# Patent

## Title
AXMI-031, AXMI-039, AXMI-040 and AXMI-049, a family of novel delta-endotoxin genes and methods for their use

## Abstract

Compositions and methods for conferring pesticidal activity to bacteria, plants, plant cells, tissues and seeds are provided. Compositions comprising a coding sequence for a delta-endotoxin polypeptide are provided. The coding sequences can be used in DNA constructs or expression cassettes for transformation and expression in plants and bacteria. Compositions also comprise transformed bacteria, plants, plant cells, tissues, and seeds. In particular, isolated delta-endotoxin nucleic acid molecules are provided. Additionally, amino acid sequences corresponding to the polynucleotides are encompassed, and antibodies specifically binding to those amino acid sequences. In particular, the present invention provides for isolated nucleic acid molecules comprising nucleotide sequences encoding the amino acid sequence shown in SEQ ID NO:2, 4, 6, 8, 10, 12, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, or 38, or the nucleotide sequence set forth in SEQ ID NO:1, 3, 5, 7, 9, 11, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, or 37, as well as variants and fragments thereof.

## Background
CROSS REFERENCE TO RELATED APPLICATION
This application is a divisional of U.S. application Ser. No. 11/762,886, filed Jun. 14, 2007, which claims the benefit of U.S. Provisional Application Ser. No. 60/813,774, filed Jun. 14, 2006, the contents of which are herein incorporated by reference in their entirety.


REFERENCE TO SEQUENCE LISTING SUBMITTED ELECTRONICALLY
The official copy of the sequence listing is submitted electronically via EFS-Web as an ASCII formatted sequence listing with a file named “366899_SequenceListing.txt”, created on Jan. 31, 2009, and having a size of 347 kilobytes and is filed concurrently with the specification. The sequence listing contained in this ASCII formatted document is part of the specification and is herein incorporated by reference in its entirety.
FIELD OF THE INVENTION
This invention relates to the field of molecular biology. Provided are novel genes that encode pesticidal proteins. These proteins and the nucleic acid sequences that encode them are useful in preparing pesticidal formulations and in the production of transgenic pest-resistant plants.
BACKGROUND OF THE INVENTION
Bacillus thuringiensis is a Gram-positive spore forming soil bacterium characterized by its ability to produce crystalline inclusions that are specifically toxic to certain orders and species of insects, but are harmless to plants and other non-targeted organisms. For this reason, compositions including Bacillus thuringiensis strains or their insecticidal proteins can be used as environmentally-acceptable insecticides to control agricultural insect pests or insect vectors for a variety of human or animal diseases.
Crystal (Cry) proteins (delta-endotoxins) from Bacillus thuringiensis have potent insecticidal activity against predominantly Lepidopteran, Dipteran, and Coleopteran larvae. These proteins also have shown activity against Hymenoptera, Homoptera, Phthiraptera, Mallophaga, and Acari pest orders, as well as other invertebrate orders such as Nemathelminthes, Platyhelminthes, and Sarcomastigorphora (Feitelson (1993) The Bacillus thuringiensis family tree. In Advanced Engineered Pesticides, Marcel Dekker, Inc., New York, N.Y.) These proteins were originally classified as CryI to CryV based primarily on their insecticidal activity. The major classes were Lepidoptera-specific (I), Lepidoptera- and Diptera-specific (II), Coleoptera-specific (III), Diptera-specific (IV), and nematode-specific (V) and (VI). The proteins were further classified into subfamilies; more highly related proteins within each family were assigned divisional letters such as Cry1A, Cry1B, Cry1C, etc. Even more closely related proteins within each division were given names such as Cry1C1, Cry1C2, etc.
A new nomenclature was recently described for the Cry genes based upon amino acid sequence homology rather than insect target specificity (Crickmore et al. (1998) Microbiol. Mol. Biol. Rev. 62:807-813). In the new classification, each toxin is assigned a unique name incorporating a primary rank (an Arabic number), a secondary rank (an uppercase letter), a tertiary rank (a lowercase letter), and a quaternary rank (another Arabic number). In the new classification, Roman numerals have been exchanged for Arabic numerals in the primary rank. Proteins with less than 45% sequence identity have different primary ranks, and the criteria for secondary and tertiary ranks are 78% and 95%, respectively.
The crystal protein does not exhibit insecticidal activity until it has been ingested and solubilized in the insect midgut. The ingested protoxin is hydrolyzed by proteases in the insect digestive tract to an active toxic molecule. (Hofte and Whiteley (1989) Microbiol. Rev. 53:242-255). This toxin binds to apical brush border receptors in the midgut of the target larvae and inserts into the apical membrane creating ion channels or pores, resulting in larval death.
Delta-endotoxins generally have five conserved sequence domains, and three conserved structural domains (see, for example, de Maagd et al. (2001) Trends Genetics 17:193-199). The first conserved structural domain consists of seven alpha helices and is involved in membrane insertion and pore formation. Domain II consists of three beta-sheets arranged in a Greek key configuration, and domain III consists of two antiparallel beta-sheets in “jelly-roll” formation (de Maagd et al., 2001, supra). Domains II and III are involved in receptor recognition and binding, and are therefore considered determinants of toxin specificity.
Because of the devastation that insects can confer there is a continual need to discover new forms of Bacillus thuringiensis delta-endotoxins.
SUMMARY OF INVENTION
Compositions and methods for conferring pest resistance to bacteria, plants, plant cells, tissues and seeds are provided. Compositions include nucleic acid molecules encoding sequences for delta-endotoxin polypeptides, vectors comprising those nucleic acid molecules, and host cells comprising the vectors. Compositions also include the polypeptide sequences of the endotoxin, and antibodies to those polypeptides. The nucleotide sequences can be used in DNA constructs or expression cassettes for transformation and expression in organisms, including microorganisms and plants. The nucleotide or amino acid sequences may be synthetic sequences that have been designed for expression in an organism including, but not limited to, a microorganism or a plant. Compositions also comprise transformed bacteria, plants, plant cells, tissues, and seeds.
In particular, isolated nucleic acid molecules corresponding to delta-endotoxin nucleic acid sequences are provided. Additionally, amino acid sequences corresponding to the polynucleotides are encompassed. In particular, the present invention provides for an isolated nucleic acid molecule comprising a nucleotide sequence encoding the amino acid sequence shown in SEQ ID NO:2, 4, 6, 8, 10, 12, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, or 38, a nucleotide sequence set forth in SEQ ID NO:1, 3, 5, 7, 9, 11, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, or 37, or the delta-endotoxin nucleotide sequences deposited in bacterial hosts as Accession Nos. B-30935, B-30936, B-30937, and B-50046, as well as variants and fragments thereof. Nucleotide sequences that are complementary to a nucleotide sequence of the invention, or that hybridize to a sequence of the invention are also encompassed.
Methods are provided for producing the polypeptides of the invention, and for using those polypeptides for controlling or killing a lepidopteran or coleopteran pest. Methods and kits for detecting the nucleic acids and polypeptides of the invention in a sample are also included.
Methods for controlling or killing a nematode pest population are further provided. The methods comprise introducing into a plant a polynucleotide encoding a nematode-active polypeptide with a molecular size greater than 22 kDa. These nematode-active polypeptides are useful for controlling or killing plant-parasitic nematodes, particularly cyst nematodes.
The compositions and methods of the invention are useful for the production of organisms with pesticide resistance, specifically bacteria and plants. These organisms and compositions derived from them are desirable for agricultural purposes. The compositions of the invention are also useful for generating altered or improved delta-endotoxin proteins that have pesticidal activity, or for detecting the presence of delta-endotoxin proteins or nucleic acids in products or organisms.


DETAILED DESCRIPTION
The present invention is drawn to compositions and methods for regulating pest resistance in organisms, particularly plants or plant cells. The methods involve transforming organisms with a nucleotide sequence encoding a delta-endotoxin protein of the invention. In particular, the nucleotide sequences of the invention are useful for preparing plants and microorganisms that possess pesticidal activity. Thus, transformed bacteria, plants, plant cells, plant tissues and seeds are provided. Compositions are delta-endotoxin nucleic acids and proteins of Bacillus thuringiensis. The sequences find use in the construction of expression vectors for subsequent transformation into organisms of interest, as probes for the isolation of other delta-endotoxin genes, and for the generation of altered pesticidal proteins by methods known in the art, such as domain swapping or DNA shuffling. The proteins find use in controlling or killing lepidopteran, coleopteran, and nematode pest populations, and for producing compositions with pesticidal activity.
Plasmids containing the nucleotide sequences of the invention were deposited in the permanent collection of the Agricultural Research Service Culture Collection, Northern Regional Research Laboratory (NRRL), 1815 North University Street, Peoria, Ill. 61604, United States of America, on Jun. 9, 2006, and assigned Accession Nos. NRRL B-30935 (for axmi-031), NRRL B-30936 (for axmi-039), and NRRL B-30937 (for axmi-040); and on May 29, 2007 and assigned NRRL B-50046 (axmi-049). These deposits will be maintained under the terms of the Budapest Treaty on the International Recognition of the Deposit of Microorganisms for the Purposes of Patent Procedure. These deposits were made merely as a convenience for those of skill in the art and are not an admission that a deposit is required under 35 U.S.C. §112.
By “delta-endotoxin” is intended a toxin from Bacillus thuringiensis that has toxic activity against one or more pests, including, but not limited to, members of the Lepidoptera, Diptera, and Coleoptera orders or members of the Nematoda phylum, or a protein that has homology to such a protein. In some cases, delta-endotoxin proteins have been isolated from other organisms, including Clostridium bifermentans and Paenibacillus popilliae. Delta-endotoxin proteins include amino acid sequences deduced from the full-length nucleotide sequences disclosed herein, and amino acid sequences that are shorter than the full-length sequences, either due to the use of an alternate downstream start site, or due to processing that produces a shorter protein having pesticidal activity. Processing may occur in the organism the protein is expressed in, or in the pest after ingestion of the protein. Delta-endotoxins include proteins identified as cryl through cry43, cyt1 and cyt2, and Cyt-like toxin. There are currently over 250 known species of delta-endotoxins with a wide range of specificities and toxicities. For an expansive list see Crickmore et al. (1998), Microbiol. Mol. Biol. Rev. 62:807-813, and for regular updates see Crickmore et al. (2003) “Bacillus thuringiensis toxin nomenclature,” at www.biols.susx.ac.uk/Home/Neil_Crickmore/Bt/index.
Provided herein are novel isolated nucleotide sequences that confer pesticidal activity. Also provided are the amino acid sequences of the delta-endotoxin proteins. The protein resulting from translation of this gene allows cells to control or kill pests that ingest it.
Isolated Nucleic Acid Molecules, and Variants and Fragments Thereof
One aspect of the invention pertains to isolated or recombinant nucleic acid molecules comprising nucleotide sequences encoding delta-endotoxin proteins and polypeptides or biologically active portions thereof, as well as nucleic acid molecules sufficient for use as hybridization probes to identify delta-endotoxin encoding nucleic acids. As used herein, the term “nucleic acid molecule” is intended to include DNA molecules (e.g., recombinant DNA, cDNA or genomic DNA) and RNA molecules (e.g., mRNA) and analogs of the DNA or RNA generated using nucleotide analogs. The nucleic acid molecule can be single-stranded or double-stranded, but preferably is double-stranded DNA.
An “isolated” or “purified” nucleic acid molecule or protein, or biologically active portion thereof, is substantially free of other cellular material, or culture medium when produced by recombinant techniques, or substantially free of chemical precursors or other chemicals when chemically synthesized. Preferably, an “isolated” nucleic acid is free of sequences (preferably protein encoding sequences) that naturally flank the nucleic acid (i.e., sequences located at the 5′ and 3′ ends of the nucleic acid) in the genomic DNA of the organism from which the nucleic acid is derived. For purposes of the invention, “isolated” when used to refer to nucleic acid molecules excludes isolated chromosomes. For example, in various embodiments, the isolated delta-endotoxin encoding nucleic acid molecule can contain less than about 5 kb, 4 kb, 3 kb, 2 kb, 1 kb, 0.5 kb, or 0.1 kb of nucleotide sequences that naturally flank the nucleic acid molecule in genomic DNA of the cell from which the nucleic acid is derived. A delta-endotoxin protein that is substantially free of cellular material includes preparations of protein having less than about 30%, 20%, 10%, or 5% (by dry weight) of non-delta-endotoxin protein (also referred to herein as a “contaminating protein”).
Nucleotide sequences encoding the proteins of the present invention include the sequence set forth in SEQ ID NO:1, 3, 5, 34, and 37, the delta endotoxin nucleotide sequences deposited in bacterial hosts as Accession Nos. NRRL B-30935, B-30936, B-30937, and B-50046, and variants, fragments, and complements thereof (for example, SEQ ID NO:7, 9, 11, 14, 16, 18, 20, 22, 24, 26, 28, 30, and 32). By “complement” is intended a nucleotide sequence that is sufficiently complementary to a given nucleotide sequence such that it can hybridize to the given nucleotide sequence to thereby form a stable duplex. The corresponding amino acid sequence for the delta-endotoxin protein encoded by this nucleotide sequence are set forth in SEQ ID NO:2, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, and 37.
Nucleic acid molecules that are fragments of these delta-endotoxin encoding nucleotide sequences are also encompassed by the present invention (for example, SEQ ID NO:9, 11, 14, 18, 20, 22, and 24). By “fragment” is intended a portion of the nucleotide sequence encoding a delta-endotoxin protein. A fragment of a nucleotide sequence may encode a biologically active portion of a delta-endotoxin protein, or it may be a fragment that can be used as a hybridization probe or PCR primer using methods disclosed below. Nucleic acid molecules that are fragments of a delta-endotoxin nucleotide sequence comprise at least about 50, 100, 200, 300, 400, 500, 600, 700, 800, 900, 1000, 1050, 1100, 1150, 1200, 1250, 1300, 1350, 1400, 1450, 1500, 1550, 1600, 1650, 1700, 1750, 1800, 1850, 1900, 1950, 2000, 2050, 2100, 2150, 2200, 2250, 2300, 2350, 2400, 2450, 2500, 2550, 2600, 2650, 2700, 2750, 2800, 2850, 2900, 2950, 3000, 3050, 3100, 3150, 3200, 3250, 3300, 3350 contiguous nucleotides, or up to the number of nucleotides present in a full-length delta-endotoxin encoding nucleotide sequence disclosed herein (for example, 3558 nucleotides for SEQ ID NO:1, 3984 nucleotides for SEQ ID NO:3, 3720 nucleotides for SEQ ID NO:5, and 3669 nucleotides for SEQ ID NO:34) depending upon the intended use. By “contiguous” nucleotides is intended nucleotide residues that are immediately adjacent to one another. Fragments of the nucleotide sequences of the present invention will encode protein fragments that retain the biological activity of the delta-endotoxin protein and, hence, retain pesticidal activity. By “retains activity” is intended that the fragment will have at least about 30%, at least about 50%, at least about 70%, 80%, 90%, 95% or higher of the pesticidal activity of the delta-endotoxin protein. Methods for measuring pesticidal activity are well known in the art. See, for example, Czapla and Lang (1990) J. Econ. Entomol. 83:2480-2485; Andrews et al. (1988) Biochem. J. 252:199-206; Marrone et al. (1985) J. of Economic Entomology 78:290-293; and U.S. Pat. No. 5,743,477, all of which are herein incorporated by reference in their entirety.
A fragment of a delta-endotoxin encoding nucleotide sequence that encodes a biologically active portion of a protein of the invention will encode at least about 15, 25, 30, 50, 75, 100, 125, 150, 175, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1050, 1100 contiguous amino acids, or up to the total number of amino acids present in a full-length delta-endotoxin protein of the invention (for example, 1185 amino acids for SEQ ID NO:2, 1327 amino acids for SEQ ID NO:4, 1239 amino acids for SEQ ID NO:6, and 1223 amino acids for SEQ ID NO:35).
Preferred delta-endotoxin proteins of the present invention are encoded by a nucleotide sequence sufficiently identical to the nucleotide sequence of SEQ ID NO:1, 3, 5, 7, 9, 11, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, or 37. By “sufficiently identical” is intended an amino acid or nucleotide sequence that has at least about 60% or 65% sequence identity, about 70% or 75% sequence identity, about 80% or 85% sequence identity, about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or greater sequence identity compared to a reference sequence using one of the alignment programs described herein using standard parameters. One of skill in the art will recognize that these values can be appropriately adjusted to determine corresponding identity of proteins encoded by two nucleotide sequences by taking into account codon degeneracy, amino acid similarity, reading frame positioning, and the like.
To determine the percent identity of two amino acid sequences or of two nucleic acids, the sequences are aligned for optimal comparison purposes. The percent identity between the two sequences is a function of the number of identical positions shared by the sequences (i.e., percent identity=number of identical positions/total number of positions (e.g., overlapping positions)×100). In one embodiment, the two sequences are the same length. The percent identity between two sequences can be determined using techniques similar to those described below, with or without allowing gaps. In calculating percent identity, typically exact matches are counted.
The determination of percent identity between two sequences can be accomplished using a mathematical algorithm. A nonlimiting example of a mathematical algorithm utilized for the comparison of two sequences is the algorithm of Karlin and Altschul (1990) Proc. Natl. Acad. Sci. USA 87:2264, modified as in Karlin and Altschul (1993) Proc. Natl. Acad. Sci. USA 90:5873-5877. Such an algorithm is incorporated into the BLASTN and BLASTX programs of Altschul et al. (1990) J. Mol. Biol. 215:403. BLAST nucleotide searches can be performed with the BLASTN program, score=100, wordlength=12, to obtain nucleotide sequences homologous to delta-endotoxin-like nucleic acid molecules of the invention. BLAST protein searches can be performed with the BLASTX program, score=50, wordlength=3, to obtain amino acid sequences homologous to delta-endotoxin protein molecules of the invention. To obtain gapped alignments for comparison purposes, Gapped BLAST (in BLAST 2.0) can be utilized as described in Altschul et al. (1997) Nucleic Acids Res. 25:3389. Alternatively, PSI-Blast can be used to perform an iterated search that detects distant relationships between molecules. See Altschul et al. (1997) supra. When utilizing BLAST, Gapped BLAST, and PSI-Blast programs, the default parameters of the respective programs (e.g., BLASTX and BLASTN) can be used. Alignment may also be performed manually by inspection.
Another non-limiting example of a mathematical algorithm utilized for the comparison of sequences is the ClustalW algorithm (Higgins et al. (1994) Nucleic Acids Res. 22:4673-4680). ClustalW compares sequences and aligns the entirety of the amino acid or DNA sequence, and thus can provide data about the sequence conservation of the entire amino acid sequence. The ClustalW algorithm is used in several commercially available DNA/amino acid analysis software packages, such as the ALIGNX module of the Vector NTI Program Suite (Invitrogen Corporation, Carlsbad, Calif.). After alignment of amino acid sequences with ClustalW, the percent amino acid identity can be assessed. A non-limiting example of a software program useful for analysis of ClustalW alignments is GENEDOCTM. GENEDOCTM (Karl Nicholas) allows assessment of amino acid (or DNA) similarity and identity between multiple proteins. Another non-limiting example of a mathematical algorithm utilized for the comparison of sequences is the algorithm of Myers and Miller (1988) CABIOS 4:11-17. Such an algorithm is incorporated into the ALIGN program (version 2.0), which is part of the GCG Wisconsin Genetics Software Package, Version 10 (available from Accelrys, Inc., 9685 Scranton Rd., San Diego, Calif., USA). When utilizing the ALIGN program for comparing amino acid sequences, a PAM120 weight residue table, a gap length penalty of 12, and a gap penalty of 4 can be used.
Unless otherwise stated, GAP Version 10, which uses the algorithm of Needleman and Wunsch (1970) J. Mol. Biol. 48(3):443-453, will be used to determine sequence identity or similarity using the following parameters: % identity and % similarity for a nucleotide sequence using GAP Weight of 50 and Length Weight of 3, and the nwsgapdna.cmp scoring matrix; % identity or % similarity for an amino acid sequence using GAP weight of 8 and length weight of 2, and the BLOSUM62 scoring program. Equivalent programs may also be used. By “equivalent program” is intended any sequence comparison program that, for any two sequences in question, generates an alignment having identical nucleotide residue matches and an identical percent sequence identity when compared to the corresponding alignment generated by GAP Version 10.
The invention also encompasses variant nucleic acid molecules (for example, SEQ ID NO:7, 9, 11, 16, 18, 22, 24, 26, 28, 30, and 32). “Variants” of the delta-endotoxin encoding nucleotide sequences include those sequences that encode the delta-endotoxin proteins disclosed herein but that differ conservatively because of the degeneracy of the genetic code as well as those that are sufficiently identical as discussed above. Naturally occurring allelic variants can be identified with the use of well-known molecular biology techniques, such as polymerase chain reaction (PCR) and hybridization techniques as outlined below. Variant nucleotide sequences also include synthetically derived nucleotide sequences that have been generated, for example, by using site-directed mutagenesis but which still encode the delta-endotoxin proteins disclosed in the present invention as discussed below. Variant proteins encompassed by the present invention are biologically active, that is they continue to possess the desired biological activity of the native protein, that is, retaining pesticidal activity. By “retains activity” is intended that the variant will have at least about 30%, at least about 50%, at least about 70%, or at least about 80% of the pesticidal activity of the native protein. Methods for measuring pesticidal activity are well known in the art. See, for example, Czapla and Lang (1990) J. Econ. Entomol. 83: 2480-2485; Andrews et al. (1988) Biochem. J. 252:199-206; Marrone et al. (1985) J. of Economic Entomology 78:290-293; and U.S. Pat. No. 5,743,477, all of which are herein incorporated by reference in their entirety.
The skilled artisan will further appreciate that changes can be introduced by mutation of the nucleotide sequences of the invention thereby leading to changes in the amino acid sequence of the encoded delta-endotoxin proteins, without altering the biological activity of the proteins. Thus, variant isolated nucleic acid molecules can be created by introducing one or more nucleotide substitutions, additions, or deletions into the corresponding nucleotide sequence disclosed herein, such that one or more amino acid substitutions, additions or deletions are introduced into the encoded protein. Mutations can be introduced by standard techniques, such as site-directed mutagenesis and PCR-mediated mutagenesis. Such variant nucleotide sequences are also encompassed by the present invention.
For example, conservative amino acid substitutions may be made at one or more predicted, nonessential amino acid residues. A “nonessential” amino acid residue is a residue that can be altered from the wild-type sequence of a delta-endotoxin protein without altering the biological activity, whereas an “essential” amino acid residue is required for biological activity. A “conservative amino acid substitution” is one in which the amino acid residue is replaced with an amino acid residue having a similar side chain. Families of amino acid residues having similar side chains have been defined in the art. These families include amino acids with basic side chains (e.g., lysine, arginine, histidine), acidic side chains (e.g., aspartic acid, glutamic acid), uncharged polar side chains (e.g., glycine, asparagine, glutamine, serine, threonine, tyrosine, cysteine), nonpolar side chains (e.g., alanine, valine, leucine, isoleucine, proline, phenylalanine, methionine, tryptophan), beta-branched side chains (e.g., threonine, valine, isoleucine) and aromatic side chains (e.g., tyrosine, phenylalanine, tryptophan, histidine).
Delta-endotoxins generally have five conserved sequence domains, and three conserved structural domains (see, for example, de Maagd et al. (2001) Trends Genetics 17:193-199). The first conserved structural domain consists of seven alpha helices and is involved in membrane insertion and pore formation. Domain II consists of three beta-sheets arranged in a Greek key configuration, and domain III consists of two antiparallel beta-sheets in “jelly-roll” formation (de Maagd et al., 2001, supra). Domains II and III are involved in receptor recognition and binding, and are therefore considered determinants of toxin specificity.
Amino acid substitutions may be made in nonconserved regions that retain function. In general, such substitutions would not be made for conserved amino acid residues, or for amino acid residues residing within a conserved motif, where such residues are essential for protein activity. Examples of residues that are conserved and that may be essential for protein activity include, for example, residues that are identical between all proteins contained in an alignment of the amino acid sequences of the present invention and known delta-endotoxin sequences. Examples of residues that are conserved but that may allow conservative amino acid substitutions and still retain activity include, for example, residues that have only conservative substitutions between all proteins contained in an alignment of the amino acid sequences of the present invention and known delta-endotoxin sequences. However, one of skill in the art would understand that functional variants may have minor conserved or nonconserved alterations in the conserved residues.
Alternatively, variant nucleotide sequences can be made by introducing mutations randomly along all or part of the coding sequence, such as by saturation mutagenesis, and the resultant mutants can be screened for ability to confer delta-endotoxin activity to identify mutants that retain activity. Following mutagenesis, the encoded protein can be expressed recombinantly, and the activity of the protein can be determined using standard assay techniques.
Using methods such as PCR, hybridization, and the like corresponding delta-endotoxin sequences can be identified, such sequences having substantial identity to the sequences of the invention. See, for example, Sambrook and Russell (2001) Molecular Cloning: A Laboratory Manual. (Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.) and Innis, et al. (1990) PCR Protocols: A Guide to Methods and Applications (Academic Press, NY).
In a hybridization method, all or part of the delta-endotoxin nucleotide sequence can be used to screen cDNA or genomic libraries. Methods for construction of such cDNA and genomic libraries are generally known in the art and are disclosed in Sambrook and Russell, 2001, supra. The so-called hybridization probes may be genomic DNA fragments, cDNA fragments, RNA fragments, or other oligonucleotides, and may be labeled with a detectable group such as 32P, or any other detectable marker, such as other radioisotopes, a fluorescent compound, an enzyme, or an enzyme co-factor. Probes for hybridization can be made by labeling synthetic oligonucleotides based on the known delta-endotoxin-encoding nucleotide sequence disclosed herein. Degenerate primers designed on the basis of conserved nucleotides or amino acid residues in the nucleotide sequence or encoded amino acid sequence can additionally be used. The probe typically comprises a region of nucleotide sequence that hybridizes under stringent conditions to at least about 12, at least about 25, at least about 50, 75, 100, 125, 150, 175, 200, 250, 300, 350, or 400 consecutive nucleotides of delta-endotoxin encoding nucleotide sequence of the invention or a fragment or variant thereof. Methods for the preparation of probes for hybridization are generally known in the art and are disclosed in Sambrook and Russell, 2001, supra herein incorporated by reference.
For example, an entire delta-endotoxin sequence disclosed herein, or one or more portions thereof, may be used as a probe capable of specifically hybridizing to corresponding delta-endotoxin-like sequences and messenger RNAs. To achieve specific hybridization under a variety of conditions, such probes include sequences that are unique and are preferably at least about 10 nucleotides in length, or at least about 20 nucleotides in length. Such probes may be used to amplify corresponding delta-endotoxin sequences from a chosen organism by PCR. This technique may be used to isolate additional coding sequences from a desired organism or as a diagnostic assay to determine the presence of coding sequences in an organism. Hybridization techniques include hybridization screening of plated DNA libraries (either plaques or colonies; see, for example, Sambrook et al. (1989) Molecular Cloning: A Laboratory Manual (2d ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.).
Hybridization of such sequences may be carried out under stringent conditions. By “stringent conditions” or “stringent hybridization conditions” is intended conditions under which a probe will hybridize to its target sequence to a detectably greater degree than to other sequences (e.g., at least 2-fold over background). Stringent conditions are sequence-dependent and will be different in different circumstances. By controlling the stringency of the hybridization and/or washing conditions, target sequences that are 100% complementary to the probe can be identified (homologous probing). Alternatively, stringency conditions can be adjusted to allow some mismatching in sequences so that lower degrees of similarity are detected (heterologous probing). Generally, a probe is less than about 1000 nucleotides in length, preferably less than 500 nucleotides in length.
Typically, stringent conditions will be those in which the salt concentration is less than about 1.5 M Na ion, typically about 0.01 to 1.0 M Na ion concentration (or other salts) at pH 7.0 to 8.3 and the temperature is at least about 30° C. for short probes (e.g., 10 to 50 nucleotides) and at least about 60° C. for long probes (e.g., greater than 50 nucleotides). Stringent conditions may also be achieved with the addition of destabilizing agents such as formamide. Exemplary low stringency conditions include hybridization with a buffer solution of 30 to 35% formamide, 1 M NaCl, 1% SDS (sodium dodecyl sulphate) at 37° C., and a wash in 1× to 2×SSC (20×SSC=3.0 M NaCl/0.3 M trisodium citrate) at 50 to 55° C. Exemplary moderate stringency conditions include hybridization in 40 to 45% formamide, 1.0 M NaCl, 1% SDS at 37° C., and a wash in 0.5× to 1×SSC at 55 to 60° C. Exemplary high stringency conditions include hybridization in 50% formamide, 1 M NaCl, 1% SDS at 37° C., and a wash in 0.1×SSC at 60 to 65° C. Optionally, wash buffers may comprise about 0.1% to about 1% SDS. Duration of hybridization is generally less than about 24 hours, usually about 4 to about 12 hours.
Specificity is typically the function of post-hybridization washes, the critical factors being the ionic strength and temperature of the final wash solution. For DNA-DNA hybrids, the Tm can be approximated from the equation of Meinkoth and Wahl (1984) Anal. Biochem. 138:267-284: Tm=81.5° C.+16.6 (log M)+0.41 (% GC)-0.61 (% form)-500/L; where M is the molarity of monovalent cations, % GC is the percentage of guanosine and cytosine nucleotides in the DNA, % form is the percentage of formamide in the hybridization solution, and L is the length of the hybrid in base pairs. The Tm is the temperature (under defined ionic strength and pH) at which 50% of a complementary target sequence hybridizes to a perfectly matched probe. Tm is reduced by about 1° C. for each 1% of mismatching; thus, Tm, hybridization, and/or wash conditions can be adjusted to hybridize to sequences of the desired identity. For example, if sequences with ≧90% identity are sought, the Tm can be decreased 10° C. Generally, stringent conditions are selected to be about 5° C. lower than the thermal melting point (Tm) for the specific sequence and its complement at a defined ionic strength and pH. However, severely stringent conditions can utilize a hybridization and/or wash at 1, 2, 3, or 4° C. lower than the thermal melting point (Tm); moderately stringent conditions can utilize a hybridization and/or wash at 6, 7, 8, 9, or 10° C. lower than the thermal melting point (Tm); low stringency conditions can utilize a hybridization and/or wash at 11, 12, 13, 14, 15, or 20° C. lower than the thermal melting point (Tm). Using the equation, hybridization and wash compositions, and desired Tm, those of ordinary skill will understand that variations in the stringency of hybridization and/or wash solutions are inherently described. If the desired degree of mismatching results in a Tm of less than 45° C. (aqueous solution) or 32° C. (formamide solution), it is preferred to increase the SSC concentration so that a higher temperature can be used. An extensive guide to the hybridization of nucleic acids is found in Tijssen (1993) Laboratory Techniques in Biochemistry and Molecular Biology—Hybridization with Nucleic Acid Probes, Part I, Chapter 2 (Elsevier, N.Y.); and Ausubel et al., eds. (1995) Current Protocols in Molecular Biology, Chapter 2 (Greene Publishing and Wiley-Interscience, New York). See Sambrook et al. (1989) Molecular Cloning: A Laboratory Manual (2d ed., Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.).
Isolated Proteins and Variants and Fragments Thereof
Delta-endotoxin proteins are also encompassed within the present invention. By “delta-endotoxin protein” is intended a protein having the amino acid sequence set forth in SEQ ID NO:2, 4, 6, 8, 10, 12, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, or 38. Fragments, biologically active portions, and variants thereof are also provided, and may be used to practice the methods of the present invention.
“Fragments” or “biologically active portions” include polypeptide fragments comprising amino acid sequences sufficiently identical to the amino acid sequence set forth in SEQ ID NO:2, 4, 6, 8, 10, 12, 16, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, or 38 and that exhibit pesticidal activity (for example, SEQ ID NO:15, 19, 21, 23, or 25). A biologically active portion of a delta-endotoxin protein can be a polypeptide that is, for example, 10, 25, 50, 100 or more amino acids in length. Such biologically active portions can be prepared by recombinant techniques and evaluated for pesticidal activity. Methods for measuring pesticidal activity are well known in the art. See, for example, Czapla and Lang (1990) J. Econ. Entomol. 83:2480-2485; Andrews et al. (1988) Biochem. J. 252:199-206; Marrone et al. (1985) J. of Economic Entomology 78:290-293; and U.S. Pat. No. 5,743,477, all of which are herein incorporated by reference in their entirety. As used here, a fragment comprises at least 8 contiguous amino acids of SEQ ID NO:2, 4, 6, 8, 10, 12, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, or 38. The invention encompasses other fragments, however, such as any fragment in the protein greater than about 10, 20, 30, 50, 100, 150, 200, 250, 300, 350, 400, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1000, 1050, 1100, 1150, 1200, 1250, or 1300 amino acids.
By “variants” is intended proteins or polypeptides having an amino acid sequence that is at least about 60%, 65%, about 70%, 75%, about 80%, 85%, about 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98% or 99% identical to the amino acid sequence of SEQ ID NO:2, 4, 6, 8, 10, 12, 16, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, or 38 (e.g., SEQ ID NO:10, 12, 17, 19, 23, 25, 27, 29, 31, or 33). Variants also include polypeptides encoded by a nucleic acid molecule that hybridizes to the nucleic acid molecule of SEQ ID NO:1, 3, 5, 7, 9, 11, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, or 37, or a complement thereof, under stringent conditions. Variants include polypeptides that differ in amino acid sequence due to mutagenesis. Variant proteins encompassed by the present invention are biologically active, that is they continue to possess the desired biological activity of the native protein, that is, retaining pesticidal activity. Methods for measuring pesticidal activity are well known in the art. See, for example, Czapla and Lang (1990) J. Econ. Entomol. 83:2480-2485; Andrews et al. (1988) Biochem. J. 252:199-206; Marrone et al. (1985) J. of Economic Entomology 78:290-293; and U.S. Pat. No. 5,743,477, all of which are herein incorporated by reference in their entirety.
Bacterial genes, such as the axmi-031, axmi-039, axmi-040, and axmi-049 genes of this invention, quite often possess multiple methionine initiation codons in proximity to the start of the open reading frame. Often, translation initiation at one or more of these start codons will lead to generation of a functional protein. These start codons can include ATG codons. However, bacteria such as Bacillus sp. also recognize the codon GTG as a start codon, and proteins that initiate translation at GTG codons contain a methionine at the first amino acid. Furthermore, it is not often determined a priori which of these codons are used naturally in the bacterium. Thus, it is understood that use of one of the alternate methionine codons may also lead to generation of delta-endotoxin proteins that encode pesticidal activity. These delta-endotoxin proteins are encompassed in the present invention and may be used in the methods of the present invention.
Antibodies to the polypeptides of the present invention, or to variants or fragments thereof, are also encompassed. Methods for producing antibodies are well known in the art (see, for example, Harlow and Lane (1988) Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory, Cold Spring Harbor, N.Y.; U.S. Pat. No. 4,196,265).
Altered or Improved Variants
It is recognized that DNA sequences of a delta-endotoxin may be altered by various methods, and that these alterations may result in DNA sequences encoding proteins with amino acid sequences different than that encoded by a delta-endotoxin of the present invention. This protein may be altered in various ways including amino acid substitutions, deletions, truncations, and insertions of one or more amino acids of SEQ ID NO:2, 4, 6, 8, 10, 12, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, or 38, including up to about 2, about 3, about 4, about 5, about 6, about 7, about 8, about 9, about 10, about 15, about 20, about 25, about 30, about 35, about 40, about 45, about 50, about 55, about 60, about 65, about 70, about 75, about 80, about 85, about 90, about 100, about 105, about 110, about 115, about 120, about 125, about 130 or more amino acid substitutions, deletions or insertions.
Methods for such manipulations are generally known in the art. For example, amino acid sequence variants of a delta-endotoxin protein can be prepared by mutations in the DNA. This may also be accomplished by one of several forms of mutagenesis and/or in directed evolution. In some aspects, the changes encoded in the amino acid sequence will not substantially affect the function of the protein. Such variants will possess the desired pesticidal activity. However, it is understood that the ability of a delta-endotoxin to confer pesticidal activity may be improved by the use of such techniques upon the compositions of this invention. For example, one may express a delta-endotoxin in host cells that exhibit high rates of base misincorporation during DNA replication, such as XL-1 Red (Stratagene). After propagation in such strains, one can isolate the delta-endotoxin DNA (for example by preparing plasmid DNA, or by amplifying by PCR and cloning the resulting PCR fragment into a vector), culture the delta-endotoxin mutations in a non-mutagenic strain, and identify mutated delta-endotoxin genes with pesticidal activity, for example by performing an assay to test for pesticidal activity. Generally, the protein is mixed and used in feeding assays. See, for example Marrone et al. (1985) J. of Economic Entomology 78:290-293. Such assays can include contacting plants with one or more pests and determining the plant's ability to survive and/or cause the death of the pests. Examples of mutations that result in increased toxicity are found in Schnepf et al. (1998) Microbiol. Mol. Biol. Rev. 62:775-806.
Alternatively, alterations may be made to the protein sequence of many proteins at the amino or carboxy terminus without substantially affecting activity. This can include insertions, deletions, or alterations introduced by modern molecular methods, such as PCR, including PCR amplifications that alter or extend the protein coding sequence by virtue of inclusion of amino acid encoding sequences in the oligonucleotides utilized in the PCR amplification. Alternatively, the protein sequences added can include entire protein-coding sequences, such as those used commonly in the art to generate protein fusions. Such fusion proteins are often used to (1) increase expression of a protein of interest (2) introduce a binding domain, enzymatic activity, or epitope to facilitate either protein purification, protein detection, or other experimental uses known in the art (3) target secretion or translation of a protein to a subcellular organelle, such as the periplasmic space of Gram-negative bacteria, or the endoplasmic reticulum of eukaryotic cells, the latter of which often results in glycosylation of the protein.
Variant nucleotide and amino acid sequences of the present invention also encompass sequences derived from mutagenic and recombinogenic procedures such as DNA shuffling. With such a procedure, one or more different delta-endotoxin protein coding regions can be used to create a new delta-endotoxin protein possessing the desired properties. In this manner, libraries of recombinant polynucleotides are generated from a population of related sequence polynucleotides comprising sequence regions that have substantial sequence identity and can be homologously recombined in vitro or in vivo. For example, using this approach, sequence motifs encoding a domain of interest may be shuffled between a delta-endotoxin gene of the invention and other known delta-endotoxin genes to obtain a new gene coding for a protein with an improved property of interest, such as an increased insecticidal activity. Strategies for such DNA shuffling are known in the art. See, for example, Stemmer (1994) Proc. Natl. Acad. Sci. USA 91:10747-10751; Stemmer (1994) Nature 370:389-391; Crameri et al. (1997) Nature Biotech. 15:436-438; Moore et al. (1997) J. Mol. Biol. 272:336-347; Zhang et al. (1997) Proc. Natl. Acad. Sci. USA 94:4504-4509; Crameri et al. (1998) Nature 391:288-291; and U.S. Pat. Nos. 5,605,793 and 5,837,458.
Domain swapping or shuffling is another mechanism for generating altered delta-endotoxin proteins. Domains II and III may be swapped between delta-endotoxin proteins, resulting in hybrid or chimeric toxins with improved pesticidal activity or target spectrum. Methods for generating recombinant proteins and testing them for pesticidal activity are well known in the art (see, for example, Naimov et al. (2001) Appl. Environ. Microbiol. 67:5328-5330; de Maagd et al. (1996) Appl. Environ. Microbiol. 62:1537-1543; Ge et al. (1991) J. Biol. Chem. 266:17954-17958; Schnepf et al. (1990) J. Biol. Chem. 265:20923-20930; Rang et al. 91999) Appl. Environ. Microbiol. 65:2918-2925).
Vectors
A delta-endotoxin sequence of the invention may be provided in an expression cassette for expression in a plant of interest. By “plant expression cassette” is intended a DNA construct that is capable of resulting in the expression of a protein from an open reading frame in a plant cell. Typically these contain a promoter and a coding sequence. Often, such constructs will also contain a 3′ untranslated region. Such constructs may contain a “signal sequence” or “leader sequence” (i.e., SEQ ID NO:9, 11, 28, 30, and 32) to facilitate co-translational or post-translational transport of the peptide to certain intracellular structures such as the chloroplast (or other plastid), endoplasmic reticulum, or Golgi apparatus.
By “signal sequence” is intended a sequence that is known or suspected to result in cotranslational or post-translational peptide transport across the cell membrane. In eukaryotes, this typically involves secretion into the Golgi apparatus, with some resulting glycosylation. By “leader sequence” is intended any sequence that when translated, results in an amino acid sequence (i.e., SEQ ID NO:10, 12, 29, 31, and 33) sufficient to trigger co-translational transport of the peptide chain to a sub-cellular organelle. Thus, this includes leader sequences targeting transport and/or glycosylation by passage into the endoplasmic reticulum, passage to vacuoles, plastids including chloroplasts, mitochondria, and the like.
By “plant transformation vector” is intended a DNA molecule that is necessary for efficient transformation of a plant cell. Such a molecule may consist of one or more plant expression cassettes, and may be organized into more than one “vector” DNA molecule. For example, binary vectors are plant transformation vectors that utilize two non-contiguous DNA vectors to encode all requisite cis- and trans-acting functions for transformation of plant cells (Hellens and Mullineaux (2000) Trends in Plant Science 5:446-451). “Vector” refers to a nucleic acid construct designed for transfer between different host cells. “Expression vector” refers to a vector that has the ability to incorporate, integrate and express heterologous DNA sequences or fragments in a foreign cell. The cassette will include 5′ and 3′ regulatory sequences operably linked to a sequence of the invention. By “operably linked” is intended a functional linkage between a promoter and a second sequence, wherein the promoter sequence initiates and mediates transcription of the DNA sequence corresponding to the second sequence. Generally, operably linked means that the nucleic acid sequences being linked are contiguous and, where necessary to join two protein coding regions, contiguous and in the same reading frame. The cassette may additionally contain at least one additional gene to be cotransformed into the organism. Alternatively, the additional gene(s) can be provided on multiple expression cassettes.
“Promoter” refers to a nucleic acid sequence that functions to direct transcription of a downstream coding sequence. The promoter together with other transcriptional and translational regulatory nucleic acid sequences (also termed “control sequences”) are necessary for the expression of a DNA sequence of interest.
Such an expression cassette is provided with a plurality of restriction sites for insertion of the delta-endotoxin sequence to be under the transcriptional regulation of the regulatory regions.
The expression cassette will include in the 5′-3′ direction of transcription, a transcriptional and translational initiation region (i.e., a promoter), a DNA sequence of the invention, and a translational and transcriptional termination region (i.e., termination region) functional in plants. The promoter may be native or analogous, or foreign or heterologous, to the plant host and/or to the DNA sequence of the invention. Additionally, the promoter may be the natural sequence or alternatively a synthetic sequence. Where the promoter is “native” or “homologous” to the plant host, it is intended that the promoter is found in the native plant into which the promoter is introduced. Where the promoter is “foreign” or “heterologous” to the DNA sequence of the invention, it is intended that the promoter is not the native or naturally occurring promoter for the operably linked DNA sequence of the invention.
The termination region may be native with the transcriptional initiation region, may be native with the operably linked DNA sequence of interest, may be native with the plant host, or may be derived from another source (i.e., foreign or heterologous to the promoter, the DNA sequence of interest, the plant host, or any combination thereof). Convenient termination regions are available from the Ti-plasmid of A. tumefaciens, such as the octopine synthase and nopaline synthase termination regions. See also Guerineau et al. (1991) Mol. Gen. Genet. 262:141-144; Proudfoot (1991) Cell 64:671-674; Sanfacon et al. (1991) Genes Dev. 5:141-149; Mogen et al. (1990) Plant Cell 2:1261-1272; Munroe et al. (1990) Gene 91:151-158; Ballas et al. (1989) Nucleic Acids Res. 17:7891-7903; and Joshi et al. (1987) Nucleic Acid Res. 15:9627-9639.
Where appropriate, the gene(s) may be optimized for increased expression in the transformed host cell. That is, the genes can be synthesized using host cell-preferred codons for improved expression, or may be synthesized using codons at a host-preferred codon usage frequency. Generally, the GC content of the gene will be increased. See, for example, Campbell and Gowri (1990) Plant Physiol. 92:1-11 for a discussion of host-preferred codon usage. Methods are available in the art for synthesizing plant-preferred genes. See, for example, U.S. Pat. Nos. 5,380,831, and 5,436,391, and Murray et al. (1989) Nucleic Acids Res. 17:477-498, herein incorporated by reference.
In one embodiment, the delta-endotoxin is targeted to the chloroplast for expression. In this manner, where the delta-endotoxin is not directly inserted into the chloroplast, the expression cassette will additionally contain a nucleic acid encoding a transit peptide to direct the delta-endotoxin to the chloroplasts. Such transit peptides are known in the art. See, for example, Von Heijne et al. (1991) Plant Mol. Biol. Rep. 9:104-126; Clark et al. (1989) J. Biol. Chem. 264:17544-17550; Della-Cioppa et al. (1987) Plant Physiol. 84:965-968; Romer et al. (1993) Biochem. Biophys. Res. Commun. 196:1414-1421; and Shah et al. (1986) Science 233:478-481.
The delta-endotoxin gene to be targeted to the chloroplast may be optimized for expression in the chloroplast to account for differences in codon usage between the plant nucleus and this organelle. In this manner, the nucleic acids of interest may be synthesized using chloroplast-preferred codons. See, for example, U.S. Pat. No. 5,380,831, herein incorporated by reference.
Plant Transformation
Methods of the invention involve introducing a nucleotide construct into a plant. By “introducing” is intended to present to the plant the nucleotide construct in such a manner that the construct gains access to the interior of a cell of the plant. The methods of the invention do not require that a particular method for introducing a nucleotide construct to a plant is used, only that the nucleotide construct gains access to the interior of at least one cell of the plant. Methods for introducing nucleotide constructs into plants are known in the art including, but not limited to, stable transformation methods, transient transformation methods, and virus-mediated methods.
By “plant” is intended whole plants, plant organs (e.g., leaves, stems, roots, etc.), seeds, plant cells, propagules, embryos and progeny of the same. Plant cells can be differentiated or undifferentiated (e.g. callus, suspension culture cells, protoplasts, leaf cells, root cells, phloem cells, pollen).
“Transgenic plants” or “transformed plants” or “stably transformed” plants or cells or tissues refers to plants that have incorporated or integrated exogenous nucleic acid sequences or DNA fragments into the plant cell. These nucleic acid sequences include those that are exogenous, or not present in the untransformed plant cell, as well as those that may be endogenous, or present in the untransformed plant cell.
“Heterologous” generally refers to the nucleic acid sequences that are not endogenous to the cell or part of the native genome in which they are present, and have been added to the cell by infection, transfection, microinjection, electroporation, microprojection, or the like.
Transformation of plant cells can be accomplished by one of several techniques known in the art. The delta-endotoxin gene of the invention may be modified to obtain or enhance expression in plant cells. Typically a construct that expresses such a protein would contain a promoter to drive transcription of the gene, as well as a 3′ untranslated region to allow transcription termination and polyadenylation. The organization of such constructs is well known in the art. In some instances, it may be useful to engineer the gene such that the resulting peptide is secreted, or otherwise targeted within the plant cell. For example, the gene can be engineered to contain a signal peptide to facilitate transfer of the peptide to the endoplasmic reticulum. It may also be preferable to engineer the plant expression cassette to contain an intron, such that mRNA processing of the intron is required for expression.
Typically this “plant expression cassette” will be inserted into a “plant transformation vector”. This plant transformation vector may be comprised of one or more DNA vectors needed for achieving plant transformation. For example, it is a common practice in the art to utilize plant transformation vectors that are comprised of more than one contiguous DNA segment. These vectors are often referred to in the art as “binary vectors”. Binary vectors as well as vectors with helper plasmids are most often used for Agrobacterium-mediated transformation, where the size and complexity of DNA segments needed to achieve efficient transformation is quite large, and it is advantageous to separate functions onto separate DNA molecules. Binary vectors typically contain a plasmid vector that contains the cis-acting sequences required for T-DNA transfer (such as left border and right border), a selectable marker that is engineered to be capable of expression in a plant cell, and a “gene of interest” (a gene engineered to be capable of expression in a plant cell for which generation of transgenic plants is desired). Also present on this plasmid vector are sequences required for bacterial replication. The cis-acting sequences are arranged in a fashion to allow efficient transfer into plant cells and expression therein. For example, the selectable marker gene and the delta-endotoxin are located between the left and right borders. Often a second plasmid vector contains the trans-acting factors that mediate T-DNA transfer from Agrobacterium to plant cells. This plasmid often contains the virulence functions (Vir genes) that allow infection of plant cells by Agrobacterium, and transfer of DNA by cleavage at border sequences and vir-mediated DNA transfer, as is understood in the art (Hellens and Mullineaux (2000) Trends in Plant Science 5:446-451). Several types of Agrobacterium strains (e.g. LBA4404, GV3101, EHA101, EHA105, etc.) can be used for plant transformation. The second plasmid vector is not necessary for transforming the plants by other methods such as microprojection, microinjection, electroporation, polyethylene glycol, etc.
In general, plant transformation methods involve transferring heterologous DNA into target plant cells (e.g. immature or mature embryos, suspension cultures, undifferentiated callus, protoplasts, etc.), followed by applying a maximum threshold level of appropriate selection (depending on the selectable marker gene) to recover the transformed plant cells from a group of untransformed cell mass. Explants are typically transferred to a fresh supply of the same medium and cultured routinely. Subsequently, the transformed cells are differentiated into shoots after placing on regeneration medium supplemented with a maximum threshold level of selecting agent. The shoots are then transferred to a selective rooting medium for recovering rooted shoot or plantlet. The transgenic plantlet then grows into a mature plant and produces fertile seeds (e.g. Hiei et al. (1994) The Plant Journal 6:271-282; Ishida et al. (1996) Nature Biotechnology 14:745-750). Explants are typically transferred to a fresh supply of the same medium and cultured routinely. A general description of the techniques and methods for generating transgenic plants are found in Ayres and Park (1994) Critical Reviews in Plant Science 13:219-239 and Bommineni and Jauhar (1997) Maydica 42:107-120. Since the transformed material contains many cells; both transformed and non-transformed cells are present in any piece of subjected target callus or tissue or group of cells. The ability to kill non-transformed cells and allow transformed cells to proliferate results in transformed plant cultures. Often, the ability to remove non-transformed cells is a limitation to rapid recovery of transformed plant cells and successful generation of transgenic plants.
Transformation protocols as well as protocols for introducing nucleotide sequences into plants may vary depending on the type of plant or plant cell, i.e., monocot or dicot, targeted for transformation. Generation of transgenic plants may be performed by one of several methods, including, but not limited to, microinjection, electroporation, direct gene transfer, introduction of heterologous DNA by Agrobacterium into plant cells (Agrobacterium-mediated transformation), bombardment of plant cells with heterologous foreign DNA adhered to particles, ballistic particle acceleration, aerosol beam transformation (U.S. Published Application No. 20010026941; U.S. Pat. No. 4,945,050; International Publication No. WO 91/00915; U.S. Published Application No. 2002015066), Lec1 transformation, and various other non-particle direct-mediated methods to transfer DNA.
Methods for transformation of chloroplasts are known in the art. See, for example, Svab et al. (1990) Proc. Natl. Acad. Sci. USA 87:8526-8530; Svab and Maliga (1993) Proc. Natl. Acad. Sci. USA 90:913-917; Svab and Maliga (1993) EMBO J. 12:601-606. The method relies on particle gun delivery of DNA containing a selectable marker and targeting of the DNA to the plastid genome through homologous recombination. Additionally, plastid transformation can be accomplished by transactivation of a silent plastid-borne transgene by tissue-preferred expression of a nuclear-encoded and plastid-directed RNA polymerase. Such a system has been reported in McBride et al. (1994) Proc. Natl. Acad. Sci. USA 91:7301-7305.
Following integration of heterologous foreign DNA into plant cells, one then applies a maximum threshold level of appropriate selection in the medium to kill the untransformed cells and separate and proliferate the putatively transformed cells that survive from this selection treatment by transferring regularly to a fresh medium. By continuous passage and challenge with appropriate selection, one identifies and proliferates the cells that are transformed with the plasmid vector. Molecular and biochemical methods can then be used to confirm the presence of the integrated heterologous gene of interest into the genome of the transgenic plant.
The cells that have been transformed may be grown into plants in accordance with conventional ways. See, for example, McCormick et al. (1986) Plant Cell Reports 5:81-84. These plants may then be grown, and either pollinated with the same transformed strain or different strains, and the resulting hybrid having constitutive expression of the desired phenotypic characteristic identified. Two or more generations may be grown to ensure that expression of the desired phenotypic characteristic is stably maintained and inherited and then seeds harvested to ensure expression of the desired phenotypic characteristic has been achieved. In this manner, the present invention provides transformed seed (also referred to as “transgenic seed”) having a nucleotide construct of the invention, for example, an expression cassette of the invention, stably incorporated into their genome.
Evaluation of Plant Transformation
Following introduction of heterologous foreign DNA into plant cells, the transformation or integration of heterologous gene in the plant genome is confirmed by various methods such as analysis of nucleic acids, proteins and metabolites associated with the integrated gene.
PCR analysis is a rapid method to screen transformed cells, tissue or shoots for the presence of incorporated gene at the earlier stage before transplanting into the soil (Sambrook and Russell (2001) Molecular Cloning: A Laboratory Manual. Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.). PCR is carried out using oligonucleotide primers specific to the gene of interest or Agrobacterium vector background, etc.
Plant transformation may be confirmed by Southern blot analysis of genomic DNA (Sambrook and Russell, 2001, supra). In general, total DNA is extracted from the transformant, digested with appropriate restriction enzymes, fractionated in an agarose gel and transferred to a nitrocellulose or nylon membrane. The membrane or “blot” is then probed with, for example, radiolabeled 32P target DNA fragment to confirm the integration of introduced gene into the plant genome according to standard techniques (Sambrook and Russell, 2001, supra).
In Northern blot analysis, RNA is isolated from specific tissues of transformant, fractionated in a formaldehyde agarose gel, and blotted onto a nylon filter according to standard procedures that are routinely used in the art (Sambrook and Russell, 2001, supra). Expression of RNA encoded by the delta-endotoxin is then tested by hybridizing the filter to a radioactive probe derived from a delta-endotoxin, by methods known in the art (Sambrook and Russell, 2001, supra).
Western blot, biochemical assays and the like may be carried out on the transgenic plants to confirm the presence of protein encoded by the delta-endotoxin gene by standard procedures (Sambrook and Russell, 2001, supra) using antibodies that bind to one or more epitopes present on the delta-endotoxin protein.
Pesticidal Activity in Plants
In another aspect of the invention, one may generate transgenic plants expressing a delta-endotoxin that has pesticidal activity. Methods described above by way of example may be utilized to generate transgenic plants, but the manner in which the transgenic plant cells are generated is not critical to this invention. Methods known or described in the art such as Agrobacterium-mediated transformation, biolistic transformation, and non-particle-mediated methods may be used at the discretion of the experimenter. Plants expressing a delta-endotoxin may be isolated by common methods described in the art, for example by transformation of callus, selection of transformed callus, and regeneration of fertile plants from such transgenic callus. In such process, one may use any gene as a selectable marker so long as its expression in plant cells confers ability to identify or select for transformed cells.
A number of markers have been developed for use with plant cells, such as resistance to chloramphenicol, the aminoglycoside G418, hygromycin, or the like. Other genes that encode a product involved in chloroplast metabolism may also be used as selectable markers. For example, genes that provide resistance to plant herbicides such as glyphosate, bromoxynil, or imidazolinone may find particular use. Such genes have been reported (Stalker et al. (1985) J. Biol. Chem. 263:6310-6314 (bromoxynil resistance nitrilase gene); and Sathasivan et al. (1990) Nucl. Acids Res. 18:2188 (AHAS imidazolinone resistance gene). Additionally, the genes disclosed herein are useful as markers to assess transformation of bacterial or plant cells. Methods for detecting the presence of a transgene in a plant, plant organ (e.g., leaves, stems, roots, etc.), seed, plant cell, propagule, embryo or progeny of the same are well known in the art. In one embodiment, the presence of the transgene is detected by testing for pesticidal activity.
Fertile plants expressing a delta-endotoxin may be tested for pesticidal activity, and the plants showing optimal activity selected for further breeding. Methods are available in the art to assay for pest activity. Generally, the protein is mixed and used in feeding assays. See, for example Marrone et al. (1985) J. of Economic Entomology 78:290-293.
The present invention may be used for transformation of any plant species, including, but not limited to, monocots and dicots. Examples of plants of interest include, but are not limited to, corn (maize), sorghum, wheat, sunflower, tomato, crucifers, peppers, potato, cotton, rice, soybean, sugarbeet, sugarcane, tobacco, barley, and oilseed rape, Brassica sp., alfalfa, rye, millet, safflower, peanuts, sweet potato, cassaya, coffee, coconut, pineapple, citrus trees, cocoa, tea, banana, avocado, fig, guava, mango, olive, papaya, cashew, macadamia, almond, oats, vegetables, ornamentals, and conifers.
Vegetables include, but are not limited to, tomatoes, lettuce, green beans, lima beans, peas, and members of the genus Curcumis such as cucumber, cantaloupe, and musk melon. Ornamentals include, but are not limited to, azalea, hydrangea, hibiscus, roses, tulips, daffodils, petunias, carnation, poinsettia, and chrysanthemum. Preferably, plants of the present invention are crop plants (for example, maize, sorghum, wheat, sunflower, tomato, crucifers, peppers, potato, cotton, rice, soybean, sugarbeet, sugarcane, tobacco, barley, oilseed rape, etc.).
Use in Pest Control
General methods for employing strains comprising a nucleotide sequence of the present invention, or a variant thereof, in pesticide control or in engineering other organisms as pesticidal agents are known in the art. See, for example U.S. Pat. No. 5,039,523 and EP 0480762A2.
The Bacillus strains containing a nucleotide sequence of the present invention, or a variant thereof, or the microorganisms that have been genetically altered to contain a pesticidal gene and protein may be used for protecting agricultural crops and products from pests. In one aspect of the invention, whole, i.e., unlysed, cells of a toxin (pesticide)-producing organism are treated with reagents that prolong the activity of the toxin produced in the cell when the cell is applied to the environment of target pest(s).
Alternatively, the pesticide is produced by introducing a delta-endotoxin gene into a cellular host. Expression of the delta-endotoxin gene results, directly or indirectly, in the intracellular production and maintenance of the pesticide. In one aspect of this invention, these cells are then treated under conditions that prolong the activity of the toxin produced in the cell when the cell is applied to the environment of target pest(s). The resulting product retains the toxicity of the toxin. These naturally encapsulated pesticides may then be formulated in accordance with conventional techniques for application to the environment hosting a target pest, e.g., soil, water, and foliage of plants. See, for example EPA 0192319, and the references cited therein. Alternatively, one may formulate the cells expressing a gene of this invention such as to allow application of the resulting material as a pesticide.
Nematode Control
Plant-parasitic nematodes, including cyst nematodes, root knot nematodes, and other nematodes, cause billions of dollars in damage to crops every year. Plant-parasitic nematodes pierce plant cell walls with their stylet, which is formed by some of the mouth and esophagus parts, and pump up the plant cell just into their digestive system. Numerous publications in the art conclude that sedentary plant parasitic nematodes do not ingest molecules larger than about 23-28 kDa in vivo. This has led to the widespread belief that the feeding tube produced by these nematodes acts as a molecular sieve, restricting the size of molecules that can be ingested. Bockenhoff and Grundler ((1994) Parasitology 109:249-254) injected fluorescently labeled dextrans into syncytia that were being fed upon by Heterodera schachtii. They found that the nematodes ingested 22 kDa dextrans, but not 40 kDa dextrans. Urwin et al. ((1998) Planta 204:472-479) found that a 23 kDa fusion protein expressed in transgenic Arabidopsis could not be ingested by H. schachtii, although a protein of about 11 kDa could be ingested. Similarly, Unwin et al. ((1997) Molecular Plant-Microbe Interactions 10:394-400) found that 28 kDa green fluorescent protein (GFP) expressed in transgenic Arabidopsis could not be ingested by H. schachtii. Thus, it was not previously recognized or demonstrated that nematodes could be controlled by expressing a protein greater than 22 kDa in a plant since it was understood that nematodes would not ingest such a protein.
Provided herein are methods and compositions for conferring resistance to nematodes in plants. The methods comprise introducing into a plant at least one nucleotide sequence encoding a nematode-active polypeptide and growing the plant in a field containing nematodes. By “nematode-active polypeptide” is intended a polypeptide that, when ingested by the nematode, results in the death or stunting of growth or proliferation of at least one nematode. In one embodiment, the nematode-active polypeptide has a molecular weight greater than about 22 kDa, about 23 kDa, about 24, about 25, about 26, about 27, about 28, about 29, about 30, about 31, about 32, about 33, about 34, about 35, about 36, about 37, about 38, about 39, about 40, about 41, about 42, about 43, about 44, about 45, about 46, about 47, about 48, about 49, about 50, about 51, about 52, about 53, about 54, about 55, about 56, about 57, about 58, about 59, about 60, about 61, about 62, about 63, about 64, about 65, about 66, about 67, about 68, about 69, about 70, about 71, about 72, about 73, about 74, about 75, about 76, about 77, about 78, about 79, about 80 kDa, or greater.
In another embodiment, the nematode-active polypeptide has activity against plant-parasitic nematodes. Expression of the nematode-active polypeptide in a plant reduces the ability of nematodes to infest or feed on roots of the plant. Examples of plant-parasitic nematodes sensitive to the compositions of the present invention include root knot nematodes (Meloidogyne sp.), stunt nematode (Tylenchorhynchus sp.), lance nematode (Hoplolaimus sp.), spiral nematode (Helicotylenchus sp.), lesion nematode (Pratylenchus sp.), cyst nematode (Heterodera sp. and Globodera sp.), and ring nematode (Criconema sp.).
Pesticidal Compositions
The active ingredients of the present invention are normally applied in the form of compositions and can be applied to the crop area or plant to be treated, simultaneously or in succession, with other compounds. These compounds can be fertilizers, weed killers, cryoprotectants, surfactants, detergents, pesticidal soaps, dormant oils, polymers, and/or time-release or biodegradable carrier formulations that permit long-term dosing of a target area following a single application of the formulation. They can also be selective herbicides, chemical insecticides, virucides, microbicides, amoebicides, pesticides, fungicides, bacteriocides, nematocides, molluscicides or mixtures of several of these preparations, if desired, together with further agriculturally acceptable carriers, surfactants or application-promoting adjuvants customarily employed in the art of formulation. Suitable carriers and adjuvants can be solid or liquid and correspond to the substances ordinarily employed in formulation technology, e.g. natural or regenerated mineral substances, solvents, dispersants, wetting agents, tackifiers, binders or fertilizers. Likewise the formulations may be prepared into edible “baits” or fashioned into pest “traps” to permit feeding or ingestion by a target pest of the pesticidal formulation.
Methods of applying an active ingredient of the present invention or an agrochemical composition of the present invention that contains at least one of the pesticidal proteins produced by the bacterial strains of the present invention include leaf application, seed coating and soil application. The number of applications and the rate of application depend on the intensity of infestation by the corresponding pest.
The composition may be formulated as a powder, dust, pellet, granule, spray, emulsion, colloid, solution, or such like, and may be prepared by such conventional means as desiccation, lyophilization, homogenation, extraction, filtration, centrifugation, sedimentation, or concentration of a culture of cells comprising the polypeptide. In all such compositions that contain at least one such pesticidal polypeptide, the polypeptide may be present in a concentration of from about 1% to about 99% by weight.
Lepidopteran, coleopteran, or nematode pests may be killed or reduced in numbers in a given area by the methods of the invention, or may be prophylactically applied to an environmental area to prevent infestation by a susceptible pest. Preferably the pest ingests, or is contacted with, a pesticidally-effective amount of the polypeptide. By “pesticidally-effective amount” is intended an amount of the pesticide that is able to bring about death to at least one pest, or to noticeably reduce pest growth, feeding, or normal physiological development. This amount will vary depending on such factors as, for example, the specific target pests to be controlled, the specific environment, location, plant, crop, or agricultural site to be treated, the environmental conditions, and the method, rate, concentration, stability, and quantity of application of the pesticidally-effective polypeptide composition. The formulations may also vary with respect to climatic conditions, environmental considerations, and/or frequency of application and/or severity of pest infestation.
The pesticide compositions described may be made by formulating either the bacterial cell, crystal and/or spore suspension, or isolated protein component with the desired agriculturally-acceptable carrier. The compositions may be formulated prior to administration in an appropriate means such as lyophilized, freeze-dried, desiccated, or in an aqueous carrier, medium or suitable diluent, such as saline or other buffer. The formulated compositions may be in the form of a dust or granular material, or a suspension in oil (vegetable or mineral), or water or oil/water emulsions, or as a wettable powder, or in combination with any other carrier material suitable for agricultural application. Suitable agricultural carriers can be solid or liquid and are well known in the art. The term “agriculturally-acceptable carrier” covers all adjuvants, inert components, dispersants, surfactants, tackifiers, binders, etc. that are ordinarily used in pesticide formulation technology; these are well known to those skilled in pesticide formulation. The formulations may be mixed with one or more solid or liquid adjuvants and prepared by various means, e.g., by homogeneously mixing, blending and/or grinding the pesticidal composition with suitable adjuvants using conventional formulation techniques. Suitable formulations and application methods are described in U.S. Pat. No. 6,468,523, herein incorporated by reference.
“Pest” includes but is not limited to, insects, fungi, bacteria, nematodes, mites, ticks, and the like. Insect pests include insects selected from the orders Coleoptera, Diptera, Hymenoptera, Lepidoptera, Mallophaga, Homoptera, Hemiptera, Orthroptera, Thysanoptera, Dermaptera, Isoptera, Anoplura, Siphonaptera, Trichoptera, etc., particularly Coleoptera, Lepidoptera, and Diptera.
The order Coleoptera includes the suborders Adephaga and Polyphaga. Suborder Adephaga includes the superfamilies Caraboidea and Gyrinoidea, while suborder Polyphaga includes the superfamilies Hydrophiloidea, Staphylinoidea, Cantharoidea, Cleroidea, Elateroidea, Dascilloidea, Dryopoidea, Byrrhoidea, Cucujoidea, Meloidea, Mordelloidea, Tenebrionoidea, Bostrichoidea, Scarabaeoidea, Cerambycoidea, Chrysomeloidea, and Curculionoidea. Superfamily Caraboidea includes the families Cicindelidae, Carabidae, and Dytiscidae. Superfamily Gyrinoidea includes the family Gyrimidae. Superfamily Hydrophiloidea includes the family Hydrophilidae. Superfamily Staphylinoidea includes the families Silphidae and Staphylinidae. Superfamily Cantharoidea includes the families Cantharidae and Lampyridae. Superfamily Cleroidea includes the families Cleridae and Dermestidae. Superfamily Elateroidea includes the families Elateridae and Buprestidae. Superfamily Cucujoidea includes the family Coccinellidae. Superfamily Meloidea includes the family Meloidae. Superfamily Tenebrionoidea includes the family Tenebrionidae. Superfamily Scarabaeoidea includes the families Passalidae and Scarabaeidae. Superfamily Cerambycoidea includes the family Cerambycidae. Superfamily Chrysomeloidea includes the family Chrysomelidae. Superfamily Curculionoidea includes the families Curculionidae and Scolytidae.
The order Diptera includes the Suborders Nematocera, Brachycera, and Cyclorrhapha. Suborder Nematocera includes the families Tipulidae, Psychodidae, Culicidae, Ceratopogonidae, Chironomidae, Simuliidae, Bibionidae, and Cecidomyiidae. Suborder Brachycera includes the families Stratiomyidae, Tabanidae, Therevidae, Asilidae, Mydidae, Bombyliidae, and Dolichopodidae. Suborder Cyclorrhapha includes the Divisions Aschiza and Aschiza. Division Aschiza includes the families Phoridae, Syrphidae, and Conopidae. Division Aschiza includes the Sections Acalyptratae and Calyptratae. Section Acalyptratae includes the families Otitidae, Tephritidae, Agromyzidae, and Drosophilidae. Section Calyptratae includes the families Hippoboscidae, Oestridae, Tachimidae, Anthomyiidae, Muscidae, Calliphoridae, and Sarcophagidae.
The order Lepidoptera includes the families Papilionidae, Pieridae, Lycaenidae, Nymphalidae, Danaidae, Satyridae, Hesperiidae, Sphingidae, Saturniidae, Geometridae, Arctiidae, Noctuidae, Lymantriidae, Sesiidae, and Tineidae.
Insect pests of the invention for the major crops include: Maize: Ostrinia nubilalis, European corn borer; Agrotis ipsilon, black cutworm; Helicoverpa zea, corn earworm; Spodoptera frugiperda, fall armyworm; Diatraea grandiosella, southwestern corn borer; Elasmopalpus lignosellus, lesser cornstalk borer; Diatraea saccharalis, surgarcane borer; Diabrotica virgifera, western corn rootworm; Diabrotica longicornis barberi, northern corn rootworm; Diabrotica undecimpunctata howardi, southern corn rootworm; Melanotus spp., wireworms; Cyclocephala borealis, northern masked chafer (white grub); Cyclocephala immaculata, southern masked chafer (white grub); Popillia japonica, Japanese beetle; Chaetocnema pulicaria, corn flea beetle; Sphenophorus maidis, maize billbug; Rhopalosiphum maidis, corn leaf aphid; Anuraphis maidiradicis, corn root aphid; Blissus leucopterus leucopterus, chinch bug; Melanoplus femurrubrum, redlegged grasshopper; Melanoplus sanguinipes, migratory grasshopper; Hylemya platura, seedcorn maggot; Agromyza parvicornis, corn blot leafminer; Anaphothrips obscrurus, grass thrips; Solenopsis milesta, thief ant; Tetranychus urticae, twospotted spider mite; Sorghum: Chilo partellus, sorghum borer; Spodoptera frugiperda, fall armyworm; Helicoverpa zea, corn earworm; Elasmopalpus lignosellus, lesser cornstalk borer; Feltia subterranea, granulate cutworm; Phyllophaga crinita, white grub; Eleodes, Conoderus, and Aeolus spp., wireworms; Oulema melanopus, cereal leaf beetle; Chaetocnema pulicaria, corn flea beetle; Sphenophorus maidis, maize billbug; Rhopalosiphum maidis; corn leaf aphid; Sipha flava, yellow sugarcane aphid; Blissus leucopterus leucopterus, chinch bug; Contarinia sorghicola, sorghum midge; Tetranychus cinnabarinus, carmine spider mite; Tetranychus urticae, twospotted spider mite; Wheat: Pseudaletia unipunctata, army worm; Spodoptera frugiperda, fall armyworm; Elasmopalpus lignosellus, lesser cornstalk borer; Agrotis orthogonia, western cutworm; Elasmopalpus lignosellus, lesser cornstalk borer; Oulema melanopus, cereal leaf beetle; Hypera punctata, clover leaf weevil; Diabrotica undecimpunctata howardi, southern corn rootworm; Russian wheat aphid; Schizaphis graminum, greenbug; Macrosiphum avenae, English grain aphid; Melanoplus femurrubrum, redlegged grasshopper; Melanoplus differentialis, differential grasshopper; Melanoplus sanguinipes, migratory grasshopper; Mayetiola destructor, Hessian fly; Sitodiplosis mosellana, wheat midge; Meromyza americana, wheat stem maggot; Hylemya coarctata, wheat bulb fly; Frankliniella fusca, tobacco thrips; Cephus cinctus, wheat stem sawfly; Aceria tulipae, wheat curl mite; Sunflower: Suleima helianthana, sunflower bud moth; Homoeosoma electellum, sunflower moth; zygogramma exclamationis, sunflower beetle; Bothyrus gibbosus, carrot beetle; Neolasioptera murtfeldtiana, sunflower seed midge; Cotton: Heliothis virescens, cotton budworm; Helicoverpa zea, cotton bollworm; Spodoptera exigua, beet armyworm; Pectinophora gossypiella, pink bollworm; Anthonomus grandis, boll weevil; Aphis gossypli, cotton aphid; Pseudatomoscelis seriatus, cotton fleahopper; Trialeurodes abutilonea, bandedwinged whitefly; Lygus lineolaris, tarnished plant bug; Melanoplus femurrubrum, redlegged grasshopper; Melanoplus differentialis, differential grasshopper; Thrips tabaci, onion thrips; Franklinkiella fusca, tobacco thrips; Tetranychus cinnabarinus, carmine spider mite; Tetranychus urticae, twospotted spider mite; Rice: Diatraea saccharalis, sugarcane borer; Spodoptera frugiperda, fall armyworm; Helicoverpa zea, corn earworm; Colaspis brunnea, grape colaspis; Lissorhoptrus oryzophilus, rice water weevil; Sitophilus oryzae, rice weevil; Nephotettix nigropictus, rice leafhopper; Blissus leucopterus leucopterus, chinch bug; Acrosternum hilare, green stink bug; Soybean: Pseudoplusia includens, soybean looper; Anticarsia gemmatalis, velvetbean caterpillar; Plathypena scabra, green cloverworm; Ostrinia nubilalis, European corn borer; Agrotis ipsilon, black cutworm; Spodoptera exigua, beet armyworm; Heliothis virescens, cotton budworm; Helicoverpa zea, cotton bollworm; Epilachna varivestis, Mexican bean beetle; Myzus persicae, green peach aphid; Empoasca fabae, potato leafhopper; Acrosternum hilare, green stink bug; Melanoplus femurrubrum, redlegged grasshopper; Melanoplus differentialis, differential grasshopper; Hylemya platura, seedcorn maggot; Sericothrips variabilis, soybean thrips; Thrips tabaci, onion thrips; Tetranychus turkestani, strawberry spider mite; Tetranychus urticae, twospotted spider mite; Barley: Ostrinia nubilalis, European corn borer; Agrotis ipsilon, black cutworm; Schizaphis graminum, greenbug; Blissus leucopterus leucopterus, chinch bug; Acrosternum hilare, green stink bug; Euschistus servus, brown stink bug; Delia platura, seedcorn maggot; Mayetiola destructor, Hessian fly; Petrobia latens, brown wheat mite; Oil Seed Rape: Brevicoryne brassicae, cabbage aphid; Phyllotreta cruciferae, Flea beetle; Mamestra configurata, Bertha armyworm; Plutella xylostella, Diamond-back moth; Delia ssp., Root maggots.
Nematodes include parasitic nematodes such as root-knot, cyst, and lesion nematodes, including Heterodera spp., Meloidogyne spp., and Globodera spp.; particularly members of the cyst nematodes, including, but not limited to, Heterodera glycines (soybean cyst nematode); Heterodera schachtii (beet cyst nematode); Heterodera avenae (cereal cyst nematode); and Globodera rostochiensis and Globodera pailida (potato cyst nematodes). Lesion nematodes include Pratylenchus spp.
Methods for Increasing Plant Yield
Methods for increasing plant yield are provided. The methods comprise introducing into a plant or plant cell a polynucleotide comprising a pesticidal sequence disclosed herein. As defined herein, the “yield” of the plant refers to the quality and/or quantity of biomass produced by the plant. By “biomass” is intended any measured plant product. An increase in biomass production is any improvement in the yield of the measured plant product. Increasing plant yield has several commercial applications. For example, increasing plant leaf biomass may increase the yield of leafy vegetables for human or animal consumption. Additionally, increasing leaf biomass can be used to increase production of plant-derived pharmaceutical or industrial products. An increase in yield can comprise any statistically significant increase including, but not limited to, at least a 1% increase, at least a 3% increase, at least a 5% increase, at least a 10% increase, at least a 20% increase, at least a 30%, at least a 50%, at least a 70%, at least a 100% or a greater increase in yield compared to a plant not expressing the pesticidal sequence.
In specific methods, plant yield is increased as a result of improved pest resistance of a plant expressing a pesticidal protein disclosed herein. Expression of the pesticidal protein results in a reduced ability of a pest to infest or feed on the plant, thus improving plant yield.
The following examples are offered by way of illustration and not by way of limitation.
EXPERIMENTAL
Example 1
Growth of ATX9387 and Preparation of Extracts
Strain ATX9387, identified as a member of the Bacillus cereus/Bacillus thuringiensis group by MIDI analysis, was grown in T3 medium at 30 degrees for times ranging from 16 hours to 5 days. Cultures were centrifuged and the supernatants were passed through 0.2 micron filters, resulting in sterile supernatants
Example 2
C. elegans Bioassay
Caenorhabitis elegans (“C. elegans”) hermaphrodites were reared as known in the art, to generate populations of healthy animals for bioassay. General procedures for growth, harvesting, and genetic manipulation of C. elegans including growth media, etc. may be found in the art, for example, in Wood, ed. (1988) The Nematode Caenorhabditis elegans (Cold Spring Harbor Laboratory Press, Cold Spring Harbor, N.Y.).
Sterile supernatants from strain ATX9387 were tested for activity on C. elegans. Bioassays were performed in 96-well plates. Five to ten nematodes were added to 80 μl of S medium (Wood, supra) and were mixed with 20 μl of sterile supernatant, 0.5 μl of concentrated HB101 (prepared as described in Wood, supra) and rifampicin (final concentration of 0.1 μg/l). Assays were allowed to proceed at room temperature for 3 days and nematodes were quantitated. Negative control samples (T3 medium or sterile supernatants from inactive strains) contained hundreds of active nematodes, while test samples (containing ATX9387 supernatant) contained 5 to 10 nematodes that were sluggish or dead. The results of the bioassay of ATX9387 extracts on C. elegans are shown in Table 1.







TABLE 1







Activity of ATX9387 extracts on C. elegans









Growth Time
ATX9387
Control













16
hours
−
−


1
day
−
−


2
days
−
−


3
days
++
−


4
days
++
−


5
days
++
−









Example 3
Activity of ATX9387 on Soybean Cyst Nematodes
A sterile supernatant of a 5-day culture of ATX9387 was concentrated 40-fold and fed to SCN J2 nematodes. Nematodes feeding on sterile supernatant were reproducibly observed to be sluggish, and exhibited higher motility than nematodes fed extract of a negative control concentrated to the same extent.
Example 4
Anti-Nematode Activity from ATX9387 is Conferred by a Protein
To identify the anti-nematode activity in ATX9387, the following tests were performed. First, the ability of the activity to be destroyed by heating was tested by heating samples of sterile supernatant from ATX9387 to 100° C. for 10 minutes, then assaying heated material in a nematode bioassay. Heat treatment of sterile supernatants from ATX9387 resulted in a loss of anti-nematode activity. Next, active samples were treated with pronase to degrade proteins. This treatment resulted in loss of activity. Sterile supernatants from ATX9387 were passed through a 3 kDa molecular weight cut-off (“MWCO”) concentration unit. The active ingredient was retained by the 3 kDa MWCO filter while the flow-through showed no activity. This indicates that the active molecule was larger than 3 kDa in size.
Example 5
Fractionation of Activity from ATX9387
The sterile supernatant of a 4-day culture of ATX9387 was fractionated by liquid chromatography on an anion exchange column in 20 mM Tris pH 8, using a gradient from 0 M to 1 M NaCl. Several consecutive fractions were active. The most active fraction was subjected to SDS-PAGE, and two prominent bands of approximately 130 kd and approximately 70 kd were observed.
In another experiment strain ATX9387 was grown for 5 days in T3 medium at 30° C. The culture was centrifuged at 8,000×g for 10 minutes, and the supernatant was passed through a 0.2 μm filter. The filtered supernatant was dialyzed against 20 mM Tris pH 8 using Spectra/Por 1 dialysis tubing (6-8,000 MWCO), and was then fractionated on an anion exchange column (Mono Q) using a gradient from 0 to 1 M NaCl over 20 bed volumes. The fractions were dialyzed against 20 mM Tris pH 8 using Slide-A-Lyzer (Pierce Biotechnology, Rockford, Ill.) mini dialysis units (7,000 MWCO), and bioassayed on C. elegans using 20 μl of sample in a 100 μl bioassay volume, as described herein. Fractions 12 and 13 were found to be active, and were pooled and then concentrated 7-fold using an Amicon Ultra-4 5,000 MWCO concentrator. The concentrated material was fractionated on a gel filtration column (Superdex 200) in 50 mM sodium phosphate, 150 mM NaCl, pH 7. Fractions were concentrated 10-fold using Centricon YM-3 concentrators, and were bioassayed on C. elegans as above. Fractions 5 and 6 were the most active, and fraction 7 was somewhat active. SDS-PAGE of the fractions showed that fractions 5-7 shared several proteins: a protein at about 130 kDa, a doublet at about 75 kDa, and a protein at about 53 kDa. The most prominent bands were subjected to N-terminal protein sequencing by Edman degradation. The 130 kDa protein and the 70 kDa protein had very similar N-terminal sequences (cysteine could not be detected by the method used), and thus are likely to result from the same initial protein. This protein was designated as AXMI-031 (SEQ ID NO:2).







TABLE 2





N-terminal sequence of the ~130 kDa protein from ATX9387
















1
A, S + S′, M


2
D, Q


3
?, P, N


4
N


5
L


6
Q


7
S


8
Q


9
?, Q


10
N


11
I


12
P


13
Y


14
N


15
V
















TABLE 3





N-terminal sequence of the about ~70 kDa protein from ATX9387
















1
A, G, S + S′


2
F


3
P


4
N


5
L


6
Q


7
V?


8
Q


9
?


10
N?, V?


11
I


12
P


13
Y, Q


14
?, N


15
?, V









A search of protein databases with the N-terminal sequences of the  ̃130 kDa protein and the  ̃70 kDa protein demonstrated that the N-terminal amino acids of the AXMI-031 proteins have significant similarity to the N-terminus of the endotoxin Cry14Aa (SEQ ID NO:13).

N-terminal sequence of Cry14A: MDCNLQSQQNIPYNV (amino acid residues 1 through 15 of SEQ ID NO:13).
Example 6
Cloning of the Axmi-031 Coding Region from ATX9387
A random fragment library of ATX9387 was generated, and a DNA clone (pAX031) containing the DNA sequence encoding the N-terminus of axmi-031 was identified. A second clone, pAX032, was identified as containing the C-terminus of axmi-031. Clones pAX031 and pAX032 overlap substantially, such that it is clear to one skilled in the art that both clones together comprise the entire axmi-031 coding region.
To confirm the nature of the AXMI-031, a genomic clone was amplified using a high fidelity polymerase PFU ULTRATM (Stratagene) from total DNA using primers designed to the ends of the axmi-031 open reading frame. The resulting PCR product was cloned into the PCR-TOPOII-Blunt vector (Invitrogen) to create pAX980. The DNA sequence pAX980 was determined and found to contain the same open reading frame as in the random fragment library clones pAX031 and pAX032. Translation of this open reading frame generates a protein sequence consistent with the N-terminal sequence obtained from the purified AXMI-031 protein. Thus, this open reading frame was designated axmi-031 (SEQ ID NO:1). The plasmid clone pAX2515, containing axmi-031 was deposited on Jun. 9, 2006 and assigned the accession number NRRL B-30935.
Example 7
Comparison of AXMI-031 to Other Known Endotoxins
Database searches using the AXMI-031 protein sequence demonstrate that AXMI-031 is a member of the delta-endotoxin class of insecticidal proteins. AXMI-031 is most similar to the cry14Aa1 endotoxin. The amino acid sequence of AXMI-031 is 86.6% identical to CRY14Aa1 (SEQ ID NO:13).
Example 8
Expression of the AXMI-031 Polypeptide in E. coli 
For soluble expression in E. coli, primers were designed to include the translation start and stop codons from the axmi-031 ORF. The primers added an optimal RBS and Gateway attB recombination sites. Stratagene Pfu I polymerase was used to consistently amplify the ORF from the pAX980, and recombined with pDONR221 (Invitrogen, Carlsbad, Calif.) to create the entry vector pAX2515 (as per protocols from Invitrogen). The clone was sequenced for verification. A further recombination was performed to introduce the ORF into pDEST 17 to be expressed by the T7 promoter, yielding pAX2530. The presence and orientation of the inserted axmi-031 fragment were verified by restriction digest, and transformed into E. coli BL21 (DE3) cells. This vector produces a translational fusion of 26 amino acids (3.17 kDa), including a 6× His tag, on the N-terminus of AXMI-031.
His-AXMI-031 was expressed from pAX2530 in BL21*(DE3) cells as follows. A starter culture of pAX2530 was grown overnight at 37° C. in LB with 50 μg/ml carbenicillin. The following day the saturated culture was diluted 1:100 into fresh medium, and the fresh culture grown at 37° to an OD of 0.4, at which time the culture was placed at room temperature with shaking overnight. As a control, an expression vector carrying the axmi-004 gene (pAX2530) was constructed as for axmi-031, and the AXMI-004 protein (U.S. patent application Ser. No. 10/782,020) was expressed from pAX2504 in the same E. coli host. Whole cultures were analyzed by SDS-PAGE. Cultures containing pAX2530 produced a prominent protein band at approximately 135 kDa, the expected size for His-AXMI-031 protein, while cultures containing pAX2504 did not.
Example 9
Antibodies to AXMI-031
To generate anti-AXMI-031 antibodies, affinity purified AXMI-031 (SEQ ID NO:2) protein was inoculated into rabbits, and antisera to AXMI-031 isolated and titered as known in the art. The selected antisera were found to also react with SYNAXMI-031 protein (SEQ ID NO:8).
Example 10
Activity of AXMI-031 on C. elegans 
Cultures of E. coli containing pAX2530, were prepared, and found to produce a 135 kDa protein not present in control strains, suggesting the expression of AXMI-031 in pAX2530 containing strains. These cultures were tested for activity on C. elegans and were active against C. elegans, while control cultures showed no activity against C. elegans. 
Example 11
Expression of AXMI-031 in Bacillus 
The insecticidal gene axmi-031 is amplified by PCR from pAX980, and the PCR product is cloned into the Bacillus expression vector pAX916, or another suitable vector, by methods well known in the art. The resulting Bacillus strain, containing the vector with axmi-031 is cultured on a conventional growth media, such as CYS media (10 g/l Bacto-casitone; 3 g/l yeast extract; 6 g/l KH2PO4; 14 g/l K2HPO4; 0.5 mM MgSO4; 0.05 mM MnCl2; 0.05 mM FeSO4), until sporulation is evident by microscopic examination. Samples are prepared, and AXMI-031 protein was tested for activity in bioassays against C. elegans, and found to have activity.
Example 12
Synaxmi-031, Synaxmi-031(apo) and Synaxmi-031 (ER)
In one aspect of the invention, synthetic axmi-031 sequences are generated, for example synaxmi-031 (SEQ ID NO:7). These synthetic sequences have an altered DNA sequence relative to the axmi-031 sequence, and encode a protein that is collinear with the original AXMI-031 protein, but lacks the C-terminal “crystal domain” present in AXMI-031. The synaxmi-031 gene sequence encodes SYNAXMI-031 protein (SEQ ID NO:8), which comprises the first 685 amino acids of the AXMI-031 protein.
In another aspect of the invention, modified versions of synaxmi-031 are designed such that the resulting peptide is targeted to a plant organelle, such as the endoplasmic reticulum or the apoplast. Peptide sequences known to result in targeting of fusion proteins to plant organelles are known in the art. For example, the N-terminal region of the acid phosphatase gene from the White Lupin Lupinus albus (Genebank ID GI:14276838; Miller et al. (2001) Plant Physiology 127: 594-606) is known in the art to result in endoplasmic reticulum targeting of heterologous proteins. If the resulting fusion protein also contains an endoplasmic retention sequence comprising the peptide N-terminus-lysine-aspartic acid-glutamic acid-leucine (i.e. the “KDEL” motif (SEQ ID NO:36) at the C-terminus, the fusion protein will be targeted to the endoplasmic reticulum. If the fusion protein lacks an endoplasmic reticulum targeting sequence at the C-terminus, the protein will be targeted to the endoplasmic reticulum, but will ultimately be sequestered in the apoplast.
Thus, the synaxmi-031ER gene (SEQ ID NO:11) encodes a fusion protein that contains the N-terminal thirty-one amino acids of the acid phosphatase gene from the White Lupin Lupinus albus fused to the N-terminus of SYNAXMI-031, as well as the KDEL sequence at the C-terminus. Thus, the resulting protein AXMI-031ER (SEQ ID NO:12), is predicted to be targeted the plant endoplasmic reticulum upon expression in a plant cell.
The synaxmi-031(apo) gene (SEQ ID NO:9) encodes a fusion protein that contains the N-terminal thirty-one amino acids of the acid phosphatase gene from the White Lupin Lupinus albus fused to the N-terminus of SYNAXMI-031, but lacks the KDEL sequence at the C-terminus. Thus, the resulting protein AXMI-031 (APO) (SEQ ID NO:10), is predicted to be targeted to the plant apoplast upon expression in a plant cell.
Example 13
Truncations of Synaxmi-031 to Yield Alternate AXMI-031 Proteins
DNA constructs that resulted in expression of variants of AXMI-031 protein were developed and expressed, in addition to synthetic sequences encoding AXMI-031 and variants and fragments thereof (SEQ ID NO:15-27). A subset of these genes were tested for nematode activity in vitro.







TABLE 4







Nematicidal Activity of AXMI-031 variants in vitro












Amino acid




Nucleotide SEQ ID
SEQ ID
Active on


Protein
NO:
NO:
C. elegans?





Bacterial Expression





AXMI-031-truncated
14
15
Yes


AXMI-031(m1)
16
17
Yes


AXMI-031(m1)-
18
19
Yes


truncated


AXMI-031(A-D)
20
21
Yes


SYNAXMI-031 (A-D)
26
27
NT


AXMI-031(B-C)
22
23
Yes


AXMI-031(B-D)
24
25
Yes





NT = not tested






Example 14
Truncations and Addition of Cellular Targeting Domain(s) for Plant Expression
In another aspect of the invention, modified versions of the synaxmi-031 sequences are designed such that the resulting peptide is targeted to a plant organelle, such as the endoplasmic reticulum or the apoplast.
In another aspect of the invention, the genes are truncated such that the resulting peptide is a truncated version of AXMI-031, which may or may not be further modified for targeting to plant organelles, such as the apoplast or the endoplasmic reticulum.
In another aspect of the invention, modified versions are developed that result in expression of truncated variants that contain domains designed to target the resulting protein to plant organelles.
The following variant nucleotide sequences were designed:
aposynaxmi-031 (A-D) (SEQ ID NO:28) encodes the APOAXMI-031 (A-D) protein (SEQ ID NO:29). apoSyn2axmi-031(A-D) (SEQ ID NO:30) encodes the APOAXMI-031(A-D) protein (SEQ ID NO:31). aposynaxmi-031 (fl) (SEQ ID NO:37) encodes the APOSYNAXMI-031(FL) protein (SEQ ID NO:38). Synaxmi031(t)-ER (SEQ ID NO:32) encodes the SYNAXMI-031(FL)-ER protein (SEQ ID NO:33).
Example 15
Extraction of plasmid DNA from Strains ATX16538 ATX16093 and ATX21049
Strains ATX16538, ATX16093, and ATX21049 were selected for analysis. Pure cultures of each strain were grown in large quantities of rich media. The cultures were centrifuged to harvest the cell pellet. The cell pellet was then prepared by treatment with SDS by methods known in the art, resulting in breakage of the cell wall and release of DNA. Proteins and large genomic DNA was then precipitated by a high salt concentration. The plasmid DNA was then precipitated with ethanol. In several instances, the plasmid DNA was separated from any remaining chromosomal DNA by high-speed centrifugation through a cesium chloride gradient. Alternatively, the plasmid DNA was purified by binding to a resin, as known in the art. For each strain, the quality of the DNA was checked by visualization on an agarose gel by methods known in the art.
Example 16
Cloning of Genes from Strains ATX16538 ATX16093 and ATX21049
DNA libraries were prepared from the plasmid DNA or each strain. This may be achieved in many ways as known in the art. For, example, the purified plasmid DNA can be sheared into 5-10 kb sized fragments and the 5′ and 3′ single stranded overhangs repaired using T4 DNA polymerase and Klenow fragment in the presence of all four dNTPs, as known in the art. Phosphates can then be attached to the 5′ ends by treatment with T4 polynucleotide kinase, as known in the art. The repaired DNA fragments can then be ligated overnight into a standard high copy vector (i.e. pBLUESCRIPT® SK+), suitably prepared to accept the inserts as known in the art (for example by digestion with a restriction enzyme producing blunt ends).
The quality of the resulting DNA libraries was analyzed by digesting a subset of clones with a restriction enzyme known to have a cleavage site flanking the cloning site. A high percentage of clones were determined to contain inserts, usually with an average insert size of 5-6 kb.
Example 17
High Throughput Sequencing of Library Plates
Once the DNA library quality was checked and confirmed, colonies were grown in a rich broth in 2 ml 96-well blocks overnight at 37° C., typically at a shaking speed of 350 rpm. The blocks were centrifuged to collect the cells at the bottom of the block. The blocks were then prepared by standard alkaline lysis prep in a high throughput format.
The end sequences of clones from this library were then determined for a large number of clones from each block in the following manner: The DNA sequence of each clone chosen for analysis was determined using the fluorescent dye terminator sequencing technique (Applied Biosystems), by methods known in the art using an automated DNA sequencing machine, and standard oligonucleotide primers that anneal to the plasmid vector in the region flanking the insert.
Example 18
Assembly and Screening of Sequencing Data
DNA sequences obtained were compiled into an assembly project and aligned together to form contigs. This can be done efficiently using a computer program, such as Vector NTi, or alternatively by using the Pred/Phrap suite of DNA alignment and analysis programs as described elsewhere herein. These contigs, along with any individual read that may not have been added to a contig, were compared to a compiled database of all classes of known pesticidal genes. Contigs or individual reads identified as having identity to a known endotoxin or pesticidal gene were analyzed further.
From strain ATX16538, pAX2579 was found to contain an open reading frame with homology to “cry” type delta-endotoxins. This open reading frame was designated as axmi-039 (SEQ ID NO:3), and the encoded protein was designated AXMI-039 (SEQ ID NO:4). The axmi-039 ORF and flanking sequence (151 bp upstream of the start codon and 29 bp downstream of the stop codon) was PCR amplified, cloned into pRSFIB and sequenced to yield pAX2579. pAX2579 was deposited with the ARS Patent Strain Collection on Jun. 9, 2006, and assigned NRRL B-30936. AXMI-039 is 43.9% amino acid sequence identity to Cry5Ba1, which is the closest homolog identified.
From strain ATX16093, pAX4313 was found to contain an open reading frame with homology to “cry” type delta-endotoxins. This open reading frame was designated as axmi-040 (SEQ ID NO:5), and the encoded protein was designated AXMI-040 (SEQ ID NO:6). pAX4313 was deposited with the ARS Patent Strain Collection on Jun. 9, 2006, and assigned NRRL B-30937. AXMI-040 is 42.9% amino acid sequence identity to Cry21Ba1, which is the closest homolog identified.
From strain ATX21049, an open reading frame was identified that exhibited homology to “cry” type delta-endotoxins. This open reading frame was designated as axmi-049 (SEQ ID NO:34), and the encoded protein was designated AXMI-049 (SEQ ID NO:35). This open reading frame was amplified by PCR and cloned into a vector to yield pAX5039. pAX5039 was deposited with the ARS Patent Strain Collection on May 29, 2007, and assigned NRRL B-50046. AXMI-049 has 46.1% amino acid sequence identity to Cry21Ba1, which is the closest homology identified.
Example 19
Vectoring of the Pesticidal genes of the invention for Plant Expression
Each of the coding regions of the genes of the invention are connected independently with appropriate promoter and terminator sequences for expression in plants. Such sequences are well known in the art and may include the rice actin promoter or maize ubiquitin promoter for expression in monocots, the Arabidopsis UBQ3 promoter or CaMV 35S promoter for expression in dicots, and the nos or PinII terminators. Techniques for producing and confirming promoter—gene—terminator constructs also are well known in the art.
Example 20
Transformation of the Genes of the Invention into Plant Cells by Agrobacterium-Mediated Transformation
Ears are collected 8-12 days after pollination. Embryos are isolated from the ears, and those embryos 0.8-1.5 mm in size are used for transformation. Embryos are plated scutellum side-up on a suitable incubation media, and incubated overnight at 25° C. in the dark. However, it is not necessary per se to incubate the embryos overnight. Embryos are contacted with an Agrobacterium strain containing the appropriate vectors for Ti plasmid mediated transfer for 5-10 min, and then plated onto co-cultivation media for 3 days (25° C. in the dark). After co-cultivation, explants are transferred to recovery period media for five days (at 25° C. in the dark). Explants are incubated in selection media for up to eight weeks, depending on the nature and characteristics of the particular selection utilized. After the selection period, the resulting callus is transferred to embryo maturation media, until the formation of mature somatic embryos is observed. The resulting mature somatic embryos are then placed under low light, and the process of regeneration is initiated as known in the art. The resulting shoots are allowed to root on rooting media, and the resulting plants are transferred to nursery pots and propagated as transgenic plants.
Example 21
Transgenic Plants Expressing AXMI-031 and Variants
The plant expression cassettes described herein are combined with an appropriate plant selectable marker to aid in the selections of transformed cells and tissues, and ligated into plant transformation vectors. These may include binary vectors from Agrobacterium-mediated transformation or simple plasmid vectors for aerosol or biolistic transformation. synaxmi-031 (apo) was cloned into a plant expression vector, and this vector was introduced into Agrobacterium tumefaciens as known in the art. The synaxmi-031 (apo) coding region under control of the Arabidopsis UBQ3 promoter (Norris et al. (1993) J. Plant Mol. Biol. 21:895-906) was introduced into Arabidopsis thaliana by floral dip method as known in the art, and transgenic plants were selected. The presence of synaxmi-031(apo) in the transgenic Ti population was confirmed by PCR analysis as known in the art, using oligonucleotide primers derived from the sequence of synaxmi-031, which also anneal to synaxmi-031 (apo).
Leaf and root tissue from transgenic synaxmi-031 (apo) containing plants was prepared and separated on polyacrylamide gels alongside non-transgenic controls and dilutions of AXMI-031 protein, and transferred to a membrane as known in the art. The samples were tested for the presence of the expression product of synaxmi-031(apo) by Western blot analysis as known in the art, using anti-AXMI-031 antibodies described herein. The expression product of synaxmi-031 (apo) of the expected size was detected in samples of both leaf and root tissue from transgenic synaxmi-031(apo)-containing plants, but not detected in non-transgenic controls.







TABLE 5







Antibody detection of SYNAXMI-031(APO) in transgenic plants











Detection of




SYNAXMI-



Source of Tissue
031(APO)







Non-transformed control
−



synaxmi-031(apo)
+++



containing plant ‘A’



synaxmi-031(apo)
+++



containing plant ‘B’










Example 22
Reduced Cyst Formation by AXMI-031 Expressing Plants
Transgenic plants expressing synaxmi-031 (apo) were tested for ability to resist infestation by Heterodera schachtii compared to control plants. Transgenic plants, as well as control plants transformed with vector alone, were infested with approximately 100 J2 hatchlings, and the number of nematodes entering the roots, as well as the number of cyst formed, was measured. Transgenic plants expressing SYNAXMI-031 (APO) were found to consistently have reduced numbers of nematodes entering the roots, and reduced numbers of cysts formed relative to controls.







TABLE 6







Reduced cyst formation in AXMI-031 expressing plants









Cyst formation














Control plant
++



Plants expressing AXMI-031(APO)
+










Example 23
Additional Assays for Pesticidal Activity
The ability of a pesticidal protein to act as a pesticide upon a pest is often assessed in a number of ways. One way well known in the art is to perform a feeding assay. In such a feeding assay, one exposes the pest to a sample containing either compounds to be tested, or control samples. Often this is performed by placing the material to be tested, or a suitable dilution of such material, onto a material that the pest will ingest, such as an artificial diet. The material to be tested may be composed of a liquid, solid, or slurry. The material to be tested may be placed upon the surface and then allowed to dry. Alternatively, the material to be tested may be mixed with a molten artificial diet; then, dispensed into the assay chamber. The assay chamber may be, for example, a cup, a dish, or a well of a microtiter plate.
Assays for sucking pests (for example aphids) may involve separating the test material from the insect by a partition, ideally a portion that can be pierced by the sucking mouth parts of the sucking insect, to allow ingestion of the test material. Often the test material is mixed with a feeding stimulant, such as sucrose, to promote ingestion of the test compound.
Other types of assays can include microinjection of the test material into the mouth, or gut of the pest, as well as development of transgenic plants, followed by test of the ability of the pest to feed upon the transgenic plant. Plant testing may involve isolation of the plant parts normally consumed, for example, small cages attached to a leaf, or isolation of entire plants in cages containing insects.
Other methods and approaches to assay pests are known in the art, and can be found, for example in Robertson, J. L. & H. K. Preisler. 1992. Pesticide bioassays with arthropods. CRC, Boca Raton, Fla. Alternatively, assays are commonly described in the journals “Arthropod Management Tests” and “Journal of Economic Entomology” or by discussion with members of the Entomological Society of America (ESA).
Example 24
Transformation of Maize Cells with the Pesticidal Genes of the Invention
Maize ears are collected 8-12 days after pollination. Embryos are isolated from the ears, and those embryos 0.8-1.5 mm in size are used for transformation. Embryos are plated scutellum side-up on a suitable incubation media, such as DN62A5S media (3.98 g/L N6 Salts; 1 mL/L (of 1000× Stock) N6 Vitamins; 800 mg/L L-Asparagine; 100 mg/L Myo-inositol; 1.4 g/L L-Proline; 100 mg/L Casaminoacids; 50 g/L sucrose; 1 mL/L (of 1 mg/l nL Stock) 2,4-D), and incubated overnight at 25° C. in the dark.
The resulting explants are transferred to mesh squares (30-40 per plate), transferred onto osmotic media for 30-45 minutes, then transferred to a beaming plate (see, for example, PCT Publication No. WO/0138514 and U.S. Pat. No. 5,240,842).
DNA constructs designed to express the genes of the invention in plant cells are accelerated into plant tissue using an aerosol beam accelerator, using conditions essentially as described in PCT Publication No. WO/0138514. After beaming, embryos are incubated for 30 min on osmotic media, then placed onto incubation media overnight at 25° C. in the dark. To avoid unduly damaging beamed explants, they are incubated for at least 24 hours prior to transfer to recovery media. Embryos are then spread onto recovery period media, for 5 days, 25° C. in the dark, then transferred to a selection media. Explants are incubated in selection media for up to eight weeks, depending on the nature and characteristics of the particular selection utilized. After the selection period, the resulting callus is transferred to embryo maturation media, until the formation of mature somatic embryos is observed. The resulting mature somatic embryos are then placed under low light, and the process of regeneration is initiated by methods known in the art. The resulting shoots are allowed to root on rooting media, and the resulting plants are transferred to nursery pots and propagated as transgenic plants.
Materials










DN62A5S Media









Components
per liter
Source





Chu'S N6 Basal
3.98 g/L
Phytotechnology


Salt Mixture (Prod.

Labs


No. C 416)


Chu's N6 Vitamin
  1 mL/L (of 1000x Stock)
Phytotechnology


Solution (Prod.

Labs


No. C 149)


L-Asparagine
 800 mg/L
Phytotechnology




Labs


Myo-inositol
 100 mg/L
Sigma


L-Proline
 1.4 g/L
Phytotechnology




Labs


Casaminoacids
 100 mg/L
Fisher Scientific


Sucrose
  50 g/L
Phytotechnology




Labs


2,4-D (Prod. No.
  1 mL/L (of 1 mg/mL Stock)
Sigma


D-7299)









Adjust the pH of the solution to pH to 5.8 with 1N KOH/1N KCl, add Gelrite (Sigma) to 3 g/L, and autoclave. After cooling to 50° C., add 2 ml/L of a 5 mg/ml stock solution of Silver Nitrate (Phytotechnology Labs). Recipe yields about 20 plates.
All publications and patent applications mentioned in the specification are indicative of the level of skill of those skilled in the art to which this invention pertains. All publications and patent applications are herein incorporated by reference to the same extent as if each individual publication or patent application was specifically and individually indicated to be incorporated by reference.
Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity of understanding, it will be obvious that certain changes and modifications may be practiced within the scope of the appended claims.

## Claims

1. An isolated polypeptide with pesticidal activity, selected from the group consisting of:
a) a polypeptide comprising the amino acid sequence of SEQ ID NO:2, 4, 6, 8, 10, 12, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, 35, or 38;
b) a polypeptide comprising an amino acid sequence having at least 95% sequence identity to the amino acid sequence of SEQ ID NO:2, 8, 10, 12, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33 or 38, wherein said amino acid sequence has pesticidal activity against a lepidopteran or a nematode pest;
c) a polypeptide that is encoded by the nucleotide sequence of SEQ ID NO:1, 3, 5, 7, 9, 11, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, 34, or 37; and
d) a polypeptide encoded by the delta endotoxin nucleotide sequence of the DNA insert of the plasmid deposited as Accession No. B-30935.

2. The polypeptide of claim 1 further comprising heterologous amino acid sequences.

3. A composition comprising the polypeptide of claim 1.

4. The composition of claim 3, wherein said composition is selected from the group consisting of a powder, dust, pellet, granule, spray, emulsion, colloid, and solution.

5. The composition of claim 3, wherein said composition is prepared by desiccation, lyophilization, homogenization, extraction, filtration, centrifugation, sedimentation, or concentration of a culture of Bacillus thuringiensis cells.

6. The composition of claim 3, comprising from about 1% to about 99% by weight of said polypeptide.

7. A method for controlling a lepidopteran or nematode pest population comprising contacting said population with a pesticidally-effective amount of the polypeptide of claim 1.

8. A method for killing a lepidopteran or nematode pest, said method comprising contacting said pest with, or feeding to said pest, a pesticidally-effective amount of the polypeptide of claim 1.

9. A method for producing a polypeptide with pesticidal activity, said method comprising culturing a host cell comprising a nucleic acid molecule encoding said polypeptide under conditions in which said nucleic acid molecule is expressed, wherein said nucleic acid molecule comprises a nucleotide sequence selected from the group consisting of:
a) the nucleotide sequence of SEQ ID NO:1, 7, 9, 11, 14, 16, 18, 20, 22, 24, 26, 28, 30, 32, or 37, or a complement thereof;
b) a nucleotide sequence that encodes a polypeptide comprising the amino acid sequence of SEQ ID NO:2, 8, 10, 12, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, or 38;
c) a nucleotide sequence that encodes a polypeptide comprising an amino acid sequence having at least 95% sequence identity to the amino acid sequence of SEQ ID NO:2, 8, 10, 12, 15, 17, 19, 21, 23, 25, 27, 29, 31, 33, or 38, wherein said amino acid sequence has pesticidal activity against a lepidopteran or a nematode pest; and,
d) the delta endotoxin nucleotide sequence of the DNA insert of the plasmid deposited as Accession Nos. B-30935, or a complement thereof.