Phytohormones regulate diverse aspects of plant growth and environmental responses .

Recent high-throughput technologies have promoted a more comprehensive profiling of genes regulated by different hormones .

However , these omics data generally result in large gene lists that make it challenging to interpret the data and extract insights into biological significance .

With the rapid accumulation of theses large-scale experiments , especially the transcriptomic data available in public databases , a means of using this information to explore the transcriptional networks is needed .

Different platforms have different architectures and designs , and even similar studies using the same platform may obtain data with large variances because of the highly dynamic and flexible effects of plant hormones ; this makes it difficult to make comparisons across different studies and platforms .

Here , we present a web server providing gene set-level analyses of Arabidopsis thaliana hormone responses .

GSHR collected 333 RNA-seq and 1,205 microarray datasets from the Gene Expression Omnibus , characterizing transcriptomic changes in Arabidopsis in response to phytohormones including abscisic acid , auxin , brassinosteroids , cytokinins , ethylene , gibberellins , jasmonic acid , salicylic acid , and strigolactones .

These data were further processed and organized into 1,368 gene sets regulated by different hormones or hormone-related factors .

By comparing input gene lists to these gene sets , GSHR helped to identify gene sets from the input gene list regulated by different phytohormones or related factors .

Together , GSHR links prior information regarding transcriptomic changes induced by hormones and related factors to newly generated data and facilities cross-study and cross-platform comparisons ; this helps facilitate the mining of biologically significant information from large-scale datasets .

The GSHR is freely available at http://bioinfo.sibs.ac.cn/GSHR/.


Grain quality is an important agricultural trait that is mainly determined by grain size and composition .

Here , we characterize the role of the rice transcription factor ( TF ) SALT-RESPONSIVE ERF1 ( SERF1 ) during grain development .

Through genome-wide expression profiling and chromatin immunoprecipitation , we found that SERF1 directly regulates RICE PROLAMIN-BOX BINDING FACTOR ( RPBF ) , a TF that functions as a positive regulator of grain filling .

Loss of SERF1 enhances RPBF expression resulting in larger grains with increased starch content , while SERF1 overexpression represses RPBF resulting in smaller grains .

Consistently , during grain filling , starch biosynthesis genes such as GRANULE-BOUND STARCH SYNTHASEI ( GBSSI ) , STARCH SYNTHASEI ( SSI ) , SSIIIa , and ADP-GLUCOSE PYROPHOSPHORYLASE LARGE SUBUNIT2 ( AGPL2 ) are up-regulated in SERF1 knockout grains .

Moreover , SERF1 is a direct upstream regulator of GBSSI .

In addition , SERF1 negatively regulates germination by controlling RPBF expression , which mediates the gibberellic acid (GA)-induced expression of RICE AMYLASE1A ( RAmy1A ) .

Loss of SERF1 results in more rapid seedling establishment , while SERF1 overexpression has the opposite effect .

Our study reveals that SERF1 represents a negative regulator of grain filling and seedling establishment by timing the expression of RPBF .


An important question is what genes govern the differentiation of plant embryos into suspensor and embryo proper regions following fertilization and division of the zygote .

We compared embryo proper and suspensor transcriptomes of four plants that vary in embryo morphology within the suspensor region .

We determined that genes encoding enzymes in several metabolic pathways leading to the formation of hormones , such as gibberellic acid , and other metabolites are up-regulated in giant scarlet runner bean and common bean suspensors .

Genes involved in transport and Golgi body organization are up-regulated within the suspensors of these plants as well , strengthening the view that giant specialized suspensors serve as a hormone factory and a conduit for transferring substances to the developing embryo proper .

By contrast , genes controlling transcriptional regulation , development , and cell division are up-regulated primarily within the embryo proper .

Transcriptomes from less specialized soybean and Arabidopsis suspensors demonstrated that fewer genes encoding metabolic enzymes and hormones are up-regulated .

Genes active in the embryo proper , however , are functionally similar to those active in scarlet runner bean and common bean embryo proper regions .

We uncovered a set of suspensor- and embryo proper-specific transcription factors ( TFs ) that are shared by all embryos irrespective of morphology , suggesting that they are involved in early differentiation processes common to all plants .

Chromatin immunoprecipitation sequencing ( ChIP-Seq ) experiments with scarlet runner bean and soybean WOX9 , an up-regulated suspensor TF , gained entry into a regulatory network important for suspensor development irrespective of morphology .


Isolated thylakoids from halophytic Eutrema salsugineum ( Thellungiella salsuginea ) produces more H2O2 in comparison to glycophytic Arabidopsis thaliana .

The first objective of this study was to verify whether this feature is relevant also to the intact chloroplasts and leaves .

Enhanced H2O2 levels in chloroplasts and leaves of E. salsugineum were positively verified with several methods ( electron microscopy , staining with Amplex Red and with diaminobenzidine ) .

This effect was associated with a decreased ratio of [ Formula : see text]/H2O2 in E. salsugineum in comparison to A. thaliana as detected by electron paramagnetic resonance method .

As a next step , we tested how this specific ROS signature of halophytic species affects the antioxidant status and down-stream components of ROS signaling .

Comparison of enzymatic antioxidants revealed a decreased activity of ascorbate peroxidase ( APX ) , enhanced activity of glutathione peroxidase , and the presence of thylakoid-bound forms of iron superoxide dismutase ( FeSOD ) and APX in E. salsugineum .

These cues were , however , independent from application of salt stress .

The typical H2O2-dependent cellular responses , namely the levels of glucosinolates and stress-related hormones were determined .

The total glucosinolate content in E. salsugineum water-treated leaves was higher than in A. thaliana and increased after salinity treatment .

Treatment with salinity up-regulated all of tested stress hormones , their precursors and catabolites [ abscisic acid ( ABA ) , dihydrophaseic acid , phaseic acid , 1-aminocyclopropane-1-carboxylic acid , salicylic acid , jasmonic acid , cis-(+)-12-oxo-phytodienoic acid and jasmonoyl-L-isoleucine ] in A. thaliana , whereas in E. salsugineum only a stimulation in ethylene synthesis and ABA catabolism was noted .

Obtained results suggest that constitutively enhanced H2O2 generation in chloroplasts of E. salsugineum might be a crucial component of stress-prepardeness of this halophytic species .

It shapes a very efficient antioxidant protection ( in which glucosinolates might play a specific role ) and a fine tuning of hormonal signaling to suppress the cell death program directed by jasmonate pathway .


Genetic and biochemical dissection of signaling pathways regulating plant pathogen defense has revealed remarkable similarities with the innate immune system of mammals and Drosophila .

Numerous plant proteins resembling eukaryotic receptors have been implicated in the perception of pathogen-derived signal molecules .

Receptor-mediated changes in levels of free calcium in the cytoplasm and production of reactive oxygen species and nitric oxide constitute early events generally observed in plant-pathogen interactions .

Positive and negative regulation of plant pathogen defense responses has been attributed to mitogen-activated protein kinase cascades .

In addition , salicylic acid , jasmonic acid and ethylene are components of signaling networks that provide the molecular basis for specificity of plant defense responses .

This article reviews recent advances in our understanding of early signaling events involved in the establishment of plant disease resistance .


Both gibberellic acid and abscisic acid inhibit the light induced synthesis of amaranthin in Amaranthus tricolor seedlings .

The auxin , indolyl-3-acetic acid has no effect .

The protein/RNA inhibitors , cycloheximide and 8-azaguanine , also reduced the levels of amaranthin produced .


The potassium ion ( K+ ) is vital for plant growth and development , and K+-deprivation leads to reduced crop yields .

Here we describe phenotypic , transcriptomic , and mutant analyses to investigate the signaling mechanisms mediating root architectural changes in Arabidopsis ( Arabidopsis thaliana ) Columbia .

We showed effects on root architecture are mediated through a reduction in cell division in the lateral root ( LR ) meristems , the rate of LR initiation is reduced but LR density is unaffected , and primary root growth is reduced only slightly .

This was primarily regulated through gibberellic acid ( GA ) signaling , which leads to the accumulation of growth-inhibitory DELLA proteins .

The short LR phenotype was rescued by exogenous application of GA but not of auxin or by the inhibition of ethylene signaling .

RNA-seq analysis showed upregulation by K+-deprivation of the transcription factors JUNGBRUNNEN1 ( JUB1 ) and the C-repeat-binding factor (CBF)/dehydration-responsive element-binding factor 1 regulon , which are known to regulate GA signaling and levels that regulate DELLAs .

Transgenic overexpression of JUB1 and CBF1 enhanced responses to K+ stress .

Attenuation of the reduced LR growth response occurred in mutants of the CBF1 target gene SFR6 , implicating a role for JUB1 , CBF1 , and SFR6 in the regulation of LR growth in response to K+-deprivation via DELLAs .

We propose this represents a mechanism to limit horizontal root growth in conditions where K+ is available deeper in the soil .


Jasmonates ( JAs ) are signals in plant stress responses and development .

One of the first observed and prominent responses to JAs is the induction of biosynthesis of different groups of secondary compounds .

Among them are nicotine , isoquinolines , glucosinolates , anthocyanins , benzophenanthridine alkaloids , artemisinin , and terpenoid indole alkaloids ( TIAs ) , such as vinblastine .

This brief review describes modes of action of JAs in the biosynthesis of anthocyanins , nicotine , TIAs , glucosinolates and artemisinin .

After introducing JA biosynthesis , the central role of the SCF(COI1)-JAZ co-receptor complex in JA perception and MYB-type and MYC-type transcription factors is described .

Brief comments are provided on primary metabolites as precursors of secondary compounds .

Pathways for the biosynthesis of anthocyanin , nicotine , TIAs , glucosinolates and artemisinin are described with an emphasis on JA-dependent transcription factors , which activate or repress the expression of essential genes encoding enzymes in the biosynthesis of these secondary compounds .

Applied aspects are discussed using the biotechnological formation of artemisinin as an example of JA-induced biosynthesis of secondary compounds in plant cell factories .


Plants are photosynthetic organisms that depend on sunlight for energy .

Plants respond to light through different photoreceptors and show photomorphogenic development .

Apart from Photosynthetically Active Radiation ( PAR ; 400 - 700 nm ) , plants are exposed to UV light , which is comprised of UV-C ( below 280 nm ) , UV-B ( 280 - 320 nm ) and UV-A ( 320 - 390 nm ) .

The atmospheric ozone layer protects UV-C radiation from reaching earth while the UVR8 protein acts as a receptor for UV-B radiation .

Low levels of UV-B exposure initiate signaling through UVR8 and induce secondary metabolite genes involved in protection against UV while higher dosages are very detrimental to plants .

It has also been reported that genes involved in MAPK cascade help the plant in providing tolerance against UV radiation .

The important targets of UV radiation in plant cells are DNA , lipids and proteins and also vital processes such as photosynthesis .

Recent studies showed that , in response to UV radiation , mitochondria and chloroplasts produce a reactive oxygen species ( ROS ) .

Arabidopsis metacaspase-8 ( AtMC8 ) is induced in response to oxidative stress caused by ROS , which acts downstream of the radical induced cell death ( AtRCD1 ) gene making plants vulnerable to cell death .

The studies on salicylic and jasmonic acid signaling mutants revealed that SA and JA regulate the ROS level and antagonize ROS mediated cell death .

Recently , molecular studies have revealed genes involved in response to UV exposure , with respect to programmed cell death ( PCD ) .


BACKGROUND AND AIMS : Current strategies for increased crop protection of susceptible tomato plants against pathogen infections include treatment with synthetic chemicals , application of natural pathogen-derived compounds or transfer of resistance genes from wild tomato species within breeding programmes .

In this study , a series of 45 genes potentially involved in defence mechanisms was retrieved from the genome sequence of inbred reference tomato cultivar Solanum lycopersicum ' Heinz 1706 ' .

The aim of the study was to analyse expression of these selected genes in wild and cultivated tomato plants contrasting in resistance to the biotrophic pathogen Oidium neolycopersici , the causative agent of powdery mildew .

Plants were treated either solely with potential resistance inducers or by inducers together with the pathogen .

METHODS : The resistance against O. neolycopersici infection as well as RT-PCR-based analysis of gene expression in response to the oomycete elicitor oligandrin and chemical agent β-aminobutyric acid ( BABA ) were investigated in the highly susceptible domesticated inbred genotype Solanum lycopersicum ' Amateur ' and resistant wild genotype Solanum habrochaites .

KEY RESULTS : Differences in basal expression levels of defensins , germins , β-1,3-glucanases , heveins , chitinases , osmotins and PR1 proteins in non-infected and non-elicited plants were observed between the highly resistant and susceptible genotypes .

Moreover , these defence genes showed an extensive up-regulation following O. neolycopersici infection in both genotypes .

Application of BABA and elicitin induced expression of multiple defence-related transcripts and , through different mechanisms , enhanced resistance against powdery mildew in the susceptible tomato genotype .

CONCLUSIONS : The results indicate that non-specific resistance in the resistant genotype S. habrochaites resulted from high basal levels of transcripts with proven roles in defence processes .

In the susceptible genotype S. lycopersicum ' Amateur ' , oligandrin- and BABA-induced resistance involved different signalling pathways , with BABA-treated leaves displaying direct activation of the ethylene-dependent signalling pathway , in contrast to previously reported jasmonic acid-mediated signalling for elicitins .


Gibberellic acid ( GA(3 ) ) is one of the plant growth regulators which improve salt tolerance and mitigate the salt stress impact on plants .

The extant analysis was carried out to study the effect of GA(3 ) and different salt concentrations on seed germination and physiological parameters of oat cultivars .

Oats is substantially less tolerant to salt than wheat and barley .

Experimentation was conducted as factorial with Completely Randomized Block Design with three replicates .

Different concentration of NaCl salt ( ( 25 , 50 , 75 and 100 mM ) were used in test control group and 100 and 150 ppm of GA(3 ) were used in two group by pre-treated ( after 24 h of the seed soaking ) and plants were analyzed on 15th day .

Results indicate that increasing salinity would decrease the germination percentage and growth parameter in three oat cultivars .

Quotes data indicating a 13 % , 19.9 % and 32.48 % in cultivars NDO-2 , UPO-212 and UPO-94 germination reduction when soil salinity reaches 50 mM. A 36.02 % , 47.33 % and 56.365 reduction in germination is likely when soil salinity reaches 100 mM respectively same cultivars .

Seeds treated with GA(3 ) significantly promoted the percentage of germination , shoot and root length , total fresh and dry weight of seedling , tissue water content and seedling vigor index by NDO-2 and UPO-212 under different saline concentration .

The maximum average of germination and growth parameters were observed from 150 ppm GA(3 ) treated seeds .

But this concentration was significantly inhibited root length in sensitive cultivar UPO-94 at 75 and 100 mM salt as compared to 100 ppm .

We observed that , the high concentration of GA(3 ) was not suitable for sensitive oat cultivars .

Because the plant root are the real workforce behind any plants success .

Thus , it may be concluding that , GA(3 ) treatment could curtail the toxic effect of salinity by increasing germination percentage and shoot and root length , total fresh and dry weight , tissue water content and seedling vigor index in tolerant cultivar .


• Owing to its evolutional plasticity and adaptability , barley ( Hordeum vulgare ) is one of the most widespread crops in the world .

Despite this evolutionary success , sexual reproduction of small grain cereals is poorly investigated , making discovery of novel genes and functions a challenging priority .

Barley gene Jekyll appears to be a key player in grain development ; however , its role in flowers has remained unknown .

• Here , we studied RNAi lines of barley , where Jekyll expression was repressed to different extents .

The impact of Jekyll on flower development was evaluated based on differential gene expression analysis applied to anthers and gynoecia of wildtype and transgenic plants , as well as using isotope labeling experiments , hormone analysis , immunogold- and TUNEL-assays and in situ hybridization .

• Jekyll is expressed in nurse tissues mediating gametophyte-sporophyte interaction in anthers and gynoecia , where JEKYLL was found within the intracellular membranes .

The repression of Jekyll impaired pollen maturation , anther dehiscence and induced a significant loss of fertility .

The presence of JEKYLL on the pollen surface also hints at possible involvement in the fertilization process .

• We conclude that the role of Jekyll in cereal sexual reproduction is clearly much broader than has been hitherto realized .


Ascochyta blight of lentil is an important fungal disease in many lentil-producing regions of the world causing major yield and grain quality losses .

Quick shifts in aggressiveness of the population of the causal agent Ascochyta lentis mandates developing germplasm with novel and durable resistance .

In the absence of complete resistance , lentil genotypes CDC Robin and 964a-46 have frequently been used as sources of partial resistance to ascochyta blight and carry non-allelic ascochyta blight resistance genes .

RNA-seq analysis was conducted to identify differences in the transcriptome of CDC Robin , 964a-46 and the susceptible check Eston after inoculation with A. lentis .

Candidate defense genes differentially expressed among the genotypes had hypothetical functions in various layers of plant defense , including pathogen recognition , phytohormone signaling pathways and downstream defense responses .

CDC Robin and 964a-46 activated cell surface receptors ( e.g. receptor like kinases ) tentatively associated with pathogen-associated molecular patterns ( PAMP ) recognition and nucleotide-binding site leucine-rich repeat ( NBS-LRR ) receptors associated with intracellular effector recognition upon A. lentis infection , and differed in their activation of salicylic acid , abscisic acid and jasmonic acid / ethylene signal transduction pathways .

These differences were reflected in the differential expression of downstream defense responses such as pathogenesis-related proteins , and genes associated with the induction of cell death and cell-wall reinforcement .

A significant correlation between expression levels of a selection of genes based on quantitative real-time PCR and their expression levels estimated through RNA-seq demonstrated the technical and analytical accuracy of RNA-seq for identification of genes differentially expressed among genotypes .

The presence of different resistance mechanisms in 964a-46 and CDC Robin indicates their value for pyramiding gene leading to more durable resistance to ascochyta blight .


BACKGROUND : Wheat stem rust , caused by Puccinia graminis f. sp. tritici , is a major wheat disease which is mainly controlled through the release of resistant cultivars containing one or several resistance genes .

Considerable effort has been put into the discovery of new resistance genes , but knowledge of their mechanisms of action is often lacking .

In this study , the mechanism of resistance conferred by a recently discovered stem rust resistance locus on wheat chromosome 7AL was investigated through microscopic observations and RNA-sequencing , using the susceptible line Columbus and the independent , backcrossed , resistant lines Columbus-NS765 and Columbus-NS766 .

RESULTS : Microscopic observations of infected leaves revealed that the resistance conferred by the 7AL resistance locus was initiated 2 days post-inoculation , upon the fungus entry into the plant through the stoma .

Resistance was manifested by death of guard and epidermal cells adjacent to an infection site .

Occasionally , similar observations were made in the susceptible line , suggesting that the resistance response was the same in all genotypes , but enhanced in the resistant lines .

Transcriptomic analysis , combined with assignment of genes to wheat chromosomes , revealed a disproportionately high number of differentially expressed genes were located on chromosomes 7AL and 6A .

A number of genes annotated as cysteine-rich receptor-like kinases were located on chromosome 7AL .

Closer investigation indicated that the encoded proteins were in fact putative receptor-like cytoplasmic kinases .

One of the putative RLCK genes contained a SNP marker previously shown to co-segregate with the 7AL resistance locus .

The results also indicated the presence of a large introgression on chromosome 6A in both resistant lines , but whether it has any role in the resistance response is unclear .

CONCLUSIONS : This study represents the first investigation on the resistance mechanism conferred by the wheat 7AL stem rust resistance locus .

The resistance response was associated with pre-haustorial cell death , and the transcriptome analysis suggested putative receptor-like cytoplasmic kinases as candidate resistance genes for further investigation .


Fusarium species cause serious diseases in cereal staple food crops such as wheat and maize .

Currently , the mechanisms underlying resistance to Fusarium-caused diseases are still largely unknown .

In the present study , we employed a combined proteomic and transcriptomic approach to investigate wheat genes responding to F. graminearum infection that causes Fusarium head blight ( FHB ) .

We found a total of 163 genes and 37 proteins that were induced by infection .

These genes and proteins were associated with signaling pathways mediated by salicylic acid ( SA ) , jasmonic acid ( JA ) , ethylene ( ET ) , calcium ions , phosphatidic acid ( PA ) , as well as with reactive oxygen species ( ROS ) production and scavenging , antimicrobial compound synthesis , detoxification , and cell wall fortification .

We compared the time-course expression profiles between FHB-resistant Wangshuibai plants and susceptible Meh0106 mutant plants of a selected set of genes that are critical to the plants ' resistance and defense reactions .

A biphasic phenomenon was observed during the first 24 h after inoculation ( hai ) in the resistant plants .

The SA and Ca(2 + ) signaling pathways were activated within 6 hai followed by the JA mediated defense signaling activated around 12 hai .

ET signaling was activated between these two phases .

Genes for PA and ROS synthesis were induced during the SA and JA phases , respectively .

The delayed activation of the SA defense pathway in the mutant was associated with its susceptibility .

After F. graminearum infection , the endogenous contents of SA and JA in Wangshuibai and the mutant changed in a manner similar to the investigated genes corresponding to the individual pathways .

A few genes for resistance-related cell modification and phytoalexin production were also identified .

This study provided important clues for designing strategies to curb diseases caused by Fusarium .


In tobacco , two mitogen-activated protein ( MAP ) kinases , designated salicylic acid (SA)-induced protein kinase ( SIPK ) and wounding-induced protein kinase ( WIPK ) are activated in a disease resistance-specific manner following pathogen infection or elicitor treatment .

To investigate whether nitric oxide ( NO ) , SA , ethylene , or jasmonic acid ( JA ) are involved in this phenomenon , the ability of these defense signals to activate these kinases was assessed .

Both NO and SA activated SIPK ; however , they did not activate WIPK .

Additional analyses with transgenic NahG tobacco revealed that SA is required for the NO-mediated induction of SIPK .

Neither JA nor ethylene activated SIPK or WIPK .

Thus , SIPK may function downstream of SA in the NO signaling pathway for defense responses , while the signals responsible for resistance-associated WIPK activation have yet to be determined .


The major programs of gene expression during late embryogenesis are the muturation or reserve accumulation program and , after ovule abscission , the postabscission program that is composed largely of Lea and LeaA mRNAs that probably encode desiccation protectants .

There are diverse opinions about the developmental regulators of these programs .

Several candidates are evaluated here by measuring , in cultured embryos , the accumulation kinetics of cloned mRNAs specifically expressed in the normal maturation , postabscission , or germination programs of cotton .

Maturation-stage embryos both terminate the maturation program and induce the postabscission program after excision and culture , just as they do later in the plant after ovule abscission .

However , they also induce simultaneously the germination program and are thus different from any normal stage of embryo development or germination .

The developmental induction of the postabscission program in culture does not require exogenous abscisic acid , but its expression is enhanced by precocious desiccation or culture on abscisic acid or high osmoticum , probably by an environmentally responsive mechanism that normally operates during germination .

Normal desiccation does not control any of these programs because the embryo acquires all of the characteristics of a mature embryo before it desiccates .

These and other results suggest regulation of normal embryogenesis by a maternal maturation factor , a postabscission factor , and the postabscission program .


SPINDLY ( SPY ) is an important regulator of plant development , and consists of an N-half tetratricopeptide repeat ( TPR ) domain containing 10 TPR motifs and a C-half catalytic domain , similar to O-GlcNAc transferase ( OGT ) of animals .

The best characterised role of SPY is a negative regulator of GA signalling , and all known spy alleles have been isolated based on increased GA response .

Of the eight alleles that directly affect the TPR domain , all alter TPRs 6 , 8 and/or 9 .

To test the hypothesis that a subset of TPRs , including 6 , 8 and 9 , are both essential and sufficient for the regulation of GA response , we overexpressed the full-length barley ( Hordeum vulgare L. ) SPY protein ( HvSPY ) and several deletion mutants in barley aleurone cells and in Arabidopsis wild type ( WT ) and spy-4 plants .

Transient assays in barley aleurone cells , that also express endogenous HvSPY , demonstrated that introduced HvSPY and HvTPR inhibited GA(3)-induced alpha-amylase expression .

With the exception of HvSPYDelta1 - 5 , the other deletion proteins were partially active in the barley assay , including HvSPYDelta6 - 9 which lacks TPRs 6 , 8 and 9 .

In Arabidopsis , analysis of seed germination under a range of conditions revealed that 35S : HvSPY increased seed dormancy .

Hvspy-2 , which lacks parts of the eighth and ninth TPRs , was able to partially complement all aspects of the spy-4 phenotype .

In the presence of AtSPY , 35S : HvTPR caused some phenotypes consistent with a decrease in GA signalling , including increased seed sensitivity to paclobutrazol and delayed flowering .

These plants also possessed distorted leaf morphology and altered epidermal cell shape .

Thus , despite genetic analysis demonstrating that TPRs 6 , 8 and 9 are required for regulation of GA signalling , our results suggest that these TPRs are neither absolutely essential nor sufficient for SPY activity .


The citrus rootstocks sour orange and Cleopatra mandarin display differential resistance against Tetranychus urticae .

Sour orange plants support reduced oviposition , growth rates and damage compared with Cleopatra mandarin plants .

Jasmonic acid signalling and flavonoid accumulation have been revealed as key mechanisms for the enhanced resistance of sour orange plants .

In this study , we observed that the release of T. urticae herbivore-induced plant volatiles ( HIPVs ) from sour orange plants has a marked repellent effect on conspecific mites associated with the production of the terpenes α-ocimene , α-farnesene , pinene and d-limonene , and the green leaf volatile 4-hydroxy-4-methyl-2-pentanone .

By contrast , T. urticae HIPVs from Cleopatra mandarin plants promote conspecific mite attraction associated with an increase in ( 2-butoxyethoxy ) ethanol , benzaldehyde and methyl salicylate levels .

HIPVs released from sour orange plants following T. urticae infestation induce resistance in Cleopatra mandarin plants , thereby reducing oviposition rates and stimulating the oxylipin biosynthetic gene lipoxygenase2 ( LOX2 ) .

Cleopatra HIPVs do not affect the response to T. urticae of these rootstocks .

We conclude that sour orange plants promote herbivore-induced resistance in Cleopatra mandarin plants and , despite the weak basal resistance of these rootstocks , herbivore resistance can be induced through the combination of HIPVs , such as α-ocimene and d-limonene .


Proteomics has contributed to defining the specific functions of genes and proteins involved in plant-pathogen interactions .

Proteomic studies have led to the identification of many pathogenicity and defense-related genes and proteins expressed during phytopathogen infections , resulting in the collection of an enormous amount of data .

However , the molecular basis of plant-pathogen interactions remains an intensely active area of investigation .

In this review , the role of differential analysis of proteins expressed during fungal , bacterial , and viral infection is discussed , as well as the role of JA and SA in the production of stress related proteins .

Resistance acquired upon induction of stress related proteins in intact plant leaves is mediated by potentiation of pathogens via signal elicitors .

Stress related genes extensively used in biotechnology had been cited .

Stress related proteins identified must be followed through for studying the molecular mechanism for plant defense against pathogens .


WRKY proteins form a large family of plant transcription factors implicated in the modulation of numerous biological processes , such as growth , development and responses to various environmental stresses .

However , the roles of the majority WRKY family members , especially in non-model plants , remain poorly understood .

Transient expression in onion epidermal cells showed that CaWRKY40 can be targeted to nuclei and activates expression of a W-box-containing reporter gene .

CaWRKY40 transcripts are induced in pepper by Ralstonia solanacearum and heat shock .

To assess roles of CaWRKY40 in plant stress responses we performed gain- and loss-of-function experiments .

Overexpression of CaWRKY40 enhanced resistance to R. solanacearum and tolerance to heat shock in tobacco .

In contrast , silencing of CaWRKY40 enhanced susceptibility to R. solanacearum and impaired thermotolerance in pepper .

Consistent with its role in multiple stress responses , we found CaWRKY40 transcripts to be induced by signalling mechanisms mediated by the stress hormones salicylic acid ( SA ) , jasmonic acid ( JA ) and ethylene ( ET ) .

Overexpression of CaWRKY40 in tobacco modified the expression of hypersensitive response (HR)-associated and pathogenesis-related genes .

Collectively , our results suggest that CaWRKY40 orthologs are regulated by SA , JA and ET signalling and coordinate responses to R. solanacearum attacks and heat stress in pepper and tobacco .


Allene oxide synthase ( AOS ) mediates the conversion of lipoxygenase-derived fatty acid hydroperoxides to unstable allene epoxides , which supply the precursors for the synthesis of the phytohormone jasmonic acid ( JA ) .

In this study the characterization of AOS gene expression in flax ( Linum usitatissimum ) is reported .

AOS was constitutively expressed in different organs of flax plants .

Additionally , AOS gene expression was enhanced after mechanical wounding in both the directly damaged leaves and in the systemic tissue located distal to the treated leaves .

This wound-induced accumulation of AOS required the de novo biosynthesis of other unknown proteins involved in the signaling pathway modulating wound-induced AOS gene expression .

Furthermore , the wound-induced AOS mRNA accumulation was correlated with the increase in the levels of JA .

Both JA and its precursor , 12-oxo-phytodienoic acid , activated AOS gene expression in a dose-dependent manner .

Thus , JA could activate its own biosynthetic pathway in flax leaves .

Moreover , neither salicylic acid ( SA ) nor aspirin influenced AOS enzymatic activity .

It is interesting that pretreatment with SA or aspirin inhibited wound-induced accumulation of AOS transcripts .

These results suggest that a potent inhibition of JA biosynthetic capacity in leaves can be affected by SA or aspirin at the level of AOS gene expression .


Harvestable , starch-storing organs of plants , such as fleshy taproots and tubers , are important agronomic products that are also suitable target organs for use in the molecular farming of recombinant proteins due to their strong sink strength .

To exploit a promoter directing strong expression restricted to these storage organs , we isolated the promoter region ( 3.0 kb ) of SRD1 from sweetpotato ( Ipomoea batatas cv . ' White Star ' ) and characterized its activity in transgenic Arabidopsis , carrot , and potato using the β-glucuronidase ( GUS ) gene ( uidA ) as a reporter gene .

The SRD1 promoter conferred root-specific expression in transgenic Arabidopsis , with SRD1 promoter activity increasing in response to exogenous IAA .

A time-course study of the effect of IAA ( 50 μM ) revealed a maximum increase in SRD1 promoter activity at 24 h post-treatment initiation .

A serial 5 ' deletion analysis of the SRD1 promoter identified regions related to IAA-inducible expression as well as regions containing positive and negative elements , respectively , controlling the expression level .

In transgenic carrot , the SRD1 promoter mediated strong taproot-specific expression , as evidenced by GUS staining being strong in almost the entire taproot , including secondary phloem , secondary xylem and vascular cambium .

The activity of the SRD1 promoter gradually increased with increasing diameter of the taproot in the transgenic carrot and was 10.71-fold higher than that of the CaMV35S promoter .

The SRD1 promoter also directed strong tuber-specific expression in transgenic potato .

Taken together , these results demonstrate that the SRD1 promoter directs strong expression restricted to the underground storage organs , such as fleshy taproots and tubers , as well as fibrous root tissues .


The effect of calcium on the secretion of α-amylase ( EC 3.2.1.1 ) and other hydrolases from aleurone layers of barley ( Hordeum vulgare L. cv . Himalaya ) was studied .

Withdrawal of Ca(2 + ) from the incubation medium of aleurone layers preincubated in 5 μM gibberellic acid ( GA3 ) and 5 mM CaCl2 results in a 70 - 80 % reduction in the secretion of α-amylase activity to the incubation medium .

Agar-gel electrophoresis shows that the reduction in α-amylase activity following Ca(2 + ) withdrawal is correlated with the disappearance of group B isoenzymes from the incubation medium .

The secretion of isoenzymes of group A is unaffected by Ca(2 + ) .

The addition of Ca(2 + ) stimulates the secretion of group-B isoenzymes but has no measurable effect on either the α-amylase activity or the isoenzyme pattern of aleurone-layer extracts .

Pulse-labelling experiments with [(35)S]methionine show that Ca(2 + ) withdrawal results in a reduction in the secretion of labelled polypeptides into the incubation medium .

Immunochemical studies also show that , in the absence of Ca(2 + ) , α-amylase isoenzymes of group B are not secreted into the incubation medium .

In addition to its effect on α-amylase , Ca(2 + ) influences the secretion of other proteins including several acid hydrolases .

The secretion of these other proteins shows the same dependence on Ca(2 + ) concentration as does that of α-amylase .

Other cations can promote the secretion of α-amylase to less and varying extents .

Strontium is 85 % as effective as Ca(2 + ) while Ba(2 + ) is only 10 % as effective .

We conclude that Ca(2 + ) regulates the secretion of enzymes and other proteins from the aleurone layer of barley .


GIBBERELLIN INSENSITIVE DWARF1 ( GID1 ) encodes a soluble gibberellin ( GA ) receptor that shares sequence similarity with a hormone-sensitive lipase ( HSL ) .

Previously , a yeast two-hybrid ( Y2H ) assay revealed that the GID1-GA complex directly interacts with SLENDER RICE1 ( SLR1 ) , a DELLA repressor protein in GA signaling .

Here , we demonstrated , by pull-down and bimolecular fluorescence complementation ( BiFC ) experiments , that the GA-dependent GID1-SLR1 interaction also occurs in planta .

GA(4 ) was found to have the highest affinity to GID1 in Y2H assays and is the most effective form of GA in planta .

Domain analyses of SLR1 using Y2H , gel filtration , and BiFC methods revealed that the DELLA and TVHYNP domains of SLR1 are required for the GID1-SLR1 interaction .

To identify the important regions of GID1 for GA and SLR1 interactions , we used many different mutant versions of GID1 , such as the spontaneous mutant GID1s , N- and C-terminal truncated GID1s , and mutagenized GID1 proteins with conserved amino acids replaced with Ala. The amino acid residues important for SLR1 interaction completely overlapped the residues required for GA binding that were scattered throughout the GID1 molecule .

When we plotted these residues on the GID1 structure predicted by analogy with HSL tertiary structure , many residues were located at regions corresponding to the substrate binding pocket and lid .

Furthermore , the GA-GID1 interaction was stabilized by SLR1 .

Based on these observations , we proposed a molecular model for interaction between GA , GID1 , and SLR1 .


Fungal elicitor prepared from the cell walls of Aspergillum niger induces multiple responses of Hypericum perforatum cells , including nitric oxide ( NO ) generation , jasmonic acid ( JA ) biosynthesis , and hypericin production .

Pretreatment of the cells with cPITO and JA biosynthesis inhibitors suppresses not only the elicitor-induced NO generation and JA accumulation but also the elicitor-induced hypericin production , which suggests that both NO and JA are involved in elicitor-induced hypericin biosynthesis .

External application of NO via its donor sodium nitroprusside induces hypericin production in the absence of fungal elicitor .

Sodium-nitroprusside-induced hypericin production is blocked by JA biosynthesis inhibitors , showing that JA biosynthesis is essential for NO-induced hypericin production .

The results demonstrate a causal relationship between elicitor-induced NO generation , JA biosynthesis , and hypericin production in H. perforatum cells and indicate a sequence of signaling events from NO to hypericin production , within which NO mediates the elicitor-induced hypericin biosynthesis at least partially via a JA-dependent signaling pathway .


cDNA clones encoding three additional serine carboxypeptidases ( Ser-CPs ) have been isolated from a gibberellic acid-induced barley aleurone cDNA library .

The three deduced Ser-CPs belong to the two-chain subfamily of Ser-CPs ; they are synthesized as precursors with a putative signal peptide , propeptide , and linker peptide between the A and B chains .

Their identification provides the proof for the existence of more than three Ser-CPs in cereal grains , and , based on their sequences , they may exhibit new substrate specificities .

The expression of these and of the three previously isolated Ser-CPs from barley grains ( CP-MI , CP-MII , and CP-MIII ) has been investigated by Northern and Western analysis and RNA PCR .

CP-MII is the only Ser-CP to be expressed and accumulate in the developing grain and is stored in its active form in the mature grain .

All six Ser-CPs are expressed de novo in the germinating grain , in the scutellum , and/or in the aleurone .

Furthermore , at least CP-MI , CP-MII , and CP-MIII are secreted into the endosperm .

In addition , all Ser-CPs ( except CP-MI ) are also expressed in the roots and shoots of the growing seedling .

This enzyme family thus appears to be ubiquitous in the barley plant , which suggests that Ser-CPs play additional roles besides their participation in the mobilization of storage proteins .


Jasmonates ( JAs ) are well-known regulators of stress , defence , and secondary metabolism in plants , with JA perception triggering extensive transcriptional reprogramming , including both activation and/or repression of entire metabolic pathways .

We performed RNA sequencing based transcriptomic profiling of tobacco BY-2 cells before and after treatment with methyl jasmonate ( MeJA ) to identify novel transcriptional regulators associated with alkaloid formation .

A total of 107,140 unigenes were obtained through de novo assembly , and at least 33,213 transcripts ( 31 % ) encode proteins , in which 3419 transcription factors ( TFs ) were identified , representing 72 gene families , as well as 840 transcriptional regulators ( TRs ) distributed among 19 gene families .

After MeJA treatment BY-2 cells , 7260 differentially expressed transcripts were characterised , which include 4443 MeJA-upregulated and 2817 MeJA-downregulated genes .

Of these , 227 TFs/TRs in 36 families were specifically upregulated , and 102 TFs/TRs in 38 families were downregulated in MeJA-treated BY-2 cells .

We further showed that the expression of 12 ethylene response factors and four basic helix-loop-helix factors increased at the transcriptional level after MeJA treatment in BY-2 cells and displayed specific expression patterns in nic mutants with or without MeJA treatments .

Our data provide a catalogue of transcripts of tobacco BY-2 cells and benefit future study of JA-modulated regulation of secondary metabolism in tobacco .


Phytoalexin synthesis is a defence-response- that is characterized by a requirement for a number of distinct elements , all of which must be present for the response to be expressed fully .

These same elements : a signal , a cellular receptor , a signal transduction system and a responsive metabolic system , are also used to describe a stimulus-response system .

A number of molecular species can function as signal molecules or elicitors of phytoalexin synthesis , including poly- and oligosaccharides , proteins and polypeptides , and fatty acids .

Few receptors for elicitors have been identified but those that have been are proteins located on the plasma membrane of the plant .

Induction of phytoalexin synthesis involves selective and co-ordinated activation of specific defence response genes , including those encoding the enzymes of phytoalexin synthesis , and these genes constitute the responsive metabolic system .

The separate , and distant , locations of the receptor and the responsive genes means that the event in which the signal is perceived by the receptor must be relayed to the genes by means of a second messenger system .

Several second messengers are candidates for such a coupling- or signal transduction-system , including udenosine-3',5'-cyclic monophosphate , Ca(2 + ) , diacylglycerol and inositol 1,4,5-trisphosphate , active oxygen species and jasmonic acid .

Each has been examined as a possible component of the signal transduction system mediating between the elicitor receptor interaction and the phytoalexin synthesis it induces .

Analysis of the signalling events is made complex by the simultaneous solicitation by the invading micro-organism of several defence responses , each of which might involve elements of a different signal system .

The same complexity is evident which the role of phytoalexin accumulation in resistance is analysed .

Evaluation of the contribution made by phytoalexin accumulation towards resistance has been attempted by the use of various inhibitors and enhancers of the process .

Transgenic and mutant plants with specific alterations in one or more ot those elements necessary for the plant to respond to the signals for phytoalexin synthesis and other defence responses , are beginning to aid resolution of the complex pattern ot signalling events and the respective roles of the inducible defence mechanisms in resistance .

CONTENTS Summary 1 I. Introduction 2 II .

Phytoalexin accumulation as a determinant of resistance 6 IV .

Elicitation of phytoalexin accumulation 11 References 34 .


Induced resistance response is a potent and cost effective plant defense against pathogen attack .

The effectiveness and underlying mechanisms of the suppressive ability by Bacillus cereus AR156 to Pseudomonas syringae pv . tomato DC3000 ( Pst DC3000 ) in Arabidopsis has been investigated previously ; however , the strength of induced systemic resistance ( ISR ) activity against Botrytis cinerea remains unknown .

Here , we show that root-drench application of AR156 significantly reduces disease incidence through activation of ISR .

This protection is accompanied with multilayered ISR defense response activated via enhanced accumulation of PR1 protein expression in a timely manner , hydrogen peroxide accumulation and callose deposition , which is significantly more intense in plants with both AR156 pretreatment and B. cinerea inoculation than that in plants with pathogen inoculation only .

Moreover , AR156 can trigger ISR in sid2 - 2 and NahG mutants , but not in jar1 , ein2 and npr1 mutant plants .

Our results indicate that AR156-induced ISR depends on JA/ET-signaling pathway and NPR1 , but not SA .

Also , AR156-treated plants are able to rapidly activate MAPK signaling and FRK1/WRKY53 gene expression , both of which are involved in pathogen associated molecular pattern (PAMP)-triggered immunity ( PTI ) .

The results indicate that AR156 can induce ISR by the JA/ET-signaling pathways in an NPR1-dependent manner and involves multiple PTI components .


In response to infestation by herbivores , rice plants rapidly biosynthesize defense compounds by activating a series of defense-related pathways .

However , which defensive compounds in rice are effective against herbivores remains largely unknown .

We found that the infestation of white-backed planthopper ( WBPH ) Sogatella furcifera gravid females significantly increased levels of jasmonic acid ( JA ) , jasmonoyl-isoleucine ( JA-Ile ) and H(2)O(2 ) , and reduced the level of ethylene in rice ; levels of 11 of the tested 12 phenolamides ( PAs ) were subsequently enhanced .

In contrast , WBPH nymph infestation had no effect on levels of JA , JA-Ile , ethylene and H(2)O(2 ) in rice , and enhanced levels of only 2 of 12 PAs .

Moreover , infestation by brown planthopper Nilaparvata lugens gravid females also affected the production of these PAs differently .

Bioassays revealed that 4 PAs - N-feruloylputrescine , N-feruloyltyramine , feruloylagmatine and N1,N10-diferuloylspermidine - were toxic to newly emerged WBPH female adults .

Our results suggest that WBPH- or BPH-induced biosynthesis of PAs in rice seems to be shaped primarily by the specific profile of defense-related signals elicited by the herbivore and that PAs play a role in conferring the resistance to WBPH on rice .


Pseudomonas syringae pv tomato DC3000 ( Pst DC3000 ) , which causes disease in tomato ( Solanum lycopersicum ) and Arabidopsis ( Arabidopsis thaliana ) , produces coronatine ( COR ) , a non-host-specific phytotoxin .

COR , which functions as a jasmonate mimic , is required for full virulence of Pst DC3000 and for the induction of chlorosis in host plants .

Previous genetic screens based on insensitivity to COR and/or methyl jasmonate identified several potential targets for COR and methyl jasmonate .

In this study , we utilized Nicotiana benthamiana and virus-induced gene silencing to individually reduce the expression of over 4,000 genes .

The silenced lines of N. benthamiana were then screened for altered responses to purified COR .

Using this forward genetics approach , several genes were identified with altered responses to COR .

These were designated as ALC ( for altered COR response ) genes .

When silenced , one of the identified genes , ALC1 , produced a hypersensitive/necrosis-like phenotype upon COR application in a Coronatine-Insensitive1 (COI1)-dependent manner .

To understand the involvement of ALC1 during the Pst DC3000-host interaction , we used the nucleotide sequence of ALC1 and identified its ortholog in Arabidopsis ( Thylakoid Formation1 [ THF1 ] ) and tomato ( SlALC1 ) .

In pathogenicity assays performed on Arabidopsis thf1 mutant and SlALC1-silenced tomato plants , Pst DC3000 induced accelerated coalescing necrotic lesions .

Furthermore , we showed that COR affects ALC1 localization in chloroplasts in a COI1-dependent manner .

In conclusion , our results show that the virus-induced gene silencing-based forward genetic screen has the potential to identify new players in COR signaling and disease-associated necrotic cell death .


Shoot apices of Lolium temulentum excised after exposure of the plants to one long day ( LD ) undergo floral development in vitro , whereas those excised from plants in short days ( SD ) remain vegetative .

Floral differentiation in vitro is reasonably normal and responds quantitatively to the preceding LD induction when three conditions are met .

First , excision must not precede the arrival at the apex of the LD stimulus from the leaves .

This appears to begin about 22 h after the start of the LD and is completed after a further 14 h , by which time all isolated apices have become capable of initiating inflorescence differentiation , i.e. florally determined .

Second , for apices excised on the day after the LD ( Day II ) or early on Day III , the presence of gibberellic acid in the medium is required for floral differentiation to occur in most explants .

By contrast , neither kinetin ( N(6)-furfurylaminopurine ) nor indole-3-acetic acid is required or beneficial , while abscisic acid in the medium is inhibitory to both survival and floral differentiation in excised apices .

The third requirement is for an adequate supply of sugar , particularly after floral differentiation begins .

Sucrose is taken up rapidly to reach high levels in the excised apices , but high sugar concentration in the medium , either alone or with gibberellic acid , does not suffice for floral differentiation to begin , and there is an absolute requirement for receipt of the LD stimulus .


Agricultural practices in grapevines management include water restrictions due to its positive effect on wine quality , especially when applied at fruit ripening .

Although the effects of water stress in some groups of phytohormones have already been described in leaves and whole grapes , information regarding tissue-specific variations in hormones during ripening in grapes is scarce .

Field-grown grapevines from the cv . " Merlot " were subjected to two differential water supplies , including only rainfed , non-irrigated vines ( T0 ) and vines additionally irrigated with 25Lweek(-1 ) vine(-1 ) ( T1 ) .

Tissue-specific variations in the hormonal profiling of grapes [ including changes in the contents of abscisic acid ( ABA ) , jasmonic acid ( JA ) , salicylic acid ( SA ) , the ethylene precursor 1-amino-cyclopropane-1-carboxylic acid ( ACC ) , the auxin indole-3-acetic acid , gibberellins 1 , 3 , 4 , and 7 ( GA(1 ) , GA(3 ) , GA(4 ) , and GA(7 ) ) , the cytokinins trans-zeatin , and 2-isopentenyl adenine , including as well their respective ribosylated forms ] were periodically evaluated from veraison to harvest .

The hormonal profiling in leaves was also measured at the beginning and end of the season for comparison .

Results showed that grape growth dynamics were transiently affected by the differences in water regimes , the increased water supply leading to an accelerated growth , slightly reduced accumulation of sugars , and transiently lowered pH , although grape quality did not differ between treatments at harvest .

Hormonal profiling of whole berries did not reveal any difference in the endogenous contents of phytohormones between treatments , except for a transient decrease in GA(4 ) contents in T1 compared to T0 vines , which was not confirmed at the tissular level .

Hormonal profiling at the tissue level highlighted a differential accumulation of phytohormones during ripening in berry tissues , with pulps being particularly poor in ABA , JA , and SA contents , seeds particularly accumulating ACC , gibberellins , and zeatin-type cytokinins , and the skin being particularly rich in auxin and active cytokinins .

Changes in water supply led to very small and transient changes in the endogenous contents of phytohormones in the seeds , pulp , and skin of berries , the most remarkable variations being observed in cytokinin contents , which increased earlier [ between 5 and 12days after veraison ( DAV ) ] but later kept more constant in the skin from T1 compared to T0 vines and were also 3-fold higher at 40 DAV in seeds of T1 compared to T0 vines .

It is concluded that small changes in water supply can trigger hormonal-driven physiological adjustments at the tissular level affecting the evolution of fruit growth and quality throughout grape berry ripening .


Herbivore-induced plant volatiles ( HIPVs ) are commonly emitted from plants after herbivore attack .

These HIPVs are mainly regulated by the defensive plant hormone jasmonic acid ( JA ) and its volatile derivative methyl jasmonate ( MeJA ) .

Over the past 3 decades researchers have documented that HIPVs can repel or attract herbivores , attract the natural enemies of herbivores , and in some cases they can induce or prime plant defenses prior to herbivore attack .

In a recent paper , I reported that feeding by gypsy moth caterpillars , exogenous MeJA application , and mechanical damage induce the emissions of volatiles from blueberry plants , albeit differently .

In addition , blueberry branches respond to HIPVs emitted from neighboring branches of the same plant by increasing the levels of JA and resistance to herbivores ( i.e. , direct plant defenses ) , and by priming volatile emissions ( i.e. , indirect plant defenses ) .

Similar findings have been reported recently for sagebrush , poplar , and lima beans .

Here , I describe a push-pull method for collecting blueberry volatiles induced by herbivore ( gypsy moth ) feeding , exogenous MeJA application , and mechanical damage .

The volatile collection unit consists of a 4 L volatile collection chamber , a 2-piece guillotine , an air delivery system that purifies incoming air , and a vacuum system connected to a trap filled with Super-Q adsorbent to collect volatiles .

Volatiles collected in Super-Q traps are eluted with dichloromethane and then separated and quantified using Gas Chromatography ( GC ) .

This volatile collection method was used in my study to investigate the volatile response of undamaged branches to exposure to volatiles from herbivore-damaged branches within blueberry plants .

Briefly , undamaged blueberry branches are exposed to HIPVs from neighboring branches within the same plant .

Using the same techniques described above , volatiles emitted from branches after exposure to HIPVs are collected and analyzed .


Histone acts as the core for nucleosomes and is a key protein component of chromatin .

Among different histone variants , histone H3 ( HH3 ) variants have been reported to play vital roles in plant development .

However , biological information and evolutionary relationships of HH3 genes in cotton remain to be elucidated .

The current study identified 34 HH3 genes in Gossypium hirsutum .

Phylogenetic analysis classified HH3 genes of 19 plant species into eight distinct clades .

Sequence logos analysis among Arabidopsis , rice , and G. hirsutum amino acid residues showed higher conservation in amino acids .

Using collinearity analysis , we identified 81 orthologous/paralogous gene pairs among the four genomes ( A , D , At , and Dt ) of cotton .

Further , orthologous/paralogous and the Ka/Ks ratio demonstrated that cotton HH3 genes experienced strong purifying selection pressure with restricted functional divergence resulting from segmental and whole genome duplication .

Expression pattern analysis indicated that GhHH3 genes were preferentially expressed in cotton ovule tissues .

Additionally , GhHH3 gene expression can be regulated by abiotic stresses ( cold , heat , sodium chloride ( NaCl ) , and polyethylene glycol ( PEG ) ) and phytohormonal ( brassinolide ( BL ) , gibberellic acid ( GA ) , indole-3-acetic acid ( IAA ) , salicylic acid ( SA ) , and methyl jasmonate ( MeJA ) ) treatments , suggesting that GhHH3 genes might play roles in abiotic and hormone stress resistance .

Taken together , this work provides important information to decipher complete molecular and physiological functions of HH3 genes in cotton .


Hydrogen sulfide ( H(2)S ) is a gasotransmitter and signaling molecule associated with seed germination , plant growth , organogenesis , photosynthesis , stomatal conductance , senescence , and post-harvesting .

H(2)S is produced in plants via both enzymatic and non-enzymatic pathways in different subcellular compartments .

Exogenous application of H(2)S facilitates versatile metabolic processes and antioxidant machinery in plants under normal and environmental stresses .

This compound interacts with phytohormones like auxins , abscisic acid , gibberellins , ethylene , jasmonic acid , and salicylic acid .

Furthermore , H(2)S participates in signal transductions of other signaling molecules like nitric oxide , carbon monoxide , calcium , methylglyoxal , and hydrogen peroxide .

It also mediates post-translational modification , which is a protective mechanism against oxidative damage of proteins .

This review summarizes the roles of H(2)S as intriguing molecule in plants .


Jasmonic acid ( JA ) is a fatty acid-derived signaling molecule that regulates a broad range of plant defense responses against herbivores and some microbial pathogens .

Molecular genetic studies have established that JA also performs a critical role in several aspects of plant development .

Here , we describe the characterization of the Arabidopsis mutant jasmonic acid-hypersensitive1 - 1 ( jah1 - 1 ) , which is defective in several aspects of JA responses .

Although the mutant exhibits increased sensitivity to JA in root growth inhibition , it shows decreased expression of JA-inducible defense genes and reduced resistance to the necrotrophic fungus Botrytis cinerea .

Gene cloning studies indicate that these defects are caused by a mutation in the cytochrome P450 protein CYP82C2 .

We provide evidence showing that the compromised resistance of the jah1 - 1 mutant to B . cinerea is accompanied by decreased expression of JA-induced defense genes and reduced accumulation of JA-induced indole glucosinolates ( IGs ) .

Conversely , the enhanced resistance to B. cinerea in CYP82C2-overexpressing plants is accompanied by increased expression of JA-induced defense genes and elevated levels of JA-induced IGs .

We demonstrate that CYP82C2 affects JA-induced accumulation of the IG biosynthetic precursor tryptophan ( Trp ) , but not the JA-induced IAA or pathogen-induced camalexin .

Together , our results support a hypothesis that CYP82C2 may act in the metabolism of Trp-derived secondary metabolites under conditions in which JA levels are elevated .

The jah1 - 1 mutant should thus be important in future studies toward understanding the mechanisms underlying the complexity of JA-mediated differential responses , which are important for plants to adapt their growth to the ever-changing environments .


A class II hydrophobin gene , HFB2 - 6 , was cloned from Trichoderma asperellum ACCC30536 and its biocontrol function was studied .

According to our previous transcriptome data , six of the eight class II hydrophobin genes were obviously differential expression in four inducing conditions , especially the gene HFB2 - 6 .

Moreover , HFB2 - 6 proven to be differentially transcribed under eight different treatments .

HFB2 - 6 transcripts were up-regulated under 1 % Alternaria alternata cell wall and 5 % A. alternata fermentation liquid treatments , and by nutritional stress conditions , suggesting that HFB2 - 6 plays roles in interactions with both biotic and abiotic environmental conditions .

HFB2 - 6 expression was down-regulated under 1 % poplar leaf powder culture conditions , but its expression was up-regulated under 1 % poplar root powder , indicating that HFB2 - 6 has a function in root colonization .

Furthermore , the recombinant hydrophobin rHFB2 - 6 was successfully expressed in Escherichia coli BL21-HFB2 - 6 and purified from the recombinant strain .

Genes related to both the jasmonic acid and salicylic acid signal transduction pathways were up-regulated by interaction with renatured rHFB2 - 6 .

The ORCA3 ( octadecanoid-derivative responsive Catharanthus AP2-domain ) gene of the poplar jasmonic acid signal transduction pathway showed a peak expression of 4.48 times at 2 h , and the peak expression of PR1 ( pathogenesis-related protein gene ) in the salicylic acid signal transduction pathway was 4.58 times at 72 h. Two genes , MP ( monopteros ) and GH3.17 ( auxin original response gene ) , in the auxin signal transduction pathway were also up-regulated after induction with rHFB2 - 6 , indicating that rHFB2 - 6 can promote poplar growth and confer broad-spectrum resistance to pathogens .


Jasmonates ( JAs ) regulate Arabidopsis thaliana wound and defence responses , pollen development , and stress-related growth inhibition .

Significantly , each of these responses requires COI1 , an F-box protein .

Other F-box proteins interact with SKP1 and cullin proteins to form SCF complexes that selectively recruit regulatory proteins targeted for ubiquitination .

To determine whether COI1 also functions in an SCF complex , we have characterized Arabidopsis proteins that bind to COI1 .

An Arabidopsis cDNA expression library was screened in yeast for clones that produce proteins which can bind to COI1 .

We recovered two SKP1 homologues and a histone deacetylase .

The Arabidopsis F-box protein TIR1 interacted with SKP1 proteins , but not with the histone deacetylase .

Mutant COI1 proteins revealed that the F-box is required for interaction with SKP1s , but that sequences in leucine-rich repeat domains are required for interaction with the histone deacetylase .

Epitope-tagged COI1 was introduced into Arabidopsis plants and cell cultures .

Co-immunoprecipitation experiments confirmed the interaction in planta of COI1 with SKP1-like proteins and histone deacetylase , and also indicated that COI1 interacted with cullin .

These results suggest that COI1 forms an SCFCOI1 complex in vivo .

COI1 is therefore expected to form a functional E3-type ubiquitin ligase in plants and to regulate expression of jasmonate responsive genes , possibly by targeted ubiquitination of a histone deacetylase .


We analyzed the susceptibility of Arabidopsis mutants with defects in salicylic acid ( SA ) and jasmonic acid (JA)/ethylene ( ET ) signaling to infection by Cauliflower mosaic virus ( CaMV ) .

Mutants cpr1 - 1 and cpr5 - 2 , in which SA-dependent defense signaling is activated constitutively , were substantially more resistant than the wild type to systemic infection , implicating SA signaling in defense against CaMV .

However , SA-deficient NahG , sid2 - 2 , eds5 - 1 , and pad4 - 1 did not show enhanced susceptibility .

A cpr5 eds5 double mutant also was resistant , suggesting that resistance in cpr5 may function partially independently of SA .

Treatment of cpr5 and cpr5 eds5 , but not cpr1 , with salicyl-hydroxamic acid , an inhibitor of alternative oxidase , partially restored susceptibility to wild-type levels .

Mutants etr1 - 1 , etr1 - 3 , and ein2 - 1 , and two mutants with lesions in ET/JA-mediated defense , eds4 and eds8 , also showed reduced virus susceptibility , demonstrating that ET-dependent responses also play a role in susceptibility .

We used a green fluorescent protein (GFP)-expressing CaMV recombinant to monitor virus movement .

In mutants with reduced susceptibility , cpr1 - 1 , cpr5 - 2 , and etr1 - 1 , CaMV-GFP formed local lesions similar to the wild type , but systemic spread was almost completely absent in cpr1 and cpr5 and was substantially reduced in etr1 - 1 .

Thus , mutations with enhanced systemic acquired resistance or compromised ET signaling show diminished long-distance virus movement .


The features of the formation of microshoots in in vitro culture of Silene cretacea — endangered species with narrow ecological amplitude , which is a promising source of medicinal raw materials — were studied .

It was demonstrated that , at the micropropagation step , basic Woody Plant Medium containing vitamins according to Murashige and Skoog and supplemented with 0.2 mg/L 6-benzylaminopurine , 1.0 mg/L kinetin , 1.0 mg/L gibberellic acid , and 0.5 mg/L indole-3-acetic acid is the most effective .

The combination and concentration of these growth regulators , selected using mathematical combinatorial analysis , activated axillary buds and provided a high multiplication factor ( 9.3 ± 1.3 microshoots per explant ) .

Morpho-histological analysis revealed the main stages of the formation of microshoots and proved the absence of callus formation during the whole time of the cultivation of explants .

The features of the dynamics of the culture during the year of continuous cultivation are presented .


Proteomic approaches using two-dimensional gel electrophoresis ( 2-DE ) were adopted to identify proteins from rice leaf that are differentially expressed in response to the rice blast fungus , Magnaporthe grisea .

Microscopic observation of inoculated leaf with M. grisea revealed that callose deposition and hypersensitive response was clearly visible in incompatible interactions but excessive invading hypha with branches were evident in compatible interactions .

Proteins were extracted from leaves 24 , 48 , and 72 hours after rice blast fungus inoculation .

Eight proteins resolved on the 2-DE gels were induced or increased in the inoculated leaf .

Matrix-assisted laser desorption/ionization-time of flight analysis of these differentially displayed proteins showed them to be two receptor-like protein kinases ( RLK ) , two beta-1.3-glucanases ( Glu1 , Glu2 ) , thaumatin-like protein ( TLP ) , peroxidase ( POX 22.3 ) , probenazole-inducible protein ( PBZ1 ) , and rice pathogenesis-related 10 ( OsPR-10 ) .

Of these proteins , RLK , TLP , PBZ , and OsPR-10 proteins were induced more in the incompatible interactions than in compatible ones .

A phytohormone , jasmonic acid also induced all eight proteins in leaves .

To confirm whether the expression profile is equal to the 2-DE data , seven cDNA clones were used as probes in Northern hybridization experiments using total RNA from leaf tissues inoculated with incompatible and compatible rice blast fungal races .

The genes encoding POX22.3 , Glu1 , Glu2 , TLP , OsRLK , PBZ1 , and OsPR-10 were activated in inoculated leaves , with TLP , OsRLK , PBZ1 , and OsPR-10 being expressed earlier and more in incompatible than in compatible interactions .

These results suggest that early and high induction of these genes may provide host plants with leading edges to defend themselves .

The localization of two rice PR-10 proteins , PBZ1 and OsPR-10 , was further examined by immunohistochemical analysis .

PBZ1 accumulated highly in mesophyll cells under the attachment site of the appressorium .

In contrast , OsPR-10 expression was mainly localized to vascular tissue .


Recently , six genes of the gibberellin ( GA ) biosynthesis gene cluster in Gibberella fujikuroi were cloned and the functions of five of these genes were determined .

Here we describe the function of the sixth gene , P450 - 3 , and the cloning and functional analysis of a seventh gene , orf3 , located at the left border of the gene cluster .

We have thereby defined the complete GA biosynthesis gene cluster in this fungus .

The predicted amino acid sequence of orf3 revealed no close homology to known proteins .

High performance liquid chromatography and gas chromatography-mass spectrometry analyses of the culture fluid of knock-out mutants identified GA1 and GA4 , rather than GA3 and GA7 , as the major C19-GA products , suggesting that orf3 encodes the GA4 1,2-desaturase .

This was confirmed by transformation of the SG139 mutant , which lacks the GA biosynthesis gene cluster , with the desaturase gene renamed des .

The transformants converted GA4 to GA7 , and also metabolized GA9 ( 3-deoxyGA4 ) to GA120 ( 1,2-didehydroGA9 ) , but the 2alpha-hydroxylated compound GA40 was the major product in this case .

We demonstrate also by gene disruption that P450 - 3 , one of the four cytochrome P450 monooxygenase genes in the GA gene cluster , encodes the 13-hydroxylase , which catalyzes the conversion of GA7 to GA3 , in the last step of the pathway .

This enzyme also catalyzes the 13-hydroxylation of GA4 to GA1 .

Disruption of the des gene in an UV-induced P450 - 3 mutant produced a double mutant lacking both desaturase and 13-hydroxylase activities that accumulated high amounts of the commercially important GA4 .

The des and P450 - 3 genes differ in their regulation by nitrogen metabolite repression .

In common with the other five GA biosynthesis genes , expression of the desaturase gene is repressed by high amounts of nitrogen in the culture medium , whereas P450 - 3 is the only gene in the cluster not repressed by nitrogen .


BACKGROUND : Postharvest fruit conservation relies on low temperatures and manipulations of hormone metabolism to maintain sensory properties .

Peaches are susceptible to chilling injuries , such as ' woolliness ' that is caused by juice loss leading to a ' wooly ' fruit texture .

Application of gibberellic acid at the initial stages of pit hardening impairs woolliness incidence , however the mechanisms controlling the response remain unknown .

We have employed genome wide transcriptional profiling to investigate the effects of gibberellic acid application and cold storage on harvested peaches .

RESULTS : Approximately half of the investigated genes exhibited significant differential expression in response to the treatments .

Cellular and developmental process gene ontologies were overrepresented among the differentially regulated genes , whereas sequences in cell death and immune response categories were underrepresented .

Gene set enrichment demonstrated a predominant role of cold storage in repressing the transcription of genes associated to cell wall metabolism .

In contrast , genes involved in hormone responses exhibited a more complex transcriptional response , indicating an extensive network of crosstalk between hormone signaling and low temperatures .

Time course transcriptional analyses demonstrate the large contribution of gene expression regulation on the biochemical changes leading to woolliness in peach .

CONCLUSION : Overall , our results provide insights on the mechanisms controlling the complex phenotypes associated to postharvest textural changes in peach and suggest that hormone mediated reprogramming previous to pit hardening affects the onset of chilling injuries .


We have examined the effect of gibberellic acid ( GA(3 ) ) on the distribution of the enzyme responsible for mobilizing storage triacylglycerol in aleurone cells of Hordeum vulgare L. cv Himalaya .

Using cellular fractionation techniques , we find that , in cells that have not been exposed to hormone , neutral lipase activity is principally associated with a pellet containing the membranes of protein bodies .

If the cells are exposed to GA(3 ) for at least 1 hour , the majority of the lipase activity becomes associated with the lipid body fraction .

The nature of the in vivo association between lipid bodies and protein bodies was examined using ultrarapid freezing followed by freeze-fracture electron microscopy .

Our analysis indicates that the phospholipid monolayer surrounding the lipid body is directly continuous with the outer leaflet of the bilayer surrounding the protein body .

Based on our data , we propose that lipase can be transferred from protein bodies ( storage form ) to lipid bodies ( active form ) by lateral diffusion within the plane of the fused phospholipid monolayer , and that the transfer can be controlled by gibberellic acid by an unknown mechanism .


In Arabidopsis , the flagellin-derived peptide flg22 elevates antibacterial resistance [ 1 ] and inhibits growth [ 2 ] upon perception via the leucine-rich repeat receptor-like kinase Flagellin-Sensitive 2 ( FLS2 ) [ 3 ] .

DELLA proteins are plant growth repressors whose degradation is promoted by the phytohormone gibberellin [ 4 ] .

Here , we show that DELLA stabilization contributes to flg22-induced growth inhibition .

In addition , we show that DELLAs promote susceptibility to virulent biotrophs and resistance to necrotrophs , partly by altering the relative strength of salicylic acid and jasmonic acid ( JA ) signaling .

A quadruple-DELLA mutant ( which lacks four out of the five Arabidopsis DELLA proteins [ 5 ] ) was partially insensitive to gene induction by Methyl-Jasmonate ( MeJA ) , whereas the constitutively active dominant DELLA mutant gai[6 ] was sensitized for JA-responsive gene induction , implicating DELLAs in JA-signaling and/or perception .

Accordingly , the elevated resistance of gai to the necrotrophic fungus Alternaria brassicicola and susceptibility to the hemibiotroph Pseudomonas syringae pv . tomato strain DC3000 ( Pto DC3000 ) was attenuated in the JA-insensitive coi1 - 16 mutant [ 7 ] .

These findings suggest an explanation for why the necrotrophic fungus Gibberella fujikuroi , causal agent of the foolish-seedling disease of rice , makes gibberellin .


Callus cells of Daucus carota L. have different phenylpropanoid pathways depending on the medium composition .

Cells propagated on a medium with gibberellic acid do not accumulate cyanidin but incorporate [(14)C]phenylalanine into chlorogenic acid at a high rate .

Cells grown on a medium free of gibberellic acid accumulate cyanidin in very large amounts .

We here describe partial purification of hydroxycinnamate : CoA ligase , and its properties in these two cell lines .

The enzymes extracted from the two cell populations had different substrate specifities : for that from anthocyanin-containing cells , p-coumaric acid was the best substrate , and caffeic acid and ferulic acid were also activated .

With enzyme from anthocyanin-free cells , the lowest Km values were obtained for caffeic acid , while ferulic acid had higher values , and p-coumaric acid was nearly inactive .

The enzyme did not separate into isoenzymes during purification .

Only on polyacrylamide gels the partially purified enzyme from anthocyanin-containing cells separated into three peaks , and that from anthocyanin-free cells , into only two peaks .

This difference is discussed in the context of the lack of activity with p-coumaric acid in anthocyanin-free cells .


Increasing sucrose from 20 to 50 g l(-1 ) in Uncaria tomentosa cell suspension cultures enhanced ursolic acid and oleanolic acid production from 129 + /- 61 to 553 + /- 193 microg g(-1 ) cell dry wt .

The maximal concentration of both triterpenes ( 1680 + /- 39 microg g(-1 ) cell dry wt ) was 8 days after elicitation by jasmonic acid , while yeast extract or citrus pectin treatments produced 1189 + /- 20 or 1120 + /- 26 microg g(-1 ) cell dry wt , respectively .

The ratio of ursolic acid : oleanolic acid was constant at 70:30 .


Gibberellic acid was found to have no significant effect on amylase activity in attached or detached cotyledons of peas .


Sulfur-containing compounds play an important role in plant stress defense ; however , only a little is known about the molecular mechanisms of regulation of sulfate assimilation by stress .

Using known Arabidopsis ( Arabidopsis thaliana ) mutants in signaling pathways , we analyzed regulation of the key enzyme of sulfate assimilation , adenosine 5'-phosphosulfate reductase ( APR ) , by salt stress .

APR activity and mRNA levels of all three APR isoforms increased 3-fold in roots after 5 h of treatment with 150 mm NaCl .

The regulation of APR was not affected in mutants deficient in abscisic acid ( ABA ) synthesis and treatment of the plants with ABA did not affect the mRNA levels of APR isoforms , showing that APR is regulated by salt stress in an ABA-independent manner .

In mutants deficient in jasmonate , salicylate , or ethylene signaling , APR mRNA levels were increased upon salt exposure similar to wild-type plants .

Surprisingly , however , APR enzyme activity was not affected by salt in these plants .

The same result was obtained in mutants affected in cytokinin and auxin signaling .

Signaling via gibberellic acid , on the other hand , turned out to be essential for the increase in APR mRNA by salt treatment .

These results demonstrate an extensive posttranscriptional regulation of plant APR and reveal that the sulfate assimilation pathway is controlled by a complex network of multiple signals on different regulatory levels .


Signaling networks among multiple phytohormones fine-tune plant defense responses to insect herbivore attack .

Previously , it was reported that the synergistic combination of ethylene ( ET ) and jasmonic acid ( JA ) was required for accumulation of the maize insect resistance1 ( mir1 ) gene product , a cysteine ( Cys ) proteinase that is a key defensive protein against chewing insect pests in maize ( Zea mays ) .

However , this study suggests that mir1-mediated resistance to corn leaf aphid ( CLA ; Rhopalosiphum maidis ) , a phloem sap-sucking insect pest , is independent of JA but regulated by the ET-signaling pathway .

Feeding by CLA triggers the rapid accumulation of mir1 transcripts in the resistant maize genotype , Mp708 .

Furthermore , Mp708 provided elevated levels of antibiosis ( limits aphid population)- and antixenosis ( deters aphid settling)-mediated resistance to CLA compared with B73 and Tx601 maize susceptible inbred lines .

Synthetic diet aphid feeding trial bioassays with recombinant Mir1-Cys Protease demonstrates that Mir1-Cys Protease provides direct toxicity to CLA .

Furthermore , foliar feeding by CLA rapidly sends defensive signal(s ) to the roots that trigger belowground accumulation of the mir1 , signifying a potential role of long-distance signaling in maize defense against the phloem-feeding insects .

Collectively , our data indicate that ET-regulated mir1 transcript accumulation , uncoupled from JA , contributed to heightened resistance to CLA in maize .

In addition , our results underscore the significance of ET acting as a central node in regulating mir1 expression to different feeding guilds of insect herbivores .


Cross talk between salicylic acid ( SA ) and jasmonic acid ( JA ) signaling pathways plays an important role in the regulation and fine tuning of induced defenses that are activated upon pathogen or insect attack .

Pharmacological experiments revealed that transcription of JA-responsive marker genes , such as PDF1.2 and VSP2 , is highly sensitive to suppression by SA .

This antagonistic effect of SA on JA signaling was also observed when the JA pathway was biologically activated by necrotrophic pathogens or insect herbivores , and when the SA pathway was triggered by a biotrophic pathogen .

Furthermore , all 18 Arabidopsis ( Arabidopsis thaliana ) accessions tested displayed SA-mediated suppression of JA-responsive gene expression , highlighting the potential significance of this phenomenon in induced plant defenses in nature .

During plant-attacker interactions , the kinetics of SA and JA signaling are highly dynamic .

Mimicking this dynamic response by applying SA and methyl jasmonate ( MeJA ) at different concentrations and time intervals revealed that PDF1.2 transcription is readily suppressed when the SA response was activated at or after the onset of the JA response , and that this SA-JA antagonism is long lasting .

However , when SA was applied more than 30 h prior to the onset of the JA response , the suppressive effect of SA was completely absent .

The window of opportunity of SA to suppress MeJA-induced PDF1.2 transcription coincided with a transient increase in glutathione levels .

The glutathione biosynthesis inhibitor l-buthionine-sulfoximine strongly reduced PDF1.2 suppression by SA , suggesting that SA-mediated redox modulation plays an important role in the SA-mediated attenuation of the JA signaling pathway .


Genome wide association studies enabled prediction of many candidate genes for flowering , maturity and plant height under differing day-length conditions .

Some genes were envisaged only from derived B. rapa .

Flowering and plant height are the key life history traits .

These are crucial for adaptation and productivity .

Current investigations aimed to examine genotypic differences governing days to flowering , maturity and plant height under contrasting day-length conditions ; and identify genomic regions governing the observed phenotypic variations .

An association panel comprising 195 inbred lines , representing natural ( NR ) and derived ( DR ) forms of Brassica rapa ( AA ; 2n = 20 ) , was evaluated at two sowing dates and two locations , representing different day-length regimes .

Derived B. rapa is a unique pre-breeding material extracted from B. juncea ( AABB ; 2n = 36 ) .

Population structure analysis , using DArT genotypes established derived B. rapa as a genetic resource distinct from natural B. rapa .

Genome wide association studies facilitated detection of many trait associated SNPs .

Chromosomes A03 , A05 and A09 harboured majority of these .

Functional annotation of the associated SNPs and surrounding genome space(s ) helped to predict 43 candidate genes .

Many of these were predicted under specific day-length conditions .

Important among these were the genes encoding floral meristem identity ( SPL3 , SPL15 , AP3 , BAM2 ) , photoperiodic responses ( COL2 , AGL18 , SPT , NF-YC4 ) , gibberellic acid biosynthesis ( GA1 ) and regulation of flowering ( EBS ) .

Some of the predicted genes were detected for DR subpanel alone .

Genes controlling hormones , auxins and gibberellins appeared important for the regulation of plant height .

Many of the significant SNPs were located on chromosomes harbouring previously reported QTLs and candidate genes .

The identified loci may be used for marker-assisted selection after due validation .


Hot peppers are sensitive to low temperature , and seed browning significantly reduces the fruit quality .

This study aims to clarify the mechanisms of seed browning in terms of metabolite changes .

Metabolites were analysed during a 30-day-storage period at 2 ° C and 10 ° C .

Gamma-aminobutyric acid , tyrosine , phenylalanine , and isoleucine concentrations were significantly higher at 2 ° C storage than at 10 ° C .

Reactive oxygen species ( ROS ) generation was associated with seed browning .

Transcription of jasmonic acid synthesis and ROS scavenging genes were higher in hot peppers stored at 2 ° C than those stored at 10 ° C .

This study elucidated the mechanisms underlying seed browning and chill damage in hot peppers during storage at low temperatures and our findings may help improve hot peppers ' quality following harvesting .


BACKGROUND : Besides fibers , cotton plants also produce a large amount of seeds with a high oil and protein content .

The use of these seeds is restricted by their high contents of the terpenoid gossypol , which is harmful to humans and livestock .

Using a genetic engineering approach , " Ultra-low gossypol cottonseed " ( ULGCS ) plants were produced by knocking down an enzyme that catalyzes the formation of a precursor of gossypol .

This was accomplished via RNAi-mediated silencing of the target gene using a seed-specific α-globulin promotor .

Since gossypol is also a crucial defense mechanism against leaf-feeding herbivores , ULGCS plants might possess lower herbivore resistance than non-engineered plants .

Therefore , we tested the constitutive and inducible direct insect resistance of two ULGCS cotton lines against the African cotton leafworm , Spodoptera littoralis .

RESULT : The herbivore was equally affected by both ULGCS lines and the control ( Coker 312 ) line when feeding on fully expanded true leaves from undamaged plants and plants induced by jasmonic acid .

When plants were induced by caterpillar-damage , however , S. littoralis larvae performed better on the ULGCS plants .

Terpenoid analyses revealed that the ULGCS lines were equally inducible as the control plants .

Levels of terpenoids were always lower in one of the two lines .

In the case of cotyledons , caterpillars performed better on ULGCS cotton than on conventional cotton .

This was likely caused by reduced levels of gossypol in ULGCS cotyledons .

CONCLUSION : Despite those effects , the insect resistance of ULGSC cotton can be considered as largely intact and the plants may , therefore , be an interesting alternative to conventional cotton varieties .


Changes in specialized metabolites were analyzed in wheat leaves inoculated with Bipolaris sorokiniana , the causal agent of spot blotch of Poaceae species .

HPLC analysis detected the accumulation of six compounds in B. sorokiniana-infected leaves .

Of these , we purified two compounds by silica gel and ODS column chromatography and preparative HPLC , and identified them as cinnamic acid amides , N-cinnamoyl-9-hydroxy-8-oxotryptamine and N-cinnamoyl-8-oxotryptamine , by spectroscopic analyses .

The remaining four compounds were predicted to be p-coumaric acid amides of hydroxyputrescine , hydroxyagmatine , hydroxydehydroagmatine , and agmatine by mass spectrometry .

The accumulation of two cinnamic acid amides was also induced by Fusarium graminearum infection , and by treatment with CuCl(2 ) , jasmonic acid , and isopentenyladenine .

Antifungal activity of these amides was shown by inhibition of conidial germination and germ tube elongation of F. graminearum and Alternaria brassicicola , indicating that they act as phytoalexins .

The accumulation of these amides also detected in barley leaves treated with CuCl(2 ) .

We examined the accumulation of 25 phenylamides in B. sorokiniana-infected wheat leaves using LC-MS/MS .

Hydroxycinnamic acid amides of tryptamine , serotonin , putrescine , and agmatine , were induced after infection with B. sorokiniana .

Thus , the induced accumulation of two groups of phenylamides , cinnamic acid amides with indole amines , and p-coumaric acid amides with putrescine and agmatine related amines , represents a major metabolic response of wheat to pathogen infection .


Chemically synthesized 2-hydroxyethyl jasmonate ( HEJA ) was for the first time employed to induce the ginsenoside biosynthesis and to manipulate the product heterogeneity in plant cell cultures .

The dose response and timing of HEJA elicitation were investigated in cell suspension cultures of Panax notoginseng .

The optimal concentration and timing of HEJA addition for both cell growth and ginsenoside accumulation was identified to be 200 microM added on day 4 .

It was interestingly found that HEJA could stimulate ginsenosides biosynthesis and change their heterogeneity more efficiently than methyl jasmonate ( MJA ) , i.e. , the total ginsenoside content and the Rb/Rg ratio increased about 60 and 30 % with HEJA elicitation than that by MJA , respectively .

The activity of Rb1 biosynthetic enzyme , i.e. , UDPG-ginsenoside Rd glucosyltransferase ( UGRdGT ) , was also higher in the former case .

A maximal production titer of ginsenoside Rg1 , Re , Rb1 , and Rd was 47.4+/-4.8 , 52.3+/-4.4 , 190+/-18 , and 12.1+/-2.5 mg/l with HEJA elicitation , which was about 1.3- , 1.3- , 1.7- , and 2.1-fold than that using MJA , respectively .

Early signal events in plant defense response , including oxidative burst and jasmonic acid ( JA ) biosynthesis , were also examined .

Levels of H2O2 and NO in medium and L-phenylalanine ammonia lyase activity in cells were not affected by addition of MJA and HEJA .

On the other hand , the JA content in cells was increased with external jasmonates elicitation , and it was inhibited with the addition of JA biosynthesis inhibitors .

The results suggest that oxidative burst might not be involved in the jasmonates-elicited signal transduction pathway , and MJA and HEJA may induce the ginsenoside biosynthesis via induction of endogenous JA biosynthesis and key enzymes ( such as UGRdGT ) in the ginsenoside biosynthetic pathway of P. notoginseng cells .

The information is useful for hyperproduction of plant-specific heterogeneous products .


Transcriptional regulation plays a central role in plant hormone signaling .

At the core of transcriptional regulation is the Mediator , an evolutionarily conserved , multisubunit complex that serves as a bridge between gene-specific transcription factors and the RNA polymerase machinery to regulate transcription .

Here , we report the action mechanisms of the MEDIATOR25 ( MED25 ) subunit of the Arabidopsis thaliana Mediator in regulating jasmonate- and abscisic acid (ABA)-triggered gene transcription .

We show that during jasmonate signaling , MED25 physically associates with the basic helix-loop-helix transcription factor MYC2 in promoter regions of MYC2 target genes and exerts a positive effect on MYC2-regulated gene transcription .

We also show that MED25 physically associates with the basic Leu zipper transcription factor ABA-INSENSITIVE5 ( ABI5 ) in promoter regions of ABI5 target genes and shows a negative effect on ABI5-regulated gene transcription .

Our results reveal that underlying the distinct effects of MED25 on jasmonate and ABA signaling , the interaction mechanisms of MED25 with MYC2 and ABI5 are different .

These results highlight that the MED25 subunit of the Arabidopsis Mediator regulates a wide range of signaling pathways through selectively interacting with specific transcription factors .


Potential of MoSM1 , encoding for a cerato-platanin protein from Magnaporthe oryzae , in improvement of rice disease resistance was examined .

Transient expression of MoSM1 in rice leaves initiated hypersensitive response and upregulated expression of defense genes .

When transiently expressed in tobacco leaves , MoSM1 targeted to plasma membrane .

The MoSM1-overexpressing ( MoSM1-OE ) transgenic rice lines showed an improved resistance , as revealed by the reduced disease severity and decreased in planta pathogen growth , against 2 strains belonging to two different races of M. oryzae , causing blast disease , and against 2 strains of Xanthomonas oryzae pv . oryzae , causing bacterial leaf blight disease .

However , no alteration in resistance to sheath blight disease was observed in MoSM1-OE lines .

The MoSM1-OE plants contained elevated levels of salicylic acid ( SA ) and jasmonic acid ( JA ) and constitutively activated the expression of SA and JA signaling-related regulatory and defense genes .

Furthermore , the MoSM1-OE plants had no effect on drought and salt stress tolerance and on grain yield .

We conclude that MoSM1 confers a broad-spectrum resistance against different pathogens through modulating SA- and JA-mediated signaling pathways without any penalty on abiotic stress tolerance and grain yield , providing a promising potential for application of MoSM1 in improvement of disease resistance in crops .


Auxin is one of the most important phytohormones and exerts pleiotropic effects on plant growth and development .

Aux/IAA and auxin response factor ( ARF ) are two important protein families that are well recognized for their roles in auxin-mediated responses .

Aux/IAA proteins are short-lived transcriptional regulators that mediate auxin responses through interaction with ARF transcription factors .

Here , we systematically compared the genomic organization of the two families in rice .

The expression profiles of both families were compared to show possible association of the two gene families at expression level , which would help reveal their synergistic relationships and functions .

The expression profile analysis of Aux/IAA and ARF genes in 30 organs/tissues ( collected from an entire life cycle of rice ) suggested that Aux/IAA and ARF genes are expressed in very diverse patterns .

In general , the genes showing similar expression patterns tended to be in the same phylogenetic subgroup even though their expression patterns were not always the same .

Hierarchical cluster analysis revealed that there are eight pairs of IAA and ARF genes , with each pair showing highly correlated expression .

The expression levels of the IAA gene family were also checked under various hormone treatments including abscisic acid , kinetin , gibberellin , jasmonic acid , auxin and brassinolide .

The results indicated that most of the IAA genes respond to at least one of the treatments .

Furthermore , DNA chip and real-time PCR results show that many genes in these families were responsive to various abiotic stresses , indicating an interaction between plant growth and abiotic stress .

The effect of abiotic stress on plant growth and auxin distribution was further confirmed with the root growth of DR5-GUS transgenic rice under mannitol treatment , in which a close association between mannitol-induced changes of auxin distribution and root growth was observed .


Recent evidence suggests that oxidized lipid-derived molecules play significant roles in inducible plant defence responses against microbial pathogens , either by directly deterring parasite multiplication , or as signals involved in the induction of sets of defence genes .

The synthesis of these oxylipins was hypothesized to be initiated by the phospholipase A2-mediated release of unsaturated fatty acids from membrane lipids .

Here , we demonstrate that , in tobacco leaves reacting hypersensitively to tobacco mosaic virus , a strong increase in soluble phospholipase A2 ( PLA2 ) activity occurs at the onset of necrotic lesion appearance .

This rapid PLA2 activation occurred before the accumulation of 12-oxophytodienoic and jasmonic acids , two fatty acid-derived defence signals .

Three PLA2 isoforms were separated and the most active enzyme was partially purified , its N-terminal sequence displaying similarity with patatin , the major storage protein in potato tubers .

Three related tobacco patatin-like cDNAs , called NtPat1 , NtPat2 and NtPat3 , were cloned , with NtPat2 encoding the PLA2 isolated from infected leaves .

RT-PCR experiments showed a rapid transcriptional activation of the three NtPat genes in virus-infected leaves , preceding the increase in PLA2 activity .

Recombinant NtPat1 and NtPat3 enzymes were active in an assay using labelled bacterial membranes , and also displayed high bona fide PLA2 activity on phosphatidylcholine substrate .

These results point to a possible new role of patatin-like phospholipases in inducible plant defence responses .

The induction kinetics together with the enzymatic activity data indicate that the NtPat proteins may provide precursors for oxylipin synthesis during the hypersensitive response to pathogens .


Azospirillum species are plant growth-promotive bacteria whose beneficial effects have been postulated to be partially due to production of phytohormones , including gibberellins ( GAs ) .

In this work , Azospirillum brasilense strain Cd and Azospirillum lipoferum strain USA 5b promoted sheath elongation growth of two single gene GA-deficient dwarf rice ( Oryza sativa ) mutants , dy and dx , when the inoculated seedlings were supplied with [17,17 - 2H2]GA20-glucosyl ester or [ 17,17- 2H2]GA20-glucosyl ether .

Results of capillary gas chromatography-mass spectrometry analysis show that this growth was due primarily to release of the aglycone [17,17 - 2H2]GA20 and its subsequent 3beta-hydroxylation to [17,17 - 2H2]GA1 by the microorganism for the dy mutant , and by both the rice plant and microorganism for the dx mutant .