent fiber 

(ADF) and neutral detergent fiber (NDF)). Grain samples were also assessed for levels 

of antinutrients (phytic acid and raffinose). Harvested forage samples were assessed for 

moisture and levels of nutrients including proximates (protein, total fat and ash), 

carbohydrates by calculation and fiber (ADF and NDF). In all, 27 different components 

were analyzed. Moisture values for grain and forage were measured to enable the

conversion of components from fresh to dry weight but were not statistically analyzed. 

Therefore, 25 components were statistically analyzed.

The statistical comparison of MON 87429 and the conventional control was based on 

compositional data combined across all five field sites. Statistically significant 

differences were identified at the 5% level (α = 0.05). A statistically significant 

difference between MON 87429 and the conventional control does not necessarily imply 

biological relevance from a food and feed safety perspective. Therefore, any statistically 

significant differences observed between MON 87429 and the conventional control were 

evaluated further to determine whether the detected difference indicated a biologically 

relevant compositional change or supported a conclusion of compositional equivalence, 

as follows:

Step 1 – Determination of the Magnitude of Difference between Test (MON 87429) and 

Conventional Control Means

The difference in means between MON 87429 and the conventional control was 

determined for use in subsequent steps. 

Step 2 – Assessment of the Difference in the Context of Natural Variation within the 

Conventional Control across Multiple Sites

The difference between MON 87429 and the conventional control was evaluated in the 

context of variation within the conventional control germplasm grown across multiple 

sites (i.e., variation due to environmental influence) by determining the range of replicate 

values for the conventional control (range value = maximum value minus the minimum 

value). A mean difference less than the variability seen due to natural environmental 

variation within the single, closely related germplasm is typically not a food or feed 

safety concern (Venkatesh et al., 2014).
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Step 3 – Assessment of the Difference in the Context of Natural Variation Due to 

Multiple Sources

The relative impact of MON 87429 on composition was evaluated in the context of 

sources of natural variation such as environmental and germplasm influences. This 

assessment determined whether the component mean value of MON 87429 was within 

the natural variability defined by the literature values or the ILSI Crop Composition 

Database (ILSI-CCDB) values. This natural variability is important in assessing the 

biological relevance to food and feed safety of statistically significant differences in 

composition between MON 87429 and the conventional control.

These evaluations of natural variation are important as crop composition is known to be 

greatly influenced by environment and variety (Harrigan et al., 2010). Although used in 

the comparative assessment process, detection of statistically significant differences 

between MON 87429 and the conventional control mean values does not necessarily 

imply a meaningful contribution by MON 87429 to compositional variability. Only if the 

impact of MON 87429 on levels of components is large relative to natural variation 

inherent to conventional maize would the difference in composition be potentially 

meaningful from a food and feed safety and nutritional perspective. Differences between 

MON 87429 and the conventional control that are within the observed natural variation 

for maize would support a conclusion of compositional equivalence.

Compositional Equivalence of MON 8729 Grain and Forage to that of Conventional 

Maize

There were no statistically significant differences (p<0.05) for 23 of the 25 components 

analyzed from MON 87429 grain and forage (Table VI-1–Table VI-4). There were two 

components (total fat and linoleic acid in grain) that showed a statistically significant 

difference (p<0.05) between MON 87429 and the conventional control (Table VI-1). For 

total fat, the mean value was 3.76 % dw for MON 87429 and 3.88 % dw for the 

conventional control, a difference of -0.15 % dw. For linoleic acid, the mean value was 

55.53 % Total Fatty Acid (FA) for MON 87429 and 55.21 % Total FA for the 

conventional control, a difference of 0.32 % Total FA. For these components, the mean 

difference between MON 87429 and the conventional control was less than the 

conventional control range values and the MON 87429 mean component values were also 

within the range of values observed in the literature and/or the ILSI-CCDB values (Table 

VI-5). 

These data indicated that the statistically significant differences observed in total fat and 

linoleic acid in grain were not biologically meaningful from a food and feed safety 

perspective. These results support the conclusion that MON 87429 was not a major 

contributor to variation in component levels in maize grain or forage and confirmed the 

compositional equivalence of MON 87429 to the conventional control in levels of key 

nutrients and anti-nutrients in grain and forage.
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Table VI-1. Summary of Maize Grain Proximates, Linoleic Acid, Carbohydrates by Calculation and Fiber for MON 87429

and Conventional Control

Difference (Test minus Control)

Component

MON 87429

Mean (S.E.)1

Range

Control

Mean (S.E.)

Range

Control Range

Value2

Mean

(S.E.) p-Value

Protein (% dw)39.20 (0.30)

7.95 - 10.99

9.35 (0.30)

8.04 - 11.01

2.96 -0.15 (0.14) 0.289

Total fat (% dw) 3.76 (0.050)

3.46 - 4.01

3.88 (0.050)

3.58 - 4.16

0.57 -0.12 (0.045) 0.049

Linoleic acid 

(% Total FA)4

55.53 (0.63)

53.61 - 57.87

55.21 (0.63)

53.28 - 57.38

4.10 0.32 (0.12) 0.018

Ash (% dw) 1.15 (0.057)

0.97 - 1.34

1.15 (0.057)

0.91 - 1.41

0.50 -0.0013 (0.024) 0.958

Carbohydrates by 

calculation (% dw)

85.87 (0.38)

83.97 - 87.27

85.61 (0.38)

83.62 - 87.34

3.73 0.25 (0.15) 0.104

ADF (% dw) 2.63 (0.078)

1.94 - 3.67

2.53 (0.078)

2.28 - 3.03

0.74 0.098 (0.11) 0.378
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Table VI-1. Summary of Maize Grain Proximates, Linoleic Acid, Carbohydrates by Calculation and Fiber for MON 87429

and Conventional Control (continued)

Difference (Test minus Control)

Component

MON 87429

Mean (S.E.)1

Range

Control

Mean (S.E.)

Range

Control Range

Value2

Mean

(S.E.) p-Value

NDF (% dw)37.82 (0.16)

6.97 - 8.63

8.05 (0.16)

6.44 - 9.80

3.36 -0.22 (0.23) 0.339

1Mean (S.E.) = least-square mean (standard error)

2Maximum value minus minimum value for the control maize hybrid

3dw=dry weight

4FA=Fatty Acid
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Table VI-2. Summary of Maize Grain Essential Amino Acids for MON 87429 and Conventional Control

Difference (Test minus Control)

Component 

(% dw)1

MON 87429

Mean (S.E.)2

Range

Control

Mean (S.E.)

Range

Control 

Range

Value3

Mean

(S.E.) p-Value

Arginine 0.45 (0.014)

0.40 - 0.54

0.45 (0.014)

0.38 - 0.51

0.13 0.0047 (0.0068) 0.498

Histidine 0.26 (0.0091)

0.22 - 0.31

0.25 (0.0091)

0.22 - 0.30

0.085 0.0018 (0.0053) 0.739

Isoleucine 0.34 (0.013)

0.30 - 0.43

0.34 (0.013)

0.29 - 0.41

0.12 0.0013 (0.0069) 0.850

Leucine 1.20 (0.054)

0.98 - 1.56

1.22 (0.054)

1.00 - 1.51

0.52 -0.012 (0.027) 0.672

Lysine 0.26 (0.0077)

0.22 - 0.35

0.26 (0.0077)

0.21 - 0.28

0.067 0.0062 (0.0084) 0.499

Methionine 0.20 (0.0067)

0.17 - 0.25

0.20 (0.0067)

0.17 - 0.24

0.065 -0.0040 (0.0026) 0.135
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Table VI-2. Summary of Maize Grain Essential Amino Acids for MON 87429 and Conventional Control (continued)

Difference (Test minus Control)

Component 

(% dw)1

MON 87429

Mean (S.E.)2

Range

Control

Mean (S.E.)

Range

Control 

Range

Value3

Mean

(S.E.) p-Value

Phenylalanine 0.48 (0.020)

0.40 - 0.59

0.48 (0.020)

0.40 - 0.60

0.20 0.0022 (0.010) 0.845

Threonine 0.34 (0.0097)

0.30 - 0.42

0.34 (0.0097)

0.30 - 0.39

0.096 0.0010 (0.0056) 0.853

Tryptophan 0.074 (0.0016)

0.065 - 0.080

0.075 

(0.0016)

0.066 - 0.083

0.017 -0.0012 (0.0016) 0.479

Valine 0.44 (0.015)

0.39 - 0.55

0.44 (0.015)

0.38 - 0.52

0.14 0.0032 (0.0072) 0.656

1dw=dry weight

2Mean (S.E.) = least-square mean (standard error)

3Maximum value minus minimum value for the control maize hybrid
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Table VI-3. Summary of Maize Grain Anti-Nutrients for MON 87429 and Conventional Control

Difference (Test minus Control)

Component (% dw)1

MON 87429

Mean (S.E.)2

Range

Control

Mean (S.E.)

Range

Control Range

Value3

Mean

(S.E.) p-Value

Phytic acid 0.64 (0.060)

0.39 - 0.91

0.67 (0.060)

0.44 - 0.91

0.47 -0.033 (0.032) 0.355

Raffinose 0.15 (0.020)

0.097 - 0.23

0.16 (0.020)

0.11 - 0.26

0.15 -0.010 (0.0056) 0.083

1dw=dry weight

2Mean (S.E.) = least-square mean (standard error)

3Maximum value minus minimum value for the control maize hybrid
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Table VI-4. Summary of Maize Forage Proximates, Carbohydrates by Calculation and Fiber for MON 87429 and 

Conventional Control

Difference (Test minus Control)

Component (% dw)1

MON 87429

Mean (S.E.)2

Range

Control

Mean (S.E.)

Range

Control Range

Value3

Mean

(S.E.) p-Value

Protein 7.10 (0.20)

4.57 - 8.93

7.00 (0.20)

6.03 - 8.21

2.18 0.10 (0.22) 0.654

Total fat 2.93 (0.14)

2.20 - 3.54

2.81 (0.14)

1.58 - 3.41

1.83 0.12 (0.17) 0.507

Carbohydrates by 

calculation

86.32 (0.24)

84.46 - 89.56

86.51 (0.24)

85.04 - 88.11

3.07 -0.19 (0.33) 0.594

ADF 20.59 (0.92)

15.74 - 24.53

21.06 (0.92)

14.63 - 28.26

13.63 -0.47 (0.79) 0.562

NDF 33.63 (1.20)

26.99 - 44.93

34.76 (1.20)

26.95 - 42.49

15.54 -1.13 (1.39) 0.422

Ash 3.65 (0.22)

3.06 - 4.58

3.68 (0.22)

2.80 - 4.72

1.92 -0.034 (0.10) 0.743

1dw=dry weight

2Mean (S.E.) = least-square mean (standard error)

3Maximum value minus minimum value for the control maize hybrid
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Table VI-5. Literature and ILSI-CCDB Database Ranges for Components in Maize 

Grain and Forage 

Tissue Components1 Literature Range2ILSI Range3

Grain Nutrients

Proximates

protein (% dw) 8.27-13.33a; 9.17-12.19b 5.72-17.26

total fat (% dw) 2.95-4.40a; 3.18-4.23b 1.363-7.830

ash (% dw) 1.17-2.01a; 1.27-1.63b 0.616-6.282

Amino Acids

arginine (% dw) 0.34-0.52a; 0.34-0.50b 0.12-0.71

histidine (% dw) 0.25-0.37a; 0.27-0.34b 0.14-0.46

isoleucine (% dw) 0.30-0.48a; 0.32-0.44b 0.18-0.69

leucine (% dw) 1.02-1.87a; 1.13-1.65b 0.64-2.49

lysine (% dw) 0.26-0.33a; 0.28-0.31b 0.129-0.668

methionine (% dw) 0.17-0.26a; 0.16-0.30b 0.11-0.47

phenylalanine (% dw) 0.43-0.72a; 0.45-0.63b 0.24-0.93

threonine (% dw) 0.29-0.45a; 0.31-0.39b 0.22-0.67

tryptophan (% dw) 0.047-0.085a; 0.042-0.07b 0.027-0.215

valine (% dw) 0.42-0.62a; 0.45-0.58b 0.27-0.86

Fatty Acids

linoleic acid (% Total FA) 49.31-64.70a; 56.51-65.65b 34.27-67.68

Carbohydrates By Calculation

carbohydrates by calculation 

(% dw) 81.31-87.06a

; 82.10-85.98b 77.4-89.7

Fiber

ADF (% dw) 1.82-4.48a; 1.83-3.39b 1.41-11.34

NDF (% dw) 6.51-12.28a; 6.08-10.36b 4.28-22.64

Anti-Nutrients

phytic acid (% dw) 0.69-1.09a; 0.60-0.94b 0.111-1.940

raffinose (% dw) 0.079-0.22a; 0.061-0.15b 0.020-0.466

Forage Nutrients

Proximates

protein (% dw) 5.80-10.24a; 5.56-9.14b 3.14-16.32

total fat (% dw) 1.28-3.62a; 0.20-1.76b 0.296-6.755

ash (% dw) 2.67-8.01a; 4.59-6.9b 0.66-13.20

Carbohydrates By Calculation

carbohydrates by calculation 

(% dw) 81.88-89.26a

; 84.11-87.54b 73.3-92.9

Fiber

ADF (% dw) 19.11-30.49a; 20.73-33.39b 9.90-47.39

NDF (% dw) 27.73-49.62a; 31.81-50.61b 20.29-67.80

1dw=dry weight; FA=Fatty Acid.

2Literature range references: a

(Harrigan et al., 2009) (see U.S. Field data);b(Harrigan et al., 2009)

(see Chile field data).

3

ILSI range is from ILSI Crop Composition Database, 2016 (Accessed February 21, 2017).
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VII. PHENOTYPIC, AGRONOMIC, AND ENVIRONMENTAL 

INTERACTIONS ASSESSMENT

This section provides a comparative assessment of the phenotypic, agronomic, and 

environmental interactions characteristics of MON 87429 compared to the conventional 

control. The data support a conclusion that MON 87429 is unlikely to pose a plant pest 

risk. This conclusion is based on the results of multiple evaluations including field and 

laboratory assessments. MON 87429 has been planted in the U.S. under 

permit/notification since 2014 (Appendix A). 

Phenotypic, agronomic, and environmental interactions characteristics of MON 87429

were evaluated in a comparative manner to assess plant pest potential. These assessments 

included seed germination and dormancy characteristics and pollen characteristics in the 

laboratory as well as phenotypic and agronomic characteristics and plant responses to 

abiotic stressors, diseases, and arthropod pests in the field. Results from these 

assessments demonstrate that MON 87429 does not possess 1) increased weediness 

characteristics; 2) increased susceptibility or tolerance to specific abiotic stressors, 

diseases, or arthropod pests; or 3) characteristics that would confer a plant pest risk 

compared to conventional maize.

VII.A. Characteristics Measured for Assessment

In the phenotypic, agronomic, and environmental interactions assessment of 

MON 87429, data were collected to evaluate altered plant pest potential. A detailed 

description of the regulated article phenotype is requested as part of the petition for 

determination of nonregulated status in 7 CFR § 340.6 including differences from the 

unmodified recipient organism that would “substantiate that the regulated article is 

unlikely to pose a greater plant pest risk than the unmodified organism from which it was 

derived.” As part of the characterization of MON 87429, data were collected to provide a 

detailed description of the phenotypic, agronomic, and environmental interactions 

characteristics of MON 87429. A subset of these data represents specific characteristics 

that are typically associated with altered plant pest potential (e.g., seed dormancy, 

lodging, seed loss, and environmental interactions data). 

The plant characterization of MON 87429 encompassed five general data categories: 1) 

seed germination, dormancy, and emergence; 2) vegetative growth; 3) reproductive 

development (including pollen characteristics); 4) lodging and seed retention on the 

plant; and 5) plant responses to abiotic stressors, diseases, and arthropod pests. An 

overview of the characteristics assessed is presented in Table VII-1.

The phenotypic, agronomic, and environmental interactions data were evaluated from a 

basis of familiarity (OECD, 1993) and were comprised of a combination of field and 

laboratory studies conducted by scientists who are familiar with the production and 

evaluation of maize. In each of these assessments, MON 87429 was compared to an 

appropriate conventional control that had a genetic background similar to MON 87429 

but did not possess the inserted traits. In addition, multiple commercial maize hybrids 

developed through conventional breeding and selection (see Appendices H-J and Tables 
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H-1, I-1, and J-1) were included to provide a range of comparative values for each 

characteristic that are representative of the variability in existing commercial maize 

hybrids. Data collected for the various characteristics from the commercial reference 

maize hybrids provide context for interpreting experimental results.

Table VII-1. Phenotypic, Agronomic, and Environmental Interactions 

Characteristics Evaluated in U.S. Field Trials and Laboratory Studies

Data category

Characteristic 

measured

(section where 

discussed)

Evaluation timing (setting 

of evaluation)

Evaluation description 

(measurement endpoints)

Germination, 

dormancy, and 

emergence

Germinated

(VII.C.1)

Day 4 and 7 at OT1

Day 4, 7, and 11 at SOT1 

(Laboratory)

Percentage of seed with a radicle 

protruding through the seed coat 

and greater than 1 mm in length

Dead 

(VII.C.1)

Day 4 and 7 at OT 

Day 4, 7, and 11 at SOT 

(Laboratory)

Percentage of seed that had 

visibly deteriorated and become 

soft to the touch (also included 

non-viable hard and non-viable 

firm-swollen seed)

Viable firm-swollen

(VII.C.1)

Day 7 at OT

Day 11 at SOT 

(Laboratory)

Percentage of seed that imbibed 

water and were firm to the touch 

but lacked any evidence of 

growth (viability determined by a 

tetrazolium test) 

Viable hard

(VII.C.1)

Day 7 at OT 

Day 11 at SOT 

(Laboratory)

Percentage of seed that did not 

imbibe water and remained hard 

to the touch (viability determined 

by a tetrazolium test)

Early stand count 

(VII.C.2.1)

V2 – V5 growth stage 

(Field)

Number of plants per m2

Vegetative 

growth

Plant height

(VII.C.2.1)

R1 – R6 (Field) Distance from the soil level to the 

flag leaf collar

Days to maturity

(VII.C.2.1)

R6 (Field) Number of days from planting to 

kernel black layer

Final stand count

(VII.C.2.1)

Pre-harvest (Field) Number of plants per m2

1 Optimum temperature OT = 20/30°C, Suboptimum temperature SOT = 10°C for seven days 

followed by 25°C for four days.
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Table VII-I. Phenotypic, Agronomic, and Environmental Interactions 

Characteristics Evaluated in U.S. Field Trials and Laboratory Studies (continued)

Data category

Characteristic 

measured

(section where 

discussed)

Evaluation timing 

(setting of evaluation)

Evaluation description 

(measurement endpoints)

Reproductive 

development

Days to flowering

(VII.C.2.1)

R1 (Field) Days from planting until 50% of 

the plants have begun to shed 

pollen

Pollen viability

(VII.C.3)

R1 (Laboratory) Percentage of viable pollen based 

on pollen grain staining 

characteristics

Pollen diameter

(VII.C.3)

R1 (Laboratory) Diameter of representative pollen 

grains

Grain moisture

(VII.C.2.1)

Harvest (Field) Percentage moisture of harvested 

grain

Seed weight

(VII.C.2.1)

Harvest (Field) Mass of 100 mature seeds, adjusted 

to 15.5% moisture content

Yield

(VII.C.2.1)

Harvest (Field) Mass of harvested grain per 

hectare, adjusted to 15.5% 

moisture content

Lodging and 

seed retention 

Lodging 

(VII.C.2.1)

Pre-harvest (Field) Percentage of plants leaning >45° 

from vertical or broken below the 

ear

Seed loss

(VII.C.2.1)

Pre-harvest (Field) Number of ears completely 

detached from plants in two rows

Environmental 

interactions

Abiotic stress 

response 

(VII.C.2.2)

Four times during 

growing season (Field)

Qualitative assessment of each 

plot, with categorical scale of 

increasing severity (none, slight, 

moderate, severe)

Disease damage

(VII.C.2.2)

Four times during 

growing season (Field)

Qualitative assessment of each 

plot, with categorical scale of 

increasing severity (none, slight, 

moderate, severe)

Arthropod damage

(VII.C.2.2)

Four times during 

growing season (Field)

Qualitative assessment of each 

plot, with categorical scale of 

increasing severity (none, slight, 

moderate, severe)

1 Optimum temperature OT = 20/30°C, Suboptimum temperature SOT = 10°C for seven days 

followed by 25°C for four days.
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VII.B. Data Interpretation 

Plant pest risk assessments for biotechnology-derived crops are comparative assessments 

and are considered from a basis of familiarity. The concept of familiarity is based on the 

fact that the biotechnology-derived plant is developed from a well-characterized 

conventional maize whose biological properties and plant pest potential are well-known. 

Familiarity considers the biology of the crop, the introduced traits, the receiving 

environment and the interaction of these factors, and provides a basis for comparative 

environmental risk assessment between a biotechnology-derived plant and its 

conventional counterpart. 

Expert knowledge and experience with conventionally bred maize was the basis for 

selecting appropriate endpoints and estimating the range of responses that would be 

considered typical for maize. As such, MON 87429 was compared to the conventional 

control in the assessment of phenotypic, agronomic, and environmental interactions 

characteristics. Based on all of the data collected, an assessment was made to determine 

if MON 87429 could be expected to pose an increased plant pest risk compared to 

conventional maize. 

VII.B.1. Interpretation of Phenotypic and Agronomic Data 

Comparative plant characterization data between a biotechnology-derived crop and the 

conventional control are interpreted in the context of contributions to increased 

weediness or plant pest risk. Under the framework of familiarity, characteristics for 

which no differences are detected support a conclusion of no increased weediness or 

plant pest risk of the biotechnology-derived crop compared to the conventional crop. 

Characteristics for which statistically significant differences are detected are considered 

in a step-wise method (Figure VII-1) or in a similar fashion. All detected differences for 

a characteristic are considered in the context of whether or not the difference would 

increase the crop’s pest/weed potential. Ultimately, a weight of evidence approach 

considering all characteristics and data is used for the overall risk assessment of 

differences and their significance. Figure VII-1 illustrates the stepwise assessment 

process employed.
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Figure VII-1. Interpretation of Statistical Differences

Step 1 – Evaluate Detected Statistically Significant Differences

Data on each measured characteristic are statistically analyzed. A combined-site analysis is used 

for multi-site data. All statistically significant differences are evaluated and considered in the 

context of a change in weediness or plant pest risk. Any difference detected is further assessed.

Step 2 – Evaluate Differences in the Context of Commercial Reference Materials Included in the 

Study

If a difference for a characteristic is detected then the mean value of the biotechnology-derived 

crop for the characteristic is assessed relative to the range of variation of the commercial 

reference materials included in the study (e.g., reference range).

Step 3 – Evaluate Differences in the Context of the Crop

If the mean value of the characteristics for a biotechnology-derived crop is outside the variation 

of the commercial reference materials included in the study, the mean value of the biotechnologyderived crop is assessed relative to known values common for the crop (e.g., published values).

Step 4 – Relevance of Difference to Weediness or plant pest risk

If the mean value of the characteristics for a biotechnology-derived crop is outside the 

range of values common for the crop, the difference is then assessed for whether or not it 

is meaningful in terms of weediness or plant pest risk.

Step 5 – Conduct Risk Assessment on Identified Hazard 
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If an adverse effect (hazard) is identified, a risk assessment on the difference is 

conducted. The risk assessment considers contributions to enhanced weediness or plant 

pest risk of the crop itself, the impact of differences detected in other measured 

characteristics, and potential for and effects of trait introgression into any populations 

growing outside of cultivated environments or into a sexually compatible species.

VII.B.2. Interpretation of Environmental Interactions Data

The environmental interactions data consisting of plant responses to abiotic stressors, 

diseases, and arthropod pests are categorical and were considered different in 

susceptibility or tolerance if the range of injury symptoms did not overlap between the 

biotechnology-derived crop and the conventional control across all four replications

within an observation at a site. 

Observations for which no differences are detected support a conclusion of no increased 

weediness or plant pest risk. Observations for which differences are detected are not 

considered to increase weediness or plant pest risk if the biotechnology-derived crop 

stressor responses and damage ratings are within the reference range or are not 

consistently observed in multiple environments in which the same stressor occurred.

VII.C. Comparative Assessments of the Phenotypic, Agronomic, and Environmental 

Interactions Characteristics of MON 87429

This section provides the results of comparative assessments conducted in replicated 

laboratory and/or multi-site field experiments to provide a detailed phenotypic, 

agronomic, and environmental interactions description of MON 87429. The 

characteristics for MON 87429 evaluated in these assessments included: seed 

germination and dormancy characteristics (Section VII.C.1), plant phenotypic, 

agronomic, and environmental interactions observations under field conditions (Section 

VII.C.2), and pollen characteristics (Section VII.C.3). Additional details for each 

assessment are provided in Appendix H, Appendix I, and Appendix J. 

VII.C.1. Seed Germination and Dormancy Characteristics

USDA-APHIS considers the potential for weediness to constitute a plant pest factor (7 

CFR § 340.6). Seed germination and dormancy mechanisms vary with species and their 

genetic basis tends to be complex. Seed dormancy (e.g., hard seed) is an important 

characteristic that is often associated with plants that are considered weeds (Anderson, 

1996; Lingenfelter and Hartwig, 2007). Information on germination and dormancy 

characteristics is therefore useful when assessing a plant for increased weediness 

potential. To assess germination characteristics, standardized germination assays are 

available and routinely used. The Association of Official Seed Analysts (AOSA), an 

internationally recognized seed testing organization, recommends a temperature regime 

of alternating 20°C and 30°C for testing the germination and dormancy characteristics of 

maize seed (AOSA, 2017a; b). The AOSA further recognizes a temperature regime of 

constant 10°C for seven days followed by 25°C for four days for cold testing of maize 

(AOSA, 2009). 
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A comparative assessment of seed germination and dormancy characteristics was 

conducted for MON 87429 and the conventional control. The seed lots for MON 87429

and the conventional control were harvested from one 2017 field production site in Kihei, 

Hawaii. Four reference maize hybrids were obtained from commercial sources. 

MON 87429 was compared to the conventional control for percentages of germinated, 

dead, viable firm-swollen, and viable hard seed using two temperature regimes: optimum 

(alternating 20°C and 30°C) and suboptimum (AOSA cold test: constant 10°C for seven 

days followed by 25°C for four days). The assay for each temperature regime was 

conducted using a randomized complete block design with four replications. 

Descriptions of the evaluated germination and dormancy characteristics and the timing of 

the evaluations are listed in Table VII-1. The materials and experimental methods are 

further discussed in Appendix H

In the analyses of the dormancy and germination data, no statistically significant 

differences (α = 0.05) were detected between MON 87429 and the conventional control 

in either the optimum (20/30°C) or suboptimum (10/25°C) temperature regimes for any 

of the evaluated characteristics, including viable hard seed (Table VII-2). These results 

support the overall conclusion that the introduction of the dicamba-, glufosinate-, 

quizalofop-, and 2,4-D-tolerance and RHS traits does not result in increased weediness or 

plant pest risk of MON 87429 compared to conventional maize.
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Table VII-2. Germination and Dormancy Characteristics of MON 87429 and the 

Conventional Control

Temperature

Regime (°C)1 Characteristic2

Mean % (SE)3

MON 

87429 Control Reference Range

Optimum Germinated 93.0 (1.47) 96.3 (0.48) 99.0 – 100.0

Dead 7.0 (1.47) 3.8 (0.48) 0.0 – 1.0

Viable firm-swollen 0.0 (0.00) 0.0 (0.00) 0.0 – 0.0

Viable hard 0.0 (0.00) 0.0 (0.00) 0.0 – 0.0

Suboptimum Germinated 94.5 (1.26) 96.3 (1.25) 99.3 – 100.0

Dead 5.5 (1.26) 3.8 (1.25) 0.0 – 0.8

Viable firm-swollen 0.0 (0.00) 0.0 (0.00) 0.0 – 0.0

Viable hard 0.0 (0.00) 0.0 (0.00) 0.0 – 0.0

Notes: No statistically significant differences were detected between MON 87429 and the 

conventional control (α =0.05). 

1 The optimum temperature regime was 20/30oC for seven days; The suboptimum temperature 

regime was 10oC for seven days followed by 25oC for four days.

2 Statistical comparisons were performed using ANOVA (optimum temperature regime) or 

Fisher’s Exact Test (suboptimum temperature regime). No statistical comparisons were made if 

MON 87429 and control values were 0.

3 N= 4 for means. S.E. = standard error.

VII.C.2. Field Phenotypic, Agronomic and Environmental Interactions 

Characteristics

Phenotypic and agronomic characteristics were evaluated under field conditions as part of 

the plant characterization assessment of MON 87429. These data were developed to 

provide USDA-APHIS with a detailed description of MON 87429 relative to the 

conventional control and reference maize hybrids. According to 7 CFR § 340.6, as part 

of the petition to seek deregulation, a petitioner must submit “a detailed description of the 

phenotype of the regulated article.” This information is being provided to assess whether 

there are phenotypic differences between MON 87429 and the conventional control that 

may impact its weediness or plant pest risk. Specific characteristics that are typically 

associated with weediness (e.g., lodging and seed loss) were used to assess whether there 

is a potential increase in weediness of MON 87429 compared to conventional maize. 

USDA-APHIS considers the environmental interaction of the biotechnology-derived crop 

compared to its conventional control to determine the potential for increased plant pest 

characteristics. Evaluations of environmental interactions were conducted as part of the 

plant characterization for MON 87429. In the 2017 U.S. field trials conducted to 

evaluate the phenotypic and agronomic characteristics of MON 87429, data were also 

collected on plant responses to abiotic stressors, diseases, and arthropod pests. 
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Data were collected from eight 2017 field sites within maize production regions of the 

U.S. (Table VII-3). The test material MON 87429, the conventional control, and four 

commercial reference hybrids were planted at each site in a randomized complete block 

design with four replications. Sixteen unique references were included among the sites. 

Additional details on the materials and methods are presented in Appendix I. 

VII.C.2.1. Phenotypic and Agronomic Assessments

MON 87429 was compared to the conventional control in a combined-site analysis for 

nine phenotypic and agronomic characteristics: early stand count, days to flowering, plant 

height, days to maturity, lodging, final stand count, moisture, seed weight, and yield. 

Descriptive statistics are provided for an additional characteristic, seed loss, that had 

insufficient variability for formal statistical analysis. Descriptions of the evaluated 

phenotypic and agronomic characteristics and the timing of the evaluations are listed in 

Table VII-1. The materials and methods are further discussed in Appendix I. 

The means for MON 87429 and the conventional control for seed loss, which was 

excluded from formal analysis, were low (0.2 and 0.1 ears/two rows, respectively) and 

the mean for MON 87429 was within the reference range. These results suggest that this 

characteristic does not contribute to a biological change for MON 87429 in terms of plant 

pest potential.

In a combined-site analysis of phenotypic and agronomic characteristics of MON 87429 

compared to the conventional control, no statistically significant differences (α = 0.05) 

were detected between MON 87429 and the conventional control for any of the analyzed 

characteristics (Table VII-4). These results, together with those for seed loss, support the 

overall conclusion that the introduction of the dicamba-, glufosinate-, quizalofop-, and 

2,4-D-tolerance and RHS traits does not result in increased weediness or plant pest risk of 

MON 87429 compared to conventional maize. 

Table VII-3. Phenotypic and agronomic and Environmental Interactions Sites for 

MON 87429 during 2017

Site Code County, State

IAAU Audubon, Iowa

IARL Jefferson, Iowa

ILCX Vermilion, Illinois

ILMN Warren, Illinois

INSH Boone, Indiana

NESW Seward, Nebraska

NEYO York, Nebraska

OHTR Miami, Ohio
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Table VII-4. Combined-Site Analysis of Phenotypic and Agronomic Characteristics 

of MON 87429 Compared to the Conventional Control in 2017 U.S. Field Trials

Characteristic (units) Mean (S.E.)1Reference Range2

MON 87429 Control

Early stand count (plants/m2) 9.0 (0.08) 9.1 (0.07) 8.5 – 9.5

Days to flowering 63.6 (0.86) 63.5 (0.81) 57.3 – 69.0

Plant height (cm) 241.2 (3.41) 243.3 (3.06) 181.5 – 251.1

Days to maturity 131.7 (1.34) 130.5 (1.61) 118.8 – 139.6

Lodging (%) 8.3 (2.03) 10.3 (3.60) 0.0 – 16.2

Seed loss (ears/two rows) 0.2 (0.13)†0.1 (0.09) 0.0 – 0.2

Final stand count (plants/m2) 8.4 (0.11) 8.4 (0.12) 7.8 – 9.3

Moisture (%) 18.7 (0.43) 18.6 (0.45) 15.1 – 23.6

Seed weight (g) 37.2 (0.74) 36.8 (0.75) 31.1 – 43.1

Yield (t/ha) 15.1 (0.32) 14.8 (0.34) 13.1 – 18.9

Notes: No statistically significant differences were detected between MON 87429 and the 

conventional control (α =0.05) in the combined-site, linear mixed model analysis. All plots at 

sites INSH, NESW, and NEYO were thinned to uniform density following early stand count. 

† Indicates that p values could not be generated due to insufficient variability for formal statistical 

analysis.

1 N = 32 for means. S.E. = standard error. 

2 Minimum and maximum mean values among 16 references, where each mean was combined 

over all the sites at which the reference was planted.
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VII.C.2.2. Environmental Interactions Assessments

Plant responses to abiotic stressors, diseases, and arthropod pests were assessed at natural 

levels, i.e., no artificial infestation or imposed abiotic stress; therefore, these levels 

typically varied between observations at a site and among sites. These data were 

collected from each plot using a categorical scale (none, slight, moderate, and severe) of 

increasing severity of observed damage for each stressor. This scale was utilized to allow 

for the evaluation of the wide variety of potential abiotic stressors, diseases, and 

arthropod pests potentially occurring across the season and across sites. These data were 

summarized and not subjected to ANOVA. For a particular stressor, all comparisons of 

the range of responses for MON 87429 to the range of responses for the conventional 

control across all observation times and sites are reported. Descriptions of the evaluated 

environmental interactions characteristics and the timing of the evaluations are listed in 

Table VII-1. The materials, methods, additional details concerning the qualitative 

environmental interactions assessments, and detailed results of the qualitative data 

comparisons are further discussed and presented in Appendix I. 

In an assessment of plant responses to abiotic stressors, diseases, and arthropod pests, no 

differences were observed between MON 87429 and the conventional control for any of 

the 288 observations (including 96 abiotic stressor, 96 disease, and 96 arthropod pest 

observations) among all observations at eight sites (Table VII-5). These results support 

the overall conclusion that the introduction of the dicamba-, glufosinate-, quizalofop-, 

and 2,4-D-tolerance and RHS traits does not result in increased weediness or plant pest 

risk of MON 87429 compared to conventional maize. 

Table VII-5. Summary of Qualitative Environmental Interactions Assessments for 

MON 87429 during 2017

Stressor Number of observations

across all sites

Number of observations with 

no differences between 

MON 87429 and the 

conventional control across all 

sites

Abiotic stressors 96 96

Diseases 96 96

Arthropod pests 96 96

Total 288 288

No differences were observed between MON 87429 and the conventional control during any of 

the 96 observations (8 sites, 4 timepoints, 3 stressors) for each stressor category. MON 87429 and 

the conventional control were considered different in susceptibility or tolerance if the range of 

injury symptoms across four replications did not overlap between MON 87429 and the 

conventional control. 
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VII.C.3. Pollen Characteristics

USDA-APHIS considers the potential for gene flow and introgression of the 

biotechnology-derived trait(s) into sexually compatible plants and wild relatives to be a 

factor in determining the potential for increased weedy or invasive characteristics of the 

receiving species. Pollen morphology and viability information are pertinent to this 

assessment and, therefore, were assessed for MON 87429. In addition, morphological 

characterization of pollen produced by MON 87429 and the conventional control is 

relevant to the plant pest risk assessment because it adds to the detailed description of the 

phenotype of MON 87429 compared to the conventional control.

The viability and morphology of pollen collected from MON 87429 compared to that of 

the conventional control were assessed. Pollen was collected from MON 87429, the 

conventional control, and four commercial references grown under similar agronomic 

conditions at a field site in Warren County, Illinois; a geographic area that represents 

environmentally relevant conditions for maize production for this product. The study 

was arranged in a randomized complete block design with four replications. Pollen was 

collected from three non-systematically selected plants per plot and stained for 

assessment. MON 87429 was compared to the conventional control for percentage viable 

pollen and pollen diameter. Descriptions of the evaluated pollen viability and 

morphology characteristics and the timing of the evaluations are listed in Table VII-1. 

The materials, methods, and general pollen morphology results are further discussed and 

presented in Appendix J. 

No statistically significant differences (α=0.05) were detected between MON 87429 and 

the conventional control for percentage viable pollen or pollen diameter (Table VII-6). 

Furthermore, no visual differences in general pollen morphology were observed between 

MON 87429 and the conventional control (Appendix J, Figure J-1). These results 

support the overall conclusion that the introduction of the dicamba-, glufosinate-, 

quizalofop-, and 2,4-D-tolerance and RHS traits does not result in increased weediness or 

plant pest risk of MON 87429 compared to conventional maize.

Table VII-6. Viability and Diameter of Pollen Collected from MON 87429, the 

Conventional Control, and the Reference Materials

Pollen Characteristic (unit) Mean (S.E.)1Reference Range2

MON 87429 Control

Viability (%) 98.9 (0.37) 99.1 (0.32) 98.2 – 99.1

Diameter (μm) 85.1 (0.45) 85.1 (0.34) 83.4 – 86.7

Note: No significant differences were detected between the MON 87429 and the conventional 

control (α=0.05).

1 MON 87429 and the conventional control values represent means with standard error (S.E.) in 

parentheses. N=4.

2 Reference range is the minimum and maximum mean value observed among reference 

materials.
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VII.D. Conclusions for Phenotypic, Agronomic, and Environmental Interactions 

Evaluation 

Comparative plant characterization data between a biotechnology-derived crop and the 

conventional control are interpreted in the context of contributions to increased plant pest 

potential as assessed by USDA-APHIS. Under the framework of familiarity, 

characteristics for which no statistically significant differences are detected support a 

conclusion of no increased plant pest potential of the biotechnology-derived crop 

compared to the conventional crop. Ultimately, a weight of evidence approach that 

considers all characteristics and data is used for the overall risk assessment of differences 

and their significance. 

An extensive and robust set of phenotypic, agronomic, and environmental interactions 

data were used to assess whether the introduction of the dicamba, glufosinate, quizalofop, 

and 2,4-D-tolerance and RHS traits altered the plant pest potential of MON 87429

compared to the conventional control, considered within the context of the variation 

among the reference maize hybrids. These assessments included five general data 

categories: 1) seed germination, dormancy, and emergence; 2) vegetative growth; 3) 

reproductive development (including pollen characteristics); 4) lodging and seed 

retention on the plant; and 5) plant responses to abiotic stressors, diseases, and arthropod 

pests. Within these data categories, specific characteristics typically associated with 

weediness were also assessed to determine whether there was a potential increase in 

weediness of MON 87429 compared to conventional maize. 

Results from these assessments comparing MON 87429 and the conventional control 

support the conclusion that MON 87429 does not possess: 1) increased weediness 

characteristics; 2) increased susceptibility or tolerance to specific abiotic stressors, 

diseases, or arthropod pests; or 3) characteristics that would confer a plant pest risk 

compared to conventional maize. Therefore, based on the results of multiple assessments 

discussed above and presented in the appendices, the weight of evidence supports the 

overall conclusion that the introduction of the dicamba-, glufosinate-, quizalofop-, and 

2,4-D-tolerance and RHS traits does not result in increased weediness or plant pest risk of 

MON 87429 compared to conventional maize and is unlikely to pose a plant pest risk. 
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VIII. U.S. AGRONOMIC PRACTICES

VIII.A. Introduction

As part of the plant pest assessment required by 7 CFR § 340.6(c)(4), impacts to 

agricultural and cultivation practices must be considered. This section provides a 

summary of current agronomic practices in the U.S. and North America for producing 

field maize and is included in this petition as a baseline to assess whether there is likely 

to be a significant change in agricultural practices due to the cultivation of MON 87429 

maize and whether such changes are likely to exacerbate plant pests or diseases 

associated with maize. Discussions include maize production, plant growth and 

development, general management practices during the season, management of insects, 

diseases and weeds, crop rotation, and volunteer management. Information presented in 

Section VII.C demonstrated that MON 87429 maize is no more susceptible to diseases or 

pests than commercially cultivated maize. Additionally, data presented support that, with 

the exception of the introduced traits, MON 87429 maize is phenotypically similar to 

conventional maize and is not expected to pose a greater plant pest risk compared to 

conventional maize. Thus, except for greater diversity in herbicide chemistry tolerance 

that will provide greater flexibility in weed control options, there are no expected changes 

to the inputs needed for MON 87429 maize production, and no expected impacts to most 

of the agronomic practices employed for production of maize compared to the current 

practices. 

Maize is planted in almost every U.S. state demonstrating its wide adaptation to soils and 

climate. However, the majority of maize is produced in the Midwest states because the 

fertile soils and climate are favorable for maize production. Proper seedbed preparation, 

good genetics, proper planting dates, plant population density, soil fertility, water 

availability and good integrated pest management practices are important to optimize the 

yield potential and economic returns of maize.

Annual and perennial weeds are considered to be the greatest pest problem in maize 

production (Aref and Pike, 1998). Weeds compete with maize for water, nutrients, and 

light resulting in substantial yield losses when left uncontrolled. Weed species in maize 

vary from region to region and state to state. Maintaining weed populations below 

economic thresholds in maize requires some form of weed management practice on all 

maize acreage. Weed management practices include mechanical practices (e.g., tillage), 

cultural practices (e.g., crop rotation, variety selection, optimizing planting date, plant 

population and row spacing), and chemical practices (e.g., herbicide application). 

Numerous herbicides are available for preplant, preemergence, and postemergence 

control of annual and perennial weeds in maize, and approximately 98% of the maize 

acreage in the U.S. receives an herbicide application (USDA-NASS, 2019b). 

As shown in Sections VI and VII, with the exception of introduced traits, no biologically 

meaningful phenotypic, compositional, or environmental interaction differences between 

MON 87429 maize and conventional maize have been observed. Moreover, herbicidetolerant maize is currently grown on approximately 90% of U.S. maize acres (USDAERS, 2018b). Dicamba, glufosinate, quizalofop, 2,4-D and glyphosate herbicides are 
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currently labeled for preplant and postemergence applications in maize. In support of 

Monsanto’s third generation herbicide tolerant product MON 87419 maize, Monsanto 

requested that EPA allow the 0.5 lb a.e./ac postemergence application window for 

dicamba to be extended from V5 to V8 growth stage or 36-inch height of maize, 

whichever occurs first (U.S. EPA, 2019). The combined (pre- and post-emergence) 

maximum annual application rate of dicamba in MON 87419 maize would be 2.0 lbs. a.e. 

dicamba per acre per year, increased from the current maximum annual application rate 

of 0.75 lbs. a.e. in conventional maize. Pending approval of the expanded label at EPA, 

the dicamba use pattern for MON 87429 would be no different than that of MON 87419.

Glufosinate, quizalofop and 2,4-D herbicides are currently labeled for preplant 

applications on conventional and herbicide-tolerant maize hybrids and for in-crop 

postemergence applications on herbicide-tolerant (HT) hybrids. The intended preplant 

and postemergence uses of these herbicides with MON 87429 maize would not be any 

different than current labeled uses in HT maize and therefore does not require a label 

change. The MON 87429 event confers glyphosate tolerance in specific plant tissues (i.e., 

not in tassels) and will be used to facilitate the production of hybrid seed. MON 87429 is 

not intended to be offered for commercial use as a stand-alone product, but will be 

combined, through traditional breeding methods, with other deregulated events that 

confer full-plant glyphosate tolerance (e.g., NK603). The combination of herbicidetolerance traits will allow the preplant and postemergence use of dicamba, glufosinate, 

quizalofop, 2,4-D and glyphosate herbicides in an integrated weed management program 

in maize with multiple sites-of-action to control a broad spectrum of grass and broadleaf 

weed species, including herbicide-resistant and tough to control weed species. Therefore, 

it is not anticipated that commercialization of MON 87429 maize in the U.S. would have 

a notable impact on current maize production practices, beyond the intended benefits of 

effective management of common, troublesome weeds, and/or herbicide-resistant weeds 

and additional options for growers to rotate and/or use combinations of herbicides with

multiple sites-of-action for preplant and in-crop postemergence herbicide applications. 

Hybridization is a fundamental concept used in maize breeding and production programs 

in the U.S. and most of the world. The fixation of alleles in pure lines (i.e., inbreds) 

causes a general reduction in maize vigor and productivity, but maize grown from the F1 

hybrid seed produced through crossing two inbred lines has improved vigor (e.g., 

heterosis) compared to the open pollinated varieties. Modern maize breeding is based on 

selecting inbred lines and producing crosses that possess desirable traits. Techniques such 

as marker-assisted selection can also reduce the time and cost required to achieve 

breeding goals (Yousef and Juvik, 2001). 

Tissue-specific expression of CP4 EPSPS protein in MON 87429, allowing for 

glyphosate induced non-viable pollen phenotype, is the second generation of Monsanto’s 

Roundup

® Hybridization System (RHS) for hybrid seed production. The first-generation 

RHS event, MON 87427 maize, was deregulated by USDA in 2013 (USDA-APHIS 

Petition #10-281-01p). Similar to the MON 87427 RHS trait, the second-generation RHS 

trait in MON 87429 allows inbred MON 87429 lines, treated with glyphosate at the 

appropriate timings (V8 to V13) to serve as female parents in the production of hybrid 

seed. Inbred MON 87429 lines receive two glyphosate applications at vegetative growth 

stages ranging from V8 to V13, resulting in the intended non-viable pollen phenotype due 
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to tissue-specific glyphosate tolerance. An additional benefit of including the RHS trait 

in MON 87429 maize at a single locus with dicamba, glufosinate, quizalofop and 2,4-D 

tolerance traits, is the reduction in the number of trait loci that would otherwise need to 

be managed and combined, via traditional breeding methods.

In hybrid maize production systems, inbred MON 87429 plants treated with glyphosate 

during tassel development will be pollinated by male pollen donor plants that contain a 

glyphosate tolerance trait (e.g., NK603). Male donor inbred plants are cultivated in 

proximity to female inbred MON 87429 plants and the male donor inbred plants are not 

impacted by the glyphosate applications due to full glyphosate tolerance in all tissues. 

This cross results in hybrid offspring (e.g., MON 87429 × NK603) with full-plant

tolerance to glyphosate, both in vegetative and reproductive tissues, as well as tolerance 

to dicamba, glufosinate, quizalofop, and 2,4-D herbicides. 

VIII.B. Overview of U.S. Maize Production

VIII.B.1. Maize Grain Production 

The U.S., China, Brazil, European Union and Argentina are the top five countries/regions 

producing maize globally (USDA-FAS, 2019). The U.S. is the largest producer of maize 

(Zea mays), producing approximately 35% of the world maize production in 2017/18 

(USDA-FAS, 2019). China follows with approximately 24% of the maize production. 

Maize for all purposes was planted on approximately 89 million acres in 2018 in the U.S. 

(Table VIII-1), consistent with soybean acres and more than the 47.8 million wheat acres 

(USDA-NASS, 2019c). Much of that production occurs in the upper Midwest States 

(Figure VIII-1). The 2018 maize acreage was down 1.04 million acres from 2017 (Table 

VIII-1). Approximately 81.7 million acres were harvested for grain in 2018 and 6.1 

million acres were harvested for silage in 2018 (USDA-NASS, 2019c). Total maize 

grain production was approximately 14.6 billion bushels in 2018 with an average yield of 

178.6 bushels per acre (Table VIII-1). The value of maize grain production reached 

$48.46 billion in the U.S. in 2017 (Table VIII-1). The value of maize production in the 

U.S. has ranged from $46.73 to $76.94 billion in the past 10 years. The principal uses of 

maize are feed and residuals, ethanol fuel, exports, food, seed and industrial uses 

(Capehart et al., 2018). 
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Table VIII-1. Field Maize Production in the U.S., 2007-20181

Year

Acres 

Planted

(×1000)

Acres 

Harvested

(×1000)

Average

Yield

(bushels/acre)

Total

Production

(×1000 bushels)

Value

(billions $)

2018 89,140 81,767 178.9 14,625,974 -

2

2017 90,167 82,703 176.6 14,604,067 48.46

2016 94,004 86,748 174.6 15,148,038 51.30

2015 88,019 80,753 168.4 13,601,964 49.34

2014 90,597 83,136 171.0 14,215,532 52.95

2013 95,365 87,668 158.8 13,925,147 62.72

2012 97,155 87,375 123.4 10,780,296 74.33

2011 91,936 83,989 147.2 12,359,612 76.94

2010 88,192 81,446 152.8 12,446,865 64.64

2009 86,382 79,490 164.7 13,091,862 46.73

2008 85,982 78,570 153.9 12,091,648 49.31

2007 93,527 86,520 150.7 13,037,875 54.67

1Source: (USDA-NASS, 2018a)

2Data not available

Source:(USDA-NASS, 2018b)

Figure VIII-1. U.S. Maize Acreage by County in 2017

VIII.B.2. Maize Seed Production

Commercial hybrid maize seed production is a labor intensive process. Single cross 

hybrid maize seed production involves planting male and female parent inbreds in 

separate rows or blocks in an isolated field. The female parent inbred is prevented from 

shedding pollen to prevent self-pollination and ensure pollination only by the intended 

male parent inbred. The male parent inbred is usually destroyed by mechanical means 
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following pollination to prevent seed mixing during harvest. Ears that are produced from 

the cross-pollinated female parent inbred are harvested, processed, and the seed sold to 

farmers for planting as hybrid maize seed.

Maintaining an adequate supply of the parental inbred lines is vital to producing an 

adequate supply of hybrid maize seed. Often referred to as foundation seed, parental 

inbred lines are produced and maintained under strict isolation in the production field to 

preserve the identity and integrity of the genetics within each inbred. Quality control 

checks performed during the production of inbreds include visual inspections of the 

plants grown in isolation, and the use of molecular tools to verify the genetics of each 

inbred line (Gowda et al., 2017).

Maize seed production is not expected to be affected by the introduction of MON 87429. 

Over the last 18 years, the volume of hybrid maize seed planted in the U.S. has increased 

from 22.45 million bushels (MBu) planted in 2000 to 30.90 MBu planted in 2018 

(USDA-ERS, 2018a). Grain yields have increased significantly over this same period 

from 9,915 MBu in the year 2000 to 14,420 MBu in 2018 (Figure VIII-2). 

A number of factors must be considered in hybrid maize seed production, including: 1) 

forecasting the quantity of specific hybrid maize seed that will be needed at least a year in 

advance; 2) selection of a production area that mitigates risks and maximizes the yield of 

hybrid maize seed; and 3) agronomic practices. Key considerations and practices for 

producing hybrid maize seed are described in detail in MON 87427 USDA-APHIS 

Petition #10-281-01p (p. 123), the first generation RHS event and include: input 

considerations, control of weeds, disease and pests, plant density, plot isolation, parent 

delay to synchronize flowering, pollen control methods such as detasseling and 

cytoplasmic male sterility, harvesting and labeling requirements. These practices may 

differ from those used in commercial maize grain production. 

The practices for producing hybrid maize seed using MON 87429 are generally similar to 

those using manual or mechanical detasseling methods or cytoplasmic male sterility 

(CMS), except for the use of glyphosate at early tassel development timings to confer the 

male sterile phenotype through tissue-specific glyphosate tolerance. 
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Source: (USDA-ERS, 2018a)

Figure VIII-2. Hybrid maize seed planted, and grain produced in the U.S. from 

2000-2018.

VIII.C. Production Management Considerations

MON 87429 provides tolerance to the same herbicides (glufosinate, quizalofop and 

2,4-D, and tissue-selective glyphosate) as several other events present in herbicide 

tolerant maize hybrids being grown in the U.S. (e.g., Genuity® SmartStax®, Genuity® VT 

Double PRO®, LibertyLink®, Enlist® maize, and first generation RHS MON 87427 

maize), or for dicamba, events previously deregulated by USDA-APHIS (Petition #15-

113-01p). With the widespread use of herbicide tolerant maize hybrids since 1997 

(USDA-ERS, 2018b), it is anticipated that no major changes in production management 

practices will occur beyond the intended benefits of more effective and improved 

management of common, troublesome and/or herbicide-resistant weeds and the 

opportunity for growers to rotate and/or use combinations of herbicides with multiple 

sites-of-action for preemergence and in-crop postemergence herbicide applications.

Cultivation practices for hybrid maize, containing the RHS trait in MON 87429, used in 

grain production will not differ from other commercially available, glyphosate tolerant 

maize.

The RHS trait in MON 87429 maize offers the same benefits to hybrid maize seed 

production as the RHS trait in MON 87427, described in detail in USDA-APHIS Petition 

#10-281-01p (p. 5). Briefly, these benefits include enabling maize hybrid seed producers 

to discontinue the practice of manually or mechanically detasseling female inbred plants 

in their production field, which must occur during a critical 3-4 day time period of maize 

tassel development that can be influenced by changes in weather (e.g., extreme heat).

The ability to treat MON 87429 maize inbreds with glyphosate (between V8 to V13), in 

 

® Genuity, SmartStax, and Genuity VT DoublePRO are registered trademarks of Monsanto Technology 

LLC.

® LibertyLink is a registered trademark of BASF.

®Enlist is a registered trademark of Dow AgroSciences, DuPont or Pioneer and their affiliated companies 

or respective owners.

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10

20

30

40

50

60

70

80

90

100

0

2000

4000

6000

8000

10000

12000

14000

16000

Seed Use (Mbu)

Production (Mbu)

Year
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place of detasseling, provides flexibility to hybrid maize seed producers as well as 

reduces the cost of hybrid seed production by removing the reliance on costly, labor 

intensive manual/mechanical detasseling. For weed management during the production 

of hybrid seeds using MON 87429, seed producers will be provided best management 

practices for herbicide resistance management, including the use of herbicides with 

multiple sites-of-action. An additional benefit of including the RHS trait in MON 87429 

maize at a single locus with herbicide tolerance traits is the reduction in the number of 

trait loci that would otherwise need to be managed and combined, via traditional breeding 

methods. Further, the amount of glyphosate recommended for use with MON 87429 

maize for hybrid seed or grain production will not exceed the total amount of glyphosate 

already approved for in crop use with other commercially available, glyphosate tolerant 

maize events. 

VIII.D. Management of Insect Pests

Monsanto summarized major issues associated with the management of insect pests in its 

petition for nonregulated status for corn rootworm-protected maize MON 87411 (USDAAPHIS Petition #13-290-01p). MON 87429 maize does not contain insect protection 

traits, therefore the information on this subject is incorporated here by reference (USDAAPHIS Petition #13-290-01p p. 166). In brief, insect pests continue to cause damage to 

maize and are commonly addressed by biotechnology-derived insect-tolerant traits, 

insecticide treatment of seeds, soil or foliar application of insecticides, or use of crop 

rotation or other integrated pest management practices. The EPA under the Federal 

Insecticide, Fungicide and Rodenticide Act (FIFRA), regulates the distribution, sale, use 

and testing of pesticidal substances (including those produced in plants), that are intended 

to control insect pests. 

MON 87429 was developed to improve the management of weeds and has no unique 

insect pest control attributes. Environmental observations in field studies indicated that 

the presence of the dicamba, glufosinate, quizalofop, and 2,4-D-tolerance and RHS traits 

did not meaningfully alter the susceptibility of MON 87429 maize to arthropod-related 

damage (Section VII.C). Therefore, no changes in current insect pest management 

practices in maize are anticipated from the introduction of MON 87429.

VIII.E. Management of Diseases and Other Pests

Monsanto summarized major issues associated with the management of diseases and noninsect pests in its petition for nonregulated status for Corn Rootworm-Protected Maize

MON 87411 (USDA-APHIS Petition #13-290-01p). MON 87429 does not contain 

disease protection traits, therefore the information on this subject is incorporated here by 

reference (USDA-APHIS Petition #13-290-01p p. 171). Briefly, management of diseases 

and pests of maize are important to protecting the yield of harvested grain. Disease and 

pest incidence vary from year to year and growers may choose to use pesticides or a 

variety of management practices to control problematic diseases or pests. 

MON 87429 was developed to improve the management of weeds and has no unique 

attributes for control of diseases or other pests. Environmental observations in field 

studies indicated that the presence of the dicamba, glufosinate, quizalofop, and 2,4-D-
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tolerance and RHS traits did not meaningfully alter the susceptibility of MON 87429 

maize to diseases or other pests (Section VII.C). Therefore, no changes in current 

management practices for diseases or other pests in maize are anticipated from the 

introduction of MON 87429 maize. 

VIII.F. Weed Management 

VIII.F.1. Methods of Weed Control in Maize

Annual and perennial weeds are considered to be the greatest pest problem in maize 

production (Aref and Pike, 1998). Weed control in maize is essential for optimizing yield 

because weeds compete with maize for light, nutrients, and moisture and can lead to 

reductions in yield (Knake et al., 1990). The duration of competition from weeds is 

important to determine the potential loss of yield in maize and the critical time period can 

vary with the density and species of the weed and environmental factors (Hall et al., 

1992). Early weed competition studies indicated that weeds must be removed by a 

certain time and maize heights to avoid yield losses in maize (Carey and Kells, 1995; 

Hall et al., 1992; Knake and Slife, 1965; Tapia et al., 1997). Weed control in the first 

several weeks after maize emergence is the most critical period to avoid yield losses in 

maize (Bosnic and Swanton, 1997; Carey and Kells, 1995; Hall et al., 1992; Knezevic 

and Datta, 2015). Some weeds can tolerate cold, wet conditions better than maize, and 

can gain an advantage prior to planting. A number of weeds compete with maize and 

reduce yield significantly with delay in weed control. Some of these weeds are difficult to 

control since they have similar life cycle and growth habit as those of maize plant (Jhala 

et al., 2014). Annual weed species such as giant foxtail (Setaria faberi), barnyardgrass 

(Echinochloa crus-galli (L.) Beauv.) and Palmer amaranth (Amaranthus palmeri) have 

been shown to reduce maize yields by up to 13% (Fausey et al., 1997; Knake and Slife, 

1965), 35% (Bosnic and Swanton, 1997) and 91% (Massinga et al., 2003), respectively. 

A compilation of data from 2007-2013 on weeds impacting yield in North America 

showed that uncontrolled weeds in maize could reduce yield at an average of 50% 

annually (Soltani et al., 2016). In a study of mixed weed populations competing with 

maize, yields were reduced by up to 20% when the weeds reached a height of eight 

inches (Carey and Kells, 1995). 

A case study on herbicide tolerant field maize within a larger survey involving Extension 

Service weed scientists solicited estimates of the percent of maize acreage infested with 

individual weed species by state or region, as well as the potential impact on maize yields 

if the species were left uncontrolled. In this survey, at least twelve annual broadleaf, nine 

annual grass, and seven perennial species were identified as troublesome weeds (Table 

VIII-2) (Gianessi et al., 2002). Estimates of yield loss in this case study ranged from a 

low of 15% due to wirestem muhly and sandburs to a high of 48% from bur cucumber.

Crop rotations and environment have a significant impact on the adaptation and 

occurrence of weeds in maize. A national weed survey conducted in 2015 has identified 

Palmer amaranth (Amaranthus palmeri), common lambsquarters (Chenopodium album), 

Canada thistle (Cirsium arvense), kochia (Bassia scoparia), common waterhemp 

(Amaranthus rudis), giant ragweed (Ambrosia trifida), morningglory spp (Ipomoea spp.), 

yellow nutsedge (Cyperus esculentus), common ragweed (Ambrosia artimisiifolia) and 
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downy brome (Bromus tectorum) as top 10 most troublesome weeds in the US (Van 

Wychen, 2015). Waterhemp, Palmer amaranth, morningglory, giant ragweed, horseweed 

and johnsongrass are common troublesome weeds in Midwest fields. The most 

frequently reported common weeds in the Southeast region are pigweeds (Amaranthus

spp.), morningglory, crabgrass (Digitaria spp.), nutsedge (Cyperus spp.) and broadleaf 

signalgrass (Brachiaria platyphylla) (Webster et al., 2012). Morning glory, pigweeds, 

nutsedge, johnsongrass (Sorghum halepense), crabgrass and horseweed (Conyza 

canadensis) are the most frequently mentioned troublesome weeds in the Southeast 

region (Webster et al., 2012).

Until the early 1950s, tillage and cultivation practices were primarily used for weed

control in maize, but they have been largely replaced by the use of herbicides. Herbicide 

use in maize became widespread by the end of the 1970s (Timmons, 2005). In 2018, 

herbicides were applied to 98% of the planted maize acreage (USDA-NASS, 2019b). 

Glyphosate is the most widely applied herbicide in maize being applied on [ ] of the 

planted acreage (Table VIII-3). Triketones and Isoxazole are the second most widely 

used group of herbicides at [ ] followed by chloroacetamide and isoxazoline 

herbicides at [ ] and Triazines (atrazine, metribuzin, simazine) at [ ]

[ ].

In 2018, approximately 90% of the total maize acreage in the U.S. was planted with 

hybrids possessing biotechnology-derived herbicide-tolerance traits (USDA-ERS, 

2018b). Maize hybrids possessing both herbicide-tolerance and insect-protected traits 

were planted on 80% of the maize acreage in 2018 (USDA-ERS, 2018b). The 

introduction of herbicide-tolerant crops such as Roundup Ready®, LibertyLink® and 

recently Enlist® maize, have offered growers an alternative and effective solution for the 

weeds control in maize by enabling in-crop postemergence use of glyphosate, 

glufosinate, quizalofop and 2,4-D herbicides. Although these herbicides (glyphosate, 

glufosinate, quizalofop and 2,4-D) provide control of numerous annual and perennial 

weed species, preemergence herbicides are a key component of weed control programs in 

maize. This is evident in the widespread use of triketones, chloroacetamide and triazine 

herbicides in maize (Table VIII-3, Table VIII-4 and Table VIII-5). Preemergence 

residual herbicides provide early season weed control to reduce early weed competition, 

improve control of certain hard to control broadleaf weed species (morningglory spp.), 

and help provide control of some glyphosate-resistant weeds. 

Table VIII-4 and Table VIII-5 provide a summary of the crop tolerance ratings of 

herbicides applied in maize production and the efficacy of these herbicides on 26 

common weed species. These tables list only the most commonly used herbicides in 

maize production. Seldom would one field or farm have all 26 weed species, but they 

generally have a mixture of grass and broadleaf weed species. These ratings can be used 

by growers to facilitate the selection of an herbicide program in maize, which offers the 

 

® LibertyLink is a registered trademark of BASF.

®Enlist is a registered trademark of Dow AgroSciences, DuPont or Pioneer and their affiliated companies 

or respective owners.

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best overall control of the weed species present. Generally, a mixture or premixture of 

two or more herbicide active ingredients is needed to achieve broad spectrum control of 

both grasses and broadleaf weed species. However, glyphosate, glufosinate, tembotrione, 

and topramezone each provide control of numerous grass and broadleaf weed species. 
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Table VIII-2. Troublesome Weeds in Maize Production1

Weed Species

Latin name

Area Infested

State/Region2

Acreage 

Infested

(%)

Potential 

Yield 

Loss (%)

Annual Broadleaves

Bur Cucumber (Sicyos angulatus) PA/OH/TN/SE 5-10 48

Cocklebur (Xanthiums strumarium) MW/NP/SE 20-60 33

Jimsonweed (Datura stramonium) MW/CO 5-20 17

Kochia (Bassia scoparia) NP/NW 10-70 33

Lambsquarters (Chenopodium album) MW/SE/NE/CA 15-80 33

Morningglory (Ipomoea spp.) MW/SE/SP 20-75 33

Nightshade (Solanum spp.) MW/NP/CA 25-50 26

Pigweeds/Waterhemp (Amaranthus spp.) US 30-90 36

Ragweed, Common (Ambrosia 

artemisiifolia)

MW/SE/NE 20-70 30

Ragweed, Giant (Ambrosia trifida) MW/NP 10-45 28

Smartweeds (Polygonum spp.) MW/SD/NE/SE 30-70 22

Velvetleaf (Abutilon theophrasti) MW/NE/NP 25-70 28

Annual Grasses

Barnyardgrass (Echinochloa crus-galli) SP/NW/CA 80-90 23

Bermudagrass (Cynodon dactylon) MD/SE/UT/CA 10-20 47

Crabgrass spp. (Digitaria spp.) MW/SE/NE 20-80 29

Cupgrass, Woolly (Eriochloa villosa) IA/WI 15-20 29

Foxtail spp. (Setaria spp.) MW/NE/NP 50-90 31

Millet, Wild-Proso (Panicum miliaceum) UT/WY/CO/ID 15-40 31

Panicum, Fall (Panicum dichotomiflorum) MW/SE/NE/NP 15-80 30

Sandburs (Cenchrus spp.) NP/UT/WY 5-30 15

Shattercane (Sorghum bicolor) MW/SP 5-40 33

Perennials

Bindweed, Field (Convolvulus arvensis) ND/SW/CA 40-80 18

Dogbane, Hemp (Apocynum cannabinum) IL/MO 2-20 21

Johnsongrass (Sorghum halepense) MW/SE/SW/CA 20-60 45

Muhly, Wirestem (Muhlenbergia frondosa) PA 2 15

Nutsedge, Yellow (Cyperus esculentus) MW/SE/NE/NP/

CA 10-70 21

Quackgrass (Elytrigia repens) MW/NE/UT 10-70 27

Thistle, Canada (Cirsium arvense) NE/MW/NP/CO 5-25 26

1Source: (Gianessi et al., 2002).

2Regions: MW = Midwest, NE = Northeast, NP = Northern Plains, NW = Northwest, SE = 

Southeast, SW = Southwest, SP = Southern Plains.
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Table VIII-3. Herbicide Applications in Maize in 2018 in the U.S.1

Herbicide Chemical Family

Site-of-Action2

(SOA)

Percent 

of Maize 

Acres

Treated

Percent of 

Maize 

Acres 

Treated 

per SOA

Glyphosate Glycine EPSPS inhibitor [ ] [ ]

Atrazine Triazine

PSII inhibitor

[ ]

Metribuzin Triazine [ ] [ ]

Simazine Triazine [ ]

Acetochlor Chloroacetamide

Long-chain

fatty acid 

inhibitor

[ ]

[ ]

Alachlor Chloroacetamide [ ]

Dimethenamid Chloroacetamide [ ]

Metolachlor Chloroacetamide [ ]

Pyroxasulfone Isoxazoline [ ]

Isoxaflutole Isoxazole

HPPD inhibitor

[ ]

[ ]

Mesotrione Triketone [ ]

Tembotrione Triketone [ ]

Topramezone Triketone [ ]

Bicyclopyrone Triketone [ ]

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Table VIII-3. Herbicide Applications in Maize in 2018 in the U.S.1(continued)

Herbicide Chemical Family

Site-ofAction2

(SOA)

Percent 

of 

Maize 

Acres 

Treated

Percent of 

Maize Acres 

Treated per 

SOA

2,4-D Phenoxy

Synthetic 

Auxin

 [ ]

[ ]

Clopyralid Carboxylic acid [ ]

Dicamba Benzoic acid [ ]

Fluroxpyr Caryridine 

Carboxylic acid

[ ]

Flumetsulam Imidazolinone

ALS 

inhibitor

[ ] 

[ ]

Halosulfuron Sulfonylurea [ ]

Nicosulfuron Sulfonylurea [ ]

Primisulfuron Sulfonylurea [ ]

Prosulfuron Sulfonylurea [ ]

Rimsulfuron Sulfonylurea [ ]

Thifensulfuron Sulfonylurea [ ]

Thiencarbazone Triazolones [ ]

Tribenuron Sulfonylurea [ ]

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Table VIII-3. Herbicide Applications in Maize in 2018 in the U.S.1(continued)

Herbicide Chemical Family

Site-of-Action2

(SOA)

Percent 

of Maize 

Acres 

Treated

Percent of 

Maize 

Acres 

Treated 

per SOA

Diflufenzopyr Semicarbazone Auxin transport [ ] [ ]

Fluthiacet Thiadiazole

PPO inhibitor

[ ]

 [ ]

Carfentrazone Aryl triazone [ ]

Saflufenacil Pyrimidinedione [ ]

Flumioxazin Nphenylphthalimide[ ]

Paraquat Bipyridylium

Photosystem-Ielectron 

diverter

[ ] [ ]

Glufosinate Phosphinic acid

Glutamine 

Synthase 

Inhibitor

[ ] [ ]

Pendimethalin Dinitroanaline Microtubule 

inhibitor [ ] [ ]

1

[ ]

2

(WSSA, 2018)

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Table VIII-4. Crop Tolerance and Grass Weed Responses to Herbicides Applied in Maize Production

Common Grass Weeds1,2

Herbicide/Application CT3 BY BS CG FP FTg FTy GG SC JGr JGs IR NSy

Preplant or Preemergence

Acetochlor 1 9 NA 9 8 9 9 NA - NA NA NA 8+

Acetochlor/atrazine 1 9 8 9 8 9 9 9 - 0 7 8 8+

Acetochlor/flumetsulam/

clopyralid 2 8 NA 8 8 8 8 NA - NA NA NA 7

Atrazine 0 8 5 - - 7 7 6 - 0 4 NA 7

Dimethenamid 1 8 NA 8+ 8 8+ 8+ NA - NA NA NA 8

Flumetsulam 2 - NA - - - - NA - NA NA NA -

Flumetsulam/clopyralid 2 - NA - - - - NA - NA NA NA -

Flumioxazin 1 - NA - - - - NA - NA NA NA -

Flumioxazin/pyroxasulfone 1 8 8 8 8 8 8 8 - 3 9 9 -

Isoxaflutole 1 8 NA 7 8 8 6 NA 6 NA NA NA -

Mesotrione 1 - NA 6 - - - NA - NA NA NA -

Metolachlor 1 8 NA 9 8+ 9 9 NA - NA NA NA 8+

Metolachlor/atrazine 1 9 8 9 8 9 9 9 - 0 7 8 8

Metolachlor/mesotrione 1 8 NA 9 8+ 9 9 NA - NA NA NA 8+

Metolachlor/mesotrione/atr 1 9 8 9 8+ 9 9 9 - 2 8 7 8

Pyroxasulfone 1 8 8 8 8 9 8 9 - 4 6 9 -

Pyroxasulfone/fluthiacet 1 8 8 8 8 9 8 9 - 4 7 9 -

Pyroxasulfone/fluthiacet/atr 1 8 8 8 8 9 8 9 - 4 7 9 6

Rimsulfuron/thifensulfuron 1 7 NA 6 6 7 7 NA - NA NA NA -

Rimsulfuron/isoxaflutole 2 8 NA 7 8 8 7 NA 6 NA NA NA -

Rimsulfuron/mesotrione 1 7 NA 6 6 7 7 NA - NA NA NA -

Saflufenacil 1 - 1 - - - - 1 - NA 1 1 -

Saflufenacil/Dimethenamid 1 8 6 8 8 8 8 8 - NA NA NA -

Simazine 0 8 5 7 7 8 8 7 - 0 4 NA -

Preemergence

Thiencarbazone/isoxaflutole 1 8 8 8+ 8+ 8+ 8+ 9 7 NA NA NA 7

Pendimethalin 2 8 6 8 8 8 8 8 6 4 7 5 -
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Table VIII-4. Crop Tolerance and Grass Weed Responses to Herbicides Applied in Maize Production (continued)

Common Grass Weeds1,2

Herbicide/Application CT3 BY BS CG FP FTg FTy GG SC JGr JGs IR NSy

Postemergence

2,4-D 2 - 0 - - - - 1 - 0 0 0 -

2,4-D/atrazine 2 - NA - - 6 6 NA - NA NA NA -

Atrazine 1 7 7 - - 8 8 6 - 0 3 NA 7

Bentazon 0 - 0 - - - - 1 - 0 0 0 8

Bromoxynil 1 - NA - - - - NA - NA NA NA -

Carfentrazone 2 - NA - - - - NA - NA NA NA -

Clopyralid 0 - NA - - - - NA - NA NA NA -

Dicamba 2 - 1 - - - - 1 - 0 0 0 -

Dicamba/diflufenzopyr 1 6 4 6 6 6 6 3 - 0 5 0 -

Fluroxypyr 1 - NA - - - - NA - NA NA NA -

Flumiclorac 2 - NA - - - - NA - NA NA NA -

Fluroxypyr/clopyralid 1 - NA - - - - NA - NA NA NA -

Fluthiacet 2 - NA - - - - NA - NA NA NA -

Glufosinate 0* 7 8 8 8 8+ 7 5 8 7 8 6 -

Glyphosate 0* 8 9 8 8 9 9 9 9 7 9 6 7

Halosulfuron 1 - 2 - - - - 2 - 1 2 NA 9

Mesotrione 1 - 7 7 - - - NA - 0 0 NA -

Nicosulfuron 1 8+ 8 4 8+ 9 9 NA 9 8 9 6 6

Nicosulfuron/rimsulfuron 1/2 8 NA - 8 9 9 NA 9 NA NA NA -

Primisulfuron 2 - NA - 8 7 7 NA 9 NA NA NA 6

Primisulfuron/dicamba 2 - NA - 7 6 6 NA 9 NA NA NA -

Prosulfuron/primisulfuron 2 - NA - 7 6 6 NA 9 NA NA NA -

Rimsulfuron/ thifensulfuron 1 7 NA - 7 7 7 NA 7 NA NA NA -

Rimsulfuron/mesotrione 1 7 7 - 7 7 7 8 7 7 9 4 -

Tembotrione 0 8 8 6 - 7 9 7 8 5 6 NA -

Thiencarbazone/tembotrione 1 8 8 8 8 8+ 9 NA 8 5 7 NA -

Topramezone 0 7 6 7+ 6 7+ 7 7 6 4 7 0 -
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1All weed control ratings except for BS, GG, JGr, JGs and IR are from the 2014 Weed Control Guide for Ohio and Indiana, Ohio State University 

and Purdue University (Loux et al., 2014). Ratings for BS, GG, JGr, JGs and IR are from the 2015 Weed Control Guidelines for Mississippi, 

Mississippi State University (Mississippi State University, 2015). Weed control rating for weeds, except BS, GG, JGr, JGs and IR, are: 9 = 90% 

to 100%, 8 = 80% to 90%, 7 = 70% to 80%, 6 = 60% to 70%, - = less than 60% control, not recommended. Weed control ratings for BS, GG, 

JGr, JGs and IR are: 9-10 = excellent, 7-8 = good, 4-6 = fair, 0-3 = none to slight, NA= data not available in (Mississippi State University, 2015). 

Ratings assume the herbicides are applied in the manner suggested in the guidelines and according to the label under optimum growing 

conditions.

2Weed species: BY = barnyardgrass, BS = broadleaf signalgrass, CG = crabgrass, FP = fall panicum, FTg = giant foxtail, FTy= yellow foxtail, 

GG = goosegrass, SC = shattercane, JGr = rhizome johnsongrass, JGs = seedling johnsongrass, IR = Italian ryegrass, and NSy = yellow nutsedge.

3Crop tolerance (CT) rating: 0 = excellent, 1 = good, 2 = fair, 3 = poor. Source: Loux et al., 2014.

*Rating based on glufosinate to Liberty Link® maize and glyphosate applied to Roundup Ready® Corn 2 maize.
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Table VIII-5. Broadleaf Weed Responses to Herbicides Applied in Maize Production

Common Broadleaf Weeds1,2

Herbicide/Application BN CB CR GR LQ MG HS PA PW PS SP SW VL WH

Preplant or Preemergence 

Acetochlor 8+ - 7 - 7+ - NA NA 8+ NA NA - - 8

Acetochlor/atrazine 9 8 9 8 9 8 6 9 9 8 6 9 8 9

Acetochlor/flumetsulam/clopyralid 8+ 8 8+ 7+ 9 6 NA NA 9 NA NA 8+ 8+ 8

Atrazine 9 8 9 8 9 8 7 9 9 8 8 9 8 9

Dimethenamid 8+ - - - 6 - NA NA 8 NA NA - - 8

Flumetsulam 8 7 7 - 9 - NA NA 9 NA NA 8 8+ -

Flumetsulam/clopyralid 8+ 8 8+ 7+ 9 6 NA NA 9 NA NA 8+ 9 -

Flumioxazin 9 - 7 - 9 7 NA NA 9 NA NA 7 7 7

Flumioxazin/pyroxasulfone 9 - 8 - 9 7 8 9 9 8 7 7 7 8

Isoxaflutole 9 - 9 6 9 - NA NA 9 NA NA 8 9 8

Mesotrione 9 7 7 6 9 6 NA NA 9 NA NA 9 9 9

Metolachlor 8 - - - 6 - NA NA 8 NA NA - - 8

Metolachlor/atrazine 9 8 9 8 9 8 6 9 9 8 6 9 8 9

Metolachlor/mesotrione 9 7 7 6 9 6 NA NA 9 NA NA 9 9 9

Metolachlor/mestrione/atr 9 8 9 8 9 8 8 9 9 9 8 9 9 9

Pyroxasulfone 8 - 7 - 8 - 3 9 8 7 NA - 7 8

Pyroxasulfone/fluthiacet 8 7 - 8 - 3 9 8 7 NA - 7 8

Pyroxasulfone/fluthiacet/atr 9 7 9 6 9 7 7 9 9 8 8 9 8 9

Rimsulfuron/ thifensulfuron - - 7 - 7 7 NA NA 7 NA NA 7 6 -

Rimsulfuron/isoxaflutole 8 - 8 6 9 7 NA NA 9 NA NA 8 9 8

Rimsulfuron/mesotrione 9 7 8 6 9 6 NA NA 9 NA NA 9 9 9

Saflufenacil 8 8 8 8 9 8 6 9 9 7 5 8 8 8

Saflufenacil/Dimethenamid 9 8 9 8 9 8 6 9 9 7 5 9 8 9

Simazine 9 7 9 7 9 7 NA 9 9 9 8 8+ 7 -

Thiencarbazone/isoxaflutole 9 8 9 8 9 7 9 NA 9 NA NA 9 9 9

Preemergence

Pendimethalin - - - - 8 - 0 7 9 0 0 - - 8
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Table VIII-5. Broadleaf Weed Responses to Herbicides Applied in Maize Production (continued) 

Common Broadleaf Weeds1,2

Herbicide/Application BN CB CR GR LQ MG HS PA PW PS SP SW VL WH

Postemergence

2,4-D 7 9 9 9 9 9 8 8 9 8 8 6 8 8

2,4-D/atrazine 9 9 9 9 9 9 NA NA 9 NA NA 9 8+ 9

Atrazine 9 9 9 8 9 9 7 9 9 9 8 9 8 9

Bentazon - 9 7 6 6 - 4 3 - 8 1 9 8+ -

Bromoxynil 9 9 9 8 9 8 NA NA 7 NA NA 8 8 6

Carfentrazone 8 - 6 - 7 8 NA NA 8+ NA NA - 9 7

Clopyralid 8 9 9 9 - - NA NA - NA NA - - -

Dicamba 8 9 9 9 8 9 9 8 8 8 8 8 7+ 8

Dicamba/diflufenzopyr 8 9 9 9 9 9 9 9 9 9 9 8+ 8 8

Fluroxypyr 7 8 9 - - 9 NA NA - NA NA 7 8 -

Flumiclorac - 7 7 - 7 - NA NA 9 NA NA - 9 7

Fluroxypyr/clopyralid 7 9 9 9 - 9 NA NA - NA NA 7 8 -

Fluthiacet - - - - 7 7 NA NA 8 NA NA - 9 7

Glufosinate 9 9 9 9 8 8 9 8 8 9 9 9 8 8

Glyphosate 8 9 8+ 8+ 8+ 6 6 9 9 7 8 8 8 8

Halosulfuron - 9 8 8 - 6 8 6 9 7 5 7 8 -

Mesotrione 9 7+ 7 8 9 7 NA 9 8 9 5 9 9 9

Nicosulfuron - - - - - 8 7 6 9 4 5 8 - 7

Nicosulfuron/rimsulfuron - 6 - - - 6 NA NA 9 NA NA 7 - -

Primisulfuron 8 9 9 9 - 6 NA NA 9 NA NA 8 8 -

Primisulfuron/dicamba 9 9 9 9 9 8 NA NA 9 NA NA 9 8+ 8

Prosulfuron/primisulfuron 8 9 9 9 6 7 NA NA 9 NA NA 8+ 8+ -
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Table VIII-5. Broadleaf Weed Responses to Herbicides Applied in Maize Production (continued) 

Common Broadleaf Weeds1,2

Herbicide/Application BN CB CR GR LQ MG HS PA PW PS SP SW VL WH

Rimsulfuron/ thifensulfuron - 6 6 - 7 - NA NA 8 NA NA 6 7 -

Rimsulfuron/mesotrione 9 8 8 8 9 7 NA 8 9 9 7 9 9 9

Tembotrione 9 8 8 8 9 7 NA 9 9 7 7 8 9 9

Thiencarbazone/tembotrione 9 8 8 8 9 7 NA 9 9 7 7 8 9 9

Topramezone 9 8 7 7 9 7 7 8 9 9 6 8 9 9

1All weed control ratings except for HS, PA, PS, and SP are from the 2014 Weed Control Guide for Ohio and Indiana, Ohio State University and 

Purdue University (Loux et al., 2014). Ratings for HS, PA, PS, and SP are from the 2015 Weed Control Guidelines for Mississippi, Mississippi 

State University (Mississippi State University, 2015). Weed control ratings for weeds, except HS, PA, PS, and SP, are: 9 = 90% to 100%, 8 = 

80% to 90%, 7 = 70% to 80%, 6 = 60% to 70%, - = less than 60% control, not recommended. Weed control ratings for HS, PA, PS, and SP are: 

9-10 = excellent, 7-8 = good, 4-6 = fair, 0-3 = none to slight, NA= data not available in (Mississippi State University, 2015). Ratings assume the 

herbicides are applied in the manner suggested in the guidelines and according to the label under optimum growing conditions.

2Weed species: BN = black nightshade, CB = cocklebur, CR = common ragweed, GR = giant ragweed, LQ = lambsquarters, MG = morningglory 

spp., HS = hemp sesbania, PA = palmer and spiny amaranth, PW = pigweed, PS= prickly sida, SP = sicklepod, SW = smartweed, VL = 

velvetleaf, and WH = waterhemp. 

*Rating based on glufosinate to Liberty Link® maize and glyphosate applied to Roundup Ready® Corn 2 maize.
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VIII.F.2. Herbicide Resistant Weeds in Maize

Table VIII-6 provides a summary of the common weeds in maize that have biotypes reported 

resistant to the various herbicide sites-of-action in the U.S. To date there are only two weed 

species with biotypes confirmed to be resistant to dicamba in the U.S. after over 40 years of use 

– kochia (Bassia scoparia) and prickly lettuce (Lactuca serriola) (Heap, 2019). Additionally, a 

population of lambsquarters (Chenopodium album) has been confirmed as resistant to dicamba in 

New Zealand, common hempnettle (Galeopsis tetrahit), kochia and wild mustard (Sinapis 

arvensis) in Canada, smooth pigweed (Amaranthus hybridus) in Argentina, wild mustard in 

Turkey and bachelor’s button/cornflower (Centaurea cyanus) in Poland have been confirmed as 

resistant, for a total of 7 species worldwide with confirmed resistance to dicamba (Heap, 2019). 

Currently in the U.S., six grass species (of which three are common weeds in maize; Table 

VIII-6) and 11 broadleaf species (of which eight are common weeds in maize; Table VIII-6) 

have been confirmed to have resistance to glyphosate (Heap, 2019). Dicamba provides good to 

excellent control of all eight of the common broadleaf species resistant to glyphosate. These 

broadleaf weed species, except kochia biotypes in Kansas state, have not been reported to have 

populations that are resistant to both glyphosate and dicamba in the U.S. (Heap, 2019). There 

are a total of 3 weed species worldwide with biotypes that have resistance to glufosinate. The 

first species resistant to glufosinate in the U.S. was recently confirmed in a glyphosate-resistant 

Italian ryegrass (Lolium perenne ssp. multiflorum) population (Avila-Garcia and Mallory-Smith, 

2011). Additionally, Italian ryegrass, perennial ryegrass (L. perenne) populations in New 

Zealand (Ghanizadeh et al., 2015), goosegrass (Eleusine indica) from Malaysia (Seng et al., 

2010) and rigid ryegrass (L. rigidum) in Greece (Travlos et al., 2018) have been confirmed 

resistant to glufosinate. For quizalofop herbicide, johnsongrass (Sorghum halepense), Italian 

ryegrass, giant foxtail (Setaria faberi), cheatgrass (Bromus tectorum) and common wild oat

(Avena fatua) have been reported to be resistant in the US (Heap, 2019); and for 2,4-D herbicide, 

a total of 5 broadleaf weeds (waterhemp, Palmer amaranth, prickly lettuce, wild carrot (Daucus 

carota) and buckhorn plantain (Plantago lanceolata) have been confirmed to be resistant in the 

US (Heap, 2019). A discussion regarding the usefulness of MON 87429 in management of 

herbicide resistant weeds can be found in Section VIII.F.4. The potential for development of 

weeds resistant to dicamba, glufosinate, quizalofop, 2,4-D and glyphosate resistance can be 

found in Appendix K.
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Table VIII-6. Common Weeds in Maize and Their Resistance to Herbicide Sites-of-action

in the U.S.1

Site-of-action

Weed Species2

ACCase InhibitorsALS InhibitorsLong Cbain Fatty Acid InhibitorsMicrotubule InhibitorsEPSPS InhibitorsPhotosystem II Inhibitors 

–C1

HPPD InhibitorsPSII Inhibitors 

– C2

Synthetic AuxinsPS1 Electron DiverterPPO InhibitorsGlutamine Synthase Inhibitors

Grasses 

Barnyardgrass X3 X X X X 

Crabgrass spp. (large, 

smooth) X X 

Foxtail spp. (giant, 

green, yellow) X X X X 

Italian ryegrass X X X X X X 

Goosegrass X X X X X

Johnsongrass X X X X

Shattercane X

Yellow nutsedge X

Broadleaves 

Black nightshade 

(Eastern) X X 

Common chickweed X

Common cocklebur X 

Common purslane X X 

Common ragweed X X X X

Giant ragweed X X

Horseweed (marestail) X X X X X 

Jimsonweed X 

Kochia X X X X X

Lambsquarters X X 

Palmer amaranth X X X X X X X X

Prickly sida X 

Pigweed spp. 

(waterhemp, redroot, 

smooth, Powell,) X X X X X X X X

Russian thistle X X

Smartweed spp. 

(Pennsylvania, 

ladysthumb) X 

Sunflower X X 

Velvetleaf X 

1

(Heap, 2019). 

2Weed species and herbicide sites-of-action listed are only those common in maize. 

3

Indicates confirmed resistance in the U.S.
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VIII.F.3. Impact of MON 87429 Maize Introduction on Weed Management Practices

Monsanto has developed a new herbicide-tolerant MON 87429 maize, that can provide growers 

additional options for an effective and sustainable weed management system. MON 87429 maize 

offers dicamba, glufosinate, quizalofop and 2,4-D-tolerance, and enables RHS hybrid seed 

production. For commercial use, MON 87429 maize will be combined with deregulated 

glyphosate tolerance traits, such NK603, via traditional breeding techniques to provide full-plant 

tolerance to glyphosate. The combination of herbicide-tolerance traits will allow the preplant

and postemergence use of dicamba, glufosinate, quizalofop, 2,4-D, and glyphosate herbicides in 

an integrated weed management program to control a broad spectrum of grass and broadleaf 

weed species (Ganie and Jhala, 2017; Johnson et al., 2010). Dicamba, glufosinate and 2,4-D will 

provide additional options to control hard to control broadleaf weeds in addition to glyphosate 

(e.g., hemp sesbania, morningglory species, and prickly sida) and these herbicides (dicamba, 

glufosinate and 2,4-D) also offer an effective control option for glyphosate-resistant broadleaf 

weed species, namely marestail, common ragweed, giant ragweed, Palmer amaranth and 

waterhemp when used according to the label (Ganie and Jhala, 2017; Johnson et al., 2010). 

These herbicides will also offer an effective control option for broadleaf species resistant to 

acetolactate synthetase (ALS) and protoporphyrinogen oxidase (PPO) chemistries. Similarly, 

quizalofop and glufosinate herbicides, in addition to glyphosate provide options to control grass 

weeds effectively, when used according to the label. With the introduction of MON 87429 

maize, growers will have the ability to continue to use established maize production practices 

including crop rotation, tillage systems, labeled herbicides, and row spacing, thereby using the 

same planting and harvesting machinery currently being utilized. As MON 87429 maize will be 

stacked with deregulated glyphosate tolerance traits, such as NK603, to provide full plant 

tolerance to glyphosate, growers will also continue to have the flexibility and simplicity in weed 

control provided by glyphosate that will allow growers to continue to reap the environmental 

benefits associated with the use of conservation-tillage that is facilitated by the use of glyphosate 

for postemergence weed control (Monsanto, 2017).

Dicamba is currently authorized by U.S. EPA for preplant and/or early postemergence 

application in conventional maize. In support of Monsanto’s third generation herbicide tolerant 

product MON 87419 maize, Monsanto requested that EPA allow the 0.5 lb a.e./ac 

postemergence application window for dicamba to be extended from V5 to V8 growth stage or 

36-inch height of maize, whichever occurs first (U.S. EPA, 2019). The combined (pre- and postemergence) maximum annual application rate of dicamba in MON 87419 maize would be 2.0 

lbs. a.e. dicamba per acre per year, increased from the current maximum annual application rate 

of 0.75 lbs. a.e. in conventional maize. Pending approval of the expanded label at EPA, the 

dicamba use pattern for MON 87429 would be no different than that of MON 87419. Growers 

will be able to apply dicamba alone or tank mixed with glyphosate or in sequence with 

glyphosate or glufosinate on MON 87429 maize. Pending approval of the expanded label at 

EPA, the dicamba use pattern for MON 87429 would be no different than that of MON 87419. 

Glufosinate is currently authorized by U.S. EPA and labeled for preplant applications prior to 

planting or prior to emergence on conventional and herbicide-tolerant maize hybrids and for incrop postemergence applications on glufosinate-tolerant hybrids only (Bayer CropScience, 

2016). Glufosinate use in MON 87429 maize will not change from current labeled uses of 

glufosinate. Growers will be able to apply glufosinate alone and in sequence with dicamba, 2,4-

D or quizalofop for preplant or postemergence in-crop applications on MON 87429 maize. 
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Over-the-top postemergence application rates and timings for glufosinate alone would be the 

same as currently labeled for glufosinate use in glufosinate-tolerant hybrids (i.e., from 

emergence up to the V7 growth stage at up to 0.402 lbs. a.i./acre, seasonal maximum of 0.80 lbs. 

a.i. per acre) (Bayer CropScience, 2016). 

Quizalofop herbicide can cause severe crop injury in conventional maize. U.S. EPA has 

authorized the use of quizalofop on herbicide-tolerant maize for over-the-top application from 

V2 through V6 stages of maize development for managing grass weeds (DuPont, 2018). 

Quizalofop use in MON 87429 maize will not change from current labeled uses of quizalofop on 

herbicide-tolerant maize.

2,4-D has been used for many decades as preplant and postemergence herbicide for control of 

broadleaf weeds in maize fields and many other weed control applications including other crops, 

pastures and rangeland. 2,4-D with relative selectivity for broadleaf plants, can cause injury to 

conventional maize depending on the growth stage and method of application. U.S. EPA has 

authorized the use of 2,4-D with choline salt for over-the-top application on herbicide-tolerant 

maize (Dow, 2017) up to the V8 stage of maize development while keeping the total maximum 

seasonal rate per acre same as its use in conventional maize. 2,4-D use in MON 87429 maize is 

not anticipated to change from current labeled uses of 2,4-D on herbicide-tolerant maize.

The MON 87429 event confers glyphosate tolerance in specific plant tissues (i.e., not in tassels) 

and will be used to facilitate the production of hybrid seed. MON 87429 is not intended to be 

offered for commercial use as a stand-alone product, but will be combined, through traditional 

breeding methods, with other deregulated events that confer full-plant glyphosate tolerance (e.g., 

NK603). The general weed management recommendations for all the regions in the U.S. are 

shown in (Table VIII-7). A preemergence residual herbicide is recommended regardless of 

tillage system to 1) reduce early weed competition, and 2) to increase the likelihood that multiple

effective herbicide sites-of-action are used in maize and to provide protections against additional 

resistance development to existing maize herbicides. The variability in herbicide 

recommendations will be dictated by variations in weed spectrum, tillage systems, and 

environment across these regions and is consistent with Monsanto and academics 

recommendations for a comprehensive weed resistance management program. These 

recommendations shown in Table VIII-7 are a high-end estimate of anticipated herbicide use 

associated with MON 87429 maize combined with glyphosate-tolerant maize. 
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Table VIII-7. Anticipated Weed Management Recommendations for MON 87429 Maize 

Combined with Glyphosate-Tolerant Maize Systems1

Application 

Timing

Conventional Tillage Conservation Tillage 

(No-till or reduced till)

Hard to 

Control

Weeds2

GR3 Weeds and 

Hard to Control 

Weeds5

Hard to 

Control 

Weeds2

GR3 Weeds and 

Hard to Control Weeds5

Preemergence 

(burndown, at 

planting) Residual

Residual

+

Dicamba or 2,4-D

Glyphosate +

Residual

Glyphosate 

+ 

Residual

+

Dicamba or 2,4-D

Postemergence4

Glyphosate

or 

glufosinate

+

4

Dicamba 

or 2,4-D

Glyphosate or 

Glufosinate

+

4 Dicamba or 2,4-D

and/or Quizalofop

Glyphosate or 

Glufosinate

+ residual +4

Dicamba or 

2,4-D

Glyphosate or Glufosinate 

+

4 Dicamba or 2,4-D and/or 

Quizalofop

1 The anticipated use patterns represent a high-end estimate for potential dicamba, 2,4-D, glufosinate 

and/or quizalofop use associated with MON 87429 combined with glyphosate-tolerant maize. Actual 

weed control practices by growers will vary depending on the specific weed spectrum, agronomic 

situation of the individual maize field and herbicide label recommendations. 

2 Hard to control weeds namely, morningglory species, hemp sesbania, prickly sida ̧ and wild buckwheat.

3 GR = glyphosate resistant.

4 + = premix, tank mix or sequential application of herbicides. 

5 Dicamba and 2,4-D have broadleaf selectivity and quizalofop has grass selectivity. Follow label 

recommendations and best management practices for herbicide rotations. Recommendations for all fields 

will assume GR weeds are present.

As a result of introducing MON 87429, there are no major anticipated changes in the production 

of hybrid maize seed with the exception of the intended non-viable pollen phenotype resulting 

from glyphosate applications during reproductive development. Glyphosate can also be used for 

weed control in MON 87429 inbred seed increases or hybrid seed production (may result in non 

viable pollen phenotype). Other agricultural management practices for the production of hybrid 

maize seed and for the cultivation of commercial maize would also be no different for 

MON 87429 than for conventional maize hybrids.

Upon stacking of MON 87429 maize with deregulated glyphosate tolerance traits, such as

NK603, growers will have the ability to continue use of established maize production practices 

including tillage systems; the same planting and harvesting machinery; established practices for

management of insects, diseases, and other pests; and many of the current herbicides used for 

weed control, including glyphosate with its established environmental benefits.
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VIII.F.4. MON 87429 Maize as a Component in Weed Resistance Management

Although herbicide resistance may eventually occur in a weed species when an herbicide is 

widely used, resistance can be delayed, contained, and managed through good management 

practices, research and education. Crops engineered with tolerance to established herbicides 

combined with tolerance to glyphosate may provide more diverse weed management options 

(Pallett, 2018). The combination of dicamba, glufosinate, quizalofop and 2,4-D herbicidetolerance traits with glyphosate-tolerant maize, will facilitate the utilization of multiple herbicide 

sites-of-action in a grower’s weed control system, and thereby reduce the potential for further 

resistance development to glyphosate, dicamba, glufosinate, quizalofop and 2,4-D herbicides as 

well as other important maize herbicides. Research conducted by Monsanto showed the value of 

multiple preplant herbicides (including soil active herbicides) followed by an early 

postemergence application of a mixture of herbicides with multiple sites-of-action, including a 

soil active herbicide, against broadleaf weeds that included species in the genus Amaranthus

(Bayer CropScience, 2019b). Such a program would optimize the likelihood of using two or 

more effective sites-of-action against the targeted weeds. In areas with glyphosate-resistant and 

hard to control broadleaf weed populations, dicamba or 2,4-D may be applied pre-planting as a 

tank mix with preemergence herbicides and/or applied post-emergence in addition to glufosinate

in MON 87429 maize. For control of glyphosate-resistant grass weed species, quizalofop 

provides a post-emergence option and may also be applied in sequence with glufosinate. The 

herbicide tolerance traits in MON 87249 maize also increase the potential to target late-emerging 

weed cohorts and weeds resistant to multiple herbicides with multiple herbicide sites-of-action. 

Stewardship of dicamba, glufosinate, quizalofop and 2,4-D herbicides to preserve their 

usefulness to growers is an important aspect of Monsanto’s stewardship commitment, as is 

discussed in Appendix K. Specifically, Monsanto has implemented and will continue to develop 

and proactively provide recommended weed resistance management practices9, and will utilize 

multiple methods to distribute technical and stewardship information to growers, academics, and 

grower advisors through a variety of communication tools. Monsanto’s Technology Use Guide 

(TUG) (Monsanto, 2019) will set forth the requirements and best practices for the cultivation of 

MON 87429 maize including recommendations on weed resistance management practices. 

Growers purchasing products containing MON 87429 maize are required by Monsanto’s 

Technology Stewardship Agreement (TSA) to read and follow the TUG. For weed management 

during the production of hybrid seeds using MON 87429 as the female inbred line, seed 

producers are encouraged to follow good management practices for herbicide resistance 

management to minimize the potential for further selection of herbicide-resistant weeds. 

Furthermore, Monsanto and its affiliates are committed to actively evaluating herbicide 

performance and weed efficacy on a continuing basis, and developing additional mitigation plans 

as necessary to manage resistance development for glyphosate, dicamba, glufosinate, quizalofop 

and 2,4-D. 

 

9 Weed resistance management guidelines available at http://www.iwm.bayer.com/ and 

http://www.roundupreadyplus.com/. 
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VIII.F.5. Weed Management Conclusion

Combining MON 87429 maize with deregulated glyphosate tolerance traits, such as NK603, will 

allow the use of dicamba, glufosinate, quizalofop, 2,4-D and glyphosate herbicides in an 

integrated weed management program to control a broad spectrum of grass and broadleaf weed 

species in maize. These herbicides will also provide distinct sites-of-action for an effective 

proactive (to delay selection of additional herbicide resistant weeds) and reactive (to manage 

weed populations that have developed resistance) weed resistance management program in 

maize. With MON 87429 maize, growers will have options to use and rotate and/or use 

combinations of herbicides with effective herbicide sites-of-action for in-crop control of 

glyphosate’s hard to control and resistant broadleaf and grass weeds that are present in U.S. 

maize production. 

Furthermore, the integration of MON 87429 maize, along with the glyphosate-tolerant maize 

trait, will provide growers with the ability to continue use of established maize production 

practices including tillage systems; the same planting and harvesting machinery; established 

management of insects, diseases, and other pests; and many of the current herbicides used for 

weed control, including glyphosate with its established environmental and grower benefits. 

Therefore, it is not anticipated that the commercialization of MON 87429 maize in the U.S. will 

have significant impacts on current maize agronomic practices, beyond the intended benefits of 

more effective and durable management of common and troublesome weeds, including 

herbicide-resistant weeds and for consistently producing high-quality, high-purity hybrid maize 

seed.

VIII.G. Crop Rotation Practices in Maize

Crop rotation is a well-established farming practice and a useful management tool for maize 

production. Crop rotations are used to diversify farm income, spread labor requirements 

throughout the year, and spread the crop loss risk associated with weather and pest damage 

across two or more crops. In terms of soil and pest management, rotations are used to 1) manage 

weed, insect, and disease pests, 2) reduce soil erosion by wind and water, 3) maintain or increase 

soil organic matter, 4) provide biologically fixed nitrogen when legumes are used in the rotation, 

and 5) manage excess nutrients (Singer and Bauer, 2009). Studies in U.S. corn belt states 

indicate maize yield is about 10-15% higher in maize grown following soybean than maize 

grown following maize (Singer and Bauer, 2009). While there are tangible benefits from crop 

rotations, many other factors such as crop price fluctuations, input costs, rental agreements, 

government price supports, weather, choice of farming system and on-farm resources, and other 

factors all contribute to decisions regarding crop rotations. Table VIII-8 provides an assessment 

of the common rotational crops following maize at the U.S. country level. Approximately 30% 

of the U.S. maize acres were rotated back to maize and 57% are rotated to soybean the following 

year in 2013 (USDA-APHIS Petition #15-113-01p Table VIII-2 pg. 153). Wheat and cotton are 

other significant rotational crops with approximately 5% and 2%. In addition, based on the 

integrated pest management annual surveys of a subset of maize growers who planted maize with 

corn rootworm (CRW) trait in the U.S. in high CRW pressure states of Iowa, Illinois, Indiana, 

Minnesota, Nebraska and South Dakota, the percentage of continuous maize planting has largely 

remained the same between 2016, 2017 and 2018 (31%, 27% and 29%, respectively) (ABSTC, 

2017; 2018; 2019).
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Introduction of MON 87429 maize is not expected to limit crop rotation practices and there 

would be no significant changes anticipated in post-maize planting due to the availability of 

MON 87429 maize since (1) the use of dicamba, glufosinate, quizalofop, 2,4-D and glyphosate 

herbicides does not limit crop rotation choices due to their limited herbicidal persistence and 

carry-over potential attributes when applied according to the label; and, (2) application use

patterns for glufosinate, quizalofop, 2,4-D or glyphosate herbicides for MON 87429 maize will 

be the same as already approved rates in current biotechnology-derived herbicide tolerant 

products available to growers and pending approval of the expanded label at EPA, the dicamba 

use pattern for MON 87429 would be no different than that of Monsanto’s third-generation 

herbicide tolerance product, MON 87419 maize (U.S. EPA, 2019).

Crop rotation is a valuable tool in managing herbicide resistance. In addition, the use of 

herbicide mixtures have been shown to be effective in delaying development of herbicide 

resistance (Beckie and Harker, 2017; Evans et al., 2016). The herbicide tolerance traits in MON 

87429 combined with a deregulated glyphosate-tolerance trait support integrated weed 

management programs that include herbicides and/or herbicide mixtures with diverse sites-ofaction, both within a single maize growing season and between maize and rotational crops, to 

delay the development of herbicide resistance in weeds. Due to natural tolerances or introduced 

traits, common rotational crops for maize (e.g., soybeans, cotton) may also tolerate dicamba, 

glufosinate, 2,4-D, quizalofop, and/or glyphosate. However, given the number of sites-of-action 

for herbicides that may be applied in MON 87429 maize and rotational crops (including those 

that may be applied for the conventional crops), an herbicide program including sites-of-action 

that differ between the crops is expected to be feasible.

Table VIII-8. Rotational Crops in the U.S. Following Maize Production

United States Total 

Maize Acres1,5

Rotational Crops 

Following Maize

Rotational 

Crop Acres2,5

% Rotational Crop 

of Total Maize2

95,365 Maize

Soybean

Wheat

Cotton

Alfalfa3

Other Hay

Other crops4

28,291

54,451

4,527

1,870

1,303

1,118

3807

Total: 95,365

29.7

57.1

4.7

2.0

1.4

1.2

3.9

This table was developed by compiling the data from all four regional summaries. 

1 Maize acreage based on 2013 planting data (USDA-NASS, 2014).

2Rotational Crop Acres source: USDA Petition #15-113-01p Table VIII-2 pg. 153 

3 Newly seeded alfalfa.

4 Other crops: combined acreage of rotated crops following maize that are individually less than 1000,000 

acres. It includes sorghum, oats, sugar beets, sunflower, barley, peanut, dry beans, potatoes, tobacco, 

millet, rice, safflower and vegetables (chili peppers, cantaloupe, watermelon, tomatoes, onions, snap 

beans, sweet corn, cabbage, lima beans, cucumbers, bell peppers, squash, green peas, carrots).

5 All acreages are expressed as 1000s of acres. Totals may not be exact due to rounding.
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VIII.H. Maize Volunteer Management

Volunteer maize is defined as a maize plant that germinates and emerges unintentionally in a 

subsequent crop. Volunteer maize commonly occurs in rotational crops in the season following 

cultivation of maize. Factors reducing the numbers of volunteers in the following crop include 

the harvesting of maize for silage before grain physiological maturity (approximately 6.1 million 

U.S. maize acres in 2018 (USDA-NASS, 2019c) and warm, moist climates such as those in the 

Southeast, where many seeds will germinate in the fall but not survive the winter. In the 

Northern maize-growing regions, volunteer maize does not always occur in the rotational crop 

because of seed decomposition over the winter, efficient harvest procedures, and tillage 

practices.

Management of volunteer maize in rotational crops involves minimizing or reducing the 

potential for volunteers through practices that include: 1) adjusting harvest equipment to 

minimize the amount of maize grain lost in the field; 2) planting maize hybrids that reduce the 

extent of ear drop; 3) choosing maize hybrids with superior stalk strength and reduced lodging; 

and 4) practicing no-till production to significantly reduce the potential for volunteer growth in 

the rotational crop. If volunteer maize does occur in subsequent crops, preplant tillage (if 

significant volunteers have already emerged) and in-crop cultivation are very effective 

management tools. In addition, Gramoxone® (paraquat) is a preplant option to control volunteer 

maize, including MON 87429 (Appendix L, Table L-1) alone or with Tricor® (metribuzin), 

before planting another maize crop (Ikley et al., 2017; Steckel et al., 2009). Similarly, use of 

Gramoxone® (paraquat) tank mixed with residual herbicides such as metribuzin or linuron is 

recommended for preplant control of volunteer maize in soybean rotation (Bayer CropScience, 

2019a). Several postemergence herbicides also are available to control volunteer maize 

(conventional or herbicide-tolerant maize) in each of the major maize rotational crops. Because 

MON 87429 maize is tolerant to the ACCase ‘fop’ herbicides, quizalofop and other fop 

herbicides will not be effective to remove volunteer MON 87429 maize. Nonetheless, other 

ACCase herbicides such as cyclohexanedione or “dims” (e.g., clethodim, sethoxydim) are still 

effective in control of MON 87429 (Appendix L, Table L-1) as volunteer maize in broadleaf 

crops. Table VIII-9 provides a summary of labeled selective postemergence herbicides for the 

effective control of volunteer maize, including MON 87429 maize, in specific rotational crops 

and include Poast® (sethoxydim), and Select® 2EC (clethodim). These herbicides are labeled for 

use in 11 vegetable rotation crops and 10 field crops that include soybean, cotton, sugar beet and 

alfalfa. Imazamox (Raptor®) is an option for postemergence control of volunteer maize in 

soybean, alfalfa, dry beans, peas, lima bean, snap bean, clover, and edamame (BASF, 2015). In 

cases of farm sites with grass weed biotypes resistant to quizalofop and/or “dims”, and to delay 

weed resistance development to ACCase herbicides, there are other preplant and postemergence 

herbicide options available to control grass weeds and/or volunteer maize (see Appendix L, 

Table L-1). For volunteer control of maize including MON 87429, in wheat crop, there are

 

® Select is a trademark of Valent U.S.A. Corporation; ® Powerflex, Goldsky and Perfectmatch are the trademarks of 

Dow AgroSciences Corporation; ® Gramoxone is a trademark of Syngenta Corporation; ® Tricor is a trademark of 

United Phosphorus, Inc. ® Raptor is a trademark of BASF.
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additional postemergence herbicide options available such as Powerflex® (pyroxsulam), 

GoldSky® (florasulam+ fluroxypyr+ pyroxsulam), Perfectmatch® (clopyralid+ floroxypyr+ 

pyroxsulam), etc (NDSU, 2018). Additionally, there are also many non-chemical methods of 

weed control (mechanical removal, tilling, etc.) that are effective in removing unwanted maize, 

including MON 87429.

MON 87429 combined with deregulated glyphosate tolerance traits, such as NK603, is not 

expected to notably impact the management of maize volunteer plants based on the availability 

of various herbicidal and cultivation methods for controlling volunteer MON 87429 maize as 

well as the demonstrated lack of agronomic and phenotypic differences, including germination 

and dormancy characteristics, between MON 87429 and conventional maize (see Section 

VII.C.1).
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Table VIII-9. Herbicides Labeled for Control of Volunteer Maize in Labeled Rotational 

Crops1

Crop Poast Select 2EC

Soybeans x x

Hay Alfalfa, 

Clover 

Alfalfa, 

Clover 

Cotton x x

Sugar Beets x x

Sunflower x x

Peanuts x x

Dry Beans x x

Lentils x

Potatoes x x

Sweet Potatoes x x

Vegetables

Cabbage x

Cantaloupe x

Carrots x

Cucumbers x

Leaf Lettuce x x

Peas, green x

Peppers, Chili x x

Peppers, 

Tabasco

x

Onions Bulbs only

Tomatoes x x

Watermelon x

1Source: (BASF, 2019; Valent, 2006)
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VIII.I. Stewardship of MON 87429 Maize

Monsanto develops effective products and technologies that deliver value to growers and 

conserve resources that agriculture depends on and is committed to assuring that its products and 

technologies are safe and environmentally responsible. Monsanto demonstrates this commitment 

by implementing product stewardship processes throughout the lifecycle of a product and by 

participation in the Excellence Through Stewardship® (ETS) Program10 (BIO, 2012). These 

policies and practices include rigorous field compliance and quality management systems and 

verification through auditing. Monsanto’s Stewardship Principles are also articulated in 

Technology Use Guides (Monsanto, 2019) and Monsanto Technology Stewardship Agreements 

that are signed by growers who utilize Monsanto branded traits, to communicate stewardship 

requirements and best practices.

As an integral component of fulfilling this stewardship commitment, Monsanto will seek 

biotechnology regulatory approvals for MON 87429 maize in all important maize import 

countries with a functioning regulatory system to assure global compliance and support the flow 

of international trade. These actions will be consistent with the ETS Guide for Product Launch 

Stewardship of Biotechnology-Derived Plant Products (ETS, 2018), Biotechnology Innovation

Organization (BIO) Policy on Product Launches (BIO, 2012). Monsanto continues to monitor 

other countries that import significant quantities of maize from the U.S., for the development of 

formal biotechnology approval processes. If new functioning regulatory processes are 

developed, Monsanto will re-evaluate its stewardship plans and make appropriate modifications 

to minimize the potential for trade disruption.

Monsanto is also committed following industry best practices on seed quality assurance and 

control to ensure the purity and integrity of MON 87429 maize hybrid seed. As with all of 

Monsanto’s products, before commercializing MON 87429 maize in any country, a MON 87429 

maize detection method will be available via a third-party vendor to maize producers, processors,

and buyers regardless of whether they have purchased MON 87429 or not. 

Stewardship of glyphosate, dicamba, glufosinate, quizalofop and 2,4-D herbicides to preserve 

their usefulness to growers is also an important consideration, especially in light of recent U.S.

EPA guidance on herbicide resistance management, labeling, education, training and stewardship 

that is intended to provide growers and registrants strategies to delay herbicide resistance 

development and prolong efficacy of herbicides (U.S. EPA, 2017b; c). Detailed information 

regarding dicamba, glufosinate, quizalofop, 2,4-D and glyphosate weed resistance and the 

usefulness of the herbicide-tolerant MON 87429 maize trait in combination with 

glyphosate-tolerant traits in maize to address herbicide-resistance issues is presented in Section 

VIII.F and Appendix K. 

 

10 www.excellencethroughstewardship.org/
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VIII.J. Summary and Conclusion: Impact of the Introduction of MON 87429 Maize on 

Agricultural Practices

MON 87429 maize has been developed to facilitate greater choices for growers implementing 

effective weed management including tough-to-control and herbicide resistant broadleaf weeds. 

The ability to use dicamba, glufosinate, quizalofop and 2,4-D herbicides with multiple 

sites-of-action can be part of an effective weed management system for maize production in the 

U.S. Glufosinate, quizalofop, 2,4-D, and glyphosate herbicides are already labeled for use in 

maize (Liberty®: EPA Reg No. 264-660, Enlist OneTM: EPA Reg No 62719-695, Assure® II: EPA 

Reg No. 352-541, Durango® DMA®: EPA Reg No. 62719-556). Pending approval of the 

expanded label at EPA, the dicamba use pattern for MON 87429 would be no different than that 

of Monsanto’s third generation herbicide tolerant product MON 87419 maize. For MON 87419 

maize, Monsanto requested that EPA allow the 0.5 lb a.e./ac postemergence application window 

for dicamba to be extended from V5 to V8 growth stage or 36-inch height of maize, whichever 

occurs first (U.S. EPA, 2019). The combined (pre- and post-emergence) maximum annual 

application rate of dicamba in MON 87419 maize would be 2.0 lbs. a.e. dicamba per acre per 

year, increased from the current maximum annual application rate of 0.75 lbs. a.e. in 

conventional maize. Pending approval of the expanded label at EPA, the dicamba use pattern for 

MON 87429 would be no different than that of MON 87419. Therefore, the introduction of 

MON 87429 is not expected to have adverse impacts on current agronomic, cultivation and 

management practices for commercial grain or hybrid maize seed production. No significant 

changes are anticipated in crop rotations, tillage practices, planting practices, fertility 

management, weed and disease management, and volunteer management from the introduction 

of MON 87429 maize. 
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IX. PLANT PEST ASSESSMENT

IX.A. Introduction 

This section provides a brief review and assessment of the plant pest potential of MON 87429 

and its impact on agronomic practices and the environment. USDA-APHIS has responsibility, 

under the Plant Protection Act (PPA) (7 U.S.C. § 7701-7772), to prevent the introduction and 

dissemination of plant pests into the U.S. Regulation 7 CFR § 340.6 provides that an applicant 

may petition APHIS to evaluate submitted data to determine that a particular regulated article 

does not present a plant pest risk and should no longer be regulated. If APHIS determines that 

the regulated article is unlikely to pose a plant pest risk, the petition is granted, thereby allowing 

unrestricted introduction of the article.

According to the PPA, the definition of “plant pest” includes the living stage of any of the 

following, or a similar article, that can directly or indirectly injure, damage, or cause disease in 

any plant or plant product: (A) a protozoan; (B) a nonhuman animal; (C) a parasitic plant; (D) a 

bacterium; (E) a fungus; (F) a virus or viroid; or (G) an infectious agent or other pathogens (7 

U.S.C. § 7702(14)).

The regulatory endpoint under the PPA for biotechnology-derived crop products is not zero risk, 

but rather a determination that deregulation of the article in question is not expected to pose a 

potential for plant pest risk. Information in this petition related to plant pest risk characteristics 

includes: 1) mode-of-action and changes to plant metabolism; 2) composition; 3) expression and 

characteristics of the gene product; 4) potential for weediness of the regulated article; 5) potential 

impacts to NTOs; 6) abiotic stressor, disease and pest susceptibilities; 7) impacts on agronomic 

practices; and 8) impacts on the weediness of any other plant with which it can interbreed, as 

well as the potential for gene flow. Using the assessment above, the data and analysis presented 

in this petition lead to a conclusion that MON 87429 is unlikely to pose a plant pest risk, and 

therefore should no longer be subject to regulation under 7 CFR § 340.

IX.B. Plant Pest Assessment of MON 87429 and Expressed Protein

This section summarizes the details of the genetic insert, characteristics of the genetic 

modification, and safety and expression of the DMO, PAT, CP4 EPSPS and FT_T proteins

expressed in MON 87429 used to evaluate the food, feed, and environmental safety of 

MON 87429. 

IX.B.1. Characteristics of the Genetic Insert and Expressed Protein

IX.B.1.1. Genetic Insert

As described in Section III, MON 87429 was developed by Agrobacterium-mediated 

transformation of maize embryos using plasmid vector PV-ZMHT519224. Characterization of 

the DNA insert in MON 87429 was conducted using a combination of sequencing, PCR, and 

bioinformatics methods. The results of this characterization demonstrate that MON 87429 

contains one copy of the intended transfer DNA containing the dmo, pat, ft_t and cp4 epsps

expression cassettes that is stably integrated at a single locus and is inherited according to 

Mendelian principles over multiple breeding generations. These methods also confirmed that no 
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vector backbone or other unintended plasmid sequences are present in MON 87429. 

Additionally, the genomic organization at the insertion site was assessed by comparing the 

sequences flanking the T-DNA insert in MON 87429 to the sequence of the insertion site in 

conventional maize. This analysis determined that no major DNA rearrangement occurred at the 

insertion site in MON 87429 upon DNA integration.

IX.B.1.2. Mode-of-Action 

MON 87429 contains the dmo gene from Stenotrophomonas maltophilia that expresses a 

dicamba mono-oxygenase (DMO) protein to confer tolerance to dicamba herbicide, the pat gene 

from Streptomyces viridochromogenes that expresses the phosphinothricin N-acetyltransferase 

(PAT) protein to confer tolerance to glufosinate herbicide, the ft_t gene derived from 

Sphingobium herbicidovorans that expresses a FOPs and 2,4-D dioxygenase (FT_T) protein to 

confer tolerance to quizalofop and 2,4-D herbicides, and the cp4 epsps gene from Agrobacterium

sp. strain CP4 that expresses the CP4 EPSPS protein and contains an siRNA Target Sequence in 

the 3’ UTR, to confer tissue-specific glyphosate tolerance, to facilitate the production of hybrid 

maize seed.

DMO is an enzyme that catalyzes the demethylation of dicamba to the non-herbicidal compound 

3,6-dichlorosalicylic acid (DCSA), a well-known metabolite of dicamba in conventional cotton, 

soybean, livestock and soil (FAO-WHO, 2011b; a; U.S. EPA, 2009). PAT protein acetylates the 

free amino group of glufosinate to produce non-herbicidal N-acetyl glufosinate, a well-known 

metabolite in glufosinate-tolerant plants (OECD, 2002a). FT_T protein catalyzes a dioxygenase 

reaction, in the presence of alpha-ketoglutarate and oxygen, metabolizing quizalofop into 

quizalofop-phenol and pyruvate and metabolizing 2,4-D into 2,4-dichlorophenol (2,4-DCP) and 

glyoxylic acid. The safety of 2,4-D, quizalofop, and their metabolites have been assessed by US 

EPA which concluded that there is a reasonable certainty that no harm will result to the general 

population, or to infants and children from aggregate exposure to 2,4-D (U.S. EPA, 2017a) or 

quizalofop (U.S. EPA, 2018), residues or their metabolites. In plants, the endogenous EPSPS 

protein, an enzyme involved in the shikimate pathway for the biosynthesis of aromatic amino 

acids, is inhibited by the herbicide glyphosate resulting in cell death (Franz et al., 1997). 

MON 87429 produces the same CP4 EPSPS protein that is produced in commercial Roundup 

Ready® crop products which is insensitive to glyphosate and therefore confers tolerance to 

glyphosate. As described in Section IV.G expression of CP4 EPSPS in MON 87429 plants is 

driven by the CaMV 35S promoter, a known constitutive promoter (Holtorf et al., 1995; Terada 

and Shimamoto, 1990). In maize and other monocot plants, CaMV 35S has been shown to drive 

weak gene expression in pollen tissue (Hamilton et al., 1992; Heck et al., 2005). Additionally, 

MON 87429 maize utilizes an endogenous maize regulatory element to target CP4 

EPSPS mRNA for degradation specifically in tassel tissues, resulting in reduced CP4 EPSPS 

protein expression in pollen. Appropriately timed glyphosate applications produce a non-viable 

pollen phenotype and allow for desirable cross pollinations to be made in maize without using 

traditional methods to control self-pollination in female inbred parents. A focused study on the 

MON 87429 siRNA Target Sequence demonstrated the absence of unintended effects on 

endogenous gene regulation. These data taken together with data demonstrating a lack of change 

in pollen morphology or viability between MON 87429 and control (Section VII) suggest the 

siRNA Target Sequence for tissue-selective CP4 EPSPS expression does not result in unintended 

effect on gene regulation in male tissue. 
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IX.B.1.3. Protein Safety and Expression Levels 

The safety and expression of the DMO, PAT, CP4 EPSPS and FT_T proteins are detailed in 

Section V. MON 87429 DMO, PAT, CP4 EPSPS and FT_T protein levels in forage, root, leaf 

and grain of MON 87429 were determined using a multiplexed immunoassay. To further 

demonstrate the MON 87429 RHS trait mode-of-action (MOA), CP4 EPSPS expression in 

pollen tissue was determined to illustrate the differential expression between vegetative and 

pollen tissue. The mean DMO protein level in MON 87429 across all sites was highest in leaf at 

35 μg/g dw and lowest in root at 2.3 μg/g dw. The mean PAT protein level in MON 87429 

across all sites was highest in leaf at 5.8 μg/g dw and lowest in grain at 0.84 μg/g dw. The mean 

CP4 EPSPS protein level in MON 87429 across all sites was the highest in leaf at 54 μg/g 

dw and lowest in grain at 0.63 μg/g dw. As intended the mean CP4 EPSPS protein level in 

MON 87429 pollen across all sites was below the limit of quantitation (0.11 μg/g dw). The 

mean FT_T protein level in MON 87429 across all sites was the highest in leaf at 440 μg/g 

dw and lowest in root at 41 μg/g dw.

MON 87429 DMO is an enzyme that catalyzes the demethylation of dicamba to the 

non-herbicidal compound 3,6-dichlorosalicylic acid (DCSA) and formaldehyde. DMO proteins 

have been previously characterized and the safety of these proteins have been well established. 

Therefore, the consumption of the DMO protein from MON 87429 or its progeny is considered 

safe for humans and animals.

PAT protein is an acetyltransferase that catalyzes the acetylation of the herbicide glufosinate. 

PAT proteins, including the PAT protein isolated from MON 87429, have been previously 

characterized and the safety of the PAT protein has been extensively assessed and in 1997 a 

tolerance exemption was issued for the PAT protein by U.S. EPA (40 CFR § 

180.1151). Therefore, the consumption of the PAT protein from MON 87429 or its progeny is 

considered safe for humans and animals.

The CP4 EPSPS is key enzyme involved in aromatic amino acid biosynthesis and catalyzes the 

reaction where the enolpyruvyl group from phosphoenol pyruvate (PEP) is transferred to the 

5-hydroxyl of shikimate-3-phosphate to form 5-enolpyruvylshikimate-3-phosphate (EPSP) and 

inorganic phosphate. CP4 EPSPS proteins, including the CP4 EPSPS protein from MON 87429, 

have been previously characterized and the safety of the CP4 EPSPS protein has been 

extensively assessed. U.S. EPA has established an exemption from the requirement of a 

tolerance for residues of CP4 EPSPS protein and the genetic material necessary for its production 

in all plants (U.S. EPA, 1996b). Therefore, the consumption of the CP4 EPSPS protein from 

MON 87429 or its progeny is considered safe for humans and animals.

The FT_T protein catalyzes a dioxygenase reaction in the presence of αKG and oxygen to 

metabolize quizalofop, a FOP herbicide, into the herbicidally-inactive quizalofop phenol and 

pyruvate. The FT_T protein also catalyzes the dioxygenase reaction that degrades 

2,4-dichlorophenoxyacetic acid (2,4-D), a synthetic auxin herbicide, into herbicidally-inactive 

2,4-dichlorophenol (2,4-DCP) and glyoxylic acid in the presence of alpha-ketoglutarate and 

oxygen. The physicochemical characteristics of the MON 87429-produced FT_T protein were 

determined and equivalence between MON 87429-produced FT_T and E. coli-produced FT_T 

proteins was demonstrated. Therefore E. coli-produced FT_T is an appropriate test substance for 
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the protein safety studies (heat susceptibility and digestibility). Expression studies demonstrated 

that FT_T is expressed at low levels in grain. An assessment of the allergenic and toxic potential 

of the FT_T protein found that the FT_T protein does not pose a significant allergenic risk and 

was not similar to know toxins. In addition, the donor organism for the MON 87429 FT_T 

coding sequence is from a genus, Sphingobium, that is ubiquitous in the environment and is not 

commonly known for allergenicity and human or animal pathogenicity. The FT_T protein is 

rapidly digested by proteases found in the human gastrointestinal tract (pepsin and pancreatin) 

and demonstrates no acute oral toxicity in mice at the level tested. Based on the above 

information, the consumption of the FT_T protein from MON 87429 or its progeny is considered 

safe for humans and animals. Taken together, the results of these analyses support a 

determination that MON 87429 is no more likely to pose a plant pest risk than conventional 

maize.

IX.B.2. Compositional Characteristics 

For MON 87429, the introduced proteins, DMO, PAT, CP4 EPSPS and FT_T, confer herbicide 

tolerance and lack catalytic activity that is intended to or expected to affect the plant’s 

metabolism. Given the nature of these introduced traits and the overall lack of meaningful 

unintended compositional characteristics observed for biotechnology-derived products 

characterized to date (Herman and Price, 2013; Venkatesh et al., 2015), compositional changes 

that would affect the levels of components in MON 87429 maize were not expected. Monsanto is 

currently in consultation with the Food and Drug Administration following their policy, “Foods 

Derived from New Plant Varieties,” on the food and feed safety of MON 87429 maize 

(Submitted 05-Feb-2019). Composition data for 25 components including major nutrients in 

grain (protein, amino acids, total fat, linoleic acid, carbohydrates, acid detergent fiber, neutral 

detergent fiber and ash), major nutrients in forage (protein, total fat, carbohydrates, acid 

detergent fiber, neutral detergent fiber and ash) and anti-nutrients in grain (phytic acid and 

raffinose) were submitted to FDA as part of the voluntary food/feed safety and nutritional 

assessment for MON 87429 maize. The results of the compositional assessment found that 

MON 87429 did not meaningfully alter component levels in maize and confirms the 

compositional equivalence of MON 87429 to conventional maize.

IX.B.3. Phenotypic, Agronomic, and Environmental Interaction Characteristics

An extensive set of comparative plant characterization data were used to assess whether the 

introduction of dicamba-, glufosinate-, quizalofop- and 2,4-D-tolerance and RHS traits altered 

the plant pest potential of MON 87429 compared to the conventional control (Section VII). 

Phenotypic, agronomic, and environmental interaction characteristics of MON 87429 were 

evaluated and compared to those of the conventional control. As described previously, these 

assessments included seed germination and dormancy characteristics and pollen characteristics in 

the laboratory as well as phenotypic and agronomic characteristics and plant responses to abiotic 

stressors, diseases, and arthropod pests in the field. Results from all phenotypic, agronomic, and 

environmental interaction assessments demonstrated that MON 87429 does not possess increased 

weedy characteristics or increased susceptibility or tolerance to specific abiotic stressors, 

diseases, or arthropod pests compared to the conventional control. Taken together, the 

assessments support a determination that MON 87429 is no more likely to pose a plant pest risk 

than conventional maize. 
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IX.B.3.1. Seed Germination and Dormancy

A comparative assessment of seed germination and dormancy characteristics was conducted on 

MON 87429 and the conventional control. The results of this assessment, including the lack of 

significant differences and particularly the lack of increased hard seed, support the conclusion 

that the introduction of the dicamba-, glufosinate-, quizalofop-, and 2,4-D-tolerance and RHS 

traits does not result in increased weediness or plant pest risk of MON 87429 compared to 

conventional maize. 

IX.B.3.2. Phenotypic and Agronomic Assessment

Evaluations of phenotypic and agronomic characteristics in the field are useful for assessing 

characteristics typically associated with weediness, such as lodging and seed loss. The 

characteristics early stand count, days to flowering, plant height, days to maturity, lodging, seed 

loss, final stand count, moisture, seed weight, and yield were assessed. The lack of observed 

differences between MON 87429 and the conventional control for phenotypic and agronomic 

characteristics across sites supports the overall conclusion that the introduction of the dicamba-, 

glufosinate-, quizalofop-, and 2,4-D-tolerance and RHS traits does not result in increased 

weediness or plant pest risk of MON 87429 compared to conventional maize.

IX.B.3.3. Response to Abiotic Stressors, Diseases, and Arthropod Pests

In an assessment of plant response to abiotic stressors, diseases, and arthropod pests, no 

differences were observed between MON 87429 and the conventional control for any of the 96 

observations for each stressor category across eight sites (Section VII.C.2.2.). The lack of 

observed differences between MON 87429 and the conventional control for plant responses to 

abiotic stressors, diseases, and arthropod pests in multiple field environments supports the 

overall conclusion that the introduction of the dicamba-, glufosinate-, quizalofop-, and 

2,4-D-tolerance and RHS traits does not result in increased plant pest risk of MON 87429 

compared to conventional maize. 

IX.B.3.4. Pollen Viability and Morphology

Evaluations of pollen viability and morphology from field-grown plants provide useful 

information in a plant pest assessment as it relates to the potential for gene flow to, and possible 

introgression of a biotechnology-derived trait into sexually-compatible plants and wild relatives. 

No statistically significant differences were detected between MON 87429 and the conventional 

control for percentage viable pollen or pollen diameter. Furthermore, no visual differences in 

general pollen morphology were observed between MON 87429 and the conventional control. 

The lack of observed differences between MON 87429 and the conventional control for pollen 

characteristics support the overall conclusion that the introduction of the dicamba-, glufosinate-, 

quizalofop-, and 2,4-D-tolerance and RHS traits does not result in increased weediness or plant 

pest risk of MON 87429 compared to conventional maize.
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IX.B.3.5. Interactions with Non-Target Organisms Including Those Beneficial to 

Agriculture or Threatened and Endangered Species

The potential for MON 87429 to influence non-target organisms (NTOs) was evaluated using a 

combination of biochemical information and experimental data. The modes-of-action are 

well-established and lack toxic effects; experimental evidence reviewed in the current or 

previously submitted Petitions indicates that the DMO, PAT, CP4 EPSPS and FT_T proteins are 

safe; and no safety concerns have occurred during the history of environmental exposure to 

DMO, PAT, CP4 EPSPS and the alpha-ketoglutarate-dependent dioxygenase family of proteins 

(the class of enzymes to which FT_T belongs). Additionally, molecular characterization did not 

suggest potential for unintended effects, no evidence was found for unintended changes to plant 

metabolism, compositional characteristics were substantially equivalent for MON 87429 and the 

conventional control, and the germination and dormancy, phenotypic and agronomic, and pollen 

characteristics were not indicative of increased weediness or plant pest risk for MON 87429 

compared to conventional maize. Since MON 87429 does not possess pesticidal activity, all 

organisms that interact with MON 87429 are considered to be NTOs. Environmental 

interactions data showed a lack of differences in plant responses to a subset of NTOs (specific 

diseases and arthropod pests). Taken together, these results suggest that MON 87429 is unlikely 

to adversely affect NTOs, including those beneficial to agriculture, or pose an additional risk to 

threatened or endangered species or their designated critical habitat above those posed by the 

cultivation of conventional maize. 

According to USDA-APHIS (2014), “Corn possesses few of the characteristics of successful 

weeds, and has been cultivated around the globe without any report that it is a serious weed or 

that it forms persistent feral populations.” USDA-APHIS (2014) also concluded that states 

where maize is grown have no plants listed as threatened or endangered, or that are proposed for 

listing, that are sexually compatible with maize. Because MON 87429 has been shown to be 

agronomically and phenotypically equivalent to conventional maize without increased weediness 

potential, the planting of MON 87429 is not expected to affect listed threatened or endangered 

plant species or designated critical habitat for listed plant or animal species.

The potential for maize to be a host plant for a threatened or endangered species (required by a 

listed species to complete a portion of its lifecycle) has also been considered. USDA-APHIS 

(2014) indicates that none of the listed species in states where maize is grown require maize as a 

host plant. Furthermore, according to USDA-APHIS (2014) and U.S. EPA (2014a; b), there are 

only a limited number of threatened or endangered species that may be found in maize fields, 

and there is an even more limited number of species that might feed on maize plants or maize 

grain. The safety of the MON 87429 DMO, PAT, CP4 EPSPS and FT_T proteins, and the 

compositional, agronomic and phenotypic equivalence of MON 87429 to conventional maize, 

support a conclusion that no effects to listed threatened or endangered species, including no

biologically significant changes to habitat or diet, are expected due to the planting of 

MON 87429.
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IX.C. Weediness Potential of MON 87429 

Although grown extensively throughout the world, maize is not considered a threat to invade 

natural or agricultural ecosystems. Maize does not establish self-sustaining populations outside 

of cultivation (Crawley et al., 2001; OECD, 2003; Raybould et al., 2012). This lack of 

weediness may reflect its poor competitive ability (Olson and Sander, 1988), lack of seed 

dormancy, and barriers to seed dispersal, as maize cobs retain seed and are covered in a husk 

(Wilkes, 1972). A number of other characteristics common in weeds, such as rapid flowering 

following emergence, are lacking in maize (Keeler, 1989). Traits often associated with 

weediness are typically not selected for during domestication and subsequent breeding and 

selection. Similarly, the history of maize breeding and production in the U.S. does not indicate 

there are any changes in the characteristics of maize that would increase the weediness of the 

crop. Even if kernels of maize are distributed within a field or along transportation routes from 

the fields to storage or processing facilities, self-sustaining volunteer maize populations are not 

found growing in fields, fence rows, ditches, or road sides.

In comparative studies between MON 87429 and a conventional control, germination and 

dormancy, phenotypic and agronomic, environmental interaction, and pollen characteristics were 

evaluated (Section VII) for changes that would impact the plant pest potential, and in particular, 

plant weediness potential. Results of these evaluations show that there is no biologically 

meaningful difference between MON 87429 and the conventional control for characteristics 

(percentage viable hard seed, lodging, and seed loss) typically associated with weediness. 

Furthermore, field observations of MON 87429 and the conventional control indicated no 

differences in plant responses to abiotic stressors, diseases, or arthropod pests. Collectively, these 

findings support the conclusion that MON 87429 is no more likely to become a weed than 

conventional maize.

IX.D. Potential for Pollen Mediated Gene Flow and Introgression

Pollen-mediated gene flow (cross pollination) is the first step towards introgression which is the 

transfer of one or more genes from one plant population to another. Pollen-mediated gene flow 

and introgression are natural biological processes and do not constitute inherent environmental 

risks. Gene introgression must be considered in the context of the trait in the biotechnologyderived plant and the likelihood that the presence of the trait and its subsequent transfer to 

recipient plants will result in increased plant pest potential. The potential for pollen-mediated 

gene flow from MON 87429 to other cultivated maize and the potential for introgression of the 

MON 87429 trait to species that can outcross with maize are discussed below.

IX.D.1. Hybridization with Cultivated Maize

Maize is a wind pollinated species with plant morphology that facilitates cross pollination. 

Therefore, relatively high levels of pollen-mediated gene flow can occur in this species at short 

distances (Jones and Brooks, 1950). Some biotic and abiotic factors that may influence the 

amount of pollen-mediated gene flow in maize include: (1) wind direction and speed; (2) 

distance between the pollen-source and pollen-recipient plants; (3) environmental factors that 

may impact pollen viability and dispersal (e.g. temperature and relative humidity); (4) duration 

of pollen shed and (5) floral synchrony between pollen donor and pollen recipient. 
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The results from several studies conducted on the extent of pollen-mediated gene flow between 

maize fields demonstrate consistent trends regardless of the experimental design, world region, 

or detection method. The amount of pollen-mediated gene flow is greatest within the first few 

meters and decreases sharply with increasing distance from the pollen source (Table IX-1). The 

distance >200 m (660 feet) is used for managing gene flow during breeding, seed production, 

identity preservation or other applications; in addition, it forms the basis for the USDA-APHIS 

performance standards for maize. All U.S. testing and production of regulated MON 87429 seed 

or grain have been conducted under USDA notification according to these standards. Since no 

meaningful differences were observed for MON 87429 compared to conventional maize in 

nutritional value, composition, or in pest/weed potential in field evaluations, no adverse effects 

are expected from gene flow from commercial production of MON 87429 to other maize.
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Table IX-1. Summary of Published Literature on Maize Cross Pollination

Pollinator 

Distance 

(m)

Reported 

Outcrossing 

(%)

Comments Country Reference

~1 28.6 Three- year study with one site per year. 

Outcrossing was detected by yellow seeds in the 

white-seeded pollen recipient. Values are 

averaged over years. 

USA (Jones and 

Brooks, 

1950)

25 14.2

75 5.8

126 2.3

201 1.2

302 0.5

402 0.2

503 0.2

1 19.0 Three-year study with two to three sites per year. 

Outcrossing was detected by yellow seeds in the 

white-seeded pollen recipient Values are 

averaged over site-years for the downwind 

direction.

Canada (Ma et al., 

2004) 5 2.6

10 2.0

14 0.6

19 0.4

24 0.3

28 0.5

33 0.3

36 0.1

24–32 0.69 Two-year study with two sites per year. 

Outcrossing was detected by purple seeds in the 

yellow-seeded pollen recipient. Values are the 

greatest observed between years for the site where 

outcrossing was most prevalent. 

USA (Halsey et 

al., 2005) 60–62 0.23

123–125 0.08

244–254 0.02

486–500 0.005

743–745 0.002

1 29.9 Two-year study with one site per year. 

Outcrossing was detected by yellow seeds in the 

non-transgenic white-seeded pollen recipient and 

confirmed by tests for a glyphosate tolerance gene 

in the yellow seeds. Values are the greatest 

between years as averaged across all directions 

from the pollen source. 

USA (Goggi et 

al., 2006) 10 2.5

35 0.4

100 0.05

150 0.03

200 0.03

250 0.03
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Table IX-1. Summary of Published Literature on Maize Cross Pollination (continued). 

Pollinator 

Distance 

(m)

Reported 

Outcrossing 

(%)

Comments Country Reference

0 12.65 One-year study with one site. Outcrossing was 

detected by yellow seeds in the white-seeded 

pollen recipient. Values are the greatest reported at 

listed distances from the edge of two sampling 

areas, one adjacent to and one 10 m from the 

pollen source. The values are half of those 

observed to reflect flow of a hemizygous gene.

Spain (Pla et al., 

2006) 2 8.81

5 2.33

10 3.69

20 1.05

40 0.74

80 0.65

0 0.74 Three-year study with a total of 55 sites. 

Outcrossing was quantified on ground samples of 

nontransgenic pollen recipient grain using a PCR 

assay for the pat herbicide tolerance gene. Values 

are means for percentage GM DNA for distances 

with >30 samples. 

UK (Weekes et 

al., 2007) 2 0.66

5 0.35

10 0.27

20 0.16

25 0.14

50 0.12

100 0.10

150 0.12
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Table IX-1. Summary of Published Literature on Maize Cross Pollination (continued). 

Pollinator 

Distance 

(m)

Reported 

Outcrossing 

(%)

Comments Country Reference

1 44 Two-year study with one site per year. 

Outcrossing was detected by herbicide tolerance 

and PCR tests for an herbicide tolerance transgene 

in progeny of the non-transgenic pollen recipient. 

Values are the greatest between years as averaged 

across all directions from the pollen source. 

China (Zhang et 

al., 2011) 5 16

10 10

15 5

30 1

60 1

100 0

150 0

200 0

300 0

1 12.9 Three-year study with a total of eight sites. 

Outcrossing was detected by yellow seeds in the 

white-seeded pollen recipient. Values are 

averaged over all directions and sites.

Mexico (Baltazar et 

al., 2015) 2 4.6

4 2.7

8 1.4

12 1.0

16 0.8

20 0.5

25 0.5
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IX.D.2. Hybridization with Teosinte

For gene flow to occur by typical sexual transmission, the following conditions must exist: (1) 

the two parents must be sexually compatible; (2) there must be flowering synchrony between the 

pollen source and pollen recipient; (3) the plants must be within sufficient proximity to each 

other; and (4) suitable environmental factors, such as relative humidity, temperature, or wind, 

must be present.

Maize is sexually compatible with certain species or subspecies of teosinte. Although teosinte is 

not native to the U.S., a compatible subspecies of annual teosinte (Zea mays subsp. mexicana) is 

reported to have feral populations in Florida, Alabama, and Maryland (USDA-NRCS, 2019). 

Hybrids of maize and teosinte are not expected in the U.S. In a study of maize and Zea mays

subsp. mexicana, very few ovules (approximately 1-2%) produced seed after hand pollination 

with pollen from the other subspecies (Baltazar et al., 2005). Natural hybridization rates for 

maize and Zea mays subsp. mexicana have also been reported to be low (≤0.2% of progeny) 

(Ellstrand et al., 2007). A genetic barrier to hybridization of maize and teosinte has been 

described (Evans and Kermicle, 2001) and if present may limit hybridization rates of maize and 

Zea mays subsp. mexicana. In addition, differences in developmental and morphological factors 

(Baltazar et al., 2005), potential differences in flowering time, and limited geographical 

distribution of teosinte make natural crosses and gene introgression from maize into teosinte 

unlikely in the U.S.

IX.D.3. Hybridization with Tripsacum

Tripsacum is a genus with 15 recognized species (Zuloaga et al., 2003). There are three species 

of Tripsacum that are native to the U.S.: T. floridanum (Florida gamagrass), T. lanceolatum

(Mexican gamagrass), and T. dactyloides (Eastern gamagrass) (USDA-NRCS, 2019). Two 

additional species have introduced populations: T. latifolium (wideleaf gamagrass) and 

T. fasciculatum (Guatemalan gamagrass) (USDA-NRCS, 2019).

Tripsacum floridanum (Florida gamagrass) naturally grows in the extreme southern Florida 

counties of Miami-Dade, Collier, Martin, and Monroe (USDA-NRCS, 2019; Wunderlin et al., 

2019). Florida gamagrass has been described as rare and occurring in “low, rocky pinelands” 

(Blakey et al., 2007) and is categorized as a threatened species in Florida (USDA-NRCS, 2019). 

Tripsacum lanceolatum (Mexican gamagrass) has been reported in Arizona and New Mexico 

(USDA-NRCS, 2019) and is found on “stream banks or moist cliffs” (de Wet and Harlan, 1978). 

Tripsacum dactyloides (eastern gamagrass) is found primarily throughout the eastern U.S. It is 

categorized as endangered in Massachusetts and Pennsylvania, threatened in New York, and 

special concern in Rhode Island (USDA-NRCS, 2019). Tripsacum fasciculatum (Guatemalan 

gamagrass) and T. latifolium (wideleaf gamagrass) and are present as introduced populations in 

Puerto Rico (USDA-NRCS, 2019).

To our knowledge, hybrids between maize and Tripsacum do not occur in nature. The formation 

of hybrids between maize and Tripsacum species requires human intervention under specific 

controlled laboratory conditions, and the hybrids exhibit male sterility that is not resolved by 

several backcrosses to maize (Russell and Hallauer, 1980). Empirical data showed that “no 

evidence of gene flow from transgenic maize to eastern gamagrass in nature was observed even 
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though the two species have grown in close proximity for years and have had ample

opportunities for outcrossing” (Lee et al., 2017). Thus, no species of Tripsacum is expected to 

form viable hybrid progeny with maize under natural conditions. 

In summary, although hybrids between maize and Tripsacum have been produced using 

specialized laboratory techniques, there is no evidence of hybrid existence in nature. Therefore, 

gene flow from maize to any Tripsacum species is extremely unlikely. Under natural conditions, 

as is the case with conventional maize, pollen-mediated gene flow from MON 87429 to any 

species of Tripsacum is not expected. 

IX.D.4. Transfer of Genetic Information to Species with which Maize Cannot Interbreed 

(Horizontal Gene Flow)

Monsanto is unaware of any reports regarding the unaided transfer of genetic material from 

maize species to other sexually-incompatible plant species. The likelihood for horizontal gene 

flow to occur is exceedingly small. Therefore, potential ecological risk associated with 

horizontal gene flow from MON 87429 due to the presence of the dicamba, glufosinate, 

quizalofop and 2,4-D-tolerance and RHS traits are not expected. The consequence of horizontal 

gene flow of the MON 87429 traits into other plants that are sexually-incompatible is negligible 

since, as data presented in this petition confirm, the genes and traits confer no increased plant 

pest potential to maize. Thus, in the highly unlikely event that horizontal gene transfer was to 

occur, the presence of the MON 87429 traits would not be expected to increase pest potential in 

the recipient species.

IX.E. Potential Impact on Maize Agronomic Practices

An assessment of current maize agronomic practices was conducted to determine whether the 

cultivation of MON 87429 has the potential to impact current maize management practices 

(Section VIII). Maize fields are typically highly managed agricultural areas that are dedicated to 

crop production. Other than the specific insertion of the dmo, pat, ft_t and cp4 epsps coding 

sequence that provides tolerance to dicamba, glufosinate, quizalofop and 2,4-D, and glyphosate 

herbicides, MON 87429 is similar to other conventional maize hybrids.

The data presented demonstrate that MON 87429 is similar to conventional maize in its 

phenotypic and agronomic characteristics, and has levels of susceptibility to abiotic stressors, 

diseases, and arthropod pests comparable to other conventional maize. Based on this assessment, 

the introduction of MON 87429 is not likely to impact current U.S. maize agronomic or 

cultivation practices or lead to an increased plant pest potential compared to other maize hybrids 

widely available to growers.

IX.F. Conventional Breeding with Other Biotechnology-derived or Conventional Maize 

Several biotechnology-derived maize products have been deregulated or are under consideration 

for deregulation. Once deregulated, MON 87429 may be bred with these deregulated 

biotechnology-derived maize products, as well as with conventional maize, creating new 

improved hybrids. APHIS has determined that none of the individual biotechnology-derived 

maize products it has previously deregulated displays increased plant pest characteristics. 

APHIS has also concluded that any progeny derived from crosses of these deregulated 
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biotechnology-derived maize products with conventional or previously deregulated 

biotechnology-derived maize are unlikely to exhibit new plant pest properties. This 

presumption, that combined-trait biotechnology products are unlikely to exhibit new 

characteristics that would pose new plant pest risks or potential environmental impacts not 

observed in the single event biotech product, is based upon several facts. Namely: 1) stability of 

the genetic inserts is confirmed in each approved biotech-derived maize product across multiple 

generations (See Section IV.E for MON 87429 data); 2) stability of each of the introduced traits 

is continually and repeatedly assessed as new combined-trait hybrids are created by plant 

breeders and tested over multiple seasons prior to commercialization; 3) combined-trait products 

are developed using the well-established process of conventional breeding that has been safely 

used for thousands of years to generate new varieties (Cellini et al., 2004; NRC, 2004; WHO, 

1995); 4) worldwide organizations, such as World Health Organization, Food and Agriculture 

Organization/World Health Organization, International Seed Federation, CropLife International 

and U.S. FDA, conclude that the safety of the combined-trait product can be based on the safety 

of the parental GE events (CLI, 2005; FAO-WHO, 1996; ISF, 2005; U.S. FDA, 2001; WHO, 

1995); and 5) practical applications in the field have shown that two unrelated biotechnology 

traits combined together by conventional breeding do not display new characteristics or 

properties distinct from those present in the single event biotech products (Brookes and Barfoot, 

2012; James, 2010; Lemaux, 2008; Pilacinski et al., 2011; Sankula, 2006).

Therefore, based on the considerations above and the conclusion that MON 87429 is no more 

likely to pose a plant pest risk than conventional maize it can be concluded that any progeny 

derived from crosses between MON 87429 and conventional maize or other maize with

deregulated biotechnology-derived events are no more likely to pose a plant risk than 

conventional maize.

IX.G. Summary of Plant Pest Assessments

A plant pest, as defined in the Plant Protection Act, is the living stage of any of the following

that can directly or indirectly injure, damage, or cause disease in any plant or plant product: (A) a 

protozoan; (B) a nonhuman animal; (C) a parasitic plant; (D) a bacterium; (E) a fungus; (F) a 

virus or viroid; (G) an infectious agent or other pathogens; or (H) any article similar to or allied 

with any of the articles specified in the preceding subparagraphs (7 U.S.C. § 7702(14)). 

Characterization data presented in Sections III through VII of this petition confirm that 

MON 87429, with the exception of the dicamba, glufosinate, quizalofop and 2,4-D-tolerance and 

RHS traits, is not meaningfully different from conventional maize in terms of plant pest 

potential. Monsanto is not aware of any other study results or observations associated with 

MON 87429 that would suggest an increased plant pest risk would result from its introduction. 

The plant pest assessment was based on multiple lines of evidence developed from a detailed 

characterization of MON 87429 compared to conventional maize, followed by a risk assessment 

on detected differences. The plant pest risk assessment in this petition was based on the 

following lines of evidence: 1) insertion of a single functional copy of the pat, dmo, ft_t and cp4 

epsps cassette; 2) characterization and safety of the expressed products; 3) compositional 

equivalence of MON 87429 grain and forage compared to a conventional control; 4) phenotypic, 

agronomic, and environmental interactions characteristics demonstrating no increased plant pest 

potential compared to conventional maize; 5) negligible risk to NTOs; 6) familiarity with maize 
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as a cultivated crop and 7) no greater likelihood to impact agronomic practices, cultivation 

practices, or the management of weeds, diseases and pests, than conventional maize. 

Based on the data and information presented in this petition, it is concluded that, like 

conventional maize and previously deregulated biotechnology-derived maize, MON 87429 is 

unlikely to pose a plant pest risk. Therefore, Monsanto Company requests a determination from 

USDA-APHIS that MON 87429 and any progeny derived from crosses between MON 87429 

and other commercial maize be granted nonregulated status under 7 CFR part 340. 
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X. ADVERSE CONSEQUENCES OF INTRODUCTION

Monsanto knows of no study results or observations associated with MON 87429 indicating that 

there would be adverse consequences from its introduction. MON 87429 produces the DMO, 

PAT, CP4 EPSPS and FT_T proteins. The safety of the MON 87429 DMO, PAT and CP4 

EPSPS proteins, which have been fully characterized, has been thoroughly assessed in this and 

previous submissions. The safety of the MON 87429 FT_T protein, which has been fully 

characterized, has been thoroughly assessed in this submission. As demonstrated by field results 

and laboratory tests, the only phenotypic differences between MON 87429 and conventional 

maize are dicamba, glufosinate, quizalofop and 2,4-D tolerance and tissue-specific glyphosate 

tolerance to facilitate the production of hybrid maize seed. 

The data and information presented in this request demonstrate that MON 87429 is unlikely to 

pose an increased plant pest risk compared to conventional maize. This conclusion is reached 

based on multiple lines of evidence developed from a detailed characterization of the product 

compared to conventional maize, followed by risk assessment on detected differences. The 

characterization evaluations included molecular analyses, which confirmed the insertion of one 

copy of the intended DNA containing the pat, dmo, ft_t and cp4 epsps expression cassettes that is 

stably integrated at a single locus and is inherited according to Mendelian principles over 

multiple generations. 

Analysis of key nutrients of MON 87429 demonstrate that MON 87429 is compositionally 

equivalent to conventional maize. The phenotypic evaluations, including an assessment of seed 

germination and dormancy characteristics, phenotypic and agronomic characteristics, pollen 

characteristics, environmental interactions also indicated MON 87429 is unchanged compared to 

conventional maize. There is no indication that MON 87429 would have an adverse impact on 

beneficial or non-target organisms (NTOs), including threatened or endangered species. 

Therefore, based on the lack of increased pest potential compared to conventional maize, the 

risks for humans, animals, and other NTOs from MON 87429 are negligible.

The introduction of MON 87429 will not adversely impact cultivation practices or the 

management of weeds, diseases, and pests in maize production systems. Farmers familiar with 

commercial maize hybrids will be advised to continue to employ crop rotational practices, weed 

control practices and/or volunteer control measures that consider the presence of the herbicide 

tolerance traits while providing the desired agronomic practice(s).
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APPENDICES

Appendix A: USDA Notifications and Permits

Field trials of MON 87429 have been conducted in the U.S. since 2014. The protocols for these 

trials include field performance, breeding and observation, agronomics, and generation of field 

materials and data necessary for this petition. In addition to the MON 87429 phenotypic 

assessment data, observational data on pest and disease stressors were collected from these 

product development trials. The majority of the final reports have been submitted to the USDA. 

However, some final reports, mainly from the 2017-2018 seasons, are still in preparation. A list 

of trials conducted under USDA notifications or permits and the status of the final reports for 

these trials are provided in Table A-1. 

Table A-1. USDA Notifications and Permits Approved for MON 87429 and Status of 

Trials Planted under These Notifications 

Field 

Trial 

Year USDA No.

Effective 

Date Trial Status

Release 

State(s) Sites

2014 14-080-103n 4/20/2014 Submitted

HI 1

PR 1

14-120-113rm 9/2/2014 Submitted HI 1

2015

14-120-113rm 9/2/2014 Submitted PR 1

14-302-112rm 3/1/2015

Submitted HI 1

PR 1

14-309-102rm 3/15/2015

Submitted IL 5

IN 1

KS 5

NE 4

14-309-108rm 3/15/2015

Submitted IA 9

IL 2

NE 1
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Table A-1. USDA Notifications and Permits Approved for MON 87429 and Status of 

Trials Planted under These Notifications (continued)

2015

15-042-103n 3/13/2015 Submitted IA 1

15-120-112rm 9/1/2015 Submitted HI 1

2016

15-120-112rm 9/1/2015

Submitted HI 1

PR 1

15-289-112rm 3/2/2016 Submitted HI 2

15-306-101rm 3/15/2016

Submitted IA 6

IL 2

KS 4

15-306-107rm 3/15/2016

Submitted IA 3

IL 6

NE 3

16-047-104n 3/17/2016 Submitted IA 1

16-104-104n 5/11/2016 Submitted NE 1

16-116-104n 5/25/2016

Submitted HI 1

PR 1

16-117-104rm 9/1/2016

Submitted HI 1

PR 1

16-117-111rm 9/1/2016 Submitted HI 1

16-117-112rm 9/1/2016 Submitted HI 1

16-299-102n 11/24/2016 Submitted HI 1

2017

16-117-111rm 9/1/2016 Submitted PR 1

16-182-104rm 12/1/2016 Submitted HI 1

16-299-102n 11/24/2016 Submitted HI 2
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Table A-1. USDA Notifications and Permits Approved for MON 87429 and Status of 

Trials Planted under These Notifications (continued)

2017

16-302-110rm 3/1/2017 Submitted HI 1

16-302-111rm 3/1/2017 Submitted HI 1

16-315-101rm 3/15/2017

Submitted IA 5

IL 10

16-315-105rm 3/15/2017 Submitted NE 3

17-037-101n 3/9/2017 Submitted CA 1

17-052-103n 3/23/2017

Submitted IA 2

IN 1

MO 1

NC 1

NE 1

OH 1

PA 1

17-053-103n 3/18/2017

Submitted IA 2

IL 3

NE 1

17-053-105n 3/24/2017 Submitted 

IA 1

IL 2

17-065-103n 4/5/2017 Submitted IL 1

17-100-104n 6/1/2017 Submitted HI 2

17-115-111rm 9/1/2017 Submitted HI 1

2018 17-214-101rm 12/1/2017 Submitted HI 2
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Table A-1. USDA Notifications and Permits Approved for MON 87429 and Status of 

Trials Planted under These Notifications (continued)

2018

17-304-101n 11/30/2017 Submitted HI 3

17-304-101rm 3/1/2018 In Progress HI 1

17-320-101rm 3/15/2018 In Progress

IA 3

IL 5

NE 2

17-320-102rm 3/15/2018 In Progress

IL 2

NE 1

18-031-104rm 5/25/2018 In Progress HI 1

18-060-107n 3/31/2018 In Progress IL 2

18-065-105n 4/5/2018 In Progress

CA 1

IA 2

IL 2

KS 1

NE 1

TX 1

WI 1

18-085-101n 4/25/2018 In Progress HI 2

18-122-103rm 9/1/2018 In Progress HI 1

18-122-104rm 9/1/2018 In Progress HI 1

18-122-105rm 9/1/2018 In Progress HI 1

18-122-106rm 9/1/2018 In Progress HI 2

18-283-103n 11/7/2018 In Progress IL 1

18-290-101n 11/12/2018 In Progress IA 1

Total 158
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Appendix B: Overview, Materials, Methods and Supplementary Results for Molecular 

Analyses of MON 87429

B.1. Test Substance

The test substance in this study was MON 87429. Five breeding generations of MON 87429 

were used to assess the stability of the T-DNA insert. Genomic DNA for use in this study was 

extracted from seed tissue listed in the table below.

MON 87429 Breeding Generation Seed ID

R3 11464932

R3F1 11464934

R4 11464931

R4F1 11465707

R5 11465738

B.2. Control Substance

The control substance is the conventional crop variety which is the similar genetic background as 

the test substances. Genomic DNA was extracted from seed as listed in the table below.

Control Substance Seed ID Breeding 

Generations

LH244 11464930 R3, R4, R5

LH244 × HCL617 11464933 R3F1

LH244 × L7126Z 11465706 R4F1

B.3. Reference Substance

The reference substance was plasmid vector PV-ZMHT519224, which was used to develop 

MON 87429. Whole plasmid DNA and its sequence served as a positive control for sequencing 

and bioinformatic analyses. The identity of the reference plasmid was confirmed by sequencing 

within the study. Documentation of the confirmation of the plasmid vector identity was archived 

with the raw data. Appropriate molecular weight markers from commercial sources were used 

for size estimations on agarose gels. The unique identity of the molecular weight markers was 

documented in the raw data.
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B.4. Characterization of Test, Control, and Reference Substances

The Study Director reviewed the chain-of-custody forms to confirm the identity of the test and 

control substances prior to the use of these materials in the study. Further confirmation of test 

and control substances identity was determined by sequencing in the study. Test, control and 

reference DNA and sequencing library substances were considered stable during storage if they 

yield interpretable signals in sequencing experiments, or did not appear visibly degraded on the 

stained gels (DNA) or sufficient cluster amplification was observed during flow cell generation

(sequencing libraries).

B.5. Genomic DNA Isolation

For sequencing library construction and PCR reactions, genomic DNA was isolated from seed 

tissues of the test and control substances. First the seeds were decontaminated by vigorously 

agitating them by hand for 30 seconds with 0.05% (v/v) Tween-20, followed by a tap water 

rinse. The seeds were then vigorously agitated with 0.5% (w/v) NaOCl, allowed to stand for 

one minute at room temperature, and rinsed with tap water. The seeds were then vigorously 

agitated with 1% (v/v) HCl, allowed to stand for one minute at room temperature, and rinsed 

with tap water. The 1% (v/v) HCl rinse was repeated one time, and then the seeds were rinsed 

with distilled water and air dried. The dried seeds were ground to a fine powder in a Harbil paint 

shaker. Genomic DNA was extracted using a hexadecyltrimethylammonium bromide (CTAB) 

extraction protocol. Briefly, 16 ml CTAB buffer (1.5% (w/v) CTAB, 75 mM Tris HCl (pH 8.0), 

100 mM ethylenediaminetetraacetic acid (EDTA) (pH 8.0), 1.05 M NaCl, and 0.75% (w/v) PVP) 

and RNase A was added to ground seed tissue. The samples were incubated at 60°C-70°C for 

20-25 minutes with intermittent mixing. The samples were cooled to room temperature and 

subjected to multiple rounds of chloroform:isoamyl alcohol (24:1) extraction. An additional 

round of extraction with 10% CTAB solution (10% (w/v) CTAB and 0.7 M NaCl) and 

chloroform:isoamyl alcohol (24:1) was performed. Genomic DNA was precipitated by adding 

~3× volumes of CTAB precipitation buffer (1% (w/v) CTAB, 50 mM Tris HCl (pH 8.0), 10 mM 

EDTA (pH 8.0) to the samples, followed by resuspension in high salt TE buffer (10 mM Tris 

HCl (pH 8.0), 1 mM EDTA (pH 8.0), 1 M NaCl). Genomic DNA was precipitated again with 

3 M sodium acetate (pH 5.2) and 100% (v/v) ethanol, washed with 70% ethanol, air dried and 

resuspended in TE buffer (10 mM Tris HCl, 1 mM EDTA, pH 8.0). All extracted DNA was 

stored in a 4°C refrigerator.

B.6. DNA Quantification

PV-ZMHT519224 DNA and extracted genomic DNA were quantified using a NanodropTM 

Spectrophotometer (Thermo Scientific).

B.7. Agarose Gel Electrophoresis

After quantification, the extracted DNA for NGS library construction was run on a 

1% (w/v) agarose gel to check the quality.
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B.8. Shearing of DNA

Approximately 1 μg of DNA from the test, control and reference substances were sheared by 

sonication. The DNA was diluted to ~20 ng/μl in Buffer EB (Qiagen Inc.) and fragmented using 

the following settings to create approximately 325 bp fragments with 3′ or 5′ overhangs: duty 

cycle of 10; peak incident power of 175; intensity of 5.0, 200 bursts per cycle, in the frequency 

sweeping mode at ~3-10°C for 80 seconds.

B.9. Paired End Library Preparation

Paired end genomic DNA libraries were prepared for the test, control, and reference substances 

using the KAPA Hyper Prep kit (Kapa Biosystems) and a Sage Science BluePippin DNA Size 

Selection system (Sage Science Inc.) was used to size select the DNA fragments.

First, the 3' and 5' overhangs of the DNA fragments generated by the shearing process were 

converted into blunt ends and adenylated by following the manufacturer’s KAPA Hyper Prep kit 

instructions (Kapa Biosystems). 

Next, adaptors were ligated to the end repaired and A-tailing reaction products by following the 

manufacturer’s KAPA Hyper Prep kit instructions. Following adaptor ligation, an AMPure XP 

(Beckman Coulter) cleanup was performed on the libraries which were then resuspended in 25 μl 

of Buffer EB prior to PCR amplification of the libraries. A five cycle PCR amplification of the 

libraries was carried out following the manufacturer’s KAPA Hyper Prep kit instructions. A 

second AMPure XP cleanup was performed on the libraries which were then resuspended in 

22.5 μl of Qiagen Elution Buffer (EB) and stored at -20°C.

The libraries were run on the Sage Science BluePippin Size Selection system using 1.5% agarose 

gel cassettes and following the manufacturer’s instructions. After elution of the desired size 

range (~500 bp) of DNA fragments, the DNA sample in the elution chamber of the cassette was 

removed and a 1:1 bead cleanup was performed using the 1x KAPA Pure Beads according to the 

KAPA Hyper Prep kit instructions. 

After bead cleanup, an aliquot of the libraries was analyzed using a Fragment Analyzer QC 

(Advanced Analytical Technologies, Inc.) according to the manufacturer’s instructions. 

Additional, size selection was conducted using Aline DNA Size Selector-I beads to remove 

fragments under ~400 bp. An aliquot of the Aline DNA size selected libraries was analyzed 

using a Fragment Analyzer QC according to the manufacturer’s instructions. All purified library 

DNA was stored in a -20°C freezer.

B.10. Next-Generation Sequencing

The library samples described above were sequenced by Monsanto’s Sequencing Technologies 

using Illumina NextSeq technology that produced short sequence reads (~150 bp long). 

Sufficient numbers of these sequence fragments were obtained to comprehensively cover the 

entire genomes of the test samples and the conventional control (Kovalic et al., 2012). 

Furthermore, a transformation plasmid spike was sequenced to >75× to assess method sensitivity 

through modeling of 1/10th and one full genome equivalent plasmid spike. 
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B.11. Read Mapping and Junction Identification

High-throughput sequence reads were captured by aligning to the PV-ZMHT519224 

transformation plasmid sequence using the read alignment software Bowtie (V2.2.3) (Langmead 

and Salzberg, 2012) in order to collect all reads that were sourced from the plasmid as well as 

reads with sequences representing integration points. Captured reads were subsequently mapped 

using the FASTA (V36.3.6) local alignment program (Pearson, 2000). All software versions 

were documented in the archived data package and the software versions which were used in this 

study have been archived.

B.12. Mapping and Junction Detection

Captured reads from both test and control samples were mapped to the complete 

PV-ZMHT519224 transformation plasmid sequence in order to detect junction sequences using 

the FASTA (V36.3.6) local alignment program. Reads with partial matches to the 

transformation plasmid of at least 30 bases and 96.6% or greater identity were also collected as 

potential junction sequences (Kovalic et al., 2012). 

B.12.1. Effective Sequencing Depth Determination

A single copy locus from the native plant genome (Zea Mays) pyruvate decarboxylase (pdc3, 

GenBank accession AF370006.2) was used to determine the actual sequence depth coverage. 

All reads with at least 30 bases matching and 96.6% identity were considered as reads sourced 

from this locus. Read alignments were further filtered to identify the best alignment as judged 

by the numerically lowest FASTA alignment E-score. Furthermore, final sequencing depths 

were calculated using a reads best aligning position when multiple alignments were returned. In 

instances where a read yielded two alignments with identical E-scores, both were retained. 
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Table B-1. Sequencing (NGS) Conducted for the Control and Test Substance 

Sample Total Nucleotide Number (Gb)

Effective Median Depth of 

Coverage (×-fold)

LH244 286.44 121×

LH244 × HCL617 267.68 106×

LH244 × L7126Z 215.17 86×

MON 87429 (R3) 265.77 108×

MON 87429 (R3F1) 244.53 98×

MON 87429 (R4) 292.95 123×

MON 87429 (R4F1) 269.65 102×

MON 87429 (R5) 254.53 102×

For each sample, the raw data produced are presented in terms of total nucleotide number. Effective 

depth of coverage is determined by mapping and alignment of all raw data to a single copy locus within 

the maize genome (pdc3). The median effective depth of coverage is shown for all samples.

B.12.2. Positive Control

To produce the positive control sample for sequencing, a plasmid DNA library was created as 

described in Appendix Sections B.8 to B.10 and spiked into a LH244 conventional control 

library at approximately 0.03%. The collected data were scaled to represent a single genome 

equivalent dataset and a 1/10th genome equivalent dataset.
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Table B-2. Summary of NGS Data for the Conventional Control DNA Sample Spiked with 

PV-ZMHT519224

1Extent of coverage is calculated as the percent of the PV-ZMHT519224 plasmid that is observed to have

coverage by the captured sequence reads.

2Percent identity of coverage is calculated as the per position consensus relative to reference of mapped 

PV-ZMHT519224 bases from the randomly sampled reads.

B.13. PCR and DNA Sequence Analyses to Examine the Insert and Flanking Sequences in 

MON 87429

Overlapping PCR products, denoted as Product A and Product B were generated that span the 

insert and adjacent 5' and 3' flanking DNA sequences in MON 87429. For each fragment 

generation, experimental conditions were chosen to successfully produce on-target 

amplifications. These products were analyzed to determine the nucleotide sequence of the insert 

in MON 87429, as well as that of the DNA flanking the 5′ and 3′ ends of the insert, as depicted 

in Figure IV-7. 

The PCR analyses for both Product A and Product B were conducted using approximately 

100 ng of genomic DNA template in a 50 l reaction volume. The reaction contained a final 

concentration of 0.2 M of each primer, 0.2 mM of each dNTP, and 1.25 units/reaction of 

PrimeSTAR GXL Polymerase (TaKaRa Bio Inc.). 

The PCR amplification of both Product A and Product B was performed under the following 

cycling conditions: 25 cycles at 98C for 10 seconds; 60C for 15 seconds; 68C for 9 minutes.

Aliquots of each PCR product were separated on a 1.0% (w/v) agarose gel and visualized by 

ethidium bromide staining to verify that the products were the expected sizes. Each PCR product 

was purified with Agencourt AMPure XP (Beckman Coulter Life Sciences). Approximately 

200 ng of purified amplicon was submitted to Monsanto’s Genome Sequencing Center for 

library preparation and MiSeq sequencing. 

A consensus sequence was generated by compiling captured reads from MiSeq sequencing of the 

overlapping PCR products. This consensus sequence was aligned to the PV-ZMHT519224 

sequence to determine the integrity and organization of the integrated DNA and the 5' and 

3' insert to flank DNA junctions in MON 87429.

0.1 Genome Equivalent

(14× coverage)

1 Genome Equivalent

(123× coverage)

Extent of coverage1 of 

PV-ZMHT519224 100% 100%

Percent identity of coverage2 of 

PV-ZMHT519224 100% 100%
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B.14. PCR and DNA Sequence Analyses to Examine the Integrity of the DNA Insertion Site 

in MON 87429

To examine the MON 87429 T-DNA insertion site in LH244 conventional maize, PCR and 

sequence analyses were performed on genomic DNA from the LH244 conventional control as 

depicted in Figure IV-7.

The primers used in this analysis were designed from the DNA sequences flanking the insert in 

MON 87429. A forward primer specific to the DNA sequence flanking the 5' end of the insert 

was paired with a reverse complement primer specific to the DNA sequence flanking the 3' end 

of the insert. 

The PCR reactions were conducted using approximately 100 ng of genomic DNA template in a 

50 l reaction volume. The reaction contained a final concentration of 0.2 M of each primer, 

0.2 mM of each dNTP, and 1.25 units/reaction of PrimeSTAR GXL Polymerase. The PCR 

amplification was performed under the following cycling conditions: 30 cycles at 98C for 

10 seconds; 60C for 15 seconds; 68C for 30 seconds.

Aliquots of each PCR product were separated on a 1.0% (w/v) agarose gel and visualized by 

ethidium bromide staining to verify that the products were the expected sizes. Each PCR product 

was purified with Agencourt AMPure XP (Beckman Coulter Life Sciences). Approximately 

200 ng of purified amplicon was submitted to Monsanto’s Genome Sequencing Center for 

library preparation and MiSeq sequencing. 

A consensus sequence was generated by compiling sequences from MiSeq sequencing reactions 

of the verified PCR product. This consensus sequence was aligned to the 5' and 3' sequences 

flanking the MON 87429 insert to determine the integrity and any rearrangement of the insertion 

site.
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References for Appendix B 

Kovalic, D., C. Garnaat, L. Guo, Y. Yan, J. Groat, A. Silvanovich, L. Ralston, M. Huang, Q. 

Tian, A. Christian, N. Cheikh, J. Hjelle, S. Padgette and G. Bannon. 2012. The use of next 

generation sequencing and junction sequence analysis bioinformatics to achieve molecular 

characterization of crops improved through modern biotechnology. The Plant Genome 5:149-

163.

Langmead, B. and S.L. Salzberg. 2012. Fast gapped-read alignment with Bowtie 2. Nature 

Methods 9:357-359.

Pearson, W.R. 2000. Flexible sequence similarity searching with the FASTA3 program package. 

Methods in Molecular Biology 132:185-219.
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Appendix C: MON 87429 RHS Mechanism of Action

C.1. Lack of Secondary siRNA from CP4 EPSPS mRNA Suppression Materials and 

Methods

C.1.1. Low molecular weight RNA blotting

Total RNA from each sample, a 1kb RNA Ladder (Thermo Fisher Scientific) combined with the 

25-nt CP4 EPSPS RNA oligos, or the size markers were mixed with the RNA loading Buffer 

(Ambion, Grand Island, NY), denatured at 95°C for 5 min followed by 4°C for 5 min, loaded to 

wells of a Criterion Precast 15% polyacrylamide TBE-Urea gel, separated by electrophoresis in a 

Criterion Cell, and transferred onto positively charged nylon membrane via electroblotting with a 

Criterion Blotter (Bio-Rad, Hercules, CA) following the manufacture's instruction.

Using T-DNA templates and three sets of the gene-specific primers (Table C-1), three fragments 

covering the entire CP4 EPSPS transcript except the siRNA target sequence (to avoid cross 

hybridization with the endogenous mts-siRNAs) (Figure C-1) were obtained by PCR 

amplifications using Ex Taq DNA polymerase (Takara Bio Inc.) and purified with the QIAquick 

Gel Extraction Kit (Qiagen). DIG-labeled probes CP4 EPSPS 5', CP4 EPSPS 3’, and OsGRP3 

3'UTR were prepared from the PCR products with a PCR DIG Probe Synthesis Kit (Roche, 

Basel, Switzerland). A 25-nt RNA oligo with a sequence (GGGUGCUGACAUCGAGGUUAUCAAU) 

identical to a portion of the CP4 EPSPS mRNA for use as a positive control and two DIGlabeled 20- and 25-nt RNA oligos for use as size markers were synthesized. Hybridizations were 

then conducted at 38°C with rotation in DIG Easy Hyb (Sigma). Post-hybridization washes were 

done as recommended by the manufacture, and DIG detection was performed using reagents and 

Lumi-Film X-ray films from Roche. In addition, the RNA blot was rinsed in RNase-free water 

briefly, incubated in the Stripping Buffer (0.2% SDS and 0.1× SSC) for 45 min at 70°C twice to 

remove the DIG-labeled probes, equilibrated in 2× SSC, and then reprobed with a synthetic DIGlabeled 21-nt DNA oligo (DIG-CAGAGCTCCCTTCAATCCAAA) designed for detection of zmmiR159b as a control.

Figure C-1. Transgenic elements in the T-DNA for generating plants containing 

MON 87429

PAT: phosphinothricin N-acetyltransferase; DMO: dicamba mono-oxygenase; FT_T: FOPs and 2,4-D 

tolerance enzyme variant T (α-ketoglutarate-dependent dioxygenase); CP4 EPSPS: Agrobacterium sp.

strain CP4 5-enolpyruvylshikimate-3-phosphate synthase; siRNA TS: small interfering RNA Target 

Sequence. Not drawn to scale.
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C.2. Expression of Endogenous Genes with Sequence Homology to the siRNA Target 

Sequence Materials and Methods

Total RNA was used for expression analyses of endogenous genes by a TaqMan or a SYBR 

Green assay (Table C-1). One-step real-time PCR was performed in singleplex with three 

replicates for each RNA sample. Maize elongation factor 1a (EF1a) was used as a normalizer. 

Relative expression levels were determined as described in Yang et al 2009.

Table C-1. Primers and probes used in this study

Primer ID Sequence Tm

Expected 

product

For expression analyses of endogenous genes

Forward Primer 1 AAACCTACGGGAAAGTTGCG 61.33

FAM Probe 1 105 bp

6FAMACAAGAAATACCCCTGCTCCAACCTGMGBNFQ

68.10

Reverse Primer 1 TCTCGCATAATTTGTAGTTCAGCTG 61.83

Forward Primer 2 TGGATGAATGKAATCTGAACAAGCT 62.13

73 bp

Reverse Primer 2 CGGGGCAMTTGAACAATCCTA 62.97

For normalization of expression

EF1a Forward Primer GCTAGCTTTACCTCCCAGGTCATC 63.55

EF1a VIC Probe VIC-TCATGAACCACCCTGGC-MGBNFQ 73.29 64 bp

EF1a Reverse Primer GGGCATAGCCATTGCCAATC 64.68
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Table C-1. Primers and probes used in this study (continued)

For preparation of probes for Northern hybridization

CP4 EPSPS 5' Probe F AGCAGCATCCACGAGCTTAT 59.98

709 bp

CP4 EPSPS 5' Probe R ATGGGTTCAATCACGGTTGT 60.08

CP4 EPSPS 3' Probe F GCGCTAATCTAACGGTCGAA 60.33

737 bp

CP4 EPSPS 3' Probe R TCAAGCGGCCTTAGTATCAGA 59.96

OsGRP3 3'UTR Probe F CATCGTGGCCAGTTATCCTT 59.93

554 bp

OsGRP3 3'UTR Probe R TGCAAAATGGAAATGCTGTG 60.63
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References for Appendix C

Yang H, Schmuke JJ, Flagg LM, Roberts JK, Allen EM, Ivashuta S, et al. A novel real-time 

polymerase chain reaction method for high throughput quantification of small regulatory RNAs. 

Plant Biotechnol J. 2009; 7: 621–630. pmid:1961
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Appendix D: Characterization of FT_T Protein Produced in MON 87429

D.1. Characterization of the FT_T Protein

D.1.1. FT_T Protein Identity and Equivalence

The safety assessment of crops derived through biotechnology includes characterization of the 

physicochemical and functional properties and confirmation of the safety of the introduced 

protein(s). For the safety data generated using the E. coli-produced FT_T protein to be applied 

to the MON 87429-produced FT_T protein (plant-produced FT_T), the equivalence of the 

plant- and E. coli-produced proteins must first be demonstrated. To assess the equivalence 

between the MON 87429-produced FT_T and E. coli-produced FT_T proteins, a small quantity 

of the MON 87429-produced FT_T protein was purified from MON 87429 grain. The 

MON 87429-produced FT_T protein was characterized and the equivalence of the 

physicochemical characteristics and functional activity between the MON 87429-produced and 

E. coli-produced FT_T proteins was assessed using a panel of analytical tests; as shown in Table 

D-1. Taken together, these data provide a detailed characterization of the MON 87429-produced 

FT_T protein and establish the equivalence of the MON 87429-produced FT_T and 

E. coli-produced FT_T proteins. Based on this established equivalence, conclusions derived from 

digestibility, heat susceptibility and oral acute toxicology studies conducted with 

E. coli-produced FT_T protein are applicable to MON 87429-produced FT_T protein. 
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Table D-1. Summary of MON 87429 FT_T Protein Identity and Equivalence

Analytical Test Assessment Analytical Test Outcome

1. N-terminal sequence Identity • The expected N-terminal 

sequence for 

MON 87429-produced FT_T and 

was observed by Nano LCMS/MS1

2. Nano LC-MS/MS1Identity • Nano LC-MS/MS1

analysis of 

trypsin digested peptides from 

for MON 87429-produced FT_T 

protein yielded peptide masses 

consistent with expected peptide 

masses from the theoretical 

trypsin digest of the amino acid 

sequence

3. Western blot analysis Identity

and

Equivalence

• MON 87429-produced FT_T 

protein identity was confirmed 

using a western blot probed with 

antibodies specific for FT_T 

protein 

• Immunoreactive properties of the 

MON 87429-produced FT_T and

the E. coli-produced FT_T 

proteins were shown to be 

equivalent

4. Apparent molecular 

weight (MW)

Equivalence • Electrophoretic mobility and 

apparent molecular weight of the 

MON 87429-produced FT_T and 

the E. coli-produced FT_T 

proteins were shown to be 

equivalent

5. Glycosylation 

analysis

Equivalence • Glycosylation status of 

MON 87429-produced FT_T and 

E. coli-produced FT_T proteins 

were shown to be equivalent

6. FT_T enzymatic 

activity 

Equivalence • Functional activity of the 

MON 87429-produced FT_T and 

the E. coli-produced FT_T 

proteins were shown to be 

equivalent

1 Nano LC-MS/MS = Nanoscale liquid chromatography-tandem mass spectrometry

The details of the materials and methods for the panel of analytical tests used to evaluate and 

compare the properties of the MON 87429-produced FT_T and E. coli-produced FT_T proteins 

are described at the end of Appendix D. A summary of the data obtained to support a conclusion 

of protein equivalence is below. 
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D.1.2. Results of the N-Terminal Sequencing Analysis

The expected N-terminal sequence for the FT_T protein deduced from the ft_t gene present in 

maize of MON 87429 was confirmed by Nano LC-MS/MS. The experimentally determined 

sequence corresponds to the deduced FT_T protein beginning at the initial alanine position 

(Figure D-1). The alanine is derived from the chloroplast transit peptide, MDH (Section V.D.1). 

Alternative cleavage of CTP from FT_T in planta by a general stromal processing peptidase is 

common (Richter and Lamppa, 1998). The N-terminal sequencing results for MON 87429-

produced FT_T protein were consistent with the sequencing results for the E. coli-produced 

FT_T protein (Figure D-1). The expression plasmid designed to express the mature MON 87429 

FT_T protein in E. coli included an N-terminal methionine residue that was likely cleaved by 

methionine aminopeptidase and other aminopeptidases. Therefore, the E. coli-produced FT_T 

sequence begins at position 2 of the expected sequence deduced from the E. coli expression 

plasmid, which corresponds to position 1 of the mature FT_T protein present in MON 87429. 

The cleavage of the N-terminal methionine from proteins in vivo by methionine aminopeptidase 

is common in many organisms (Bradshaw et al., 1998). Hence, the sequence information confirms 

the identity of the FT_T protein isolated from the grain of MON 87429.

Amino Acids 

Residue # from 

the N-terminus → 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15

E. coli-produced 

FT_T sequence → A M H A A L T P L T N K Y R F

Expected FT_T 

Sequence →

│

A

│

M

│

H

│

A

│

A

│

L

│

T

│

P

│

L

│

T

│

N

│

K

│

Y

│

R

│

F

MON 87429-

produced FT_T 

Experimental 

Sequence

→

│

A

│

M

│

H

│

A

│

A

│

L

│

T

│

P

│

L

│

T

│

N

│

K

│

Y

│

R

│

F

Figure D-1. N-Terminal Sequence of the MON 87429-Produced FT_T Protein

The experimental sequence obtained from the MON 87429-produced FT_T was compared to the expected 

sequence of the mature protein deduced from the ft_t gene, a modified version of the 

R-2,4-dichlorophenoxypropionate dioxygenase (Rdpa) gene, present in MON 87429. The E. coliproduced FT_T sequence begins at position 2 of the expected sequence deduced from the E. coli

expression plasmid, which corresponds to position 1 of the mature FT_T protein present in MON 87429. 

The single letter International Union of Pure and Applied Chemistry- International Union of Biochemistry 

(IUPAC-IUB) amino acid code is A, alanine; M, methionine; H, histidine; L, leucine; T, threonine; P, 

proline; N, asparagine; K, lysine; Y, tyrosine; R, arginine; F, phelyalanine.
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D.1.3. Results of Mass Fingerprint Analysis

Peptide mass fingerprint analysis is a standard technique used for confirming the identity of 

proteins. The ability to identify a protein using this method is dependent upon matching a 

sufficient number of observed tryptic peptide fragment masses with predicted tryptic peptide 

fragment masses. In general, protein identification made by peptide mapping is considered to be 

reliable if  40% of the protein sequence was identified by matching experimental masses 

observed for the tryptic peptide fragments to the expected masses for the fragments (Biron et al., 

2006; Krause et al., 1999). The identity of the MON 87429-produced FT_T protein was 

confirmed by Nano LC-MS/MS analysis of peptide fragments produced by the trypsin digestion 

of the MON 87429-produced FT_T protein. 

There were 34 unique peptides identified that corresponded to the masses expected to be 

produced by trypsin digestion of the MON 87429-produced FT_T protein (Table D-2). The 

identified masses were used to assemble a coverage map of the entire FT_T protein (Figure 

D-2A). The experimentally determined coverage of the FT_T protein was 97% (Figure D-2A

288 out of 296 amino acids). This analysis further confirms the identity of 

MON 87429-produced FT_T protein. 

There were 20 unique peptides identified that corresponded to the masses expected to be 

produced by trypsin digestion of the E. coli-produced FT_T protein (Table D-3) by MALDI-TOF 

MS analysis during the protein characterization. The identified masses were used to assemble a 

coverage map of the entire FT_T protein (Figure D-2B). The experimentally determined 

coverage of the E. coli-produced FT_T protein was 65% (Figure D-2B, 194 out of 297 amino 

acids). This analysis further confirms the identity of E. coli-produced FT_T protein. 
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Table D-2. Summary of the Tryptic Masses Identified for the MON 87429-Produced FT_T 

Using Nano LC-MS/MS

1Experimental 

Mass2

Calculated 

Mass3 Diff4 Fragment5 Sequence6

1266.6764 1266.6754 0.001 1 – 12 AMHA...LTNK

1308.6891 1308.686 0.0031 1 - 12 *AMHA...LTNK

2531.3715 2531.3748 -0.0033 13 - 35 YRFI...VDLR

2212.2081 2212.2104 -0.0023 15 - 35 FIDV...VDLR

6659.3313 6659.3289 0.0024 15 - 73 FIDV...AFSR

4465.1336 4465.1291 0.0045 36 - 73 EPLD...AFSR

1336.7871 1336.7867 0.0004 74 - 85 RFGP...PILK

1180.6852 1180.6856 -0.0004 75 - 85 FGPV...PILK

2583.3786 2583.3771 0.0015 75 - 97 FGPV...QMIR

1420.7026 1420.702 0.0006 86 - 97 SIEG...QMIR

947.4422 947.442 0.0002 98 - 105 REANESSR

791.3409 791.3409 0 99 - 105 EANESSR

2560.2049 2560.2057 -0.0008 106 - 128 FIGD...VVMR

4500.1576 4500.1505 0.0071 129 - 170 AIEV...SATK

5922.8591 5922.8549 0.0042 129 - 182 AIEV...TNWR

1440.7149 1440.715 -0.0001 171 - 182 VFGS...TNWR

2204.1021 2204.1015 0.0006 171 - 189 VFGS...TSVK

781.3974 781.397 0.0004 183 - 189 FSNTSVK

3362.7007 3362.7042 -0.0035 183 - 213 FSNT...VTGR

976.4284 976.4284 0 190 - 198 VMDV...AGDR

2599.317 2599.3177 -0.0007 190 - 213 VMDV...VTGR

1640.8988 1640.8999 -0.0011 199 - 213 ETVH...VTGR

1796.9998 1797.001 -0.0012 199 - 214 ETVH...TGRR

1601.7407 1601.7442 -0.0035 214 - 225 RALY...YCQK

1445.6441 1445.6431 0.001 215 - 225 ALYC...YCQK

1078.4969 1078.4965 0.0004 226 - 235 IQGM...AESK

1448.7651 1448.7663 -0.0012 236 - 247 SLLQ...HATK

1 All imported values were rounded to 4 decimal places. 

2 Only experimental masses that matched calculated masses with the highest scores are listed.

3 The calculated mass is the relative molecular mass calculated from the matched peptide sequence.

4 The calculated difference = (experimental mass – calculated mass).

5 Position refers to amino acid residues within the predicted MON 87429-produced FT_T sequence as 

depicted in Figure D-1.

6 For peptide matches greater than nine amino acids in length the first 4 residues and last 4 residues are 

shown separated by dots (...).

*

acetylation and oxidation observed. 
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Table D-2. Summary of the Tryptic Masses Identified for the MON 87429-Produced FT_T 

Using Nano LC-MS/MS (Continued)

1Experimental 

Mass2

Calculated 

Mass3 Diff4 Fragment5 Sequence6

2275.1126 2275.1096 0.003 236 - 253 SLLQ...FTCR

844.3548 844.3538 0.001 248 - 253 FDFTCR

1913.9253 1913.924 0.0013 258 - 272 KDQV...TMHR

1785.8299 1785.8291 0.0008 259 - 272 DQVL...TMHR

819.4129 819.4127 0.0002 273 - 280 AVPDYAGK

1122.5821 1122.5822 -0.0001 273 - 282 AVPD...GKFR

1030.5409 1030.5407 0.0002 288 - 296 TTVA...KPSR

1 All imported values were rounded to 4 decimal places. 

2 Only experimental masses that matched calculated masses with the highest scores are listed.

3 The calculated mass is the relative molecular mass calculated from the matched peptide sequence.

4 The calculated difference = (experimental mass – calculated mass).

5 Position refers to amino acid residues within the predicted MON 87429-produced FT_T sequence as 

depicted in Figure D-1.

6 For peptide matches greater than nine amino acids in length the first 4 residues and last 4 residues are 

shown separated by dots (...).

*

acetylation and oxidation observed. 
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Table D-3. Summary of the Tryptic Masses Identified for E. coli-produced FT_T Using 

MALDI-TOF MS1

Experimental 

Mass2

Calculated 

Mass3 Diff.4 Fragment5 Enzyme Sequence6

1266.5457 1266.6754 -0.1297 2 - 13 Trypsin AMHA...LTNK

2211.9397 2212.2104 -0.2706 16 - 36 Trypsin FIDV...VDLR

1336.6551 1336.7867 -0.1316 75 - 86 Trypsin RFGP...PILK

1180.5685 1180.6856 -0.1171 76 - 86 Trypsin FGPV...PILK

1420.5619 1420.7020 -0.0792 87 - 98 Trypsin SIEG...QMIR

791.2727 791.3409 -0.0682 99 - 106 Trypsin REANESSR

2559.8802 2560.2057 -0.3255 107 - 129 Trypsin FIGD...VVMR

1440.5745 1440.7150 -0.1405 172 - 183 Trypsin VFGS...TNWR

781.3226 781.3970 -0.0744 184 - 190 Trypsin FSNTSVK

2598.9771 2599.3177 -0.3406 191 - 214 Trypsin VMDV...VTGR

1640.7249 1640.8999 -0.1749 200 - 214 Trypsin ETVH...VTGR

1603.5482 1603.7123 -0.1640 215 - 226 Trypsin RALY...YCQK

1447.4541 1447.6112 -0.1570 216 - 226 Trypsin ALYC...YCQK

1448.6154 1448.7663 -0.1509 237 - 248 Trypsin SLLQ...HATK

2275.8086 2276.0936 -0.2850 237 - 254 Trypsin SLLQ...FTCR

845.2653 845.3378 0.0725 249 - 254 Trypsin FDFTCR

1786.6216 1786.8131 -0.1915 260 - 273 Trypsin DQVL...TMHR

819.3327 819.4127 -0.0799 274 - 281 Trypsin AVPDYAGK

1030.4390 1030.5407 -0.1017 288 - 297 Trypsin TTVAGDKPSR

1 All imported values were rounded to 4 decimal places. 

2 Only experimental masses that matched calculated FT_T trypsin digested masses are listed in the table.

3 The calculated mass is the exact molecular mass calculated from the matched peptide sequence.

4 The calculated difference = experimental mass - calculated mass.

5 Position refers to amino acid residues within the predicted E. coli-produced FT_T sequence.

6 For peptide matches greater than nine amino acids in length, the first 4 residues and last 4 residues are 

show separated by three dots (...).
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(A)

001 AMHAALTPLT NKYRFIDVQP LTGVLGAEIT GVDLREPLDD STWNEILDAF

051 HTYQVIYFPG QAITNEQHIA FSRRFGPVDP VPILKSIEGY PEVQMIRREA

101 NESSRFIGDD WHTDSTFLDA PPAAVVMRAI EVPEYGGDTG FLSMYSAWET

151 LSPTMQATIE GLNVVHSATK VFGSLYQATN WRFSNTSVKV MDVDAGDRET

201 VHPLVVTHPV TGRRALYCNQ VYCQKIQGMT DAESKSLLQF LYEHATKFDF

251 TCRVRWKKDQ VLVWDNLCTM HRAVPDYAGK FRYLTRTTVA GDKPSR

(B)

002 MAMHAALTPL TNKYRFIDVQ PLTGVLGAEI TGVDLREPLD DSTWNEILDA

052 FHTYQVIYFP GQAITNEQHI AFSRRFGPVD PVPILKSIEG YPEVQMIRRE

102 ANESSRFIGD DWHTDSTFLD APPAAVVMRA IEVPEYGGDT GFLSMYSAWE

152 TLSPTMQATI EGLNVVHSAT KVFGSLYQAT NWRFSNTSVK VMDVDAGDRE

202 TVHPLVVTHP VTGRRALYCN QVYCQKIQGM TDAESKSLLQ FLYEHATKFD

252 FTCRVRWKKD QVLVWDNLCT MHRAVPDYAG KFRYLTRTTV AGDKPSR

Figure D-2. Peptide Map of the MON 87429-Produced FT_T and E. coli-Produced FT_T

(A) The amino acid sequence of the MON 87429-produced FT_T protein was deduced from the ft_t gene, 

a modified version of the R-2,4-dichlorophenoxypropionate dioxygenase (Rdpa) gene, present in 

MON 87429. Boxed regions correspond to peptides that were identified from the MON 87429-produced 

FT_T protein sample using Nano LC-MS/MS. In total, 97% coverage (288 out of 296 amino acids) of the 

expected protein sequence was covered by the identified peptides.

(B) The amino acid sequence of the E. coli-produced FT_T protein was deduced from the ft_t gene, a 

modified version of the R-2,4-dichlorophenoxypropionate dioxygenase (Rdpa) gene, that is contained on 

the expression plasmid. Boxed regions correspond to peptides that were identified from the E. 

coli-produced FT_T protein sample using MALDI-TOF MS. In total, 65% coverage (194 out of 297 

amino acids) of the expected protein sequence was covered by the identified peptides.
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D.1.4. Results of Western Blot Analysis of the FT_T Protein Isolated from the Grain of 

MON 87429 and Immunoreactivity Comparison to E. coli-produced FT_T Protein

Western blot analysis was conducted using mouse anti-FT_T monoclonal antibody to provide 

additional confirmation of the identity of the FT_T protein isolated from the grain of 

MON 87429 and to assess the equivalence of the immunoreactivity of the MON 87429-produced 

and E. coli-produced FT_T proteins. The results showed that immunoreactive bands with the 

same electrophoretic mobility were present in all lanes loaded with the MON 87429-produced 

and E. coli-produced FT_T proteins (Figure D-3). For each amount loaded, comparable signal 

intensity was observed between the MON 87429-produced and E. coli-produced FT_T protein 

bands. As expected, the signal intensity increased with increasing load amounts of the 

MON 87429-produced and E. coli-produced FT_T proteins, thus, supporting the identity of the 

MON 87429-produced FT_T protein. 

To compare the immunoreactivity of the MON 87429-produced and the E. coli-produced FT_T 

proteins, densitometric analysis was conducted on the bands that migrated at the expected 

apparent molecular weight (MW) for FT_T proteins (~35 kDa). The signal intensity (reported in 

OD × mm2) of the band of interest in lanes loaded with MON 87429-produced and the E. coliproduced FT_T proteins was measured (Table D-4). Because the mean signal intensity of the 

MON 87429-produced FT_T protein band was within 35% of the mean signal of the E. coliproduced FT_T protein, the MON 87429-produced FT_T and E. coli-produced FT_T proteins 

were determined to have equivalent immunoreactivity.
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Figure D-3. Western Blot Analysis and Immunoreactivity of MON 87429-Produced and 

E. coli-Produced FT_T Proteins

Aliquots of the MON 87429-produced FT_T protein and the E. coli-produced FT_T protein were 

subjected to SDS-PAGE and electrotransferred to a PVDF membrane. Proteins were detected using 

mouse anti-FT_T monoclonal antibody and then horse anti-mouse polyclonal antibody conjugated with 

peroxidase. Immunoreactive bands were visualized using an ECL system. The approximate MW (kDa) 

of the standards are shown on the left. The 45 second exposure is shown. Lane designations are as 

follows:

Lane Sample Amount (ng)

1 Precision Plus ProteinTM Standards -

2 Blank -

3 MON 87429-produced FT_T 5

4 MON 87429-produced FT_T 5

5 MON 87429-produced FT_T 10

6 MON 87429-produced FT_T 10

7 MON 87429-produced FT_T 20

8 MON 87429-produced FT_T 20

9 Blank -

10 E. coli-produced FT_T 5

11 E. coli-produced FT_T 5

12 E. coli-produced FT_T 10

13 E. coli-produced FT_T 10

14 E. coli-produced FT_T 20

15 E. coli-produced FT_T 20
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Table D-4. Immunoreactivity of the MON 87429-Produced and E. coli-Produced FT_T 

Proteins

Mean Signal Intensity from 

MON 87429-Produced FT_T1

(OD x mm2)

Mean Signal Intensity from 

E. coli-Produced FT_T1

(OD x mm2)

Acceptance Limits2

(OD x mm2)

94,017.0 97,454.4 63,345.4 – 131,563.4

1 Each value represents the mean of six values (n = 6).

2 The acceptance limits are for the MON 87429-produced FT_T protein and are based on the interval 

between -35% (97,454.4 x 0.65 = 63,345.4) and +35 % (97,454.4 x 1.35 = 131,563.4) of the mean of the 

E. coli-produced FT_T signal intensity across all loads.

D.1.5. Results of the FT_T Protein Molecular Weights and Purity Analysis

For apparent MW and purity determination, the MON 87429-produced FT_T and the E. coliproduced FT_T proteins were subjected to SDS-PAGE. Following electrophoresis, the gel was 

stained with Brilliant Blue G-Colloidal stain and analyzed by densitometry. The 

MON 87429-produced FT_T protein (Figure D-4, lanes 3-8) migrated with the same mobility on 

the gel as the E. coli-produced FT_T protein (Figure D-4, lane 2) and the apparent MW was 

calculated to be 36.0 kDa (Table D-5). Because the experimentally determined apparent MW of 

the MON 87429-produced FT_T protein was within the acceptance limits for equivalence (Table 

D-6), the MON 87429-produced FT_T and E. coli-produced FT_T proteins were determined to 

have equivalent apparent molecular weights. 
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Figure D-4. Purity and Apparent Molecular Weight Analysis of the MON 87429-Produced 

FT_T Protein

Aliquots of the MON 87429-produced and the E. coli-produced FT_T proteins were subjected to SDSPAGE and the gel was stained with Brilliant Blue G-Colloidal stain. The MWs (kDa) are shown on the 

left and correspond to the standards loaded in lanes 1 and 9. Lane designations are as follows: 

Lane Sample Amount (μg)

 1 Broad Range MW Standard 5.0

 2 E. coli-produced FT_T 1.0

 3 MON 87429-produced FT_T 1.0

 4 MON 87429-produced FT_T 1.0

 5 MON 87429-produced FT_T 2.0

 6 MON 87429-produced FT_T 2.0

 7 MON 87429-produced FT_T 3.0

 8 MON 87429-produced FT_T 3.0

 9 Broad Range MW Standard 5.0

 10 Blank 
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Table D-5. Apparent Molecular Weight and Purity Analysis of the MON 87429-Produced 

FT_T Protein

Apparent MW1 (kDa) Purity2 (%)

Average (n=6) 36.0 91

1Final MW was rounded to one decimal place. 

2Average % purity was rounded to the nearest whole number.

Table D-6. Apparent Molecular Weight Comparison Between the MON 87429-Produced 

FT_T and E. coli-Produced FT_T Proteins

Apparent MW

of MON 87429-Produced 

FT_T Protein (kDa)

Apparent MW 

of E. coli-Produced 

FT_T Protein (kDa)

Acceptance Limits1

(kDa)

36.0 35.5 34.1 – 36.8

1 Data obtained from the E. coli-produced FT_T protein was used to generate a prediction interval for 

setting the acceptance limits (Table D-8).
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D.1.6. FT_T Glycosylation Equivalence

Some eukaryotic proteins are post-translationally modified by the addition of carbohydrate 

moieties (Rademacher et al., 1988). To test whether the FT_T protein was glycosylated when 

expressed in the maize grain of MON 87429, the MON 87429-produced FT_T protein was 

analyzed using an ECLTM glycoprotein detection method. Transferrin, a glycosylated protein, 

was used as a positive control in the assay. To assess equivalence of the MON 87429-produced 

and E. coli-produced FT_T proteins, the E. coli-produced FT_T protein was also analyzed. 

A clear glycosylation signal was observed at the expected molecular weight (~ 80 kDa) in the 

lanes containing the positive control (transferrin) and the band intensity increased with 

increasing concentration (Figure D-5, panel A). In contrast, no glycosylation signal was 

observed in the lanes containing the E. coli-produced FT_T protein or MON 87429-produced 

FT_T protein (Figure D-5, panel A).

To confirm that MON 87429-produced FT_T and E. coli-produced FT_T proteins were 

appropriately loaded for glycosylation analysis, a second membrane with identical loadings and 

transfer time was stained with Coomassie Blue R250 for protein detection. Both the 

MON 87429-produced and E. coli-produced FT_T proteins were detected (Figure D-5, panel B). 

These data indicate that the glycosylation status of MON 87429-produced FT_T protein is 

equivalent to that of the E. coli-produced FT_T protein and that neither is glycosylated.
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 A. B.

Figure D-5. Glycosylation Analysis of the MON 87429-Produced and E. coli-Produced 

FT_T Proteins 

Aliquots of the transferrin (positive control), E. coli-produced FT_T and MON 87429-produced FT_T 

were subjected to SDS-PAGE and electrotransferred to a PVDF membrane. The MWs (kDa) correspond 

to the Precision Plus Dual Color ProteinTM Standards. The arrows show the expected migration of the 

MON 87429-produced and E. coli-produced FT_T proteins and transferrin. (A) Where present, the 

labeled carbohydrate moieties were detected by addition of streptavidin conjugated to HRP followed by a 

luminol-based detection using ECL reagents and exposure to Hyperfilm®. The 30 second exposure is 

shown. (B) An equivalent blot was stained with Coomassie Blue R250 to confirm the presence of proteins. 

Lane designations are as follows:

Lane Sample Amount (ng)

 1 Precision Plus ProteinTM Standards -

 2 Blank -

 3 Transferrin (positive control) 100

 4 Transferrin (positive control) 200

 5 Blank -

 6 MON 87429-produced FT_T 100

 7 MON 87429-produced FT_T 200

 8 Blank -

 9 E. coli-produced MON 87429 FT_T 100

10 E. coli-produced MON 87429 FT_T 200
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D.1.7. FT_T Functional Activity

The functional activities of the MON 87429-produced and E. coli-produced FT_T proteins were 

determined using a colorimetric assay that measures the FT_T catalyzed degradation of 2,4-D to 

2,4-DCP. In this assay, protein-specific activity is expressed as units per microgram of protein 

(U/mg), where a unit (U) is 1 nmole of 2,4-D to 2,4-DCP per min at 25°C. The 

MON 87429-produced and E. coli-produced FT_T proteins were considered to have equivalent 

functional activity if the specific activity of both were within the preset acceptance limits of 183 

to 974 U/mg (the prediction interval calculated from a data set of historically determined FT_T 

protein activity; see Table D-9). 

The experimentally determined specific activity for the MON 87429-produced and 

E. coli-produced FT_T proteins are presented in Table D-7. The specific activities of 

MON 87429-produced and E. coli-produced FT_T proteins were 723 U/mg and 720 U/mg of 

FT_T protein, respectively. Because the specific activities of MON 87429-produced and 

E. coli-produced FT_T proteins fall within the preset acceptance limits (Table D-7), the 

MON 87429-produced FT_T protein was considered to have equivalent functional activity to 

that of the E. coli-produced FT_T protein.

Table D-7. Functional Activity of MON 87429-Produced and E. Coli-Produced FT_T 

Protein

MON 87429-Produced

FT_T 1

(U/mg)

E. coli-Produced

FT_T 1

(U/mg)

Acceptance Limits2

(U/mg)

723 720 183.4 – 974.0

1 Value refers to mean calculated based on samples spectrophotometrically read in triplicate plate wells.

2 Data obtained from two E. coli-produced FT_T lots were used to generate a prediction interval for 

setting the acceptance limits (Appendix D, Table D-9)

 
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D.1.8. FT_T Protein Identity and Equivalence Conclusion

The MON 87429-produced FT_T protein was purified from MON 87429 grain, was 

characterized, and a comparison of the physicochemical and functional properties between the 

MON 87429-produced and the E. coli-produced FT_T proteins was conducted following a panel 

of analytical tests: 1) N-terminal sequence analysis established the same identity for the 

MON 87429-produced and E. coli-produced FT_T proteins; 2) Nano LC-MS/MS analysis 

yielded peptide masses consistent with the expected peptide masses from the theoretical trypsin

digest of the ft_t gene product present in MON 87429; 3) the MON 87429-produced and the E. 

coli-produced FT_T proteins were both detected on a western blot probed with antibodies 

specific for FT_T protein and the immunoreactive properties of both proteins was shown to be 

equivalent; 4) the electrophoretic mobility and apparent molecular weight of the 

MON 87429-produced and E. coli-produced FT_T proteins were shown to be equivalent; 5) 

the glycosylation status of MON 87429-produced and E. coli-produced FT_T proteins was 

determined to be equivalent; and 6) the functional activity of the MON 87429-produced and 

E. coli-produced FT_T was demonstrated to be equivalent. These results demonstrate that the 

MON 87429-produced FT_T protein and the E. coli-produced FT_T protein are equivalent. This 

demonstration of protein equivalence confirms that the E. coli-produced FT_T protein is 

appropriate for use in the evaluation of the safety of the MON 87429-produced FT_T protein.

D.2. Materials and Methods for Characterization of FT_T Protein Produced in 

MON 87429

D.2.1. Materials

The test substance is the MON 87429-produced FT_T protein (lot 11478812) purified from grain 

of MON 87429 (lot 11464934). The MON 87429-produced FT_T protein was stored in a -80 oC 

freezer in a buffer containing 50 mM Tris, pH 8, 200 mM NaCl.

The reference substance is the E. coli-produced FT_T protein (lot 11478164). The FT_T 

reference substance was generated from cell paste produced by fermentation of E. coli containing 

pMON374248 expression plasmid. The DNA sequence encoding FT_T protein contained in the 

expression plasmid was confirmed both prior to and following fermentation. 

D.2.2. Protein Purification

The plant-produced FT_T protein used in this equivalence study was purified from grain of 

MON 87429. The purification procedure was not performed under a good laboratory practice 

(GLP) plan; however, all procedures were documented in an electronic lab notebook (ELN) and, 

where applicable, standard operating procedures (SOPs) were followed. All purification steps 

were performed at ~4°C, except where specifically stated. FT_T was purified from an extract of 

ground grain using immunoaffinity chromatography (IAC). A detailed description of the 

purification procedure specific for FT_T was archived in the Monsanto Regulatory Archives and 

a brief purification procedure was described below.

Grain of MON 87429 was ground to fine powder in the presence of dry ice and stored at -80°C 

until use. A total of ~50 g of ground powder was mixed with 0.5 L of Extraction Buffer (50 mM 

Tris, pH 8.0, 200 mM NaCl, 2 mM benzamidine-HCl) at room temperature for ~1 hr. The slurry 
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was centrifuged twice at 13,500 x g for 15 min at ~4°C to be clarified, and about 410 ml 

supernatant was collected, filtered, and loaded onto a ~1 ml IAC column (Column size: ID = 1 

cm, h ≈ 1.5 cm; Resin: MabSelect Protein A resin cross-linked with ~3 mg of anti-FT_T mAb 

(Monsanto, lot 109529) following the manufacturer’s instruction Catalog #: 17-5199-03, GE 

Healthcare, IL) which was connected to a AKTA FPLC system at 4°C. Before sample load, the 

resin was equilibrated with Equilibration Buffer (50 mM Tris, pH 8.0, 200 mM NaCl). The 

sample was loaded on the resin at 500 cm/hr. The resin was subsequently washed 50 column 

volumes (CV) Equilibration Buffer and 35 CV Wash Buffer (50 mM Tris, pH 8.0, 1 M NaCl). 

The protein was eluted with 50 CV Elution Buffer (2 M arginine, 50 mM Tris, pH 8.0, 1 M 

NaCl). As the fractions were collected, they were immediately diluted 1:3 with Equilibrium 

Buffer. Fractions containing FT_T, identified by SDS-PAGE analyses, were pooled to a final 

volume of ~200 ml. This pooled sample was concentrated and buffer-exchanged to storage 

buffer (50 mM Tris, pH 8.0, 200 mM NaCl) using centrifugal filtration devices (Millipore, Cat. 

#: UFC901024). This FT_T protein, purified from the grain of MON 87429, was aliquoted, 

assigned lot 11478812, and stored in a -80 °C freezer.

D.2.3. Methods for Characterization

D.2.3.1. N-Terminal Sequencing/Mass Fingerprint Analysis

The test substance was analyzed for N-terminal amino acid sequence and peptide mass 

fingerprint analysis by Nano LC-MS/MS. An aliquot of the test substance was subjected to 

acetone precipitation to remove buffer components and re-suspended in 30 μl 40% TFE/100 mM 

NH4HCO3. The sample was reduced by 10 mM DTT at 37oC for 1 hr, alkylated by incubation in 

the dark for 30 min at room temperature with 50 mM iodoacetamide (IAM), and then trypsin 

digested in an enzyme to protein ration of 1:20. at 37oC. After 15 hr the digestion was quenched

with 1μl of formic acid. The digest was extracted with 30 μl of 60% acetonitrile/0.1% FA twice. 

The sample was dried to completion using vacuum centrifugation and then solubilized in 20 μl of 

0.1 % FA for LC-MS/MS analysis. 

The LC-MS/MS data acquisition was performed on a Dionex 3000 Ultimate nanoLC system 

(Dionex) interfaced to an Orbitrap Fusion mass spectrometer (Thermo Scientific), which is 

equipped with a nano-ESI source. The sample was loaded and separated online using an 

Acclaim PepMap100 C18 nano column (75 μm- id × 150 mm, 2 μm, 100 Å, Dionex). The 

separation of the digests was achieved at a 300 nl/min flow rate using an acetonitrile gradient as 

follows: 0-4 min sustaining 2% solvent B (100% acetonitrile with 0.1% FA), 4-80 min ramping 

solvent B 2-40%, 80-85 min ramping solvent B 40-90%. The column was washed/equilibrated 

between injections as follows: 85-90 min ramping maintaining solvent B at 90%, 90-90.1 min 

decreasing solvent B 90-2%, and 90.1-100 min maintaining solvent B at 2%. Solvent A was 

0.1% FA. 

The Orbitrap Fusion mass spectrometer was operated with two scan events. The first scan event 

was a full Fourier transform mass spectrometry scan with a range of m/z from 200 to 1800 and a 

mass resolution of 120,000 at m/z of 200. The second scan event was a tandem mass 

spectrometry scan of fragments from collision induced dissociation (CID) of precursor ions from 

the first scan event with an isolation width of 2.0 m/z. 
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The LC-MS/MS dataset were analyzed using Mascot (version 2.5, Matrix Science). MS/MS 

spectra were searched against the theoretical FT_T protein sequence. The mass tolerances of 

MS1 mass and MS/MS mass were set as 5 ppm and 0.5 Da, respectively. Carboxymethylation of 

cysteine was set as a fixed modification. Methionine oxidation and N-terminal acetylation were 

set as variable modifications. A maximum of two missed cleavages for trypsin were allowed. 

The mass coverage was accepted if it is greater than 40% of the protein sequence.

D.2.3.2. Western Blot Analysis-Immunoreactivity

Western blot analysis was performed to confirm the identity of the MON 87429-produced FT_T 

protein and to compare the immunoreactivity of the MON 87429-produced and E. coli-produced 

FT_T protein. MON 87429-produced and E. coli-produced FT_T proteins were initially diluted 

to 200 ng/μl (purity-corrected FT_T protein concentration) with Milli-Q water, and finally 

diluted to 2 ng/μl in 5 × LB and Milli-Q water and then heated to 100°C for 5 min. Three 

amounts (~5, ~10, and ~20 ng) of the intact test substance (total protein concentration × purity of 

the intact FT_T protein) and the intact reference substance (total protein concentration × purity 

of the intact FT_T protein) were loaded in duplicate onto a pre-cast Tris-glycine 4-20% 

polyacrylamide mini-gel (Invitrogen). Pre-stained molecular weight standards (Precision Plus 

Protein Dual Color StandardsTM, Bio-Rad) were loaded on the gel for molecular weight reference 

and to verify electrotransfer of the proteins to the membrane. Following electrophoresis at a 

constant voltage, proteins were electrotransferred to a PVDF membrane (Invitrogen). 

The Western blotting procedure was performed using an iBindTM Western System apparatus 

(Life Technologies). The membrane was blocked with 1 × iBindTM Solution (Life Technologies) 

and incubated with mouse anti-FT_T monoclonal antibody (Monsanto, lot #: 109529) at a 

dilution of 1:1250 in 1 × iBindTM Solution. The membrane was then washed with 1 × iBindTM

Solution and incubated with horse anti-mouse polyclonal antibody conjugated with peroxidase 

(Vector, Cat #: PI-2000, lot #: X0328) at a dilution of 1:1250 in 1 × iBindTM Solution. After 

washing with 1 × iBindTM Solution, immunoreactive bands were visualized using the enhanced 

chemiluminescence (ECL) detection system (GE Healthcare) and exposed to Hyperfilm ECL 

high performance chemiluminescence film (GE Healthcare). The film was developed using a 

Konica SRX-101A automated film processor (Konica Minolta).

Quantification of the bands on the blot was performed on a Bio-Rad GS-900 densitometer with 

the supplied Image Lab 5.0 Security Edition software using the volume tool. The signal 

intensities of the immunoreactive bands migrating at the expected position for the FT_T protein 

were quantified as volume values. The immunoreactivity was reported in OD × mm2.

D.2.3.3. Apparent Molecular Weight and Purity Determination by SDS-PAGE 

MON 87429-produced and E. coli-produced FT_T proteins were diluted in 5 × loading buffer 

(LB, 0.31 M Tris-Cl, pH 7.5, 10% SDS, 50% glycerol, 25% (v/v) 2-mercaptoethanol, 0.025% 

(w/v) Bromophenol blue) and Milli-Q water and then heated to 95-105°C for 3-5 min. The 

MON 87429-produced FT_T protein was loaded in duplicate at ~1.0, ~2.0, and ~3.0 μg, based 

on total protein concentration, onto a Tris-glycine 4-20% polyacrylamide mini-gel (Invitrogen) 

in lanes 3, 4, 5, 6, 7 and 8. The E. coli-produced FT_T protein was loaded at ~1.0 μg total 

protein in lane 2. Broad Range Molecular Weight Standards (Bio-Rad) were prepared and 
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loaded in lanes 1 and 9 on the gel. Following electrophoresis at a constant voltage, proteins were 

briefly fixed in 40% (v/v) methanol, 7% (v/v) acetic acid and stained for 18 hr with Brilliant 

Blue G-Colloidal stain (Sigma). Gels were briefly destained in 10% (v/v) acetic acid, 25% (v/v) 

methanol followed by 7 hr in 25% (v/v) methanol. Analysis of the gel was performed using a 

Bio-Rad GS-900 densitometer supplied with Image Lab 5.0 Security Edition software. Apparent 

MW and purity were reported as an average of all 6 lanes containing the MON 87429-produced 

FT_T protein.

D.2.3.4. Glycosylation Analysis

ECL Glycoprotein Detection method (GE Healthcare) was used for glycoprotein detection. The 

MON 87429-produced FT_T protein, E. coli-produced FT_T protein and a positive control 

(Transferrin, Sigma) were diluted in 5 × LB and water to a final concentration of 25 μg/ml 

protein and 1 × LB and then heated to 100.0°C for 5 min. Two amounts (~100 ng and ~200 ng) 

of the intact MON 87429-produced FT_T protein (purity-corrected), the E. coli-produced FT_T 

protein (purity-corrected), and the positive control were loaded onto a pre-cast Tris-glycine 4-

20% polyacrylamide mini-gel (Invitrogen). Pre-stained molecular weight markers (Precision 

Plus Protein Dual Color StandardsTM, Bio-Rad) were also loaded for molecular weight reference 

and to verify electrotransfer of the proteins to the membrane. Following electrophoresis at a 

constant voltage, proteins were electrotransferred to a PVDF membrane (Invitrogen). 

Glycosylation analysis was performed on the PVDF membrane at room temperature using the 

ECL Glycoprotein Detection Module (GE Healthcare) as directed by the manufacturer. 

Glycosylated proteins were detected using equivalent chemical reagents to the ECLTM reagents 

(GE Healthcare) and Amersham Hyperfilm (GE Healthcare). The film was developed using a 

Konica SRX-101A automated film processor (Konica Minolta). An identical gel was run and 

electrotransferred to a PVDF membrane in parallel. Proteins were stained with Coomassie 

Brilliant Blue R-250 staining solution (Bio-Rad) and then destained with 1 Coomassie Brilliant 

Blue R-250 Destaining Solution (Bio-Rad). After washing with water, the blot was scanned 

using Bio-Rad GS-900 densitometer with the supplied Image Lab 5.0 Security Edition software. 

D.2.3.5. Functional Activity

In preparation for analysis, the E. coli-produced FT_T protein was initially diluted with storage 

buffer to the same purity-corrected concentration as the MON 87429-produced FT_T protein 

(0.82 mg FT_T/ml). Prior to functional analysis, both MON 87429-produced and E. coliproduced FT_T proteins were diluted with assay reaction buffer (20 mM MOPS, pH 6.8, 50 μM 

(NH4)2Fe(SO4)2, 50 μM sodium ascorbate, 0.5 mM α-ketoglutarate) to a purity-corrected 

concentration of ~10 μg/ml. The reactions were performed in assay reaction buffer with 5 μg/ml 

FT_T at ~25°C for 30 min. The reactions for both proteins were conducted in triplicate and were 

initiated by the addition of 2,4-D to a final concentration of 0.5 mM. After 30 min incubation, 

the reactions were quenched with 15 μl stop buffer (50 mM Boric acid, pH 10.0, 50 mM 

potassium chloride, 1 mM EDTA). A 800 μM 2,4-dichlorolphenol (2,4-DCP) solution was used 

to prepare a standard curve ranging from 0 to 400 μM 2,4-DCP in assay reaction buffer and then 

quenched with 15 μl stop buffer. An assay blank (assay reaction buffer only) and negative 

control (0.5 mM 2,4-D in assay reaction buffer) were also run in triplicate. After quenching the 

reactions, 15 μl of 0.8% potassium ferricyanide was added to standard, blank, negative control 
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and sample wells and incubated at ~25°C for 1 min. The absorbance of each reaction and 

standard was measured at 510 nm with a reference wave length of 700 nm using SpectraMax 384 

plus Microplate Reader. The amount of 2,4-DCP in each reaction was determined using the 

standard curve. The specific activity of FT_T was defined in unit per μg of protein (U/mg), 

where a unit (U) is 1 nmole of 2,4-D to 2,4-DCP per min at 25°C. 

D.2.3.6. Prediction Intervals as Acceptance Criteria

Acceptance criteria (acceptance limits) based on prediction intervals were used to assess the 

equivalence of the MON 87429-produced and E. coli-produced FT_T proteins for apparent MW 

and functional activity. A prediction interval is an estimate of an interval in which a randomly 

selected future observation from a population will fall, with a certain degree of confidence, given 

what has already been observed; i.e., prediction intervals are generated based on statistical 

analysis of existing data.

The source of the data used to generate the prediction intervals for apparent MW and functional 

activity for FT_T protein equivalence assessment are provided in Table D-8 and Table D-9, 

respectively. The data used were generated under GLP guidelines and included apparent MW 

and functional activity estimates for the reference E. coli-produced FT_T protein during the 

initial characterization and for an additional E. coli-produced FT_T protein lot during recharacterization (functional assay only). 

The two-sided 95% prediction interval (PI) for one future assay was calculated using JMP

software (version 9.00, SAS Institute, Inc., Cary, NC) according to the guidance document of 

Ramírez (2009).
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Table D-8. Individual Assay Data and 95% Prediction Interval Generated for the 

Apparent MW of FT_T Protein for One Future Assay

Assay Number1 Apparent MW of FT_T Protein (kDa)2

1 35.833

2 35.589

3 36.033

4 35.989

5 34.827

6 35.006

7 34.690

8 35.729

Mean 35.5

Standard Deviation 0.54

95% Prediction Interval 34.1 – 36.8

1 Assay 1-8 represents the MW data from the initial characterization of E. coli-produced FT_T (lot 11478164). 

2 The values in the table represent the mean of six (n=6) data points within each assay. With 95% confidence, the 

mean of the 6 data points from the next single assay of the population will fall within the stated interval. Mean and 

prediction interval values rounded to one decimal point.
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Table D-9. Individual Assay Data and 95% Prediction Interval Generated for the 

Functional Activity of the FT_T Protein for One Future Assay

Assay Number1 Functional Activity of FT_T Protein2

(U/mg)

1 742.671

2 756.702

3 842.367

4 775.289

5 748.196

6 761.855

7 554

8 486

9 293

10 343

11 440

12 410

13 471

14 583

15 473

Mean 578.7

Standard Deviation 178.46

95% Prediction Interval 183.4 – 974.0

1 Assay 1-6 represents the specific activity from the initial characterization of E. coli-produced FT_T (lot 

11478164). Assays 7-15 represent the specific activity data for re-characterization of a different lot of E. coliproduced FT_T (lot 11462796). 

2 The values in the table represent the mean of 3 replicates (n=3) within each assay. With 95% confidence, the mean 

of the 3 replicates from the next single assay of the population will fall within the stated interval. Mean and 

prediction interval values rounded to one decimal point.
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References for Appendix D 

Bradshaw, R.A., W.W. Brickey and K.W. Walker. 1998. N-terminal processing: The methionine 

aminopeptidase and Na-acetyl transferase families. Trends in Biochemical Sciences 23:263-267.

Biron, D.G., C. Brun, T. Lefevre, C. Lebarbenchon, H.D. Loxdale, F. Chevenet, J.-P. Brizard 

and F. Thomas. 2006. The pitfalls of proteomics experiments without the correct use of 

bioinformatics tools. Proteomics 6:5577-5596.

Krause, E., H. Wenschuh and P.R. Jungblut. 1999. The dominance of arginine-containing 

peptides in MALDI-derived tryptic mass fingerprints of proteins. Analytical Chemistry 71:4160-

4165.

Rademacher, T.W., R.B. Parekh and R.A. Dwek. 1988. Glycobiology. Annual Review of 

Biochemistry 57:785-838.

Ramírez, J.G. 2009. Statistical Intervals: Confidence, Prediction, Enclosure. JMP White Paper

(SAS Institute, Inc., Cary, NC). http://www.sas.com/reg/wp/corp/4430.

Richter, S. and G.K. Lamppa. 1998. A chloroplast processing enzyme functions as the general 

stromal processing peptidase. Proceedings of the National Academy of Science of the United 

States of America 95:7463-7468.
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Appendix E: Specificity of the MON 87429 Dicamba Mono-Oxygenase (DMO) 

Enzyme Using o-Anisic Acid as a Substrate 

E.1. MON 87429 DMO o-Anisic Acid Substrate Specificity

Dicamba mono-oxygenase (DMO) is an enzyme that catalyzes the demethylation of the 

herbicide dicamba (3,6-dichloro-2-methoxybenzoic acid) to the non-herbicidal 3,6-

dichlorosalycilic acid (DCSA) (Chakraborty et al., 2005). In order to evaluate the 

selectivity of DMO for dicamba herbicide as compared to potential endogenous 

substrates, a series of in vitro studies were previously performed and reported in 

MON 87708 USDA-AHPIS Petition #10-188-01p. Endogenous compounds evaluated in 

those studies included ferulic acid, o-anisic acid, sinapic acid, syringic acid, and vanillic 

acid. These substrates were chosen because they are structurally similar to dicamba and 

are found in plants. The results demonstrated that DMO did not catabolize the potential 

endogenous substrates tested and supported the conclusion that DMO has a high 

specificity for dicamba. The Escherichia coli (E. coli)-produced DMO used in MON 

87708 USDA-AHPIS Petition #10-188-01p had an identical amino acid sequence to the 

wild-type DMO found in Stenotrophomonas maltophilia, with the exception of a 

histidine-tag at the N-terminus.

MON 87429 maize contains a dmo expression cassette that results in two forms of the 

DMO protein, DMO+0 and DMO+1, collectively referred to herein as MON 87429 

DMO. The DMO+0 differs from the wild-type DMO by only a leucine added at position 

2 (Wang et al., 2016). The DMO+1 has one additional cysteine on the N-terminus of the 

DMO+0, which is derived from a chloroplast transit peptide. Due to the close similarity 

of the DMO protein used in MON 87708 USDA-AHPIS Petition #10-188-01p and 

MON 87429 DMO, the two enzymes were expected to exhibit the same level of substrate 

specificity. This was evaluated by testing for potential catabolism of o-anisic acid by 

E. coli-produced MON 87429 DMO, using the same qualitative assay reported in MON

87708 USDA-AHPIS Petition #10-188-01p. Although o-anisic acid is not known to be 

present in corn, this substance was chosen for this confirmatory experiment since, among 

the five substrates used in the MON 87708 USDA-AHPIS Petition #10-188-01p, this is 

the substrate that is most structurally similar to dicamba. The results were evaluated 

qualitatively. For o-anisic acid, similarly to the previously reported results in MON 

87708 USDA-AHPIS Petition #10-188-01p, no new peaks that would be indicative of the 

predicted demethylated product were observed, confirming that the MON 87429 DMO 

did not catabolize o-anisic acid. These results taken together with the previously reported 

results demonstrate that DMO has a high specificity for dicamba as a substrate.

E.2. Materials and Methods for MON 87429 DMO o-Anisic Acid Substrate 

Specificity

MON 87429 produces two forms of the DMO protein, DMO+0 and DMO+1, collectively 

referred to herein as MON 87429 DMO. The MON 87429 DMO used in the in vitro 

enzyme assays was co-expressed in E. coli using a single expression vector designed to 
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match the DMO+0 and DMO+1 produced in MON 87429. The DMO+0 has an identical 

amino acid sequence to the wild-type DMO protein isolated from S. maltophilia, with the 

exception of a leucine added at position 2 (Wang et al., 2016). The DMO+1 has an 

identical amino acid sequence to the DMO+0, with the exception of one additional 

cysteine on its N-terminus derived from a chloroplast transit peptide. 

The compounds tested and standards used in the in vitro enzyme assays are shown in 

Table E-1.

Table E-1. Compounds Used in Specificity In Vitro Enzyme Assays

E.3. In Vitro Enzymatic Reaction Method

The reaction of the E. coli-produced MON 87429 DMO with dicamba or o-anisic acid 

was carried out using the three enzymes necessary for demethylation: 0.077 μg/μL 

reductase (lot 11406970), 0.02 μg/μL ferredoxin (lot 11423290), and 0.005 μg/μL E. coliproduced MON 87429 DMO (lot 11472501), in a reaction mixture containing 

25 mM KPi, H2O, 10 mM MgCl2, 0.7 mM NADH, 0.0004 U/μL formaldehyde 

dehydrogenase, 0.5 mM FeSO4, and the tested compound at 0.3 mM. Control assays 

were run by substituting dilution buffer (25 mM KPi, pH 7.2, 10 mM MgCl2 ) for DMO 

in equal volume for the above reactions. The final volume for each assay sample was 

200 μl. Each assay sample was incubated for 15 min at ~30oC before quenching the 

reaction by the addition of 5% H2SO4. The activity of DMO with dicamba provided a 

positive control for DMO functional activity. 

E.4. Liquid Chromatography Separation Method

Each reaction mixture was separated by UPLC using an ACQUITY UPLC BEH C18 

Column containing 1.7 μm Bridged Ethyl Hybrid (BEH) particles. The column was 

heated to and maintained at 40°C. The substrates and products formed were detected by 

ACQUITY UPLC UV detector with optimized wavelengths (dicamba at 226 and 280nm, 

anisic acid at 210 and 280 nm) (LC-UV). The chromatography was performed at 

0.05 ml/min and following the separation the column effluent was then directed to the 

mass spectrometer. Both mobile phase A (H2O) and solvent B (acetonitrile) contained 

0.1% v/v formic acid. Gradients used were as following:

The gradient was run from 40 to 60% solvent B in 6 min, 60 to 100% solvent B in 4 min 

and then kept at 100% solvent B for 2 min before returning to 40% solvent B in 0.1 min. 

DCSA was used as a standard to determine product retention time.

Manufacturer/

Retailer Compound

Common 

Name

Compounds Tested:

Millipore 2-methoxybenzoic acid o-anisic acid

Sigma 3,6-dichloro-2-methoxybenzoic acid dicamba
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A 5 μl injection of reaction mixture was used to monitor the presence of the tested 

compound. 

E.5. Mass Spectrometry Method

Elution from the UPLC column flowed directly to a Waters Micro Q-TOF mass 

spectrometer. The parameters used for the mass determination of all compounds were: 

negative mode, capillary voltage of 2500 V, extraction cone of 1.5 V, source temperature 

of 80°C, and the desolvation temperature was 120°C. The sample cone voltage was 25 V 

for dicamba, DCSA, and o-anisic acid. The desolvation gas flow was 500 L/hour and

scan time was 0.76 seconds and inter scan delay was 0.1 sec. The m/z range used was 

specific to each tested compound and product. The m/z range scanned for dicamba and 

DCSA was from 160 to 224 from 0 to 15 min. The m/z at 175, which is a fragment ion 

of dicamba, was used as the detection ion for dicamba. This fragment ion of dicamba 

gave better sensitivity than the parent ion. The m/z at 205 was used to detect DCSA. 

The m/z range scanned for o-anisic acid was from 120 to 230 within 15 min. The m/z at 

151 was used to detect o-anisic acid, and the m/z at 137 was used to look for a new peak 

that would be indicative of a potential demethylation product of o-anisic acid.

E.6. Results and Discussion

The potential catabolism of o-anisic acid by E. coli-produced MON 87429 DMO was 

evaluated using the same qualitative enzymatic assay reported in MON 87708 USDAAHPIS Petition #10-188-01p. The conversion of dicamba to DCSA was also assessed. 

Mass spectrometry scans from 120 m/z to 230 m/z were analyzed to cover the range of 

tested compounds and all potential demethylated products formed by the reaction of 

o-anisic acid and E. coli-produced MON 87429 DMO. For o-anisic acid, no additional 

peaks that might be associated to the predicted demethylated product were observed in 

the mass spectrometry scans from 120 m/z to 230 m/z. Figure E-1 shows a representative 

result from the reaction mixtures containing o-anisic acid, with and without E. coliproduced MON 87429 DMO. o-Anisic acid is shown at its respective detection mass 

(m/z 151; Figure E-1B). A single demethylation of o-anisic acid to produce a compound 

with m/z 137 was predicted based on the known mode of action of DMO. No new peaks 

were observed at m/z 137 in the chromatograms (Figure E-1C) for the samples containing 

DMO as compared to the negative controls, which did not contain DMO. As expected, a 

novel peak was present at the respective m/z (205) for DCSA in reactions containing both 

dicamba and DMO (Figure E-2C), confirming that the E. coli-produced MON 87429

DMO used for this analysis was functionally active. The data demonstrate that o-anisic 

acid was not catabolized by E. coli-produced MON 87429 DMO.

E.7. Conclusions

The data reported herein, together with the previously reported data (MON 87708 

USDA-AHPIS Petition #10-188-01p) demonstrate that DMO, including E. coli-produced 

MON 87429 DMO, is selective for its substrate, dicamba.
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Figure E-1. Representative Assay Results for o-Anisic Acid

0.3 mM of o-anisic acid was included in a reaction mixture made with (+DMO, upper) or without 

(-DMO, lower) MON 87429 DMO, and the presence of the added compound and formation of 

the predicted demethylated product was monitored by LC-UV (Panel A) and LC-MS (Panels B 

and C). Panel B chromatograms with a 5 μl injection show the monitored m/z (151) for o-anisic 

acid, while the panel C chromatograms with a 5 μl injection show the monitored m/z (137) for the 

predicted product. Only peaks of interest that eluted between 4-8 min were shown in the figure. 
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Figure E-2. Representative Assay Results for Dicamba

0.3 mM of dicamba was included in a reaction mixture made with (+DMO, upper) or without 

(-DMO, lower) MON 87429 DMO, and the presence of the added compound and formation of 

the expected demethylated product, DCSA, was monitored by LC-UV (Panel A) and LC-MS 

(Panels B and C). Panel B chromatograms with a 5 μl injection show the monitored m/z (175) for 

dicamba, while the panel C chromatograms with a 5 μl injection show the monitored m/z (205) 

for DCSA. The peak corresponding to DCSA is indicated by arrow in panels A and C. Only 

peaks of interest that eluted between 4-8 min were shown in the figure. 
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References for Appendix E

Chakraborty, S., M. Behrens, P.L. Herman, A.F. Arendsen, W.R. Hagen, D.L. Carlson, 

X.Z. Wang and D.P. Weeks. 2005. A three-component dicamba O-demethylase from 

Pseudomonas maltophilia, strain DI-6: purification and characterization. Arch Biochem 

Biophys 437:20-28.

Burzio, L. and McCann, M. 2010. Specificity of Dicamba Mono-Oxygenase for 

Potential Endogenous Substrates. RPN-10-365.

Wang, C., K.C. Glenn, C. Kessenich, E. Bell, L.A. Burzio, M.S. Koch, B. Li and A. 

Silvanovich. 2016. Safety assessment of dicamba mono-oxygenases that confer dicamba 

tolerance to various crops. Regul Toxicol Pharmacol 81:171-182.
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Appendix F: Materials and Methods Used for the Analysis of the Levels of 

DMO, PAT, CP4 EPSPS and FT_T Proteins Expressed in MON 87429

F.1. Materials

MON 87429 forage, leaf, root, grain and pollen tissue samples were harvested from five 

sites grown in United States during the 2017 growing season from starting seed lot 

11464934. CP4 EPSPS (10000739), PAT (11383593), FT_T (11462796) and DMO 

(11402310) were used as the analytical reference standards.

F.2. Characterization of the Materials

The identity of the test substance was confirmed by analysis of the starting seed DNA by 

an event-specific polymerase chain reaction method.

F.3. Field Design and Tissue Collection

The test substance was planted in four replicated plots at five sites using randomized 

complete block design. 

F.4. Tissue Processing and Protein Extraction

The CP4 EPSPS, PAT, FT_T and DMO proteins were extracted from tissue samples as 

described in Table F-1.

Table F-1. DMO, PAT, FT_T and CP4 EPSPS Extraction Parameter

Sample Type1 Target Tissue to Buffer 

Ratio

Extraction 

Buffer

Forage, Leaf, Root, Grain and Pollen 1:100 TB pH 7.82

1 All proteins analyzed by Multiplexed Immunoassay were extracted by adding the appropriate 

volume of extraction buffer, stainless steel beads, and shaking in a Geno Grinder (SPEX Inc., 

Metuchen, NJ). The extracted samples were clarified by centrifugation.

2 Tris borate buffer (pH 7.8) (0.1 M Tris, 0.1 M Na2B4O7, 0.005 M MgCl2, 0.05% (v/v) Tween 

20)

F.5. Immunoassay Reagent and Methods

F.5.1. CP4 EPSPS Antibodies

Mouse monoclonal antibody clone 39B6.1 specific for the CP4 EPSPS protein was 

purified from mouse ascites fluid using Protein A affinity chromatography. The 

concentration of the purified antibody was determined to be 5.9 mg/ml by 

spectrophotometric methods. The purified antibody (lot G-893017) was stored in a 
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phosphate buffered saline (1 × PBS, 15 mM NaN3) and was used as the capture antibody 

in the multiplexed immunoassay. 

Mouse monoclonal antibody clone 39B10.1.28 specific for the CP4 EPSPS protein was 

purified from mouse ascites fluid using Protein A affinity chromatography. The purified 

antibodies were coupled with biotin (Thermo Fisher Scientific) per the manufacturer’s 

instructions and assigned lot 209368-A. The detection reagent was streptavidin 

conjugated to R-Phycoerythrin.

F.5.2. PAT Antibodies

Purified mouse monoclonal antibody clone PAT (pat)-4 specific for PAT (pat) protein

was purified by Protein G affinity chromatography. The concentration of the purified 

IgG was determined to be 0.9 mg/ml by spectrophotometric methods. The purified 

antibody (lot 276600E) was stored in 1 × PBS and was used as the capture antibody in 

the multiplexed immunoassay. 

Purified rabbit polyclonal anti-PAT (pat) antibodies specific for the PAT (pat) protein 

were purified from serum using Protein G affinity chromatography and coupled with 

biotin per the manufacturer’s instructions and assigned lot 351209. The detection reagent 

was streptavidin conjugated to R-Phycoerythrin.

F.5.3. FT_T Antibodies

Mouse monoclonal antibody clone 6-34.2.5 specific for the FT_T protein was purified by 

Protein G affinity chromatography. The concentration of the purified IgG was 

determined to be 2.95 mg/ml by spectrophotometric methods. The purified antibody 

(lot 546797) was stored in a phosphate buffered saline (1 × PBS, 15 mM NaN3).

Mouse monoclonal antibody clone 6-35.2.11 specific for the FT_T protein was purified 

using Protein G affinity chromatography. The detection antibody was coupled with 

biotin (Thermo Fisher Scientific), per the manufacturer’s instructions and assigned 

lot 546735.

F.5.4. DMO Antibodies

Mouse monoclonal antibody clone D712 specific for the DMO protein was purified from 

mouse ascites fluid using Protein A affinity chromatography. The concentration of the 

purified antibody was determined to be 3.3 mg/ml by spectrophotometric methods. The 

purified antibody (lot 151586) was stored in a phosphate buffered saline (1 × PBS, 

15 mM NaN3) and was used as the capture antibody in the multiplexed immunoassay.

Mouse monoclonal antibody clone 1-10C3.1.16.2 specific for the DMO protein was 

purified from mouse ascites fluid using Protein G affinity chromatography. The purified 

antibodies were coupled with biotin per the manufacturer’s instructions and assigned 

lot 125874. The detection reagent was streptavidin conjugated to R-Phycoerythrin 

(Thermo Fisher Scientific).
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F.6. Multiplexed Immunoassay Method

All CP4 EPSPS, PAT, FT_T and DMO proteins were analyzed using a validated 

multiplexed immunoassay method. Capture antibodies were covalently coupled to 

xMAP beads (Luminex Corp., Austin, TX) using the Antibody Coupling Kit (Luminex 

Corp., Austin, TX) as per the manufacturer’s instructions. Antibody-coupled xMAP 

beads specific to each protein were diluted in sample buffer (1 × PBS containing 1% 

BSA (w/v)) to a final concentration of 50 beads/μl. Standards, QCs, and tissue samples 

were added to wells as appropriate followed by diluted beads and incubated for 30-60 

minutes (min) at room temperature (RT) while shaking on a plate shaker at ~800. Plates 

were washed with 1 × PBS containing 0.05 % (v/v) Tween 20 (1 × PBST). A cocktail of 

biotinylated secondary antibodies was prepared in sample buffer containing 0.5% NFDM 

(w/v) and 0.5 mg/ml of mouse, rabbit, and goat IgG. The biotinylated antibody cocktail 

was added and incubated for 30-60 min at RT while shaking on a plate shaker at ~800. 

Plates were washed with 1 × PBST. Streptavidin RPE conjugate was added at a final 

concentration of 4 μg/ml and incubated for 30-60 min at RT by shaking on a plate shaker 

at ~800. Plates were washed with 1 × PBST. The beads were re-suspended by adding 

sample buffer and shaking on a plate shaker at ~800 for at least 10 min at 

RT. Quantification of each of the proteins was accomplished by interpolation from each 

of the protein standard curves.

F.7. Data Analyses

Multiplexed immunoassay plates for DMO, PAT, FT_T and CP4 EPSPS proteins were 

analyzed on the FLEXMAP 3D (Luminex Corp.). Plates were run as a batch on 

FLEXMAP 3D using appropriate methods, standards and control definitions. Data 

reduction analyses were performed using Milliplex Analyst software. Protein standard 

concentrations for each of the reference standards were fitted to a curve by the software 

using a best fit analysis (i.e. multiple models are fitted and the statistical best fit is used). 

Following the interpolation from the standard curve, for data that determined to be 

greater than or equal to the LOQ, the protein levels (ng/ml) in the tissues were converted 

to a μg/g dw value. For each protein, this conversion utilized a sample dilution factor 

and a tissue-to-buffer ratio in Core Informatics Laboratory Information Management 

System (LIMS, version 5.1.28). 

The across-site sample means, standard errors (SEs), and ranges were calculated by 

Microsoft Excel 2016. 

One grain sample from IAAU site of MON 87429 resulted in an unexpectedly negative 

result for CP4 EPSPS protein. The sample was re-extracted twice and re-analyzed for 

CP4 EPSPS protein to confirm the results. The sample was found to be expressing 

slightly above LOQ and was included in calculations.
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Appendix G: Mode of Action and Specificity of MON 87429 FT_T Protein

G.1. Materials and Methods Used for FT_T Enzyme Kinetics Characterization and 

Protein Melting Temperature Determination

Enzyme kinetics characterization was conducted using a modified phenolic‐based 

colorimetric detection assay (Fukomori, F. et al. 1993). Purified proteins were tested 

with selected substrates. All substrates were obtained from Sigma Aldrich in the racemic 

form, except where indicated; all other reaction components were obtained from Sigma 

Aldrich. The reaction buffer contains 20 mM MOPS pH 6.75, 50 μM (NH4)2 Fe(SO4)2, 

50 μM Ascorbic Acid (Na salt), and 1 mM alpha‐ketoglutarate. Reactions were 

performed in 150 μl final reaction volumes in 96‐well assay plates. All reactions for 

kinetic characterization were completed with four replications. Reactions were stopped 

with 15μl of stop solution (50 mM Boric Acid, 50 mM KCl, pH 10.0 (KOH) with 2% 

4‐aminoantipyrine w/v (in water) freshly diluted 1:10 into stop buffer). Color 

development agent was added (15 ul of an 8% potassium ferricyanide w/v (in water), 

freshly diluted 1:10). Following color development, assays were recorded with a 

SpectraMax spectrometer at an absorbance of 510 nm. Back calculations were completed 

with product standards in mock reactions (standards from Sigma Aldrich or custom 

synthesis). Control reactions without alpha‐ketoglutarate were inactive, and reactions 

with purified enzyme without (NH4)2 Fe(SO4)2 and ascorbic Acid were significantly 

inhibited. Unless indicated, all reactions were completed at 23 °C.

Protein melting temperatures were determined by fluorescence tracking of the 

hydrophobic protein binding dye, SYPRO Orange (Invitrogen) with progressive increases 

in temperature. The assays were run in a 20 mM Tris, pH 7.75 and 150 mM NaCl buffer 

(with or without the addition of (NH4)2 Fe(SO4)2 and Ascorbic Acid, as in the enzyme 

reaction) containing the FT_T protein and a 1:100 dilution of SYPRO Orange dye in a 

Bio‐Rad CFX96 PCR thermocycler with a fluorescence detector. The temperature was 

progressively increased from room temperature to full protein denaturation. The 

temperature at which the protein was 50% denatured was calculated.
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Table G-1. Characterization of FT_T Enzyme

RdpA FT_T

Protein melting Buffer 43 58

Buffer (Fe and

αKG)

53 62

FOPs

Quizalofop Vmax 2.76 (0.11) 1.62 (0.05)

Km 0.09 (0.01) 0.12 (0.01)

Haloxyfop Vmax 2.37 (0.05) 1.05 (0.02)

Km 0.06 (0.01) 0.04 (0.004)

Synthetic auxins

Dichlorprop Vmax 5.32 (0.09) 2.09 (0.03)

Km 0.06 (0.004) 0.03 (0.002)

2,4-D Vmax 0.25 (0.01) 1.17 (0.01)

Km 0.13 (0.02) 0.03 (0.002)

MCPA Vmax 0.20 (0.01) 1.23 (0.02)

Mecoprop Vmax 4.11 (0.15) 3.04 (0.07)

FT_T and RdpA as a control are characterized for enzyme temperature stability and enzyme 

kinetics with FOP and synthetic auxin herbicides. Protein melting is recorded as the temperature 

(C) in which the protein is 50% denatured in buffer alone or with supplemental Fe2 and αketoglutarate. Enzyme kinetic parameters are recorded for representative FOP and synthetic auxin 

herbicides with Vmax (μmol mg-1 min-1) and Km (mM) shown. Standard error shown in parenthesis. 

ND, not determined.
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G.2. Materials and Method for Endogenous Substrate Specificity Testing

The endogenous substrate screen utilized a computational screening method with 

chemical similarity and chemical docking screens followed by in vitro screening of the 

compounds that passed both computational screens and were thus the most likely 

candidates for substrates to the FT_T enzyme. The computational nature of the first two 

steps in this three-step screening process enabled screening of large datasets of small 

plant-based molecules in an efficient and robust manner. For these screens, a plant 

specific small molecule dataset from NAPRALERT (https://www.napralert.org/) (Bisson 

et al., 2016) was used (as of March 1, 2016). NAPRALERT is a relational database of 

natural products from different sources. Over 900 small molecules from maize, canola, 

cotton, wheat and soybean were identified from the literature and cataloged in this 

NAPRALERT dataset. Small molecules were curated digitally using publicly available 

tools (https://pubchem.ncbi.nlm.nih.gov/ and downloading the 2D sdf file). 

A control database was also curated. The herbicide control database included 11 known 

substrates for the FT enzymes, including chemical ID: 15118048 (Cyhalofop), 7153 

(Mecoprop), 7204 (MCPA), 86134 (Fenoxaprop), 91701 (Fluazifop), 1486 (2,4-

dichlorophenoxyacetic acid), 41428 (Triclopyr), 50465 (Fluroxypyr), 50895 (Haloxyfop), 

178795 (Quizalofop), 8427 (Dichlorprop). These compounds are not plant metabolites 

but are synthetic herbicide compounds. 

For Step 1 of the screen (the compound similarity search) we internally solved the 

structure of FT_T bound to its substrate, dichlorprop. The details of the software 

parameters and coding are provided for computation methods below. The computational 

methods summarized here provide an overview of the process. The dichlorprop structure 

was used as the query with Blaze search engine from Cresset. The Blaze software 

searched our curated plant small molecule database for similar compounds based on 

electrostatic characteristics and shape (field print). The top 50% of the field print search 

from databases were refined using Clique and followed by simplex refinement using the 

top 50% from Clique refinement. The field similarity and 2D Tanimoto similarity were 

determined. From the output, only entries with field similarity greater than 0.6 and a 

Tanimoto coefficient greater than 0.1 were selected using Forge (no refinement was 

performed). These thresholds, which were chosen such that all herbicide control 

compounds were recovered, returned a total of 71 novel compounds from the original 

database. 

Step 2 of the screens included docking and analysis of the selected compounds. To 

leverage the structural information of FT_T, we used protein-small molecule docking in 

Rosetta to evaluate the fitness of 71 candidate molecules within the active site of FT_T. 

The candidate molecules were superimposed onto the query (Dichlorprop) from Blaze. 

Conformations of the candidate molecule were generated from OpenBabel and Frog2. 

We used default methods from Rosetta Macromolecule Modeling Suite to generate 

molecular mechanics parameters and performed local docking and refinement of 

candidate molecules within the active site. A total of 1000 refinement decoys were 

generated using Rosetta ligand docking. Since the goal was to evaluate the fitness of 
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aligned candidate molecules within the protein active site after refinement, we selected 

the top 1% (10 decoys) with least centroid movement while maintaining favorable 

(negative) interaction energy between protein and ligand. We then analyzed several 

interface features between FT_T and the selected small molecules, including repulsion 

energy between protein and small molecule, coulombic interaction energy, and buried 

SASA (solvent accessible surface area). Using the averages of these three features, we 

selected cutoff values to recover all herbicide compounds. This process resulted 38 novel 

compounds that were as compatible as the putative substrate, and were selected as 

candidates for in vitro enzymatic screening. 

All 38 compounds from the computational screening plus 11 control herbicide 

compounds and cinnamate (a compound identified as a marginal substrate in a similar 

enzyme family (Griffin, S. L. et al, 2013) were ordered through www.chemnavigator.com

or Sigma Aldrich. Six of the compounds selected from Step 2 of the computational 

screens could not be screened in vitro because they were not commercially available or 

available from custom synthesis groups. Therefore, the in vitro enzymatic screening was 

conducted with a total of 44 compounds (11 herbicides and 32 compounds that passed the 

in-silico screen and cinnamate) (Table V-1). 

For the final in vitro enzymatic screening of oxidation by FT_T of the selected 

compounds, we used a coupled enzyme screen because it uses a common detection 

system that does not require standards of the final reaction products. This assay was 

adapted from a coupled assay previously described (Luo et al. 2006). The reaction 

mixture contained 100 mM MOPS (pH 7.0), 1 mM PEP, 0.4 mM NADH, 0.4mM 

coenzyme A, 0.4 mM ATP, 0.1 mM MgCl2, 0.1 mM (NH4)2Fe (SO4)2, 0.2 mM Na 

ascorbate, 1 μM succinate CoA synthetase, 6-10 units pyruvate kinase, 6-10 units lactate 

dehydrogenase, 2 μg recombinant purified FT_T and 200 μM of each test compound 

diluted from a 5 mM DMSO. All reagents were purchased from Sigma Aldrich except 

succinyl CoA Synthetase, which was purchased from Megazyme. Reactions were arrayed 

in a 96-well plate and pre-incubated at room temperature for 10 min. The reaction was 

started by the addition of 1 mM α-ketoglutarate. For measurement of both herbicides and 

putative endogenous substrates, the assay was performed in triplicate (each with 3 

technical replicates for a total n=9, with fenoxaprop assayed twice for a total n=18) by 

measuring absorbance at 340 nm continuously for up to one hour using a TECAN 

spectrometer. A positive (2,4-D) and negative (blank; DMSO without a test compound) 

control were included on each plate.

To screen for false positive, all positive reactions were confirmed with control reactions 

using either no α-ketoglutarate or no FT_T enzyme reactions. In addition, all the 

compounds were monitored for solubility and absorbance spectra before testing to ensure 

that did not interfere with the assay. To ensure that any change in A340 was due to the 

oxidation of NADH rather than the direct oxidation of the compounds, all the compounds 

were tested in the assay without the coupling system. To ensure that the compound did 

not inhibit the coupling system producing a false negative effect, 1 mM succinate was 

added to each well that had a negative result and the A340 was compared to a control 

without additional succinate.
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References for Appendix G

Bisson, J., J. McAlpine, J. Graham, and G.F. Pauli. 2016. NAPRALERT, from an 

historical information silo to a linked resource able to address the new challenges in 

natural products chemistry and pharmacognosy. CEUR Workshop Proceedings 1747 

Fukomori, F. and R. P. Hausinger. 1993. Purification and characterization of 

2,4‐dichlorophenoxyacetate/α‐ketoglutarate dioxygenase. The Journal of Biological 

Chemistry 268:24311‐24317

Griffin, S. L., J. A. Godbey, T. J. Oman, S. K. Embrey, A. Karnoup, K. Kuppannan, B. 

W. Barnett, G. Lin, N. V. J. Harpham, A. N. Juba, B. W. Schafer, and R. M. Cicchillo. 

2013. Characterization of Aryloxyalkanoate Dioxygenase-12, a Nonheme Fe(II)/αKetoglutarate-Dependent Dioxygenase, Expressed in Transgenic Soybean and 

Pseudomonas fluorescense. Journal of Agricultural and Food Chemistry 61:6589-6596 

Luo, C., X. Wang, J. Long and J. Liu . 2006. An NADH-tetrazolium-coupled sensitive 

assay for malate dehydrogenase in mitochondria and crude tissue homogenates. J 

Biochem Biophys Methods 68(2):101-111
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Appendix H: Materials and Methods for Seed Germination and Dormancy 

Assessment of MON 87429

H.1. Materials

Seed germination and dormancy characteristics were assessed on seed from MON 87429 

and the conventional control harvested from one 2017 field production site in Kihei, 

Hawaii, and on four reference maize hybrids obtained from commercial sources (Table 

H-1)

H.2. Characterization of the Materials

The presence of the MON 87429 event in the starting seed of the test material and the 

absence of the MON 87429 event in the starting seed of the conventional control were 

verified by event-specific polymerase chain reaction (PCR) analyses. 

H.3. Germination Testing Facility and Experimental Methods

Germination and dormancy evaluations were conducted at SGS North America, Inc, 

Brookings, SD. The Principal Investigator was qualified to conduct seed germination and 

dormancy testing consistent with the standards established by the Association of Official 

Seed Analysts (AOSA, 2017a; b; AOSA, 2009; AOSA/SCST, 2010). 

The seed lots of MON 87429, the conventional control, and four reference hybrids were 

tested under two temperature regimes. The optimum temperature regime consisted of 

alternating temperatures of approximately 20°C for 16 hours followed by 30°C for 8 

hours and was maintained for seven days (AOSA, 2017a; b). The suboptimum 

temperature regime consisted of constant temperatures of approximately 10°C for seven 

days followed by 25°C for four days (AOSA, 2009). One germination chamber was used 

for each temperature regime. Each chamber was maintained dark. The temperature inside 

each germination chamber was monitored and recorded throughout the duration of the 

study.

Rolled germination towels were assembled for each material by placing approximately 50 

seeds on a pre-moistened and labeled germination towel. An additional pre-moistened 

germination towel was placed on top of the seed, and the towels and seed were rolled up. 

Approximately 100 seeds (a set of two germination towel rolls secured together with a 

rubber band) of each material were placed into a bucket to form a replication. Each 

temperature regime constituted a separate experiment that was conducted using a 

randomized complete block design with four replications (i.e., buckets). 

Each set of rolled germination towels in each temperature regime was assessed at 

prescribed timings for germinated, dead, firm swollen (viable and nonviable), and hard 

(viable and nonviable) seed. Additional details for each germination characteristic 

evaluated and the timing of evaluations are presented in Table VII-1. Seeds placed under 

the optimum temperature regime were evaluated according to AOSA standards for testing 
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of maize (AOSA, 2017a; b). Seeds placed under the suboptimum temperature regime 

were evaluated according to AOSA standards for cold testing of maize (AOSA, 2009). 

Within both the optimum and suboptimum temperature regimes, firm-swollen and hard 

seeds remaining at the final evaluation date were subjected to a tetrazolium (Tz) test for 

viability according to AOSA standards (AOSA/SCST, 2010). The numbers of non-viable 

firm-swollen and non-viable hard seeds were added to the number of dead seed counted 

on all collection dates to determine the total number of dead seed. Total numbers of 

viable firm-swollen and viable hard seed were determined from the Tz test. 

The percentage of seed in each assessment category was based on the number of seeds 

evaluated. Across temperature regimes, the total number of seeds evaluated from each 

set of rolled germination towels was approximately 100.

H.4. Statistical Analysis

For each temperature regime, ANOVA was conducted according to a randomized 

complete block design using SAS® (SAS, 2012) to compare MON 87429 to the 

conventional control for the germination and dormancy characteristics. If analysis of 

variance assumptions were not satisfied, Fisher’s Exact test was conducted for that 

characteristic using SAS (SAS, 2012). The level of statistical significance was 

predetermined to be 5% (α = 0.05). The reference range for each characteristic was 

determined from the minimum and maximum mean values among the four references.
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Table H-1. Starting Seed for Germination and Dormancy Assessment of 

MON 87429

Material Name Regulatory Lot 

Number Phenotype Material Type

MON 87429 11478364 Herbicide Tolerant Test

LH244+HCL617 11478363 Conventional Control

Dekalb DKC64-85 11464651 Conventional Reference

Dekalb DKC 61-52 11427255 Conventional Reference

Kruger K-0708 11427267 Conventional Reference

Agrigold A 6300 11446938 Conventional Reference
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References for Appendix H

AOSA. 2009. Seedling evaluation. Rules for Testing Seeds. Volume 4. Association of 

Official Seed Analysts, Ithaca, New York.

AOSA. 2017a. AOSA Rules for testing seeds. Volume 1: Principles and procedures. 

Association of Official Seed Analysts, Washington, D.C.

AOSA. 2017b. AOSA Rules for testing seeds. Volume 4: Seedling evaluation. 

Association of Official Seed Analysts, Washington, D.C.

AOSA/SCST. 2010. Tetrazolium testing handbook. Association of Official Seed Analysts 

and the Society of Commercial Seed Technologists, Ithaca, New York.

SAS. 2012. Software Release 9.4 (TS1M4). Copyright 2002-2012 by SAS Institute, Inc., 

Cary, North Carolina.
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Appendix I: Material and Methods for Phenotypic, Agronomic, and 

Environmental Interaction Assessment of MON 87429 under Field Conditions

I.1. Materials

Agronomic, phenotypic, and environmental interaction characteristics were assessed for 

MON 87429, the conventional control, and reference hybrids grown under similar 

agronomic conditions. Four reference hybrids were planted per site (Table I-1). A total 

of 16 unique reference hybrids were evaluated among the eight sites. 

I.2. Characterization of the Materials

The presence of the MON 87429 event in the starting seed of the test material and the 

absence of the MON 87429 event in the starting seed of the conventional control were 

verified by event-specific polymerase chain reaction (PCR) analyses. 

I.3. Field Sites and Plot Design

Field trials in 2017 at eight sites provided a range of environmental and agronomic 

conditions representative of U.S. maize growing regions. The Principal Investigator at 

each site was familiar with crop growth and production and evaluation of crop 

characteristics. The study was established at each site in a randomized complete block 

design with four replications. Plot and row dimensions are listed in Table I-2. 

I.4. Planting and Field Operations

Planting information, soil description, and cropping history of the sites are listed in Table 

I-2. The Principal Investigator at each site followed local agronomic practices including 

those related to seed bed preparation and trial maintenance such as application of 

agricultural chemicals, fertilizer, and irrigation. All maintenance operations were 

performed uniformly across all plots within each site.
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Table I-1. Starting Seed for Phenotypic, Agronomic, and Environmental 

Interactions Assessment of MON 87429 

Site 

Code1 Material Name Regulatory Lot Number Phenotype Material Type

All MON 87429 11464934 Herbicide 

Tolerant

Test

All LH244+HCL617 11464933 Conventional Control

IAAU Dekalb DKC61-52 11427255 Conventional Reference

IAAU Lewis 1407 11427264 Conventional Reference

IAAU Golden Harvest G12J11-A 11446928 Conventional Reference

IAAU LG Seeds LG2549 11446934 Conventional Reference

IARL Lewis 1613 11427265 Conventional Reference

IARL Stone 5820 11427266 Conventional Reference

IARL Agrigold A6472 11446939 Conventional Reference

IARL Agrigold A6574 11446940 Conventional Reference

ILCX Dekalb DKC64-85 11427257 Conventional Reference

ILCX Lewis 1613 11427265 Conventional Reference

ILCX Kruger K-0708 11427267 Conventional Reference

ILCX Mycogen Seeds MY09V40 11446930 Conventional Reference

ILMN Dekalb DKC61-52 11427255 Conventional Reference

ILMN Dekalb DKC65-18 11427258 Conventional Reference

ILMN Golden Harvest G09C43 11446927 Conventional Reference

ILMN Agrigold A6574 11446940 Conventional Reference

INSH Kruger K-0708 11427267 Conventional Reference

INSH Mycogen Seeds 2H721 11446932 Conventional Reference

INSH LG Seeds LG2549 11446934 Conventional Reference

INSH LG Seeds LG2636 11446935 Conventional Reference

NESW Lewis 1407 11427264 Conventional Reference

NESW Lewis 1613 11427265 Conventional Reference

NESW Golden Harvest G12J11-A 11446928 Conventional Reference

NESW Mycogen Seeds MY09V40 11446930 Conventional Reference

NEYO Dekalb DKC64-85 11427257 Conventional Reference

NEYO Golden Harvest G12J11-A 11446928 Conventional Reference

NEYO LG Seeds LG2549 11446934 Conventional Reference

NEYO Agrigold A6574 11446940 Conventional Reference

OHTR Dekalb DKC62-06 11427256 Conventional Reference

OHTR Dekalb DKC64-85 11427257 Conventional Reference

OHTR Kruger K-0708 11427267 Conventional Reference

OHTR Golden Harvest G09C43 11446927 Conventional Reference

Note: Starting seed of test and control materials were produced in Kihei, HI in 2017.

1 Site codes: IAAU = Audubon County, IA; IARL = Jefferson County, IA; ILCX = Vermilion 

County, IL; ILMN = Warren County, IL; INSH = Boone County, IN; NESW = Seward County, 

NE; NEYO = York County, NE; OHTR = Miami County, OH.
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Table I-2. Field Information for Phenotypic, Agronomic, and Environmental Interactions Assessment of MON 87429 

Site 

Code1

Planting 

Date2

Harvest 

Date2

Planting 

Rate

(seeds/m2)

Rows/

Plot

Inter-row 

Distance

(cm)

Row 

Length

(m)

Plot

Size

(m2)

Soil Texture

Organic 

Matter 

(%)

Previous 

Crop

2016

IAAU 05/13/2017 11/01/2017 9.5 8 76 6.1 37.2 Silty Clay Loam 2.8 Soybean

IARL 05/05/2017 10/05/2017 9.5 8 76 6.1 37.2 Silty Clay Loam 3.4 Soybean

ILCX 06/01/2017 10/10/2017 8.6 8 76 6.2 38.1 Clay Loam 4.0 Maize

ILMN 05/09/2017 10/09/2017 9.5 8 76 6.1 37.2 Clay Loam 5.1 Soybean

INSH 05/18/2017 10/31/2017 9.5 8 76 6.1 37.2 Loam 2.2 Maize

NESW 05/08/2017 10/12/2017 9.5 8 76 6.1 37.2 Loam 3.1 Maize

NEYO 05/08/2017 10/19/2017 9.5 8 76 6.1 37.2 Loam 3.1 Soybean

OHTR 06/07/2017 11/17/2017 9.5 8 76 6.4 39.0 Loam 1.8 Maize

Note: Planting rate and plot/row dimensions are approximate. 

1 Site codes: IAAU = Audubon County, IA; IARL = Jefferson County, IA; ILCX = Vermilion County, IL; ILMN = Warren County, IL; INSH = 

Boone County, IN; NESW = Seward County, NE; NEYO = York County, NE; OHTR = Miami County, OH.

2 Date format = mm/dd/yyyy.
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I.5. Phenotypic Characteristic Assessments

Phenotypic characteristics assessed and the timing of each assessment are listed in Table 

VII-1.

I.6. Environmental Interaction Assessments

The test, conventional control, and commercial references were evaluated at each site for 

differences in plant responses to abiotic stressors, diseases, and arthropod pests. 

Evaluations were performed four times during the growing season at the following 

growth stages: V5 – V8, V12 – R1, R1 – R3, and R4 – R5.

The Field Co-operator at each site identified abiotic stressors, diseases, and arthropod 

pests that were either actively causing plant injury in the plots or likely to occur in maize 

during a given observation period. Stressors assessed often varied among observations 

and sites. 

Ratings were made using the categorical scale of increasing severity listed below:

Category Severity of plant damage

None No symptoms observed

Slight Symptoms not damaging to plant development (e.g., minor feeding or 

minor lesions); mitigation likely not required

Moderate Intermediate between slight and severe; likely requires mitigation

Severe Symptoms damaging to plant development (e.g., stunting or death); 

mitigation unlikely to be effective

I.7. Statistical Analysis/Data Summarization

A combined-site analysis was conducted according to a randomized complete block 

design using SAS® (SAS, 2012) to compare the test to the conventional control for the 

phenotypic characteristics listed in Table VII-1. The level of statistical significance was 

predetermined to be 5% (α = 0.05). Descriptive statistics are provided for one 

characteristic, seed loss, that had insufficient variability for formal statistical analysis. 

The reference range for each phenotypic characteristic was determined from the 

minimum and maximum mean values among the 16 references, where each mean was 

combined over all the sites at which the reference was planted. There were no plots for 

which data were excluded from the study. 

The environmental interactions data consisting of plant responses to abiotic stressors, 

diseases, and arthropod pests are categorical and were considered different in 

susceptibility or tolerance if the range of injury symptoms did not overlap between the 
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biotechnology-derived crop and the conventional control across all four replications 

within an observation. 

I.8. Detailed Results for Environmental Interactions Assessments for MON 87429

No differences were observed between the test and the conventional control for any of the 

96 comparisons of plant responses to the assessed abiotic stressors: cold temperatures, 

drought, excessive rain (i.e. waterlogging), hail, high temperatures, high winds (lodged 

plants), nutrient deficiency, soil compaction, and sun scald (Table I-3). 

No differences were observed between the test and the conventional control for any of the 

96 comparisons of damage from the assessed diseases: anthracnose, corn stunt, eyespot, 

Goss's bacterial wilt, gray leaf spot, leaf blight, northern leaf spot, rust, smut (head and 

ear), and Stewart's wilt (Table I-4).

No differences were observed between the test and the conventional control for any of the 

96 comparisons of damage from the assessed arthropods: aphids, armyworms, billbugs, 

corn earworms, corn flea beetles, corn rootworm beetles, cutworms, European corn 

borers, grasshoppers, Japanese beetles, sap beetles, slugs, spider mites, and stink bugs 

(Table I-5).

The results of the assessed environmental interactions support the conclusion that 

MON 87429 is not expected to pose increased plant pest risk compared to conventional 

maize.
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Table I-3. Summary of Abiotic Stressor Response Evaluations for MON 87429 and 

the Conventional Control in 2017 U.S. Field Trials

Abiotic Stressor

Total 

Observation

s across 

Sites

Number of Observations 

without Differences 

between the Test and the 

Conventional Control

Total 96 96

Cold Temperatures 1 1

Drought 13 13

Excessive Rain (i.e. waterlogging) 14 14

Hail 10 10

High Temperatures 10 10

High Winds (lodged plants) 26 26

Nutrient deficiency 12 12

Soil compaction 3 3

Sun scald 7 7

Notes: No differences were observed between the test and the conventional control during any 

observation for responses to any of the assessed abiotic stressors. Categorical data were 

summarized across sites and observation times.
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Table I-4. Summary of Disease Damage Evaluations for MON 87429 and the 

Conventional Control in 2017 U.S. Field Trials

Disease

Total 

Observations 

across Sites

Number of Observations 

without Differences 

between the Test and the 

Conventional Control

Total 96 96

Anthracnose 8 8

Corn stunt 4 4

Eyespot 8 8

Goss's bacterial wilt 12 12

Gray leaf spot 20 20

Leaf blight113 13

Northern leaf spot 3 3

Rust218 18

Smut (head and ear) 8 8

Stewart's wilt 2 2

Notes: No differences were observed between the test and the conventional control during any 

observation for damage caused by any of the assessed diseases. Categorical data were 

summarized across sites and observation times.

1

Includes Northern.

2

Includes common.
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Table I-5. Summary of Arthropod Damage Evaluations for MON 87429 and the 

Conventional Control in 2017 U.S. Field Trials

Arthropod 

Total 

Observations 

Across Sites

Number of Observations 

without Differences 

between the Test and the 

Conventional Control

Total 96 96

Aphids (Aphididae) 12 12

Armyworms (Noctuidae) 13 13

Billbugs (weevil) 1 1

Corn earworms (Helicoverpa zea) 7 7

Corn flea beetles (Chaetocnema pulicaria) 7 7

Corn rootworm beetles (Diabrotica spp.) 12 12

Cutworms (Noctuidae)17 7

European corn borers (Ostrinia nubilalis) 2 2

Grasshoppers (Melanoplus spp.) 15 15

Japanese beetles (Popillia japonica) 10 10

Sap beetles (Nitidulidae) 1 1

Slugs21 1

Spider mites (Tetranychus spp.) 2 2

Stink bugs (Pentatomidae) 6 6

Notes: No differences were observed between the test and the conventional control during any 

observation for damage caused by any of the assessed arthropods. Categorical data were 

summarized across sites and observation times.

1

Includes Western bean cutworm.

2 Slugs are not arthropods but are occasional pests in maize.
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References for Appendix I

SAS. 2012. Software Release 9.4 (TS1M4). Copyright 2002-2012 by SAS Institute, Inc., 

Cary, North Carolina.
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Appendix J: Materials and Methods for Pollen Morphology and Viability 

Assessment

J.1. Plant Production

Pollen Morphology and Viability were assessed for MON 87429, the conventional 

control, and four conventional reference hybrids grown under similar agronomic 

conditions in a field trial in Warren County, Illinois in 2017 (Table J-1). The trial was 

arranged in a randomized complete block design with four replications. Each plot 

consisted of 8 rows approximately 6 m in length. 

J.2. Pollen Collection and Pollen Sample Preparation

Pollen was collected from the three plants (tassels) per plot. The pollen collected from an 

individual tassel represented a subsample. Each subsample was transferred to a uniquely 

labeled tube containing approximately 400 μl of Alexander’s stain solution (Alexander, 

1980) diluted 1:5 with distilled water. The tubes were closed and shaken until thoroughly 

mixed. Pollen was allowed to stain and fix for at least 20 hours at ambient temperatures 

before assessments.

J.3. Data Collection

Slides were prepared by aliquoting suspended pollen/stain solution onto a slide. Pollen 

characteristics were assessed under an OlympusÓ BX53 light microscope equipped with 

an Olympus© DP72 digital color camera at a target magnification of 200x. The 

microscope and camera were connected to a computer running Microsoft Windows XPÒ

and installed with Olympus© cellSens version 1.4.1 software.

J.3.1. Pollen Viability

When pollen grains are exposed to the staining solution, viable pollen grains stain red to 

purple due to the presence of living cytoplasmic content. Non-viable pollen grains stain 

light blue to green or colorless, and the shape can appear round to collapsed depending on 

the degree of hydration. For each pollen sample, the number of viable and non-viable 

pollen grains were counted from a random field of view under the microscope. A 

minimum of 125 pollen grains were counted for each of the three subsamples per plot. 

Mean pollen viability for each plot was calculated from the subsamples and expressed as 

a percentage of total number of evaluated pollen grains.

 

 Olympus Corporation.

 Windows XP is a registered trademark of Microsoft Corporation.
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J.3.2. Pollen Diameter 

For a single predetermined subsample from each plot, pollen grain diameter was 

measured along two perpendicular axes for 10 representative pollen grains. Mean pollen 

diameter for each plot was calculated from the total of 20 diameter measurements.

J.3.3. General Pollen Morphology 

General pollen morphology was observed from micrographs of the test, control, and the 

reference materials that were also used for the pollen diameter measurements. 

J.3.4. Statistical Analysis

An analysis was conducted according to a randomized complete block design using SASÒ

(SAS, 2012) to compare the test to the conventional control for percent viable pollen and 

pollen grain diameter. The level of statistical significance was predetermined to be 5% 

(α=0.05). The reference range for each phenotypic characteristic was determined from the 

minimum and maximum mean values among the four references. General pollen 

morphology was qualitative; therefore, no statistical analysis was conducted on these 

observations. There were no plots for which data were excluded from the study.

J.3.5. General Pollen Morphology Results

No visual differences in general pollen morphology were observed between MON 87429 

and the conventional control (Figure J-1).

 

SAS is a registered trademark of SAS Institute, Inc.
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Table J-1. Starting Seed for Pollen Morphology and Viability Assessment

Material Name Material Type Phenotype Regulatory Lot 

Number

MON 87429 Test Herbicide Tolerant 11464934

LH244+HCL617 Control Conventional 11464933

Agrigold A6574 Reference Conventional 11446940

Dekalb DKC61-52 Reference Conventional 11427255

Dekalb DKC65-18 Reference Conventional 11427258

Golden Harvest G09C43 Reference Conventional 11446927
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Figure J-1. General Morphology of Pollen from MON 87429, the Conventional 

Control, and Commercially Available Conventional Reference Materials under 

200X Magnification

Viable pollen grains stained red to purple, while non-viable pollen grains stained lighter 

or colorless and the shape appeared round to collapsed depending on the degree of 

hydration.
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References for Appendix J

Alexander, M.P. 1980. A versatile stain for pollen fungi, yeast and bacteria. Stain 

Technology 55:13-18.

SAS. 2012. SAS/STAT software version 9.3. SAS Institute, Inc., Cary, North Carolina.
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Appendix K: Herbicide Resistance 

K.1. Introduction

Based upon theory of natural selection, plant populations can develop resistance to an 

herbicide due to the selection of individuals that carry variations in genes that can render 

those individuals unaffected by the typical lethal effects of an herbicide. Over time, those 

few plant biotypes naturally containing resistant gene(s) become dominant in the 

population as they survive repeated use of the herbicide in the absence of other control 

methods (e.g., other herbicides with different mechanism of actions, mechanical, cultural 

or biological methods). The development of resistant populations is a possibility for all 

herbicides. The probability for resistance to develop is a function of: frequency of 

resistant allele(s) 11 , mechanism of resistance, dominance or recessive nature of the 

resistant allele(s), relative fitness of the resistant biotype, and frequency or duration of 

herbicide use in the absence of other control methods (Beckie, 2006; Jasieniuk et 

al.,1996; Sammons et al., 2007). The probability of resistance is not the same for all 

herbicides, with some herbicides (e.g., ALS and ACCase classes) exhibiting resistance 

more quickly than other herbicides (e.g. auxin, glyphosate, glufosinate, and acetanilide, 

classes).

Herbicide resistance can become a limiting factor in crop production if the resistant weed 

population cannot be controlled with other herbicides, or with other methods of control. 

In general, this has not been the case for any herbicide. In most crops, there are multiple 

herbicide options for growers to use. However, good management practices to delay the 

development of herbicide resistance have been identified and are being actively promoted 

by the public and private sectors (HRAC, 2015; Norsworthy et al., 2012; WSSA, 2019)

12

and are being implemented by growers.

Monsanto considers product stewardship to be a fundamental component of customer 

service and business practices. Stewardship of dicamba, glufosinate, quizalofop, 2,4-D 

and glyphosate herbicides to preserve their usefulness for growers is an important aspect 

of Monsanto’s stewardship commitment. Although herbicide resistance may eventually 

occur in weed species when any herbicide is widely used, resistance can be postponed, 

contained, and managed through implementation of good management practices by 

growers and associated research and education. These activities are key elements of 

Monsanto’s approach to providing stewardship of dicamba, glufosinate, quizalofop, 

 

11 An allele is any of several forms of a gene, usually arising through mutations, that are responsible for 

hereditary variation.

12 The Herbicide Resistance Action Committee (HRAC; www.hracglobal.com) is an international body 

founded by the agrochemical industry for the purpose of supporting a cooperative approach to the 

management of herbicide resistance and the establishment of a worldwide herbicide resistance database. 
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2,4-D and glyphosate used on MON 87429 maize that will be combined with deregulated 

full plant glyphosate tolerance traits, such as NK603. Monsanto will continue to invest in 

research, and grower/retailer education and training programs to provide information on 

best practices to delay the selection for weed resistance and to manage weeds already 

selected for resistance to dicamba, glufosinate, quizalofop, 2,4-D and glyphosate in maize 

production. This appendix provides an overview of Monsanto’s approach to the 

development of best management practices to delay selection for weed resistance to 

dicamba, glufosinate, quizalofop, 2,4-D and/or glyphosate herbicides. Monsanto works 

closely with weed scientists in academia and with other companies to develop best 

management practices and to consistently communicate such practices to growers. An 

example of this collaboration is the development and posting of herbicide-resistance

training modules on the WSSA website (www.wssa.net) and publication of guidelines by 

the Herbicide Resistance Action Committee (HRAC) on their website 

(www.hracglobal.com). The EPA is the U.S. federal regulatory agency that administers 

federal law governing pesticide sale and use under the Federal Insecticide, Fungicide and 

Rodenticide Act (FIFRA). EPA recommends pesticide registrants to provide growers 

with information regarding an herbicide’s sites-of-action and resistance management 

practices via labeling to aid growers in planning herbicide use practices and to foster the 

adoption of effective weed resistance management practices as specified by EPA in 

Pesticide Registration (PR) Notices 2017-1 and 2017-2 (U.S. EPA, 2017b; U.S. EPA, 

2017c). Monsanto incorporates EPA’s guidelines for pesticide site-of-action and 

resistance management labeling on its agricultural herbicide labels and will continue to 

do so in the future.

K.2. The Herbicides Dicamba and 2,4-D

Dicamba (3,6-dichloro-2-methoxybenzoic acid) is classified as a benzoic acid herbicide 

belonging to the synthetic auxin group of herbicides (WSSA, 2018). The herbicides in 

this group act as growth regulators similar to endogenous indole acetic acid (IAA) but are 

structurally diverse. The synthetic auxin group includes five chemical families (benzoic 

acid, pyridine-carboxylic acid, quinoline carboxylic acid, phenoxy-carboxylic acid and a 

separate class which includes one herbicide, benazolin ethyl). The specific site-of-action 

among the different synthetic auxin chemical families may be different. In addition to 

dicamba, other herbicides in the synthetic auxin group include 2,4-D, clopyralid, 

quinclorac and several other active ingredients. 2,4-D (2,4-Diclorophenoxy acetic acid) 

is classified as a phenoxy carboxylic acid herbicide (WSSA, 2018). As they regulate 

plant growth through an auxin receptor site-of-action, dicamba, 2,4-D and other synthetic 

auxin herbicides are classified in Herbicide Group 4 by the Weed Science Society of 

America (WSSA, 2018). Most herbicides in Group 4 are active on broadleaf weeds only, 

but a few have significant activity on grasses, e.g., quinclorac. Dicamba provides control 

of over 95 annual and biennial broadleaf weed species, approximately 50 perennial 

broadleaf species and control or suppression of over 50 woody species (Bayer 

CropScience, 2018). 2,4-D provides control of approximately 70 annual broadleaf and 

approximately 30 perennial broadleaf weed species (Dow, 2017). Dicamba and 2,4-D are 

not active on grass weeds and are often used in combination with other herbicides to 

provide broad spectrum weed control.
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Dicamba was commercialized in the U.S. for agricultural use in 1967 and 2,4-D has been 

used as an herbicide since mid-1940s. They are currently labeled for use preplant and/or 

preemergence and/or postemergence to control emerged weeds in maize, sorghum, rice, 

small grains (wheat, barley, rye and oats), millet, pasture, rangeland, asparagus, 

sugarcane, turf, grass grown for seed, various other crops, conservation reserve program 

land, fallow cropland, and/or for non-crop uses (U.S. EPA, 2005; U.S.EPA, 2009). In 

addition, dicamba and 2,4-D are approved for preplant application in conventional 

soybean and cotton. Dicamba is approved for postemergence in-crop use in

dicamba-tolerant soybean and cotton (Bayer CropScience, 2018), and 2,4-D is approved

for postemergence in-crop use in 2,4-D-tolerant soybean, cotton and maize (Dow, 2017). 

Dicamba and 2,4-D are sold as standalone formulations which can be tank-mixed, based 

on the approved label, with one or more active ingredients depending upon the specific 

herbicide, the crop and the weed spectrum. Dicamba and 2,4-D are each sold as premix 

formulations with certain other herbicides.

K.3. The Herbicide Glufosinate

Glufosinate [2-amino-4-(hydroxymethylphosphinyl) butanoic acid] is classified by the 

Weed Science Society of America as a phosphinic acid herbicide belonging to the Group 

10 glutamine synthetase inhibitor group of herbicides (WSSA, 2018). Bialaphos is the 

only other herbicide belonging to the phosphinic acid chemical family. Glufosinate 

provides control of approximately 70 annual broadleaf, 30 annual grass weed species and 

control or suppression of over 30 biennial and perennial grass and broadleaf weed species 

(Bayer CropScience, 2016). 

Glufosinate was first registered for use in the U.S. in 1989 (U.S. EPA. 1989) and is 

currently labeled for non-crop uses, preplant burndown for glufosinate-tolerant and 

non-glufosinate-tolerant crops and/or in-crop postemergence weed control in 

glufosinate-tolerant canola, maize, cotton, and soybean (Bayer CropScience, 2016). 

Glufosinate is sold as a stand-alone formulation which can be tank mixed with other 

herbicides depending upon the specific herbicide, the crop and the weed spectrum.

K.4. The Herbicide Quizalofop

Chloroplastic acetyl-CoA carboxylase (ACCase) inhibitors Aryloxyphenoxypropionate 

(AOPP) and cyclohexanedione (CHD) herbicides have been widely used to control grass 

weed species since their introduction in the 1970s and 1980s, respectively 

(Kraehmer et al., 2014). These AOPP and CHD post-emergence grass herbicides are 

frequently referred to as “fops” and “dims”, respectively. While “fops” and “dims”

herbicides are two chemically dissimilar classes of herbicides, they both inhibit the

ACCase enzyme, which catalyzes the first committed step in fatty acid biosynthesis, 

causing plant death (Kraehmer et al 2014). Quizalofop-p-ethyl 

(Ethyl(R)-2-[4-(6-chloroquinoxalin-2-yloxy)phenoxy]propionic acid), is a systemic 

herbicide absorbed by the leaves with translocation throughout the plant 

(Mantzos et al., 2016). Quizalofop is classified as ACCase-inhibiting “fops” herbicide 
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belonging to the Herbicide Group 1 by the Weed Science Society of America (WSSA, 

2018). 

Quizalofop-p-ethyl was first approved for use as a registered product in 1990 (Assure® 

II: EPA Reg No. 352-541). It is used to selectively control post-emergent annual and 

perennial grass weeds in dicot crops such as potatoes, soybeans, peanuts, sugar beet, 

oilseed rape, sunflower, vegetables, cotton and flax and in quizalofop-tolerant maize

(Wright et al., 2010; U.S. EPA, 2018). 

K.5. The Herbicide Glyphosate

Glyphosate [N-(phosphonomethyl) glycine] is classified by the Weed Science Society of 

America as an EPSPS (5-enolpyruvylshikimate-3-phosphate synthase) inhibitor herbicide 

belonging to the Group 9 (WSSA, 2018). Glyphosate is the only herbicide within Group 

9 and is a non‐selective, systemic, postemergence herbicide that translocates primarily to 

metabolic sinks, killing meristematic tissues away from the application site. Its 

phloem‐mobile properties and slow action in killing weeds allow the herbicide to move 

throughout the plant, making it effective for weed control including perennial weeds 

(Duke 2018). Glyphosate provides control of approximately 100 annual weed species 

(grass and broadleaf), over 60 perennial weed species (grass and broadleaf) and control or 

suppression of approximately 65 woody brush, trees and vines (e.g., Roundup 

PowerMax® II; EPA Reg. No. 524-537).

Glyphosate was first registered for use in the U.S. in 1974 and has been extensively used 

globally (Duke, 2018). It is currently labeled for non-crop uses, preplant burndown to 

glyphosate- and non-glyphosate-tolerant crops and/or in-crop postemergence weed

control in glyphosate-tolerant canola, maize, cotton, soybean, sugarbeet and alfalfa 

(Monsanto, 2017). Glyphosate is sold as a stand-alone formulation which can be tank 

mixed with other herbicides depending upon the specific herbicide, the crop and the weed 

spectrum. Glyphosate is also sold as premix formulations with certain other herbicides.

K.6. Herbicide-Resistant Weeds and Resistance Management Strategies

The development of herbicide-resistant weeds is not a new phenomenon and resistance is 

not limited to certain select herbicides. In 1957, the first U.S. herbicide-resistant weed, a 

spreading dayflower (Commelina diffusa) biotype resistant to 2,4-D, was identified in 

Hawaii (Heap, 2019). Through October 2018, there are approximately 160 unique cases 

of herbicide resistance by weed species with known herbicide-resistant biotypes to one or 

more herbicides in the U.S (Heap, 2019). Growers have been managing herbicideresistant weeds for decades with the use of alternative herbicides and/or other methods of 

weed control. The occurrence of an herbicide-resistant weed biotype usually does not end 

the useful lifespan or preclude the effective use of the herbicide as part of an overall 

diversified weed management system but may change the way the herbicide is used in the 

cropping system.
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As defined by the Weed Science Society of America, an herbicide resistant weed is one 

in which there is an inherited ability of a plant to survive and reproduce following 

exposure to a dose of herbicide normally lethal to the wild type (WSSA, 2019). An

herbicide-tolerant weed species is one that is naturally tolerant to an herbicide, for 

example a grass species is not killed by the application of a broadleaf herbicide (WSSA, 

2019). Furthermore, certain weed species, while neither resistant nor tolerant, are 

inherently difficult to control with a particular herbicide, requiring tank mixing with other 

herbicides and/or other weed management practices. 

Since the first confirmed cases of herbicide resistance, research has been directed at 

determining which practices are best for managing existing resistance situations and how 

best to reduce the development of further resistance or multiple herbicide resistance. 

Resistance management practices most often recommended by University/Cooperative 

Extension Service (CES) and industry are generally summarized as: a) Understand the 

biology of the weeds present; b) Use a diversified approach toward weed management 

focused on preventing weed seed production and reducing the number of weed seed in 

the soil seedbank; c) Plant into weed-free fields and then keep fields as weed free as 

possible; d) Plant weed-free crop seed; e) Scout fields routinely; f) Use multiple herbicide 

sites-of-action that are effective against the most troublesome weeds or those most prone 

to herbicide resistance; g) Apply the labeled herbicide rate at recommended weed sizes; 

h) Emphasize cultural practices that suppress weeds by using crop competitiveness; i) 

Use mechanical and biological management practices where appropriate; j) Prevent fieldto-field and within-field movement of weed seed or vegetative propagules; k) Manage 

weed seed at harvest and after harvest to prevent a build-up of the weed seedbank; l) 

Prevent an influx of weeds into the field by managing field borders (Beckie, 2006; 

Gressel and Segel, 1990; Norsworthy et al., 2012; HRAC, 2015).

Recent research indicates that herbicide mixtures offer a better management option than 

rotating herbicides. However, the effectiveness of herbicide mixtures depends on their 

similar efficacies, soil residual activity and/or different propensities for resistance 

selection in the target weed species (Beckie and Reboud, 2009; Lagator et al., 2013; 

Evans et al., 2016; Beckie and Harker, 2017). Simultaneously using two herbicides with 

different sites-of-action, each effective on the same weed species, significantly reduce the 

probability of weeds developing resistance to either or both herbicides (Beckie and 

Reboud, 2009). Use of multiple methods of weed control including multiple herbicides 

with different sites-of-action in a single field is the technical basis for management 

programs to delay the development of resistance. This general concept has been referred 

to as applying “diversity” within a crop or across a crop rotation (Beckie, 2006; Powles, 

2008; Andrew et al., 2015). While herbicide mixtures have been shown to be an effective 

strategy to delay the development of herbicide resistance, given that some weeds already 

evolved resistance to multiple previously effective herbicides, it could become 

challenging to find effective herbicide mixtures that individually suppress a specific weed 

species in the future (Evans et al., 2016). Broad use of herbicide mixtures may increase 

the chance of development of cross-resistance, especially if use rates are below the 

effective rates approved on the herbicide label (Evans et al., 2016). These challenges

highlight the need to follow each best management practice described in the paragraph 
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above (a-l), including applying label rates of herbicides and using other cultural practices 

to assist in delaying the development of herbicide resistance.

K.7. Characteristics of Herbicides and Herbicide Use Influencing Resistance

While the incidence of weed resistance is often associated with repeated applications of 

an herbicide resulting in recurrent selection of the weed in the absence of other herbicides 

or methods of weed control, the actual probability for the development of resistant 

populations is related, in part, to the specific herbicide active ingredient, chemical family 

and herbicide group and especially the resistance mechanism. Some herbicides are more 

prone to the development of resistance than others (Heap, 2019; Figure K-1). The graph 

in Figure K-1 illustrates the global instances of weed resistance to various herbicide 

groups. The different slopes of observed resistance are largely due to the factors 

described above, which relate to the specific herbicide active ingredient as well as to the 

group and herbicide family and its function. 

Figure K-1. Global Weed Resistance to Various Herbicide Families

Weed resistance to the synthetic auxins (O) group of herbicides has been slower to develop than 

for other herbicide groups even though these were the first synthetic herbicides discovered and 

used commercially. Possible reasons for this are discussed in this Section K-8.
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K.8. Weeds Resistant to Dicamba, Glufosinate, Quizalofop, 2,4-D or Glyphosate 

Herbicides

As noted earlier in Section K.7, like other herbicides, the use of dicamba may lead to the 

development of dicamba-resistant weed species. To date, there are four species with 

known resistant biotypes to dicamba in the North America after over 40 years of use: 

common hempnettle, kochia, prickly lettuce and wild mustard (Heap, 2019). 

Additionally, a population of common lambsquarters has been confirmed to be resistant 

in New Zealand, wild mustard in Turkey, cornflower in Poland and smooth pigweed in 

Argentina have been confirmed to be resistant for a total of seven species worldwide with 

confirmed resistant biotypes to dicamba. For the synthetic auxin group of herbicides, 

there exist a total of appropriately 30 broadleaf species globally with biotypes having 

confirmed resistance to at least one member of this group, but only seven broadleaf 

species in the U.S. and six broadleaf species in Canada (Heap, 2019). Broadleaf weed 

species that are resistant to synthetic auxins in the U.S. include Palmer amaranth, tall 

waterhemp, yellow starthistle (Centaurea solstitialis), wild carrot, kochia, prickly lettuce 

and buckhorn plantain. In Canada, kochia, wild mustard, wild carrot, common 

hempnettle, spotted knapweed (Centaurea maculosa) and false cleavers (Galium 

spurium) were reported to be resistant to synthetic auxins. For 2,4-D herbicide, a total of 

5 broadleaf weeds (Palmer amaranth, waterhemp, prickly lettuce, wild carrot, and 

buckhorn plantain) have been confirmed to be resistant in the U.S. All the broadleaf 

populations are found in the Midwest (Palmer amaranth in KS, waterhemp in NE and IL 

and wild carrot in OH and MI, and buckhorn plantain in IN), western U.S. (prickly 

lettuce in WA) or western Canadian provinces. In some weed species, cross-resistance 

between different herbicides within the auxin group has been confirmed (plant crossresistance to another herbicide because of exposure to a similarly acting herbicide). 

Therefore, consideration must be given to the possibility that dicamba and/or 2,4-D 

resistance could extend to some of the other broadleaf species listed as resistant to other 

synthetic auxin herbicides (Cranston et al., 2001; Jasieniuk et al., 1995; Miller et al., 

2001; Tehranchian et al., 2017). However, because of differences in sites-of-action 

among the chemistry families within the synthetic auxin herbicide group (i.e., benzoic 

acids compared to pyridine-carboxylic acids), cross-resistance between them is 

uncommon (Beckie and Tardif, 2012).

MON 87429 maize will be combined with deregulated glyphosate tolerance traits, such 

as NK603, where dicamba or 2,4-D can be applied in combination with glyphosate and 

glufosinate. It is important to note that in the U.S., kochia is the only broadleaf species 

with biotypes with herbicides resistance to dicamba, 2,4-D and glyphosate (LeClere et al.,

2018; Heap, 2019). In addition, dicamba (only) resistant kochia biotypes were reported in 

4 other states (Nebraska, Colorado, Idaho and North Dakota). In Kansas, 2 separate

kochia biotypes, one with multiple resistance to dicamba, glyphosate, atrazine and 

chlorsulfuron and another with multiple resistance to dicamba, fluroxypyr and glyphosate

were reported. A kochia biotype in Montana was reported to be resistant to dicamba and 

fluroxypyr (Heap, 2019). A biotype of waterhemp in Illinois was reported to be resistant 

to 2,4-D, HPPD, PS II, ALS and PPO inhibitors (Heap, 2019). In Nebraska, a waterhemp 

biotype was reported to be resistant to 2,4-D, aminopyralid, atrazine, chlorimuron, 
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imazethapyr and picloram (Heap, 2019). Biotypes of waterhemp with resistance to 2,4-D 

or glyphosate exist both in Illinois and Kansas (Heap 2019), and there is a high potential 

for biotypes with resistance to both herbicides to occur via crossing in this crosspollinated dioecious species. A Palmer amaranth biotype in Kansas was reported to be 

resistant to both 2,4-D and glyphosate (also resistant to HPPD, PS II and ALS inhibitors) 

(Heap, 2019). In addition, a prickly lettuce biotype was reported to be resistant to 2,4-D 

and dicamba and MCPA in Washington state, outside of the main corn-growing regions 

of the U.S. (Heap, 2019). MON 87429 maize hybrids combined with deregulated 

glyphosate tolerance traits, such as NK603, provide tools to reduce the likelihood of 

resistance development in many broadleaf weed species and/or delay the likelihood of 

further selection or spread of biotypes that are already resistant to one or more herbicides 

with different sites-of-action. For example, growers would have options to rotate 

herbicides or use herbicide mixtures with dicamba or 2,4-D, glyphosate, and/or 

glufosinate, each with a distinct site-of-action, based on the approved label and the weed 

spectrum (Table VIII-7) to reduce the likelihood of resistance development. If additional 

weed populations with resistance to both glyphosate and dicamba or 2,4-D herbicides 

were to occur there are other preplant and/or postemergence herbicide options for 

managing the weed in maize and in its rotational crops (Table K-1). 

There is no known broadleaf weed species reported to be resistant to glufosinate in the 

U.S (Heap, 2019). To date there are three grass weed species with confirmed resistance 

to glufosinate globally: goosegrass in Malaysia, rigid ryegrass in Greece, perennial 

ryegrass in New Zealand and Italian ryegrass in New Zealand and the U.S. (in Oregon 

and California states) (Heap, 2019). In the case of goosegrass (Eleusine indica), a 

population was found in Malaysia that is resistant to glufosinate and paraquat herbicides. 

Resistance to glufosinate evolved likely due to the repeated use of glufosinate for at least 

six times a year and for more than four consecutive years as standalone or in combination 

with paraquat in a bitter gourd field. It is speculated that paraquat resistance in this 

goosegrass population might have evolved earlier than glufosinate resistance since this 

vegetable field which was originally a rubber plantation had exposure to paraquat 

treatment since the 1970s (Seng et al., 2010). In rigid ryegrass (Lolilum rigidum Gaud.), 

glufosinate resistance was confirmed in Greece with the level of resistance ranging from 

three-to seven-fold. It was also demonstrated that the level of glufosinate-resistance of 

rigid ryegrass was dependent on the growth stage at which it was applied (Travlos et al.,

2018). In the case of an observed Italian ryegrass biotype (Lolium perenne ssp. 

multiflorum), glufosinate resistance was discovered in populations not previously 

exposed to the herbicide. Avila-Garcia and Mallory-Smith (2011) found that resistance 

was not due to an insensitive or altered target site and hypothesized that reduced 

translocation is responsible for the resistance to both glyphosate and glufosinate in these 

populations. No resistance to glufosinate in a broadleaf species has been reported to date

(Heap, 2019).

In the case of AOPP ACCase inhibitor “fops” (i.e. quizalofop) herbicides, johnsongrass, 

Italian ryegrass, giant foxtail, cheatgrass and common wild oat have been reported to be 

resistant in the U.S. (Heap, 2019). Certain biotypes of johnsongrass, Italian ryegrass, 

giant foxtail and cheatgrass were confirmed to be resistant to “fops” and/or “dims” 
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ACCase inhibitor herbicides. ACCase-resistant johnsongrass biotypes in the U.S. were 

reported in 5 states (Mississippi, Kentucky, Tennessee, Virginia and Louisiana), with 2 of 

these states (Mississippi and Louisiana) having different biotypes that are resistant to 

glyphosate (Heap, 2019). In addition, ACCase-resistant Italian ryegrass biotypes in the 

U.S. were reported in 13 states and biotypes in California were also resistant to 

glyphosate (Heap, 2019). However, these weeds are controlled by using other effective 

herbicides such as photosystem I and II inhibitors, HPPD (4-hydroxyphenylpyruvate 

dioxygenase) inhibitors, long-chain fatty acid inhibitors or glufosinate and/or glyphosate 

on non-glyphosate-tolerant grasses depending upon the crop and the weed spectrum. See 

Table K-1 for other herbicide options in maize and its rotational crops to control “fops”-

resistant grass weeds.

For glyphosate, there are 44 weed species reported to be resistant globally (Heap, 2019). 

In the U.S. there were 17 weed species reported to be glyphosate resistant, six of those 

being grass species (junglerice, goosegrass, Italian ryegrass, rigid ryegrass, annual 

bluegrass and johnsongrass) and 11 broadleaf weed species (Palmer amaranth, 

waterhemp, common ragweed, giant ragweed, kochia, spiny amaranth, horseweed, hairy 

fleabane, common sunflower, ragweed parthenium and Russian thistle) (Heap, 2019). 

Many of the glyphosate-resistant broadleaf weeds, particularly, Palmer amaranth, 

horseweed, waterhemp, common ragweed, giant ragweed and kochia were found in at 

least 10 states in the U.S (Heap and Duke, 2018). Palmer amaranth was predominantly 

found in the southern U.S. states and glyphosate-resistant Palmer amaranth biotypes have 

been found in 24 states in the U.S. (Heap and Duke, 2018; Heap, 2019). Furthermore, 

waterhemp was more commonly seen in northern U.S. states (Heap and Duke, 2018) with

biotypes resistant to glyphosate reported in 18 states (Heap, 2019).

K.9. Mechanisms of Resistance and Inheritance of Resistance

To date, three basic mechanisms by which weed species develop resistance to an 

herbicide have been identified: 1) target site alteration (point mutations and/or increased 

expression), 2) enhanced metabolism of the herbicides (via chemical modification of the 

herbicide either by conjugation or degradation), and 3) reduced herbicide access to the 

site-of-action within the plant cell (exclusion) (Sammons et al., 2007; Sammons and 

Gaines 2014). Avoidance was proposed as an additional mechanism of resistance 

whereby weeds avoid toxic effect by its biochemical ability to handle the toxic agent 

produced by the herbicide (Sammons and Gaines 2014).

Over 200 distinct weed biotypes worldwide have developed herbicide resistance with the 

most common resistance mechanism occuring via target site alteration (Devine and 

Shukla, 2000). It has been found that target site resistance is the most common 

mechanism for ALS inhibitors, ACCase inhibitors, and triazines, but is less common for 

other herbicide groups, such as glyphosate and synthetic auxins (Devine and Shukla, 

2000; Sammons et al., 2007; Sammons and Gaines, 2014; Powles and Yu, 2010; Busi et 

al 2017). The most common type of target site alteration is one where amino acid 

substitution(s) occur in the protein that is the target of the herbicide such that the 

alteration prevents herbicide binding to the protein and as a result the activity of the 
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targeted protein is not altered, and the plant grows normally (Devine and Shukla, 

2000). Recently five species (Bassia scoparia, Amaranthus spinosus, Amaranthus 

palmeri, Amaranthus tuberculatus, Lolium perenne ssp multiflorum) have managed to 

duplicate the EPSPS gene creating much higher expression levels of EPSPS protein 

(Sammons and Gaines, 2014; Koo et al., 2018a; Koo et al., 2018b).

In the case of synthetic auxin herbicides, there is limited evidence for any single 

mechanism conferring weed resistance and known evidence indicate different resistance 

mechanisms between weed species and/or biotypes within a weed species. Resistance to 

synthetic auxins has been speculated to be due to mutation(s) in genes encoding an auxinbinding protein, ABP1 causing reduced herbicide binding or due to impaired auxin signal 

transduction pathway, including transport inhibitor response gene, TIR1 (Zheng and Hall, 

2001; Goss and Dyer, 2003; Grossmann, 2010). In several studies, differential herbicide 

absorption, translocation, and metabolism were ruled out as possible mechanisms of 

resistance to certain auxinic herbicides in kochia (Cranston et al., 2001) and in wild 

mustard (Zheng and Hall, 2001). In a recent study, it was demonstrated that a single 

amino acid change from glycine to asparagine in a conserved region within KsIAA16

gene (a homologue of IAA16 in arabidopsis) in a kochia biotype found in Nebraska, could 

result in cross-resistance between dicamba, 2,4-D and fluroxypyr herbicides (LeClere et 

al., 2018). This conserved protein domain in IAA16 was previously shown to be 

important for auxin binding and interaction between TIR1/F-box proteins and AUX/IAA 

in Arabidopsis (Tan et al., 2007). Pettinga et al., (2017) have shown that increased 

expression of CHS (chalcone synthase) gene in a resistant kochia biotype found in 

Nebraska (the same biotype studied by LeClere et al., 2018), co-segregated with dicamba 

resistance primarily by reducing dicamba translocation while no change was observed in 

herbicide uptake. The 2,4-D-resistant prickly lettuce biotype appears to have evolved 

resistance to other auxins in the phenoxy-carboxylate and benzoate subgroups, including 

MCPA and dicamba (Lyon and Burke 2016). Inheritance of 2,4-D resistance in prickly 

lettuce was governed by a single codominant gene and it was observed that the resistant 

biotype showed reduced translocation of 2,4-D in the treated leaf or crown but showed no 

difference in rate of 2,4-D metabolism compared to the susceptible biotypes (Riar et al 

2011). Walsh et al., (2006) identified seven alleles at two distinct genetic loci that 

conferred significant resistance to picolinate auxins (picloram) in arabidopsis yet had 

minimal cross-resistance to 2,4-D and IAA, a naturally occurring plant growth regulator. 

Jasieniuk et al. (1995) reported results indicating that inheritance of dicamba resistance in 

wild mustard is determined by a single, completely dominant nuclear allele. While wild 

mustard biotype was highly resistant to dicamba, it was moderately resistant to 2,4-D

indicating differences in resistance phenotypes for herbicides within the synthetic auxin 

site-of-action (Zheng and Hall, 2001). However, Cranston et al. (2001) reported results 

indicating that dicamba resistance in kochia biotype (found in Montana) is a quantitative 

trait (two or more genes). The slow development of weed resistance to synthetic auxin 

herbicides may in part be due to their proposed multiple sites of physiological action in 

plants (Jasieniuk et al., 1996) and to the possibility that inheritance, at least in some 

species, is a quantitative trait (Cranston et al., 2001). It is also demonstrated that reduced 
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fitness due to the auxin resistance in the kochia biotype found in Nebraska may be 

partially responsible for the rarity of auxin resistant weeds (LeClere et al., 2018). 

Little is known about the resistance mechanisms in glufosinate-resistant 

biotypes. Avila-Garcia and Mallory-Smith (2011) conducted an initial set of experiments 

to understand the mechanism of resistance in the ryegrass population collected from 

Oregon that was also resistant to glyphosate. They found that resistance was not due to 

an insensitive or altered target site and hypothesized that reduced translocation is 

responsible for the resistance to both glyphosate and glufosinate in these populations. In 

another study conducted with an Italian ryegrass biotype resistant to glufosinate, it was 

shown that resistance to glufosinate was due to the target site mutation in plastidic GS2

(Glutamine Synthetase2) gene causing a single amino acid change from asparagine to 

aspartic acid (Avila-Garcia et al., 2012). In a more recent study, Jalaludin et al. (2017)

demonstrated that glufosinate resistance in resistant goosegrass population was not due to 

an insensitive glutamine synthase (GS), or increased GS activity, or altered glufosinate 

uptake and translocation, or enhanced glufosinate metabolism. They excluded the 

possibility of target-site resistance to glufosinate in goosegrass, however, the exact 

resistance mechanism(s) remain to be determined. 

For ACCase inhibitors including “fops” and “dims” different patterns of resistance may 

be conferred by separate mutations in the gene for plastidic ACCase (Devine and Shulka 

2000). A single modification (a single isoleucine-to-leucine substitution) confers crossresistance to the “fops” and “dims” herbicides in wild oat (Christoffers et al., 2002), rigid 

ryegrass (Delye et al., 2002b; Tal and Rubin 2004; Zagnitko et al., 2001), green foxtail 

(Delye et al., 2002c), and blackgrass (Alopecurus myosuroides Huds.) (Delye et al.,

2002a; Delye et al., 2002b). This isoleucine-to-leucine substitution at the 1781 position in 

ACCase gene in blackgrass confers resistance to certain “fops” (fenoxaprop and diclofop) 

and to “dims” (cycloxydim) and does not confer resistance to haloxyfop and clodinafop, 

nor to clethodim (Delye et al., 2002a; Delye et al., 2003b). A second substitution (an 

isoleucine-to-asparagine substitution) at position 2041 was associated with resistance to 

“fops” (fenoxaprop, diclofop, clodinafop and haloxyfop) but not “dims” (cycloxydim and 

clethodim) in blackgrass (Delye et al., 2003a). Both isoleucine-to-leucine substitution at 

the 1781 position and isoleucine-to-asparagine substitution at position 2041 in ACCase

gene were dominant alleles (Delye et al., 2002a; Delye et al., 2003a) and arose 

independently in geographically distant blackgrass populations (Delye et al., 2003b). A 

recent study on large crabgrass (Digitaria sanguinalis) biotype collected from Ontario, 

Canada revealed that over expression of the ACCase enzyme conferred resistance to the 

ACCase inhibitor herbicides (both “fops” and “dims”) and that over expression of the 

ACCase enzyme in the resistant biotype was likely due to ACCase gene duplication 

(Laforest et al., 2017). Another large crabgrass biotype collected from South Australia 

that is resistant to “fops” (fluazifop, haloxyfop and quizalofop) and has reduced 

sensitivity to sethoxydim herbicides, was studied for mechanism of resistance to 

fluazifop. This study revealed that an enhanced metabolism of fluazifop acid conferred

resistance to fluazifop herbicide rather than reduction in ACCase enzyme sensitivity, 

reduced absorption or translocation (Hidayat and Preston, 1997).
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Studies of resistance to glyphosate have revealed a wider range of molecular mechanisms 

of resistance than are known for any other herbicide site-of-action (Sammons and Gaines, 

2014), including herbicide sequestration in the vacuole, reduced translocation presumably 

due to a rapid cell death response, genetic polymorphisms in the herbicide target 

(5‐enolpyruvylshikimate‐3‐phosphate synthase, EPSPS) and increased copy number for 

the gene encoding EPSPS. It was further observed that resistance mechanism due to copy 

number of epsps, had two distinct molecular mechanisms, a tandem duplication in kochia 

(Jugulam et al., 2014) and a large extrachromosomal circular DNA (eccDNA) that is 

tethered to the chromosomes and passed to gametes at meiosis in Palmer amaranth (Koo 

et al., 2018a). Target‐site mutations in epsps have been documented at amino acid 

position Pro106 (to primarily Ser, Thr or Ala) in few weed species including Poa annua

(Cross et al., 2015), Eleusine indica, Lolium rigidum, Lolium multiflorum, Echinochloa 

colona, Digitaria insularis, Amaranthus tuberculatus (Sammons & Gaines, 2014), at 

Thr102Ser in Tridax procumbens (Li et al., 2018), at Thr102Ile and Pro106Ser in 

combination in Eleusine indica (Yu et al., 2015), and recently a triple mutation involving 

Thr102Ile, Ala103Val, and Pro106Ser in Amaranthus hybridus (Perotti et al., 2019). The 

simultaneous occurrence of multiple mutations within the same allele appears to be 

unique to glyphosate resistance and epsps (Gaines et al., 2019).

K.10. Sustainable Use of Dicamba, Glufosinate, Quizalofop, 2,4-D and Glyphosate 

as a Weed Management Option in Maize

Diversified use of herbicides with different and effective sites-of-action is one of the key 

weed management strategies to minimize selection for herbicide resistance. MON 87429 

maize will likely be sold in maize hybrids that also contain other herbicide-tolerant traits, 

including glyphosate-tolerance. Maize hybrids containing both MON 87429 and 

glyphosate tolerance traits, such as NK603, will enable dicamba, glufosinate, quizalofop 

or 2,4-D herbicides to be applied with glyphosate and/or other maize herbicides 

depending upon the specific herbicide use labels and the weed spectrum in an integrated 

weed management program. Either dicamba or 2,4-D will likely be used in mixtures with 

glyphosate or in sequence with glyphosate or glufosinate to control a broad spectrum of 

grass and broadleaf weed species. Glyphosate and glufosinate will likely not be used in 

mixtures due to antagonism (i.e., glufosinate damages the leaf tissue before glyphosate 

gets into the plant and/or translocated to growing parts of the plant) and reduced efficacy 

of glyphosate on susceptible weed species. Either dicamba or 2,4-D and glufosinate 

applications on MON 87429 maize will provide effective control of glyphosate-resistant 

broadleaf weeds and improve the control of annual and perennial broadleaf weed species, 

some of which are difficult to control with glyphosate. Either dicamba or 2,4-D and 

glufosinate (Ganie and Jhala, 2017; Joseph et al., 2018) will also help delay development 

and/or combat existing weed resistance issues that can limit the use of other herbicides

such as glyphosate. Likewise, dicamba or 2,4-D with or without glyphosate (depending 

on the presence of glyphosate- resistant weeds) may help delay or minimize potential 

evolution of resistance to glufosinate in broadleaf species and similarly, glufosinate may 

delay or minimize the potential evolution of broadleaf species biotypes resistant to 

dicamba, 2,4-D or glyphosate (Ganie and Jhala, 2017; Joseph et al., 2018). In addition, 

residual herbicides also will be recommended for use, to provide early season weed 
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control and to supplement dicamba or 2,4-D and glufosinate activity on certain 

hard-to-control and glyphosate-resistant weed biotypes, such as glyphosate-resistant 

Palmer amaranth where weed population density can be very substantial. However, overreliance on any herbicide(s) for weed control including dicamba, 2,4-D, glufosinate, 

“fops” or glyphosate should be avoided and a diversity of herbicide sites-of-action must 

be maintained by using herbicide tank-mixtures or premixes with multiple effective sitesof-action, along with non-chemical weed control methods including crop rotation, tillage, 

competitive cultivars, weed seed destruction, and cover crops, among others (Norsworthy 

et al., 2012; Ganie and Jhala, 2017). 

MON 87429 maize in combination with a deregulated glyphosate tolerance trait, such as 

NK603, will also enable use of quizalofop to control a broad spectrum of grass weed 

species in addition to non-selective herbicides, glufosinate and glyphosate. Quizalofop 

can be used either in mixture with glyphosate or in sequence with glyphosate or 

glufosinate to provide options for postemergence control of grass weed species. Many 

mixtures of graminicides including ACCase herbicides with glufosinate have been 

demonstrated to exhibit antagonism (Gardener et al., 2006; Burke et al., 2005). Either 

quizalofop or glufosinate applications on MON 87429 maize can provide control of 

glyphosate-resistant grass weeds and improve the control of annual and perennial grass 

weed species, some of which are difficult to control with glyphosate. Combinations of 

these application options may help delay potential evolution of resistance to quizalofop, 

glufosinate or glyphosate in grass species.

Dicamba, glufosinate, quizalofop and 2,4-D, as complementary herbicides to glyphosate, 

will provide additional weed control options in maize that strengthen the utility and 

sustainability of glyphosate as a weed control tool in glyphosate-tolerant maize systems. 

Likewise, glyphosate would be complementary to and strengthen the utility and 

sustainability of dicamba, glufosinate, quizalofop or 2,4-D as weed control tools for the 

combined commercial hybrid product containing MON 87429 and a deregulated 

glyphosate tolerance trait, such as NK603. 

In the event there is known or suspected resistance to dicamba, glufosinate, quizalofop, 

2,4-D, or glyphosate, or other herbicides, cultural and mechanical weed control options 

are available to the grower in the U.S. for managing resistant biotypes. There are 

multiple preplant and postemergence herbicide options (including soil residuals) for 

managing weed populations that are resistant or may potentially develop resistance to 

dicamba, glufosinate, quizalofop, 2,4-D or glyphosate in maize, as well for crops grown 

in rotation with maize. A representative short list of the effective herbicide options are 

noted in Table K-1 for a sub-set of common weed species in maize in the U.S., chosen 

based on if a weed species has biotype(s) that are resistant to herbicide(s) tolerated by 

MON 87429 maize (dicamba, glufosinate, 2,4-D and/or “fops”) and biotypes of these 

species reported to have resistance to glyphosate either as multiple resistance (kochia, 

Palmer amaranth, Italian ryegrass) or resistance to glyphosate exist separately in biotypes

with high potential for biotypes with combined resistance development (waterhemp, 

johnsongrass) (Heap, 2019; see Table VIII-6 and Appendix K.8). Table K-1, however, is 
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not intended to provide extensive set of weed control recommendations for any specific

biotype(s) with unique cases of resistance present in a geography (county or state) that 

may include resistance to herbicide site(s)-of-action not tolerated by MON 87429 maize. 

Geography- and biotype-specific weed control recommendations can be obtained through

state Cooperative Extension Service (CES) and/or through state-specific weed control 

guides published by the universities, where available (e.g., Kansas State University, 2019, 

Mississippi State University, 2019; University of Nebraska, 2019). 
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Table K-1. Representative Management Recommendations for Control of Common Weeds in Maize with Biotypes Resistant 

to Herbicide(s) Tolerated by MON 87429 and to Glyphosate

Weed Species1,2

Rotational Crops

Primary Crop 

Maize Soybeans Cotton Sorghum Wheat

Kochia

Paraquat+

Atrazinea

Isoxaflutole+

Atrazinea

Thiencarbazone+

Tembotrionea

Mesotrionea

Sulfentrazone+

Metribuzina

Flumioxazin+

Pyroxasulfone+

Chlorimurona

Saflufenacil+

Imazethapyra

Paraquata

Glufosinatea,3

Glufosinateb,4

Mesotrione+

s-Metolachlor +

Atrazinea

Atrazinea

Acetochlora

Saflufenacila

Carfentrazone+

2,4-Da

Triasulfuron+

Fluroxypyra

Pyrasulfotole+

Bromoxynil+

MCPAa

Tall Waterhemp

Topramezonea

Saflufenacila

Isoxaflutole+

Atrazinea

Mesotrionea

Tembotrione

a

Glufosinatea,4

Sulfentrazone+

Metribuzina

Glyphosate+

Lactofena

Acetochlora

Flumioxazina

Fomesafena

Lactofena

Glufosinatea,4

Fomesafenc

Diuronc

Lactofenc

Pyroxasulfonec

+MSMAc

Glufosinatec,4

Mesotrione+

s-Metolachlor +

Atrazinea

Saflufenacila

Acetochlora

Pyrasulfotole+

Bromoxynila

Carfentrazone+

2,4-Da

Triasulfuron+

Fluroxypyra

Prosulfuron+

2,4-Da

Pyrasulfotole+

Bromoxynil+

2,4-Da
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Table K-1. Representative Management Recommendations for Control of Common Weeds in Maize with Biotypes Resistant 

to the Herbicide(s) Tolerated by MON 87429 Maize and to Glyphosate (continued)

Weed Species1,2

Rotational Crops

Primary Crop 

Maize Soybeans Cotton Sorghum Wheat

Palmer amaranth

Acetochlor+ 

Atrazined

Thiencarbazone+ 

Isoxaflutoled

Tembotrione+

Thiencarbazoned

Bromoxynil+ 

Atrazined

Glufosinatec,4

Sulfentrazone+ 

Imazethapyrd

Flumioxazin+ 

Pyroxasulfoned

Lactofend

Glufosinatec,4

Fomesafenc

Diuronc

Pyroxasulfone + 

Carfentrazonec

Glyphosate+ 

s-Metolachlor c

Glufosinatec,4

s-Metolachlor + 

Mesotrioned

Bromoxynil+ 

Atrazined

Carfentrazoned

Triasulfurond

Thifensulfuron+ 

Tribenuron+ 

Metsulfuron+ 

Dicambad

Bromoxynil+ 

MCPAd

Italian ryegrass

Carfentrazone+ 

Pyroxasulfonec

Acetochlor+

Atrazinec

Glyphosatec

Pyroxasulfonec

Parquatc

Glufosinatec,4

Paraquat + 

Metribuzinc

Paraquat + 

Oxyfluorfenc

Paraquatc

Paraquat + 

Atrazine

c

Glyphosate + 

Saflufenacilc

Glufosinatec,4

Paraquatc

Paraquat+

Atrazinec

Glyphosate + 

Saflufenacilc, 3

Thifensulfuron + 

Tribenuronc

Pyroxasulfonec

Mesosulfuronc
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Table K-1. Representative Management Recommendations for Control of Common Weeds in Maize with Biotypes Resistant 

to the Herbicide(s) Tolerated by MON 87429 Maize and to Glyphosate (continued)

Weed Species1,2

Rotational Crops

Primary Crop 

Maize Soybeans Cotton Sorghum Wheat

Johnsongrass

Glyphosate +

s-Metolachlor + 

Mesotrionec

Mesotrione + 

Rimsulfuronec

Nicosulfuronec

Glufosinatec,4

Glyphosate + 

s-Metolachlor c

Glufosinatec,4

Trifloxysulfuronc

Trifluralinc

Glyphosate + 

s-Metolachlor c

Glufosinatec,4

Glyphosate + 

Carfentrazonec,3

Glyphosate + 

Flumioxazinc,3

Paraquat + 

Atrazinec

Glyphosate + 

Carfentrazonec,3

Glyphosate + 

Saflufenacilc,3

Paraquatc

1 Representative common weed species in maize in the U.S., chosen based on if a weed species has biotype(s) that is resistant to herbicide(s) tolerated by MON 

87429 maize (dicamba, glufosinate, 2,4-D and/or “fops”) and biotypes of these species reported to have resistance to glyphosate either as multiple resistance 

(kochia, Palmer amaranth, Italian ryegrass) or resistance to glyphosate exist separately in biotypes with high potential for biotypes with combined resistance 

development (waterhemp, johnsongrass) (Heap, 2019; see Table VIII-6 and Appendix K.8).

2 Herbicide(s) represent a sub-set of recommendations only; unique case(s) of weed resistance in a state to be managed through local extension scientists and/or 

university weed control guides, if available.

3 Glyphosate applied as burndown in non-glyphosate tolerant crops.

4 Glufosinate applied on glufosinate-tolerant crops. 

a University of Nebraska, 2019;b Take Action, 2016; c Mississippi State University, 2019; d Kansas State University, 2019;
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K.11. Stewardship of Dicamba, Glufosinate, Quizalofop, 2,4-D and Glyphosate Use 

on MON 87429 Maize

To steward the use of agricultural herbicides and herbicide-tolerant cropping systems 

such as MON 87429 maize and the likely combined trait glyphosate-tolerant maize 

product, Monsanto has conducted investigations and worked extensively with academics 

and other herbicide registrants to understand and recommend best practices to manage 

herbicide resistance. These investigations have demonstrated that one of the major 

factors contributing to the development of resistant weed biotypes has been poor weed 

control management practices. The primary reasons for lack of adequate management 

includes: 1) application of herbicides at rates below those indicated on the product label 

for the weed species, and 2) sole reliance on a single herbicide for weed control without 

the use of other herbicides or cultural control methods (Beckie, 2006; Norsworthy et al. 

2012).

K.11.1. Weed Control Recommendations

The proposed label for dicamba, and the labels for glufosinate, quizalofop, 2,4-D and 

glyphosate use on MON 87429 maize combined with deregulated glyphosate tolerance 

traits, such as NK603, are based on the maximum allowable use rates and patterns. Prior 

to launch of, for example, MON 87429 × NK603 maize, Monsanto, in cooperation with 

academics, will conduct trials to confirm the optimum rate and timing for dicamba, 

glufosinate, quizalofop, 2,4-D and glyphosate, alone and in combination with each other, 

and with other herbicides. Recommendations to growers will be developed from this 

information and will be provided in herbicide product labels, Monsanto’s Technology 

Use Guide (TUG), and in other education and training materials to be broadly distributed. 

Specifically, research conducted by Monsanto showed the value of multiple soil-active 

preplant herbicides followed by an early postemergence application of a mixture of 

herbicides with multiple sites-of-action, including a soil active herbicide, against 

broadleaf weeds that included species in the genus Amaranthus (Bayer CropScience, 

2019b). Such a program would optimize the likelihood of using two or more effective 

sites-of-action against the targeted weeds. In areas with glyphosate-resistant and hard to 

control broadleaf weed populations, dicamba or 2,4-D may be applied pre-planting as a 

tank mix with preemergence herbicides and/or applied post-emergence in addition to 

glufosinate in MON 87429 maize. In some situations, a second in-crop application of 

either dicamba or 2,4-D tank-mixed with glyphosate or glufosinate, with or without a soil 

residual herbicide will be recommended with options to rotate additional herbicides with 

diverse sites-of action between preplant and postemergence applications and as per the 

herbicide’s label. For postemergence grass control, quizalofop application recommended 

alone or in combination with glyphosate or in sequence with glyphosate or glufosinate. In 

cases of managing both grass and broadleaf weed species, a time interval is to be 

considered between quizalofop application and any postemergence broadleaf herbicides 

as per the label recommendation (see Section VIII.F.3. for additional details).

These recommendations will encourage the use of more than one site-of-action against 

the targeted weed species, which is a fundamental component of a good weed resistance 

management program. These management systems, which include the use of multiple 
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effective herbicide sites-of-action, will reduce the potential for further resistance 

development to dicamba, glufosinate, 2,4-D, quizalofop and glyphosate as well as other 

critical maize herbicides. 

K.11.2. Dispersal of Technical and Stewardship Information

Monsanto will use multiple methods to distribute technical and stewardship information 

to growers, academics and grower advisors. Monsanto’s TUG (Monsanto, 2019) will set 

forth the requirements and best practices for cultivation of MON 87429 maize including 

recommendations on weed resistance management practices. Growers who purchase 

maize hybrids containing MON 87429 will be required to enter into a limited use license 

with Monsanto and must sign and comply with the Monsanto Technology Stewardship 

Agreement (MTSA), which requires the grower to follow the TUG. 

The weed resistance management practices that will be articulated in the TUG will also 

be broadly communicated to growers and retailers in order to minimize the potential for 

development of resistant weed populations. These practices will be communicated 

through a variety of means, including direct mailings to each grower purchasing a maize 

hybrid containing MON 87429 and public websites

13 . The overall weed resistance 

management program will be reinforced through collaborations with U.S. academics, 

who will provide their recommendations for appropriate stewardship of dicamba, 

glufosinate, quizalofop, 2,4-D and glyphosate in maize production, as well as by 

collaboration with crop commodity groups who have launched web-based weed 

resistance educational modules. Finally, Monsanto will urge growers to report any 

incidence of non-performance of dicamba, glufosinate, quizalofop, 2,4-D or glyphosate

on weeds in fields planted with MON 87429 maize to the manufacturer of the 

herbicide. Appropriate investigations of unsatisfactory weed control will be conducted.

The EPA is the U.S. federal regulatory agency that administers federal law governing 

pesticide sale and use under the Federal Insecticide, Fungicide and Rodenticide Act 

(FIFRA). EPA encourages pesticide manufacturers to provide growers with information 

regarding an herbicide’s site-of-action to aid growers in planning herbicide use practices 

and to foster the adoption of effective weed resistance management practices as specified 

by EPA in Pesticide Registration (PR) Notices 2017-1 and 2017-2 (U.S. EPA, 2017b; 

2017c). The PR notice 2017-1 (U.S. EPA, 2017b) is a revised and updated version of an 

earlier PR notice 2001-5 (U.S. EPA, 2001), with much of its content being kept identical 

to the 2001-5 with the following changes: (1) provided additional guidance to registrants 

and a recommended format for resistance-management statements or information to place 

on labels; (2) included references to external technical resources on resistance 

management guidance; and (3) updated the instructions to submit changes to existing 

labels in order to enhance resistance-management language. The PR notice 2001-5 states 

that “this approach to resistance management is sound and would be highly beneficial to 

pesticide manufacturers and pesticide users.” The EPA approves all pesticide label use 

 

13 http://tug.monsanto.com/, https://monsanto.com/products/product-stewardship/, 

http://www.roundupreadyplus.com/
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instructions based on its evaluation of supporting data supplied by the pesticide registrant 

or manufacturer. By approving a label, EPA has concluded that the product will not 

cause unreasonable adverse effects to the environment when used in accordance with the 

label’s directions. After EPA approves a pesticide label, it is a violation of federal law to 

use the pesticide for a use or in a manner not in accordance with the label directions. 

Monsanto incorporates EPA’s guidelines for pesticide resistance management labeling on 

its agricultural herbicide labels and will continue to do so in the future.

In summary, Monsanto will require and educate weed resistance management practices 

through the Material Transfer Service Agreement (MTSA) and TUG for its 

biotechnology-derived herbicide-tolerant products, including MON 87429 maize. Upon 

deregulation, MON 87429 will be combined, via traditional breeding methods, with other 

maize traits (e.g., deregulated glyphosate tolerance traits, such as NK603), and Monsanto 

will promote these resistance management practices through product labeling and 

educational outreach efforts as an effective means to manage weed resistance 

development for dicamba, glufosinate, quizalofop, 2,4-D and glyphosate. 

K.11.3. Weed Resistance Management Practices

Monsanto will provide information to growers and grower advisors on best management 

practices to delay development of additional resistance to dicamba, glufosinate, 

quizalofop and 2,4-D herbicides. Weed resistance management recommendations for the 

use of dicamba, glufosinate, quizalofop, 2,4-D and glyphosate herbicides in conjunction 

with maize hybrids containing MON 87429 will be consistent with the Herbicide 

Resistance Action Committee’s guidelines for prevention and management of herbicide 

resistance (HRAC, 2015). These guidelines recommend an integrated approach to weed 

resistance management, including cultural, mechanical and chemical methods that 

include the use of multiple herbicide sites-of-action to manage a weed population. 

In cases where resistance is confirmed for dicamba, glufosinate, quizalofop, 2,4-D or 

glyphosate in maize producing areas, Monsanto and University/Cooperative Extension 

Service (CES) personnel will provide recommendations for alternative herbicide control 

methods to growers. These recommendations can be made available through various 

channels including Monsanto supplemental labels, Monsanto and university publications, 

and internet sites to growers, consultants, retailers and distributors. For all existing cases 

of dicamba-, glufosinate-, quizalofop-, or 2,4-D- resistant weeds in the U.S. and globally 

today, alternative herbicides and cultural methods are available to growers to effectively 

control these biotypes. Examples of alternative herbicides from University/CES 

personnel that are applicable to weed species known to be resistant to dicamba and other 

synthetic auxin herbicides, glufosinate and “fops” herbicides are found in Table K-1. 

However, these examples in Table K-1 are only a representative subset of product 

combinations of available maize herbicides.

K.12. Monsanto Weed Performance Evaluation and Weed Resistance Management 

Plan

An important part of a weed resistance management plan is the timely acquisition of 

information regarding herbicide product performance. Monsanto has an extensive 
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technical, sales and marketing presence in maize markets where MON 87429 maize will 

be grown. Through our relationships with farm advisors, key University/CES personnel, 

and growers using our seeds and traits products, Monsanto will acquire important and 

timely information regarding product performance. This will allow the timely 

recognition of performance issues that could arise related to weed resistance or other 

means. Field employees and hired consultants are trained and provided processes for 

responding to product performance inquiries. Individual performance issues that could 

be related to potential resistance are promptly handled. In addition, performance 

inquiries are periodically reviewed by Monsanto for trends that could indicate the need 

for follow up action on a broad scale. 

If new dicamba, glufosinate, quizalofop, 2,4-D or glyphosate resistance is confirmed, the 

scientific and grower communities will be notified, and a weed resistance management 

plan will be implemented by Monsanto in cooperation with the University/CES and/or 

the appropriate herbicide producer. The management plan will be designed to manage 

the resistant biotype through effective and economical weed management 

recommendations implemented by the grower. The plan considers what is technically 

appropriate for a particular weed and incorporates practical management strategies. 

After a management plan is developed, Monsanto communicates the plan to the grower 

community through various means, that may include informational fact sheets, retailer 

training programs, agriculture media and/or other means, as appropriate. 

K.13. Summary

Development of herbicide resistance in weeds is a complex process that can be difficult 

to accurately predict. Multiple methods for managing weed resistance are available and 

no single option is best for all farming situations. No single agronomic practice will 

mitigate resistance for all herbicides or all weeds. As a result, weed resistance needs to 

be managed on a case-by-case basis, tailored for the particular herbicide and weed 

species, and utilize an integrated system approach to meet grower needs. Using good 

weed management principles, built upon achieving high levels of control through proper 

application rate, choice of cultural and mechanical practices, and appropriate companion 

weed control products will allow dicamba, glufosinate, quizalofop, 2,4-D and glyphosate

herbicides to continue to be used effectively. In cases where weed populations have 

evolved or developed resistance to dicamba, glufosinate, quizalofop, 2,4-D and/or 

glyphosate, effective management options are available, and experience has shown that 

growers will continue to find value in using dicamba, glufosinate, quizalofop, 2,4-D and 

glyphosate in their weed control programs.

The key principles for effective stewardship of dicamba, glufosinate, quizalofop, 2,4-D

and glyphosate use comprise: a) Understand the biology of the weeds present; b) Use a 

diversified approach toward weed management focused on preventing weed seed 

production and reducing the number of weed seed in the soil seedbank; c) Plant into 

weed-free fields and then keep fields as weed free as possible; d) Plant weed-free crop 

seed; e) Scout fields routinely; f) Use multiple herbicide sites-of-action that are effective 

against the most troublesome weeds or those most prone to herbicide resistance; g) Apply 
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the labeled herbicide rate at recommended weed sizes; h) Emphasize cultural practices 

that suppress weeds by using crop competitiveness; i) Use mechanical and biological 

management practices where appropriate; j) Prevent field-to-field and within-field 

movement of weed seed or vegetative propagules; k) Manage weed seed at harvest and 

after harvest to prevent a buildup of the weed seedbank; l) Prevent an influx of weeds 

into the field by managing field borders

Overall, there are multiple factors that reduce the potential for dicamba or 2,4-D resistant 

broadleaf weed populations to arise from the use of dicamba or 2,4-D applied to 

MON 87429 combined with, for example, NK603. These are as follows: 

• Dicamba or 2,4-D will be used in combination with glyphosate and/or glufosinate 

in a majority of cropping situations and weed recommendations will also include 

the concurrent use of residual herbicides for weed control and use of additional 

sites-of-action. These use patterns provide herbicides with multiple sites-ofaction against major broadleaf weed species present in the maize production to

delay the development of herbicide resistance.

• The development of resistance to auxin herbicides has been found to be relatively 

slow. This observation is hypothesized to be due to multiple sites-of-action

within plants and evidence suggesting that resistance is determined by multiple 

genes (quantitative traits), at least in some species. 

• Only two and five broadleaf weed species have been confirmed to be resistant to 

dicamba and 2,4-D, respectively, in the U.S., and relatively low numbers of 

broadleaf species have been confirmed to be resistant to synthetic auxin 

herbicides even though dicamba and 2,4-D have been widely in use for over 40 

years. 

• Known resistant broadleaf weed populations to dicamba, 2,4-D and other auxin 

herbicides are primarily found in the western U.S. and, have limited presence in 

the major maize geographies. Biotypes of problematic weeds resistant to 2,4-D 

were found in key maize growing states in the U.S. (for example, biotypes of 

waterhemp in Nebraska and Illinois and Palmer amaranth in Kansas). Known

dicamba-resistant biotypes are not of major weed species present in the U.S. 

maize cropping systems. To delay resistance development in broadleaf weeds 

against dicamba or 2,4-D in the MON 87429 maize system, glufosinate can be 

used in combination and/or in sequence with 2,4-D or dicamba and in sequence 

with glyphosate, as allowed by the individual herbicide label. Residual herbicides 

will also be recommended and likely used in this cropping system.

Likewise, the probability for weed species to evolve resistance to glufosinate as a result 

of glufosinate use in the MON 87429 combined with glyphosate tolerance traits, such as 

NK603, is considered to be low because, only four species have been confirmed to be 

resistant to glufosinate worldwide and one (Italian ryegrass) in the U.S. This suggests 

that the frequency for resistant alleles in native weed populations is low. Known Italian 

ryegrass biotypes resistant to glufosinate herbicide within the U.S. are only found in 

Oregon and California, and thus, are not present in the major maize geographies. In the 

MON 87429 maize system, glufosinate can be used in combination and/or in sequence 
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with dicamba, quizalofop and/or 2,4-D and in sequence with glyphosate, as allowed by 

the individual herbicide label. Residual herbicides will also be recommended and likely 

used in this cropping system.

Resistance to quizalofop was reported in only five grass species in the U.S. Combining 

MON 87429 maize with glyphosate-tolerance traits, such as NK603, will also enable use 

of quizalofop to control a broad spectrum of grass weed species in addition to nonselective herbicides, glufosinate and glyphosate. Combination of these options will help 

delay or minimize potential evolution of resistance to quizalofop, glufosinate or 

glyphosate in grass species.

In the U.S., although resistance to glyphosate was reported in 17 weed species (11 

broadleaf and 6 grass weed species), it is critical to maintain the efficacy of glyphosate 

and delay further development of glyphosate-resistant weed biotypes. MON 87429 maize

when combined with other deregulated glyphosate-tolerant trait such as NK603, provides 

additional tools with multiple herbicide sites-of-action to manage glyphosate-tolerant 

weed biotypes and delay further glyphosate resistance development. 

As noted above, MON 87429 maize when combined with other deregulated glyphosate

tolerance traits, such as NK603, enable use of herbicides or herbicide mixtures with

multiple sites-of-action to control broadleaf and grass weed species present in the maize 

production and can be used as part of an integrated weed management program with 

other SOAs (including residuals) and other weed control practices to delay development 

of herbicide resistant weed population.
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Appendix L: MON 87429 Exogenous Substrate Specificity

L.1. Purpose

The purpose of this study was to determine if MON 87429 FT_T enzyme could 

potentially bind and catabolize various herbicides applied exogenously. The five 

herbicides tested (Table L-1) were selected based on mode of action class and agronomic 

importance for controlling grassy weeds and volunteer corn. MON 87429 and the near 

isogenic conventional control, LH244 × HCL617, were planted in pots and randomly 

placed in a greenhouse. Fourteen (14) days after herbicide application, individual plants 

were visually rated for herbicide induced injury using a scale from 0 percent (no visible 

injury) to 100 percent (plant death). The results showed that MON 87429 had no damage 

when 2,4-D and quizalofop were tested as compared to the conventional control, but 

injury ratings for the other herbicides were similar between MON 87429 and the 

conventional control. Therefore, FT_T was able to reduce 2,4-D and quizalofop injury 

through catabolization of this herbicide, but is unlikely to have catabolized any of the 

other herbicides. 

L.2. Materials

This study was conducted in a greenhouse at the Monsanto research facility in 

Chesterfield, MO in 2016. The starting seed for this study consisted of test material, 

MON 87429 (lot IHW300000879549985106881), and conventional maize control 

material, LH244 × HCL617 (lot IHW300000879550160526685), which has a genetic 

background similar to the test material. 

The herbicides used in this study (Table L-1) are commercially available and were 

selected based on mode of action class and agronomic importance for controlling grassy 

weeds and volunteer corn. For each of the five herbicides applied, two application rates 

were used that are within the labeled range for each herbicide or known to cause injury to 

conventional maize. 

L.3. Methods

The study was conducted in a greenhouse maintained at approximately 28° C during the 

day and 20° C during the night with a 16-hour photoperiod. Relative humidity was 

maintained between 30 and 70% while watering was conducted as needed.

The test and control starting seed were planted in 3.5 inch square pots with Redi-Earth® 

potting soil medium. Ten replicates of test and control seed were planted for each 

herbicide and rate combination and randomly placed in the greenhouse. At the 3-leaf 

growth stage, herbicide applications were made with a track sprayer according to 

standard practice. Visual injury ratings were assessed 14 days after herbicide application. 

A visual rating scale of 0-100% injury was used to rate the overall herbicide induced 

injury to each plant. A rating of 0% = no herbicide induced injury and 100% = plant 

death. Ratings were based on visual assessment of chlorosis, necrosis, malformation, 
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stunting, and biomass reduction. The ratings were averaged across 10 replications per 

treatment.

L.4. Results and Discussion

MON 87429 demonstrated no injury for 2,4-D and quizalofop when compared to the 

conventional control. MON 87429 and the conventional control exhibited similar injury 

ratings and therefore similar levels of susceptibility for all other herbicides tested (Table 

L-1). Clethodim, sethoxydim, and paraquat are important herbicides for grassy weed and 

volunteer maize control and will be effective in controlling volunteer MON 87429.

L.5. Conclusions

These results demonstrate that MON 87429 FT_T has a high specificity for 2,4-D and 

quizalofop as a substrate. Applications of various herbicides to MON 87429 and the near 

isogenic conventional control demonstrated that the rate of injury was similar for all of 

the herbicides tested, except 2,4-D and quizalofop, demonstrating only 2,4-D and 

quizalofop served as substrates for the FT_T present in MON 87429. Therefore, 

MON 87429 FT_T is specific for its substrates and did not catabolize other herbicides 

tested.

Table L-1 Induced Herbicide Injury to MON 87429 and Control
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Appendix M: Materials and Methods for Compositional Analysis of Maize 

MON 87429 Grain and Forage

Compositional comparisons between MON 87429 and the conventional control maize 

hybrid were performed using the principles and analytes outlined in the OECD consensus 

document for maize composition (OECD, 2002). These principles are accepted globally 

and have been employed previously in assessments of maize products derived through 

biotechnology. The compositional assessment was conducted on grain and forage 

samples harvested from multiple U.S. field sites during 2017 grown under typical 

agronomic field conditions practices. 

M.1. Materials

Harvested grain and forage from MON 87429 and a conventional control that has similar 

genetic background to that of MON 87429 hybrid were compositionally assessed.

M.2. Characterization of the Materials

The identities of MON 87429 and the conventional control were confirmed prior to use in 

the compositional assessment.

M.3. Field Production of the Samples

Grain and forage samples were harvested from MON 87429 and the conventional control 

grown in the United States during the 2017 season. The field production was conducted 

at five sites. The field sites were planted in a randomized complete block design with 

four replicates per site. MON 87429 and the conventional control were grown under 

normal agronomic field conditions for their respective growing regions. MON 87429 

plots were treated with dicamba, glufosinate, quizalofop and 2,4-D to generate samples 

under conditions of the intended use of the product. 

Grain was harvested at physiological maturity and shipped at ambient temperature from 

the field sites to Monsanto Company. Forage was harvested at R5 and shipped on dry ice 

from the field sites to Monsanto Company. A subsample for compositional analysis was 

obtained from each tissue sample collected. These subsamples were ground and stored in 

a freezer set to maintain 20C until their shipment on dry ice to Covance Laboratories 

Inc. (Madison, Wisconsin) for analysis.

M.4. Summary of Analytical Methods

Nutrients analyzed in this study included protein, total fat, ash, amino acids, linoleic acid, 

carbohydrates by calculation, fiber (acid detergent fiber (ADF), neutral detergent fiber 

(NDF)) in the grain, and protein, total fat, ash, carbohydrates by calculation and fiber 

(ADF and NDF) in the forage. The anti-nutrients assessed in grain included phytic acid 

and raffinose. 
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All compositional analyses were performed at Covance Laboratories, Inc. (Madison, 

Wisconsin). Methods for analysis were based on internationally-recognized procedures 

and literature publications. Brief descriptions of the methods utilized for the analyses are 

described below.

M.5. Acid Detergent Fiber

Sample aliquots were weighed into pre-weighed filter bags. Samples were placed in an 

ANKOM Fiber Analyzer and treated with an acid detergent solution containing sulfuric 

acid with cetyl trimethylammonium bromide, then filtered to remove proteins, starches, 

simple sugars, pectins, and ash. Fats and pigments were removed via an acetone wash 

leaving cellulose and lignin fractions. The remaining residue was the acid detergent fiber 

and was determined gravimetrically. The results are reported on a fresh weight basis. 

The limit of quantitation was calculated as 1.00%.

M.6. Amino Acids

The following 10 amino acids were analyzed:

Total arginine Total methionine

Total histidine Total phenylalanine

Total isoleucine Total threonine

Total leucine Total tryptophan

Total lysine Total valine

The samples were hydrolyzed in 6N hydrochloric acid for approximately 24 hours at 

approximately 106-118oC. Tryptophan was hydrolyzed from proteins by heating at 

approximately 110oC in 4.2N sodium hydroxide for approximately 20 hours.

The samples were analyzed by HPLC after pre-injection derivatization. The primary 

amino acids were derivatized with o-phthalaldehyde (OPA) and the secondary amino 

acids were derivatized with fluorenylmethyl chloroformate (FMOC) before injection. 

The amino acids were quantified using external standards. The results are reported on a 

fresh weight basis. The limit of quantitation for this study was 0.100 mg/g.

 Reference Standards:

Component Manufacturer Lot No. Purity (%)

L-Arginine Monohydrochloride Sigma-Aldrich SLBP2435V 100

L-Histidine Monohydrochloride Monohydrate Sigma-Aldrich SLBQ0900V 100

L-Isoleucine Sigma-Aldrich SLBF7068V 100

L-Leucine Sigma-Aldrich SLBQ0257V 99

L-Lysine Monohydrochloride Sigma-Aldrich SLBL2974V 99

L-Methionine Sigma-Aldrich SLBL7822V 100

L-Phenylalanine Sigma-Aldrich MKBQ7887V 99

L-Threonine Sigma-Aldrich SLBR2767V 100

L-Valine Sigma-Aldrich SLBS4748 100

L-Tryptophan Sigma-Aldrich SLBR5743V 100
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M.7. Ash

All organic matter was driven off when the samples were ignited at approximately 550oC 

in a muffle furnace for at least 5 hours. The remaining inorganic material was 

determined gravimetrically and referred to as ash. The results are reported on a fresh 

weight basis. The limit of quantitation was 0.100%.

M.8. Carbohydrate

The total carbohydrate level was calculated by difference using the fresh weight-derived 

data and the following equation:

% carbohydrates = 100 % - (% protein + % fat + % moisture + % ash)

The limit of quantitation was calculated as 0.100% on a fresh weight basis.

M.9. Fat by Acid Hydrolysis

The samples were hydrolyzed with hydrochloric acid. The fat was extracted using ether 

and hexane. The extracts were dried down and filtered through a sodium sulfate column. 

The remaining extracts were then evaporated, dried, and weighed. The limit of 

quantitation was calculated as 0.100% on a fresh weight basis.

M.10. Fat by Soxhlet Extraction

The samples were weighed into a cellulose thimble containing sodium sulfate and dried 

to remove excess moisture. Pentane was dripped through the samples to remove the fat. 

The extract was then evaporated, dried, and weighed. The results are reported on a fresh 

weight basis. The limit of quantitation was calculated as 0.100%.

M.11. Linoleic Acid

The lipid was extracted and saponified with 0.5N sodium hydroxide in methanol. The 

saponification mixture was methylated with 14% boron trifluoride in methanol. The 

resulting methyl esters were extracted with heptane containing an internal standard. The 

methyl esters of the fatty acids were analyzed by gas chromatography using external 

standards for quantitation. The results were converted to their triglyceride equivalent and 

reported on a fresh weight basis. The Methyl Linoleate analytical reference standard was 

purchased from Nu-Chek Prep. The lot numbers were N25-Z, AU31-A, F1-B and 

AU31A with a purity of 99.8%. The limit of quantitation was calculated as 0.00220%.

M.12. Moisture

The samples were dried in a vacuum oven at approximately 100C. The moisture weight 

loss was determined and converted to percent moisture. The results are reported on a 

fresh weight basis. The limit of quantitation was calculated as 0.100%.
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M.13. Neutral Detergent Fiber

Sample aliquots were weighed into pre-weighed filter bags. Samples were placed in an 

ANKOM Fiber analyzer and treated with a neutral detergent solution containing EDTA. 

Samples were then filtered to remove proteins, simple sugars, pectins, and ash. Fats and 

pigments were removed via an acetone wash leaving hemicellulose, cellulose, and lignin 

fractions. Starches were removed with a heat stable alpha amylase soak. The remaining 

residue was the neutral detergent fiber and was determined gravimetrically. The results 

are reported on a fresh weight basis. The limit of quantitation was calculated as 1.00%.

M.14. Phytic Acid

The samples were extracted using hydrochloric acid and sonication, purified using a 

silica-based anion exchange column, concentrated and injected onto a high-performance 

liquid chromatography (HPLC) system with a refractive index detector. The Phytic Acid 

Sodium Salt Hydrate analytical reference standard was purchased from Sigma-Aldrich. 

The lot number was BCBQ7037V with a purity of 78.280%. The results are reported on a 

fresh weight basis. The limit of quantitation was calculated as 0.125%.

M.15. Protein

The protein and other organic nitrogen in the samples were converted to ammonia by 

digesting the samples with sulfuric acid containing a catalyst mixture. The acid digest 

was made alkaline. The ammonia was distilled and then titrated with a previously 

standardized acid. Instrumentation was used to automate the digestion, distillation and 

titration processes. The percent nitrogen was calculated and converted to equivalent 

protein using the factor 6.25. The results are reported on a fresh weight basis. The limit 

of quantitation was calculated as 0.100%.

M.16. Raffinose

Sugars in the samples were extracted with a 50:50 water: methanol solution. Aliquots 

were taken, dried under inert gas, and then reconstituted with a hydroxylamine 

hydrochloride solution in pyridine containing phenyl-β-D-glucopyranoside as the internal 

standard. The resulting oximes were converted to silyl derivatives by treatment with

hexamethyldisilazane and trifluoracetic acid treatment, and then analyzed by gas 

chromatography using a flame ionization detector. The D-(+)-Raffinose pentahydrate 

analytical reference standard was purchased from Sigma-Aldrich. The lot number was 

WXBB7085V with a purity of 99.7%. The results are reported on a fresh weight basis. 

The limit of quantitation was calculated as 0.0500%.

M.17. Data Processing and Statistical Analysis

After compositional analyses were performed, data spreadsheets containing individual

values for each analysis were sent to Monsanto Company for review. Data were then 

transferred to the Monsanto Regulatory Statistics Team where they were converted into 
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the appropriate units and statistically analyzed. The following formulas were used for reexpression of composition data for statistical analysis (Table M-1):

Table M-1. Re-expression Formulas for Statistical Analysis of Composition Data

Component From (X) To Formula1

Proximates, Fiber, Phytic Acid, 

Raffinose % fw % dw X/d

Amino Acids (AA) mg/g fw % dw X/(10d)

Fatty Acids (FA), Linoleic Acid % fw % Total FA

(100)Xj/X, for 

each FAj where 

X is over all the 

FA

1

‘X’ is the individual sample value; d is the fraction of the sample that is dry 

matter.

In order to complete a statistical analysis for a compositional constituent in this 

compositional assessment, at least 50% of all the values for an analyte in grain or forage 

had to be greater than the assay limit of quantitation (LOQ). No analytes with more than 

50% of observations below the assay LOQ were observed.

The following linear mixed model was used for the combined-site analysis.

Yijk = μ + Si + R(S)j(i) + Mk + (SM)ik + εijk (1)

where:

Yijk is the observed response for the kth substance in the jth replicate of the ith site;

μ is the overall mean;

Si is the random effect of the ith site;

R(S)j(i) is the random effect of the jth replicate nested with the ith site;

Mk is the fixed effect of the kth substance;

(SM)ik is the random effect of the interaction between the ith site and kth substance;

εijk is the residual error.

SAS PROC MIXED was used to fit model (1) separately for each component to conduct 

the statistical analysis. Studentized residuals were obtained to detect potential outliers in 

the dataset. Studentized residuals tend to have a standard normal distribution when 
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outliers are absent. Thus, most values are expected to be between ± 3. Data points that are 

outside of the ± 6 studentized residual ranges are considered as potential outliers. No 

value had a studentized residual outside of the ± 6 range for this study.

The linear mixed model (1) assumes that the experimental errors, εijk, are independent, 

normally-distributed, and have a common variance. In this analysis, independence of the 

errors was controlled by the randomized complete block design. The normality and 

common variance assumptions were checked by visual examination of residual plots and 

histograms. No extreme violations were observed for any characteristic. Comparisons 

between MON 87429 and conventional control were defined within the model (1) and 

tested using t-tests.
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References for Appendix M

OECD. 2002b. Consensus document on compositional considerations for new varieties of 

maize (Zea mays): Key food and feed nutrients, anti-nutrients and secondary plant 

metabolites. OECD ENV/JM/MONO (2002)25. Organisation of Economic Co-Operation 

and Development, Paris, France.
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Appendix N: Digestive Fate of the FT_T Protein

N.1. Digestive Fate of the FT_T Protein

As part of a comprehensive evaluation, introduced proteins in biotechnology-derived 

crops are evaluated for their safety for human and animal consumption. Proteins are an 

essential dietary component for humans and animals, and most are rapidly degraded to

the component amino acids for nutritional purposes (Hammond and Jez, 2011). Although 

the vast majority of ingested proteins are non-allergenic, a small set of proteins or their 

fragments have been associated with a variety of gastrointestinal and systemic 

manifestations of immune-mediated allergy. One characteristic of several food allergens 

is their ability to withstand proteolytic digestion by enzymes present in the 

gastrointestinal tract (Astwood et al., 1996; Moreno et al., 2005; Vassilopoulou et al., 

2006; Vieths et al., 1999), although exceptions to the correlation can be identified (Fu et 

al., 2002). The enzymatic degradation of an ingested protein by exposure to gastric 

pepsin and/or intestinal pancreatic proteases (e.g., pancreatin) makes it highly unlikely 

that either the intact protein or protein fragment(s) will reach the absorptive epithelial 

cells of the small intestine where antigen processing cells reside (Moreno et al., 2005). 

Therefore, the susceptibility of FT_T to the presence of pepsin was evaluated using an 

assay protocol that has been standardized based on results obtained from an international, 

multi-laboratory ring study (Thomas et al., 2004).The susceptibility of proteins in the 

presence of pancreatin has also been used as a separate test system to assess the 

digestibility of food components (Okunuki et al., 2002; Yagami et al., 2000). The 

relationship between protein allergenicity and protein susceptibility to pancreatin 

degradation is limited, because the protein has not been first exposed to the acidic, 

denaturing conditions simulating the stomach, as would be the case with in vivo digestion 

(FAO-WHO, 2001).

N.1.1. Degradation of FT_T Protein in the Presence of Pepsin

Degradation of the FT_T protein by pepsin was evaluated over time by analyzing 

digestion mixtures incubated for targeted time intervals following a standardized protocol 

validated in an international, multi-laboratory ring study (Thomas et al., 2004) collected 

at targeted incubation time points. The specific methods used to assess the digestive 

fate/degradation of the FT_T protein in pepsin are summarized below and detailed in 

Appendix N.2. The study showed that the results of in vitro pepsin digestion assays 

using this protocol were reproducible and consistent for determining the digestive 

susceptibility of a protein. This standardized in vitro pepsin digestion protocol utilized a 

physiologically relevant acidic buffer appropriate for pepsin activity. The susceptibility 

of FT_T protein to pepsin degradation was assessed by visual analysis of a Brilliant Blue 

G Colloidal stained SDS-PAGE gel and by visual analysis of a western blot probed with 

an anti-FT_T polyclonal antibody. Both visualization methods were run concurrently 

with separate SDS-PAGE and western blot analyses to estimate the limit of detection 

(LOD) of the FT_T protein for each method. 
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For SDS-PAGE analysis of the digestibility of the FT_T protein in pepsin, the gel was 

loaded with 1 μg of total test protein (based on pre-digestion protein concentrations) for 

each of the digestion samples (Figure N-1, Panel A). The SDS-PAGE gel for the 

digestibility assessment was run concurrently with a separate SDS-PAGE gel to estimate 

the LOD of the FT_T protein (Figure N-1, Panel B). The LOD of intact FT_T protein 

was approximately 3.1 ng (Figure N-1, Panel B, lane 8). Visual examination of SDSPAGE data showed that the intact FT_T protein was digested within 0.5 min of 

incubation in pepsin (Figure N-1, Panel A, lane 5). Therefore, based on the LOD, more 

than 99.7% (100% - 0.3% = 99.7%) of the intact FT_T protein was digested within 

0.5 -min of incubation in pepsin. Transiently-stable peptide fragments at ~4-kDa were 

observed throughout the course of the digestion. There is a slight decrease in the intact 

FT_T protein band intensity and generation of fragments greater than 20 kDa observed in 

the 60 min No Pepsin Control compared to the 0 min No Pepsin Control (Figure N-1, 

Panel A, lanes 12 and 3, respectively). This likely indicates that a small portion of FT_T 

protein is instable possibly due to either the acidic conditions or minor contaminants in 

the FT_T solution; however, the rapid degradation of the intact FT_T protein and the 

subsequent fragments in the pepsin degradation samples was due to the proteolytic 

activity of pepsin. 

The 0 min No Test Protein Control and 60 min No Test Protein Control (Figure N-1, 

Panel A, lanes 2 and 13) demonstrated that the pepsin is stable throughout the 

experimental phase.
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Figure N-1. SDS-PAGE Analysis of the Degradation of FT_T Protein by Pepsin

Colloidal Brilliant Blue G stained SDS-PAGE gels were used to assess the degradation of FT_T 

protein by pepsin. Molecular weights (kDa) are shown on the left of each gel and correspond to 

the markers loaded. In each gel, the FT_T protein migrated to approximately 35 kDa and pepsin 

to approximately 38 kDa. Empty lanes and molecular weight markers that were not visible on the 

film were cropped from the images.

A: FT_T protein degradation in the presence of pepsin. Based on pre-reaction protein 

concentrations, 1 μg of test protein was loaded in each lane containing FT_T protein. 

B: LOD determination. Indicated amounts of the test protein from the Pepsin Treated T0 sample 

were loaded to estimate the LOD of the FT_T protein. 

Lane Sample Incubation 

Time (min) Lane Sample Amount(ng)

1 Mark12 MWM - 1 Mark12 MWM -

2 0 min No Test Protein Control 0 2 Pepsin Treated T0 200

3 0 min No Pepsin Control 0 3 Pepsin Treated T0 100

4 Pepsin Treated T0 0 4 Pepsin Treated T0 50

5 Pepsin Treated T1 0.5 5 Pepsin Treated T0 50

6 Pepsin Treated T2 2 6 Pepsin Treated T0 25

7 Pepsin Treated T3 5 7 Pepsin Treated T0 12.5

8 Pepsin Treated T4 10 8 Pepsin Treated T0 3.1

9 Pepsin Treated T5 20 9 Pepsin Treated T0 1.6

10 Pepsin Treated T6 30 10 Pepsin Treated T0 0.8

11 Pepsin Treated T7 60 11 Mark12 MWM -

12 60 min No Pepsin Control 60 12 Empty -

13 60 min No Test Protein Control 60 13 Empty -

14 Mark12 MWM - 14 Empty -

15 Empty - 15 Empty -
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For western blot analysis of FT_T pepsin susceptibility, the FT_T protein was loaded 

with approximately 40 ng per lane of total protein (based on pre-reaction total protein 

concentrations) for each reaction time point examined. The western blot used to assess 

FT_T protein degradation (Figure N-2, Panel A) was run concurrently with the western 

blot used to estimate the LOD (Figure N-2, Panel B). The LOD of the FT_T protein was 

approximately 0.31 ng (Figure N-2, Panel B, Lane 10). Western blot analysis 

demonstrated that the intact FT_T protein was degraded below the LOD within 0.5 min 

of incubation in the presence of pepsin (Figure N-2, Panel A, Lane 6). Based on the 

western blot LOD for the FT_T protein, more than 99.2% (100% - 0.8% = 99.2%) of the 

intact FT_T protein was degraded within 0.5 min. No peptide fragments were detected at 

the 0.5 min and beyond time points in the western blot analysis.

No change in the intact FT_T protein band intensity were observed in the 0 min No 

Pepsin Control and the 60 min No Pepsin Control. There were three antibody-recognized 

fragments greater than 20 kDa observed in the 60 min No Pepsin Control that were not 

observed in the 0 min No Pepsin Control (Figure N-2, Panel A, lanes 13 and 4, 

respectively). This indicates that small portion of the FT_T protein is slightly instable 

possibly due to either the acidic conditions or minor contaminants in the FT_T solution; 

however, a majority of the degradation of the intact FT_T protein and the subsequent 

fragments in the pepsin degradation samples was due to the proteolytic activity of pepsin. 

The transiently-stable fragments at ~4 kDa that were observed by SDS-PAGE were not 

recognized by the antibody used in this western blot.

No immunoreactive bands were observed in 0 min No Protein Control and 60 min No 

Protein Control (Figure N-2, Panel A, lanes 3 and 14). This result indicates that there 

was no non-specific interaction between the pepsin solution and the FT_T-specific 

antibody under these experimental conditions.
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Figure N-2. Western Blot Analysis of the Degradation of FT_T Protein by Pepsin

Western blots probed with an anti-FT_T antibody were used to assess the degradation of FT_T by 

pepsin. Molecular weights (kDa) are shown on the left of each gel and correspond to the 

MagicMarkTM molecular weight marker loaded in two lanes of each gel. Empty lanes and 

molecular weight markers that were not visible on the film were cropped from the images. A 30 

sec exposure is shown. 

A: FT_T protein degradation by pepsin. Based on pre-reaction protein concentrations, 40 ng of 

test protein was loaded in each lane containing FT_T protein. 

B: LOD determination. Indicated amounts of the test protein from the Pepsin Treated T0 sample 

were loaded to estimate the LOD of the FT_T protein. 

Lane Sample Incubation 

Time (min) Lane Sample Amount(ng)

1 Precision Plus MWM - 1 Precision Plus MWM -

2 MagicMark MWM - 2 MagicMark MWM -

3 0 min No Test Protein Control 0 3 Pepsin Treated T0 40

4 0 min No Pepsin Control 0 4 Pepsin Treated T0 20

5 Pepsin Treated T0 0 5 Pepsin Treated T0 10

6 Pepsin Treated T1 0.5 6 Pepsin Treated T0 5

7 Pepsin Treated T2 2 7 Pepsin Treated T0 2.5

8 Pepsin Treated T3 5 8 Pepsin Treated T0 1.25

9 Pepsin Treated T4 10 9 Pepsin Treated T0 0.63

10 Pepsin Treated T5 20 10 Pepsin Treated T0 0.31

11 Pepsin Treated T6 30 11 Pepsin Treated T0 0.16

12 Pepsin Treated T7 60 12 Pepsin Treated T0 0.08

13 60 min No Pepsin Control 60 13 MagicMark MWM -

14 60 min No Test Protein Control 60 14 Precision Plus MWM -

15 MagicMark MWM - 15 Empty -
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N.1.2. Degradation of FT_T Protein in the Presence of Pancreatin

The degradation of the FT_T protein by pancreatin was assessed by western blot analysis 

(Figure N-3). The western blot used to assess the FT_T protein degradation (Figure N-3, 

Panel A) was run concurrently with the western blot used to estimate the LOD (Figure N3, Panel B) of the FT_T protein. The LOD of the FT_T protein was observed at 

approximate 0.31 ng protein loading (Figure N-3, Panel B, lane 10). The LOD was used 

to calculate the maximum relative amount of FT_T protein that could remain visually 

undetected after digestion, which corresponded to approximately 0.8% of the total protein 

loaded.

The gel used to assess degradation of the FT_T protein by western blot was loaded with 

approximately 40 ng per lane of total protein (based on pre-reaction protein 

concentrations) for each reaction time point examined. Western blot analysis 

demonstrated that a band corresponding to the FT_T protein was degraded to a level 

below the LOD within 5 minutes of incubation with pancreatin (Figure N-3, Panel A, 

lane 5), the first time point assessed. Therefore, based on the LOD, more than 99.2% 

(100% - 0.8% = 99.2%) of the FT_T protein was digested within 5 minutes. No peptide 

fragments were detected at the 5 min and beyond time points in the western blot analysis. 

No obvious change in the intact FT_T (~35.5 kDa) band intensity was observed in the 

absence of pancreatin in the 0 min No Pancreatin Control and 24 hour No Pancreatin 

Control (Figure N-3, Panel A, lanes 3 and 13). This indicates that the degradation of all 

immunoreactive forms of the FT_T protein was due to the proteolytic activity of 

pancreatin and not due to instability of the protein when incubated in 50 mM KH2PO4, 

pH 7.5 over the course of the experiment.

No immunoreactive bands were observed in the 0 min No Test Protein Control and 24 

hour No Test Protein Control (Figure N-3, Panel A, lanes 2 and 14), demonstrating the 

absence of non-specific antibody interactions with the pancreatin solution.
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Figure N-3. Western Blot Analysis of the Degradation of FT_T Protein by 

Pancreatin

Western blots probed with an anti-FT_T antibody were used to assess the degradation of FT_T by 

pancreatin. Molecular weights (kDa) are shown on the left of each gel and correspond to the 

MagicMarkTM molecular weight marker loaded in each gel. Empty lanes and molecular weight 

markers that were not visible on the film were cropped from the images. A 60 sec exposure is 

shown.

A: FT_T protein degradation by pancreatin. Based on pre-reaction protein concentrations, 40 ng 

of test protein was loaded in each lane containing FT_T protein. 

B: LOD determination. Indicated amounts of the test protein from the Pancreatin Treated T0 

sample were loaded to estimate the LOD of the FT_T protein. 

Lane Sample Incubation 

Time Lane Sample Amount(ng)

1 MagicMark MWM - 1 Precision Plus MWM -

2 0 min No Test Protein Control 0 2 MagicMark MWM -

3 0 min No Pancreatin Control 0 3 Pancreatin Treated T0 40

4 Pancreatin Treated T0 0 4 Pancreatin Treated T0 20

5 Pancreatin Treated T1 5 min 5 Pancreatin Treated T0 10

6 Pancreatin Treated T2 15 min 6 Pancreatin Treated T0 5

7 Pancreatin Treated T3 30 min 7 Pancreatin Treated T0 2.5

8 Pancreatin Treated T4 1 h 8 Pancreatin Treated T0 1.25

9 Pancreatin Treated T5 2 h 9 Pancreatin Treated T0 0.63

10 Pancreatin Treated T6 4 h 10 Pancreatin Treated T0 0.31

11 Pancreatin Treated T7 8 h 11 Pancreatin Treated T0 0.16

12 Pancreatin Treated T8 24 h 12 Pancreatin Treated T0 0.08

13 24 h No Pancreatin Control 24 h 13 MagicMark MWM -

14 24 h No Test Protein Control 24 h 14 Precision Plus MWM -

15 Precision Plus MWM - 15 Empty -
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N.1.3. Degradation of FT_T Protein by Pepsin Followed by Pancreatin

To better understand the fate of the transiently-stable peptide fragments at ~4 -kDa that 

were observed in the reaction mixtures throughout the course of the pepsin digestion of 

FT_T, sequential digestibility of the FT_T protein was conducted. This sequential 

digestibility was assessed both by visual analysis of a Colloidal Brilliant Blue G stained 

SDS-PAGE gel, and visual analysis of a western blot probed with an anti 

FT_T-polyclonal antibody. Methods for the sequential digestibility are provided in 

Appendix E. 

For the sequential degradation assay, the FT_T protein was incubated with pepsin for 2 

min, followed by incubation with pancreatin. For the Colloidal Brilliant Blue G stained 

SDS-PAGE assessment, the gel was loaded with 1 μg of FT_T protein (based on predigestion protein concentrations) for each of the digestion samples. Examination of SDSPAGE data showed that the intact FT_T protein was digested within 2 min of incubation 

in pepsin (Figure N-4, Panel A, lane 3) and the small transient fragments at ~4 kDa was 

completely digested within 0.5 min of pancreatin exposure (Figure N-4, Panel A, lane 7). 

No change in the fragment band intensities was observed in the absence of pancreatin in 

the SEQ 0 min No Pancreatin Control and SEQ 2 hour No Pancreatin Control (Figure N4, Panel A, lanes 5 and 14). This indicates that the digestion of the fragments was due to 

the proteolytic activity of pancreatin and not due to instability of the fragment when 

incubated in 50 mM KH2PO4 at pH 7.5 over the course of the experiment.

The SEQ 0 min No Test Protein Control and SEQ 2 hour No Test Protein Control (Figure 

N-4, Panel A, lanes 4 and 15) demonstrated the integrity of the pancreatin over the course 

of the experiment. The intensity of some pancreatin bands decreased somewhat during 

the course of the experiment, most likely due to auto-digestion. This is not expected to 

adversely impact the pancreatin degradation results, as the transiently stable fragments 

were digested within 0.5 min of exposure to pancreatin.

The sequential digestion of the FT_T protein was also assessed by western blot (Figure 

N-4, Panel B), with 40 ng of the test protein (based on total protein pre-digestion 

concentrations) loaded per lane. No bands were detected in the 2 min Pepsin Treated 

sample (Figure N-4, Panel B, lane 3).
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Figure N-4. SDS-PAGE and Western Blot Analysis of the Degradation of FT_T 

Protein by Sequential Digestion

SDS-PAGE and western blot analysis were used to assess the degradation of FT_T in sequential digestion. 

Molecular weights (kDa) are shown on the left of each gel and correspond to the markers loaded (cropped 

in panel B). 

A: Colloidal Brilliant Blue G stained SDS-PAGE gel analysis of FT_T in sequential digestion. Based on 

pre-digestion protein concentrations, 1 μg of test protein was loaded in each lane containing FT_T protein. 

B: Western blot analysis of FT_T in sequential digestion. Based on pre-digestion protein concentrations, 

40 ng of test protein was loaded in each lane containing FT_T protein. A 60 sec exposure is shown.

Lane Sample Incubation 

Time

Lane Sample Incubation 

Time

1 Mark12 

MWM

- 1 Precision Plus 

MWM

-

Pepsin 

Degradation

Pepsin 

Degradation

2 0 min Pepsin 

Treated

0 min 2 0 min Pepsin 

Treated

0 min

3 2 min Pepsin 

Treated

2 min 3 2 min Pepsin 

Treated

2 min

Pancreatin 

Degradation

Pancreatin 

Degradation

4 SEQ 0 min No 

Test Protein 

Control

0 min 4 SEQ 0 min No 

Test Protein 

Control

0 min

5 SEQ 0 min No 

Pancreatin 

Control

0 min 5 SEQ 0 min No 

Pancreatin 

Control

0 min

6 SEQ T0 0 min 6 SEQ T0 0 min

7 SEQ T1 0.5 min 7 SEQ T1 0.5 min

8 SEQ T2 2 min 8 SEQ T2 2 min

9 SEQ T3 5 min 9 SEQ T3 5 min

10 SEQ T4 10 min 10 SEQ T4 10 min

11 SEQ T5 30 min 11 SEQ T5 30 min

12 SEQ T6 1 h 12 SEQ T6 1 h

13 SEQ T7 2 h 13 SEQ T7 2 h

14 SEQ 2 h No 

Pancreatin 

Control

2 h 14 SEQ 2 h No 

Pancreatin 

Control

2 h

15 SEQ 2 h No 

Test Protein 

Control

2 h 15 SEQ 2 h No 

Test Protein 

Control

2 h
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N.1.4. Degradation of FT_T Protein Conclusion

The ability of FT_T protein to be degraded by pepsin and by pancreatin was evaluated in 

this study. The results showed that at least 99.7% of the intact FT_T protein was 

degraded by pepsin within 0.5 min when analyzed by SDS-PAGE and at least 99.2% of 

the intact FT_T was degraded by pepsin within 0.5 min when analyzed by western blot 

using a FT_T specific antibody. SDS-PAGE analysis showed that transient peptide 

fragments at ~4 kDa were observed throughout the course of the pepsin digestion. At 

least 99.2% of the intact FT_T protein was degraded by pancreatin within 5 min when 

analyzed by western blot. These results show that the full-length FT_T is rapidly 

degraded by pepsin and pancreatin. The transient fragments at ~4 kDa were rapidly 

degraded by sequential digestion, indicating that gastrointestinal digestion is sufficient to 

degrade the intact FT_T protein and any fragments thereof. Rapid and complete 

degradation of the FT_T protein by pancreatin alone and pepsin followed by pancreatin 

indicates that the FT_T protein poses no meaningful risk to human or animal health.

N.2. Materials and Methods Used in Assessing Stability of FT_T Proteins in Pepsin 

and Pancreatin 

N.2.1. Test Substance

The test substance was the FT_T protein (lot # 11478164) purified from Escherichia coli 

(E. coli) transformed with the pMON374248 plasmid (E. coli-produced FT_T, referred to 

in this document as FT_T protein). The FT_T protein is stored in a -80 °C freezer in a 

buffer solution containing 40 mM Tris, pH 8, 0.2 M NaCl (storage buffer).

N.2.2. Characterization of Test Substance

The test protein (lot 11478164) had a purity of 92%, a total protein concentration of 

4.8 mg/ml, and an apparent molecular weight of 35.5 kDa. 

N.3. Experimental Design

Assays designed to assess the degradation of FT_T protein by pepsin and by pancreatin 

were performed independently. Because protein fragments attributable to the FT_T 

protein were identified after 10 min of pepsin degradation, a sequential digestion of the 

FT_T protein with pepsin followed by pancreatin was also performed.

N.3.1. Preparation of the Pepsin Stock Solution 

High purity pepsin (Sigma catalog number P6887; specific activity of 3546 U/mg, 96% 

protein, purity-corrected specific activity of 3404 U/mg) was dissolved in 10 mM HCl, 2 

mg/ml NaCl, pH ~1.2 to a concentration of ~2,632 U/ml. The amount of powder used to 

prepare the pepsin stock solution was calculated by using the purity-corrected pepsin 

specific activity value of 3404 U/mg. Activity was assessed using a pepsin activity assay 

(Section N.4.1).
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N.3.1.1. Degradation of the FT_T Protein by Pepsin

Degradation of the FT_T protein by pepsin was evaluated over time by analyzing 

samples collected at targeted incubation time points. A numerical code using the 

numbers 0 through 7 was used to distinguish incubation time points as follows:

Targeted Incubation Time Point Sample Code

0 min 0 min No Test Protein Control

0 min 0 min No Pepsin Control

0 min Pepsin Treated T0

0.5 min Pepsin Treated T1

2 min Pepsin Treated T2

5 min Pepsin Treated T3

10 min Pepsin Treated T4

20 min Pepsin Treated T5

30 min Pepsin Treated T6

60 min Pepsin Treated T7

60 min 60 min No Pepsin Control

60 min 60 min No Test Protein Control

The reaction mixture was prepared by adding 911.9 μl of pre-heated (37.2oC, 10 min) 

pepsin stock solution to a tube containing 50 μl of FT_T protein, which corresponded to 

240 μg of FT_T protein and 2400 U of pepsin. The tube contents were mixed and 

immediately returned to the water bath (37.1oC). Samples (96.2 μl) were removed at 0.5, 

2, 5, 10, 20, 30 and 60 min (corresponding to Pepsin Treated T1 through Pepsin Treated 

T7). Each 96.2 μl sample was placed immediately in a tube containing quenching 

mixture consisting of 33.7 μl of 0.7 M sodium carbonate buffer and 32.5 μl of 5 loading 

buffer (5 LB; ~310 mM Tris-HCl, 25% (v/v) 2-mercaptoethanol, 10% (w/v) sodium 

dodecyl sulfate, 0.025% (w/v) bromophenol blue, 50% (v/v) glycerol, pH 6.8).

The Pepsin Treated T0 sample was prepared in a separate tube. The pepsin stock solution 

(91.2 μl) was quenched by the addition of 0.7 M sodium carbonate buffer (33.7 μl) and 

5 LB (32.5 μl) and heated at 95-100 oC for 5-10 min prior to the addition of the FT_T 

protein (5.0 μl).

All quenched samples were frozen on dry ice and stored in a 80 oC freezer until analysis.

N.3.1.2. Pepsin Degradation Experimental Controls

Experimental control samples were prepared to determine the stability of the FT_T 

protein in 10 mM HCl, 2 mg/ml NaCl, pH ~1.2, the solution used to prepare the pepsin 

stock solution. The 0 min No Pepsin Control was prepared in a similar manner as 

described in Section N.4.1 for Pepsin Treated T0, except that 10 mM HCl, 2 mg/ml NaCl, 

pH 1.2 was added instead of the pepsin stock solution. The 60 min No Pepsin Control 

was prepared in a manner similar to 0 min No Pepsin Control, except the protein and 
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10 mM HCl, 2 mg/ml NaCl, pH 1.2 were incubated for 60 min at 37.1oC before 

quenching with 0.7 M sodium carbonate buffer and 5× LB.

Experimental control samples were also prepared to determine the stability of the pepsin 

stock solution lacking the FT_T protein. The 0 min No Test Protein Control was 

prepared in a similar manner as described in Section N.4.1 for Pepsin Treated T0, except 

that protein storage buffer (40 mM Tris, pH 8, 0.2 M NaCl) was added in place of the 

FT_T protein. The 60 min No Test Protein Control was prepared in a manner similar to 

0 min No Test Protein Control, except that protein storage buffer and the pepsin stock 

solution were incubated for 60 min at 37.1oC before quenching with 0.7 M sodium 

carbonate buffer and 5× LB.

All quenched samples were frozen on dry ice and stored in a 80 oC freezer until analysis.

N.3.2. Preparation of the Pancreatin Stock Solution 

Pancreatin contains a mixture of proteolytic enzymes and was prepared based on the 

method described in The United States Pharmacopoeia (USP, 1995). The pancreatin was 

obtained from Alfa Aesar (catalog number J62162) and was dissolved in 50 mM 

potassium phosphate buffer (pH 7.5) to a concentration of 10 mg of pancreatin 

powder/ml. Activity was assessed using a pancreatin activity assay (Section N.4.2)

N.3.2.1. Degradation of the FT_T Protein by Pancreatin

Degradation of the intact FT_T protein by pancreatin was evaluated over time by 

analyzing samples at multiple incubation time points. A numerical code using the 

numbers 0 through 8 was used to distinguish incubation time points as follows:

Targeted Incubation Time Point Sample Code

0 min 0 min No Test Protein Control 

0 min 0 min No Pancreatin Control

0 min Pancreatin Treated T0

5 min Pancreatin Treated T1

15 min Pancreatin Treated T2

30 min Pancreatin Treated T3

1 h Pancreatin Treated T4

2 h Pancreatin Treated T5

4 h Pancreatin Treated T6

8 h Pancreatin Treated T7

24 h Pancreatin Treated T8

24 h 24 h No Pancreatin Control

24 h 24 h No Test Protein Control

The reaction mixture was prepared by adding 929 μl of pre-heated (37.0oC, 10 min) 

pancreatin stock solution to a tube containing 35 μl of the FT_T protein, corresponding to 

168 μg of FT_T protein and 9,290.4 μg of pancreatin. The tube contents were vortex
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mixed and immediately returned to the water bath (37.0oC). Digestion samples (96.4 μl) 

were removed at 5, 15, 30 min, 1, 2, 4, 8, and 24 h (corresponding to time points 

Pancreatin Treated T1 through Pancreatin Treated T8) and immediately placed in a tube

containing 24.1 μl of 5 LB, heated to 95-100 oC for 5 10 min, and frozen on dry ice for 

complete quenching. 

The Pancreatin Treated T0 sample was prepared in a separate tube by first quenching 

92.9 μl of pancreatin stock solution with 24.1 μl of 5 LB buffer and heating to 95-100 

oC for 5 10 min prior to the addition of 3.5 μl of the FT_T protein. 

All quenched samples were frozen on dry ice and stored in a 80 oC freezer until analysis.

N.3.2.2. Pancreatin Degradation Experimental Controls

Experimental control samples were prepared to determine the stability of the FT_T 

protein in 50 mM KH2PO4, pH 7.5, the buffer used to prepare pancreatin stock solution. 

The 0 min No Pancreatin Control was prepared in a similar manner as described in 

Section N.4.2 for Pancreatin Treated T0, except that 50 mM KH2PO4, pH 7.5 was added 

instead of the pancreatin stock solution. The 24 hour No Pancreatin Control was also 

prepared in a similar manner, except the protein and 50 mM KH2PO4, pH 7.5 were 

incubated for 24 hour at 37.0oC before quenching with 5× LB and heating. 

Experimental control samples were also prepared to characterize the test system lacking 

the FT_T protein. The 0 min No Test Protein Control was prepared in a similar manner 

as described in Section N.4.2 for Pancreatin Treated T0, except that protein storage buffer 

(40 mM Tris, pH 8, 0.2 M NaCl) was added instead of FT_T protein. The 24 hour No 

Test Protein Control was also prepared in a similar manner, except the protein storage 

buffer and pancreatin stock solution were incubated for 24 hour at 37.0oC before 

quenching with 5× LB and heating. 

All quenched samples were frozen on dry ice and stored in a 80 oC freezer until analyzed.

N.3.3. Degradation of the FT_T Protein by Pepsin Followed by Pancreatin

Degradation of the FT_T protein by sequential digestion was evaluated by first 

incubating the FT_T protein with pepsin for 2 min, quenching the pepsin degradation 

reaction, and then incubating the reaction mixture with pancreatin. The sequential 

digestion of the FT_T protein was evaluated over time by analyzing samples at multiple 

incubation time points with a numerical code using the number 0 through 7 to distinguish 

incubation time points as follows: 
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Targeted Incubation Time Point Sample Code

Pepsin Degradation

0 min 0 min Pepsin Treated

2 min 2 min Pepsin Treated

Pancreatin Degradation

0 min SEQ 0 min No Test Protein Control

0 min SEQ 0 min No Pancreatin Control

0 min SEQ T0

0.5 min SEQ T1

2 min SEQ T2

5 min SEQ T3

10 min SEQ T4

30 min SEQ T5

1 h SEQ T6

2 h SEQ T7

2 h SEQ 2 h No Pancreatin Control

2 h SEQ 2 h No Test Protein Control

In the pepsin degradation phase, 729.5 l of pre-heated (37.4oC, 10 min) pepsin solution 

(2632 units of pepsin activity/ml) was added to 40 l of the FT_T protein, corresponding 

to 192 g of FT_T protein and 1920 U of pepsin. The tube contents were mixed by 

vortexing and immediately returned to the water bath (37.3oC). The tube was removed at 

a targeted time of 2 min, and immediately quenched by adding 269.3 l of 0.7 M sodium 

carbonate buffer. The 2 min Pepsin Treated sample was prepared by mixing 120 μl of 

the quenched sample with 30 l of 5 LB, and heating to 95-100 oC for 5-10 min. The 

sample was then frozen on dry ice and stored in a -80 °C freezer until analyzed.

In the pancreatin degradation phase, the quenched 2 min pepsin treated sample was 

digested in pancreatin. For this phase, 525.4 μl of pre-heated (37.3oC) pancreatin 

solution was added to 500 l of quenched 2 min pepsin treated sample, corresponding to 

95 g total FT_T protein (based on predigested concentration) and 5,253.5 μg of 

pancreatin. The tube contents were mixed by vortexing and immediately returned to the 

water bath (37.2oC). Digestion samples (102.5 l) were removed from the tube at 

targeted times of 30 sec, 2, 5, 10, 30 min, 1, and 2 h (corresponding to specimen codes 

SEQ T1 through SEQ T7) and immediately quenched by placing in a tube containing 

25.6 l of 5 LB, heated to 95-100 oC for 5-10 min, and frozen on dry ice for complete 

quenching.

The zero incubation time point for the pepsin degradation phase (0 min Pepsin Treated) 

was prepared in a separate tube by first quenching 73 l of pepsin solution with 26.9 l 

of sodium carbonate buffer and 26 l of 5 LB, then heating to 95-100 oC for 5-10 min 

prior to the addition of 4 l of the FT_T protein.

The zero incubation time point for the pancreatin digestion phase (SEQ T0) was prepared 

in a separate tube by first quenching 52.5 l of pancreatin solution with 25.6 l of 5 LB 
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buffer and heating to 95-100 oC for 5-10 min prior to the addition of 50 l of the 

quenched 2 min pepsin treated FT_T.

All quenched samples were frozen on dry ice and stored in a -80 oC freezer until analyzed.

N.3.3.1. Pepsin Followed by Pancreatin Degradation Experimental Controls

The SEQ 0 min No Pancreatin Control was prepared in a similar manner as described for 

SEQ T0, except that 50 mM KH2PO4, pH 7.5 was added instead of pancreatin solution. 

The SEQ 2 hour No Pancreatin Control was also prepared in a similar manner, except the 

protein and 50 mM KH2PO4 were incubated for 2 hour at 37.2°C before quenching with 

5× LB and heating.

The SEQ 0 min No Test Protein Control was prepared in a similar manner as described in 

for SEQ T0, except that protein storage buffer (40 mM Tris, pH 8, 0.2 M NaCl) was 

added instead of FT_T protein. The SEQ 2 hour No Test Protein Control was also 

prepared in a similar manner, except the protein storage buffer and pancreatin solution 

were incubated for 2 hour at 37.2oC before quenching with 5× LB and heating.

All quenched samples were frozen on dry ice and stored in a -80 oC freezer until analyzed.

N.4. Analytical Methods

N.4.1. Pepsin Activity Assay

Pepsin activity was determined by measuring the degradation of denatured hemoglobin. 

To conduct the assay, the pepsin stock solution (Section 4.1), was diluted to 0.03 mg of 

powder per ml with 10 mM HCl, 2 mg/ml NaCl, pH ~1.2 (dilution factor (DF) = 25.67). 

Five ml of acidified hemoglobin (2% (w/v)) was added to 3 test sample tubes and 3 blank 

tubes and all were pre-warmed for 8-10 min in a water bath at 37.0-37.1°C. Diluted 

pepsin stock solution (1 ml) was added to the 3 test sample tubes (test samples) and all 6 

tubes were incubated for 10 min in the water bath. Ten ml of 5% (v/v) chilled 

trichloroacetic acid (TCA) was added to each of the 6 tubes and 1 ml diluted pepsin stock 

solution was then added to the 3 blank samples. Samples were mixed and then incubated 

for another 5-10 min in the water bath. Precipitated protein was removed from each 

sample using 0.45 μm syringe filters and the absorbance of the test and blank sample 

filtrates at 280 nm were measured using a SpectraMax M2 plate reader (Molecular 

Devices). One unit of pepsin produces a change in absorbance at 280 nm of 0.001 per 

min at 37 ± 2 oC, pH 1.2. The units of pepsin in 1 ml of the stock solution were 

calculated using the following equation:

Mean TestA280nm − Mean BlankA280nm

0.001 × 10 min × 1 ml × DF

where 0.001 is the change in the absorbance at 280 nm per min produced by one unit of 

pepsin activity at 37 ± 2 oC, pH 1.2; 10 min is the reaction time; 1 ml is the volume of the 

diluted pepsin stock solution added to the reaction; and DF is the dilution factor for the 
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pepsin stock solution. The activity of pepsin was converted from units/ml to units/mg. 

Acceptable specific activity (units/mg pepsin powder) for the pepsin solution was equal 

to the specific activity determined by the manufacturer ± 1,000 units/mg.

N.4.2. Pancreatin Activity Assay

The pancreatin activity was determined by measuring the degradation of resorufinlabeled casein (Roche Life Science). To conduct the assay, 50 μl of 0.4% (w/v) 

resorufin-labeled casein and 50 μl of incubation buffer (200 mM Tris, pH 7.8, 20 mM 

CaCl2) were added to 3 test sample tubes and 3 blank tubes and all were pre-warmed for 

3 min in a water bath at 37.0-37.3°C. To initiate the reaction, 100 μl of 0.05× pancreatin 

stock solution (pancreatin stock solution was diluted to 0.05× with 50 mM KH2PO4, pH 

7.5 before the activity assay was initiated) was added to each of the 3 test sample tubes 

while 100 μl of 50 mM KH2PO4, pH 7.5 was added to each of the 3 blank tubes. All 6 

tubes were incubated for 15 min in the water bath. Reactions were quenched by adding 

480 μl of 5% (w/v) TCA to each tube, followed by vortex mixing. The samples were 

incubated in the water bath for an additional 10 min. The supernatants recovered after 

centrifugation (400 μl) were neutralized by the addition of 600 μl assay buffer (500 mM 

Tris-HCl, pH 8.8), and the absorbance of the test and blank supernatants was read at 574 

nm using a SpectraMax M2 plate reader (Molecular Devices). One unit of pancreatin 

produces a change in the absorbance at 574 nm of 0.001 per min at 37 ± 2 oC. The units 

of pancreatin in the stock solution were calculated using the following equation:

Mean ActivityA574nm − Mean BlankA574nm

0.001 × 15 min× 0.005 ml

where 0.001 is the change in the absorbance at 574 nm per min at 37 ± 2 oC produced by 

one unit of pancreatin activity, 15 min is the reaction time, 0.1 ml is the volume of diluted 

pancreatin stock solution added to the reaction, and 0.005 ml is the volume of the 

pancreatin stock solution used in the assay (0.05× Pancreatin solution, 0.1 ml). An 

acceptable specific activity for the pancreatin stock solution was defined as 11,000 ± 

3,000 U/ml. 

N.4.3. SDS-PAGE and Colloidal Brilliant Blue G Staining

Pepsin-treated samples and associated control samples were subjected to SDS-PAGE 

using pre-cast Tricine 10-20% (w/v) polyacrylamide gradient mini-gels and Tricine SDS 

running buffer (Invitrogen). The FT_T protein was loaded at 1 μg per lane based on total 

pre-digestion protein concentration. The experimental controls were loaded at the same 

volumes as those containing FT_T protein so that they would be comparable. Mark12TM 

molecular weight marker (Invitrogen) was loaded to estimate the relative molecular 

weight of proteins and peptides. Electrophoresis was performed at a constant voltage of 

165 volts for 60-61 minutes. After electrophoresis, gels were fixed in a solution 

containing 7% (v/v) acetic acid and 40% (v/v) methanol for 30 min and stained for 17-20 

hours in 1× Brilliant Blue G-Colloidal stain solution (Sigma), destained for 30 sec in 10% 

(v/v) acetic acid, 25% (v/v) methanol and then destained for 4.25-6 hours in a 25% (v/v) 
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methanol solution. The gels were scanned using a Bio Rad GS 900 densitometer (Bio 

Rad) to produce digitized images to be used as figures for reporting purposes.

To estimate the LOD of the FT_T protein, dilutions of the Pepsin Treated T0 samples 

were loaded on a second SDS-PAGE gel and the gel was run and processed exactly as the 

gel used to assess FT_T protein degradation in the presence of pepsin. Loads per lane 

were approximately 200 to 0.8 ng of the FT_T. The LOD was determined as the lowest 

amount of the FT_T protein that was visible on the gel with Colloidal staining.

Sequential digestion samples were also analyzed by SDS-PAGE as described above for 

pepsin degradation samples.

N.4.4. Western Blot Analysis

Pepsin-treated, pancreatin-treated, and sequential digestion samples, and the associated 

control samples, were subjected to SDS-PAGE using pre-cast Tricine 10-20% (w/v) 

polyacrylamide gradient mini-gels. The FT_T protein was loaded at approximately 40 ng 

per lane based on total pre-digestion protein concentration. The experimental controls 

were loaded to equal the digestion samples. Electrophoresis was performed at a constant 

voltage of 165 volts for 60-70 minutes. After electrophoresis, the proteins were 

electrotransferred to PVDF membranes (Bio Rad). Pre-stained molecular weight markers 

(Precision Plus ProteinTM Standards Dual Color Standard, Bio Rad; MagicMarkTM XP, 

Invitrogen) were used to verify electrotransfer of the proteins to the membranes and 

estimate the relative molecular weight of proteins. 

Proteins transferred to PVDF membranes were analyzed by western blot. The western 

blotting procedure was performed using an iBindTM western System apparatus (Life 

Technologies). The membranes were blocked with 1× iBindTM Solution (Life 

Technologies) and incubated with goat anti FT_T antibody (lot 27003) at a dilution of 

1:1,000 in 1× iBindTM Solution. After washing with 1× iBindTM Solution, the membrane 

was next incubated with horseradish peroxidase (HRP)-conjugated horse anti goat IgG 

(Vector Laboratories) at a dilution of 1:1,500 in 1× iBindTM Solution and washed again 

with 1× iBindTM Solution. Immunoreactive bands were visualized using the enhanced 

chemiluminescence (ECL) detection system (GE Healthcare) and exposed to Hyperfilm 

ECL high performance chemiluminescence film (GE Healthcare). The film was 

developed using a Konica SRX 101A automated film processor (Konica). The films 

were scanned using a Bio Rad GS 900 densitometer to produce electronic images to be 

used as figures for reporting purposes.

To estimate the LOD of the FT_T protein, dilutions of either the Pepsin Treated T0 or the 

Pancreatin Treated T0 samples were subjected to western blot analysis run and processed 

exactly as the western blot used to assess FT_T protein degradation in the presence of 

pepsin or pancreatin, respectively. Loads per lane were approximately 40 to 0.08 ng of 

the FT_T protein. The LOD was determined as the lowest amount of the FT_T protein 

that was visible on the film.
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References for Appendix N

Astwood, J.D., J.N. Leach and R.L. Fuchs. 1996. Stability of food allergens to digestion 

in vitro. Nature Biotechnology 14:1269-1273.

FAO-WHO. 2001. Evaluation of allergenicity of genetically modified foods. Report of a 

joint FAO/WHO expert consultation on allergenicity of foods derived from 

biotechnology. Food and Agriculture Organization of the United Nations, Rome, Italy.

Fu, T.-J., U.R. Abbott and C. Hatzos. 2002. Digestibility of food allergens and 

nonallergenic proteins in simulated gastric fluid and simulated intestinal fluid - A 

comparative study. Journal of Agricultural and Food Chemistry 50:7154-7160.

Hammond, B.G. and J.M. Jez. 2011. Impact of food processing on the safety assessment 

for proteins introduced into biotechnology-derived soybean and corn crops. Food and 

Chemical Toxicology 49:711-721.

Moreno, F.J., F.A. Mellon, M.S.J. Wickham, A.R. Bottrill and E.N.C. Mills. 2005. 

Stability of the major allergen Brazil nut 2S albumin (Ber e 1) to physciologically 

relevant in vitro gastrointestinal digestion. FEBS Journal 272:341-352.

Okunuki, H., R. Techima, T. Shigeta, J. Sakushima, H. Akiyama, Y. Goda, M. Toyoda 

and J. Sawada. 2002. Increased digestibility of two products in genetically modified food 

(CP4 EPSPS and Cry1Ab) after preheating. Journal of the Food Hygienic Society of 

Japan 43:68-73.

Thomas, K., M. Aalbers, G.A. Bannon, M. Bartels, R.J. Dearman, D.J. Esdaile, T.J. Fu, 

C.M. Glatt, N. Hadfield, C. Hatzos, S.L. Hefle, J.R. Heylings, R.E. Goodman, B. Henry, 

C. Herouet, M. Holsapple, G.S. Ladics, T.D. Landry, S.C. MacIntosh, E.A. Rice, L.S. 

Privalle, H.Y. Steiner, R. Teshima, R. van Ree, M. Woolhiser and J. Zawodny. 2004. A 

multi-laboratory evaluation of a common in vitro pepsin digestion assay protocol used in 

assessing the safety of novel proteins. Regulatory Toxicology and Pharmacology 39:87-

98.

USP. 1995. Test solutions. Page 2053 in The National Formulary. United States 

Pharmacopeia, Washington, D.C.

Vassilopoulou, E., N. Rigby, F.J. Moreno, L. Zuidmeer, J. Akkerdaas, I. Tassios, N.G. 

Papadopoulos, P. Saxoni-Papageorgiou, R. van Ree and C. Mills. 2006. Effect of in vitro 

gastric and duodenal digestion on the allergenicity of grape lipid transfer protein. Journal 

of Allergy and Clinical Immunology 118:473-480.

Vieths, S., J. Reindl, U. Müller, A. Hoffmann and D. Haustein. 1999. Digestibility of 

peanut and hazelnut allergens investigated by a simple in vitro procedure. European Food 

Research and Technology 209:379-388.
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Yagami, T., Y. Haishima, A. Nakamura, H. Osuna and Z. Ikezawa. 2000. Digestibility of 

allergens extracted from natural rubber latex and vegetable foods. Journal of Allergy and 

Clinical Immunology 106:752-762.
Supplemental Information for Technical Completeness of Petition 19-316-01p (Monsanto Petition 

Number CR279-19U4; revised December 10, 2019)

1

CR279-19U4

Monsanto1is providing the following information as a supplement to Petition Number 19-316-

01p (Monsanto Petition Number CR279-19U4) requesting the Determination of Nonregulated 

Status for Dicamba, Glufosinate, Quizalofop and 2,4-Dichlorophenoxyacetic Acid Tolerant 

MON 87429 Maize with Tissue Specific Glyphosate Tolerance Facilitating the Production of 

Hybrid Maize Seed (OECD Unique Identifier: MON 87429-9). This information also supports 

the clarifications requested in the Clarification Letter from USDA-APHIS dated November 20, 

2019.

1. The cited 2018 reference has been marked as CBI in the three locations on pages 131, 

136 and 181. 

A brief description of the methodology and production of the data cited in Table VIII-3 

has been added to the PDF reference, included with this submission. 

The discrepancy between the percent of maize acres treated with the herbicide glyphosate 

in Table VIII-3 in the petition and Table 2 in the USDA-NASS 2019b reference is due to 

reporting of a sub-set of glyphosate use data in the USDA-NASS 2019b summary report. 

Table 2 from the USDA-NASS 2019b only reports a single glyphosate formulation 

(isopropylamine salt) use in maize (34% acres treated) while the total maize acres treated 

with herbicide glyphosate irrespective of its formulations was approximately 76% as per 

the pesticide use data available at USDA-NASS survey and is summarized below. 

Table VIII-3 in the petition includes total glyphosate use in maize irrespective of its 

formulations. 

Glyphosate formulations

Percent of maize acres 

treated

CHEMICAL, HERBICIDE: (GLYPHOSATE = Code: 417300) 12%

CHEMICAL, HERBICIDE: (GLYPHOSATE AMM. SALT = Code: 103604) Data not available

CHEMICAL, HERBICIDE: (GLYPHOSATE DIM. SALT = Code: 103608) 4%

CHEMICAL, HERBICIDE: (GLYPHOSATE ISO. SALT = Code: 103601) 34%*

CHEMICAL, HERBICIDE: (GLYPHOSATE POT. SALT = Code: 103613) 26%

Total per USDA NASS Survey ~76% 

*Published in USDA-NASS 2019b.

 

1 Monsanto Company remains a legal entity holding registrations, permits and other approvals, but it is wholly 

owned by Bayer. We will let you know about any reorganization of legal entities, including transfer of 

authorizations/registrations from Monsanto and/or address updates. The names of entities holding registrations 

should not have any bearing on our approvals. These changes are for legal administrative reasons and have no 

influence on the quality of the end-use products, grain or seeds and they have no consequences for existing safety 

evaluations.
Supplemental Information for Technical Completeness of Petition 19-316-01p (Monsanto Petition 

Number CR279-19U4; revised December 10, 2019)

2

CR279-19U4

2. Typo has been corrected to chloroacetamide. 

3. Buckhorn plantain has been used throughout. 

4. Delye et al., 2003b has been added as a citation. 

5. Hidayat and Preston 1997 PDF is provided with this submission. 

6. “+MCPA” has been added to the recommendation for kochia control in wheat in Table 

K-1.