Vijai Bhadauria

University of Saskatchewan, Saskatoon, Saskatchewan, Canada

Are you Vijai Bhadauria?

Claim your profile

Publications (25)63.74 Total impact

  • Xifeng Chen · Vijai Bhadauria · Bojun Ma
    [Show abstract] [Hide abstract]
    ABSTRACT: Biotic stresses are constraints to plant growth and development negatively impacting crop production. To counter such stresses, plants have developed stress-specific adaptations as well as simultaneous responses. The efficacy and magnitude of inducible adaptive responses are dependent on activation of signaling pathways and intracellular networks by modulating expression, or abundance, and/or post-translational modification of proteins associated with defense mechanisms. Proteomics plays an important role in elucidating plant defense mechanisms by mining the differential regulation of proteins to various biotic stresses. Rice, one of the most widely cultivated food crops in world, is constantly challenged by a variety of biotic stresses, and high-throughput proteomics approaches have been employed to unravel the molecular mechanism of the biotic stresses-response in rice. In this review, we summarize the latest advances of proteomic studies on defense responses and discuss the potential relevance of the proteins identified by proteomic means in rice defense mechanism. Furthermore, we provide perspective for proteomics in unraveling the molecular mechanism of rice immunity.
    No preview · Article · Sep 2015 · Current issues in molecular biology
  • [Show abstract] [Hide abstract]
    ABSTRACT: Understanding plant's defense mechanisms and their response to biotic stresses is of fundamental meaning for the development of resistant crop varieties and more productive agriculture. The Brassica genus involves a large variety of economically important species and cultivars used as vegetable source, oilseeds, forage and ornamental. Damage caused by pathogens attack affects negatively various aspects of plant growth, development, and crop productivity. Over the last few decades, advances in plant physiology, genetics, and molecular biology have greatly improved our understanding of plant responses to biotic stress conditions. In this regard, various 'omics' technologies enable qualitative and quantitative monitoring of the abundance of various biological molecules in a high-throughput manner, and thus allow determination of their variation between different biological states on a genomic scale. In this review, we have described advances in 'omic' tools (genomics, transcriptomics, proteomics and metabolomics) in the view of conventional and modern approaches being used to elucidate the molecular mechanisms that underlie Brassica disease resistance.
    No preview · Article · Sep 2015 · Current issues in molecular biology
  • [Show abstract] [Hide abstract]
    ABSTRACT: The attack of different pathogens, such as bacteria, fungi and viruses has a negative impact on crop production. In counter such attacks, plants have developed different strategies involving the modification of gene expression, activation of several metabolic pathways and post-translational modification of proteins, which culminate into the accumulation of primary and secondary metabolites implicated in plant defense responses. The recent advancement in omics techniques allows the increase coverage of plants transcriptomes, proteomes and metabolomes during pathogen attack, and the modulation of the response after the infection. Omics techniques also allow us to learn more about the biological cycle of the pathogens in addition to the identification of novel virulence factors in pathogens and their host targets. Both approaches become important to decipher the mechanism underlying pathogen attacks and to develop strategies for improving disease-resistant plants. In this review, we summarize some of the contribution of genomics, transcriptomics, proteomics, metabolomics and metallomics in devising the strategies to obtain plants with increased resistance to pathogens. These approaches constitute important research tools in the development of new technologies for the protection against diseases and increase plant production.
    No preview · Article · Sep 2015 · Current issues in molecular biology
  • Vijai Bhadauria
    [Show abstract] [Hide abstract]
    ABSTRACT: The term OMICS, which look into the global profiling and analysis of various cellular molecules, has gained new heights with the advancement of next-generation sequencing and mass spectrometry technologies. It has broader implication in genetic improvement of crops for resistance against various diseases of economic significance. This focus issue entitled OMICS in Plant Disease Resistance highlights the implication of OMICS (genomics, transcriptomics, proteomics and metabolomics) in agricultural research.
    No preview · Article · Sep 2015 · Current issues in molecular biology
  • [Show abstract] [Hide abstract]
    ABSTRACT: Lentil (Lens culinaris) is one of the cool season grain legume crops and an important source of dietary proteins and fibre. Fungal diseases are main constraints to lentil production and account for significant yield and quality losses. Lentil has a narrow genetic base presumably due to a bottleneck during domestication and as a result, any resistance to fungal diseases in the cultivated genepool is gradually eroded and overcome by pathogens. New sources of resistance have been identified in wild lentil (Lens ervoides). This article provides an overview of harnessing resistance potential of wild germplasm to enhance genetic resistance in lentil cultivars using next-generation sequencing-based genotyping, comparative genomics and marker-assisted selection breeding.
    No preview · Article · Sep 2015 · Current issues in molecular biology
  • Vijai Bhadauria · Ron MacLachlan · Curtis Pozniak · Sabine Banniza
    [Show abstract] [Hide abstract]
    ABSTRACT: Background: The hemibiotroph Colletotrichum lentis, causative agent of anthracnose on Lens culinaris (lentil) was recently described as a new species. During its interaction with the host plant, C. lentis likely secretes numerous effector proteins, including toxins to alter the plant's innate immunity, thereby gaining access to the host tissues for nutrition and reproduction. Results: In silico analysis of 2000 ESTs generated from C. lentis-infected lentil leaf tissues identified 15 candidate effectors. In planta infection stage-specific gene expression waves among candidate effectors were revealed for the appressorial penetration phase, biotrophic phase and necrotrophic phase. No sign of positive selection pressure [ω (dN/dS) < 1] in effectors was detected at the intraspecific level. A single nucleotide polymorphism in the ORF of candidate effector ClCE6, used to develop a KASPar marker, differentiated perfectly between pathogenic race 0 and race 1 isolates when tested on 52 isolates arbitrarily selected from a large culture collection representing the western Canadian population of C. lentis. Furthermore, an EST encoding argininosuccinate lyase (Arg) was identified as a bacterial gene. A toxin protein ClToxB was further characterized as a potential host-specific toxin through heterologous in planta expression. The knock-down of ClToxB transcripts by RNAi resulted in reduced virulence, suggesting that ClToxB is a virulence factor. In silico analysis of the ClToxB sequence and comparative genomics revealed that ToxB is unlikely a foreign gene in the C. lentis genome. Incongruency between established species relationships and that established based on gene sequence data confirmed ToxB arose through evolution from a common ancestor, whereas the bacterial gene Arg identified in C. lentis was horizontally transferred from bacteria. Conclusions: EST mining and expression profiling revealed a set of in planta expressed candidate effectors. We developed a KASPar assay using effector polymorphism to differentiate C. lentis races. Comparative genomics revealed a foreign gene encoding a potential virulence factor Arg, which was horizontally transferred from bacteria into the genus Colletotrichum. ClToxB is further characterized as a host-specific toxin that is likely to contribute to quantitative differences in virulence between the races 0 and 1.
    No preview · Article · Aug 2015 · BMC Genomics
  • Source
    Vijai Bhadauria · Sabine Banniza
    [Show abstract] [Hide abstract]
    ABSTRACT: Fungal disease resistance breeding, especially for the lineage-exclusion (LEB) is essential to meet the caloric demand of ever-growing population as diseases, especially caused by fungal and fungus-like pathogens are posing a visible and imminent threat to sustainable world food supply. This article provides a fresh perspective on the application of genomics in the LEB.
    Preview · Article · Apr 2014 · Plant signaling & behavior
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Background Anthracnose of lentil, caused by the hemibiotrophic fungal pathogen Colletotrichum truncatum is a serious threat to lentil production in western Canada. Colletotrichum truncatum employs a bi-phasic infection strategy characterized by initial symptomless biotrophic and subsequent destructive necrotrophic colonization of its host. The transition from biotrophy to necrotrophy (known as the biotrophy-necrotrophy switch [BNS]) is critical in anthracnose development. Understanding plant responses during the BNS is the key to designing a strategy for incorporating resistance against hemibiotrophic pathogens either via introgression of resistance genes or quantitative trait loci contributing to host defense into elite cultivars, or via incorporation of resistance by biotechnological means. Results The in planta BNS of C. truncatum was determined by histochemical analysis of infected lentil leaf tissues in time-course experiments. A total of 2852 lentil expressed sequence tags (ESTs) derived from C. truncatum-infected leaf tissues were analyzed to catalogue defense related genes. These ESTs could be assembled into 1682 unigenes. Of these, 101 unigenes encoded membrane and transport associated proteins, 159 encoded proteins implicated in signal transduction and 387 were predicted to be stress and defense related proteins (GenBank accessions: JG293480 to JG293479). The most abundant class of defense related proteins contained pathogenesis related proteins (encoded by 125 ESTs) followed by heat shock proteins, glutathione S-transferase, protein kinases, protein phosphatase, zinc finger proteins, peroxidase, GTP binding proteins, resistance proteins and syringolide-induced proteins. Quantitative RT-PCR was conducted to compare the expression of two resistance genes of the NBS-LRR class in susceptible and partially resistant genotypes. One (contig186) was induced 6 days post-inoculation (dpi) in a susceptible host genotype (Eston) whereas the mRNA level of another ( LT21-1990) peaked 4 dpi in a partially resistant host genotype (Robin), suggesting roles in conditioning the susceptibility and conferring tolerance to the pathogen, respectively. Conclusions Data obtained in this study suggest that lentil cells recognize C. truncatum at the BNS and in response, mount an inducible defense as evident by a high number of transcripts (23% of the total pathogen-responsive lentil transcriptome) encoding defense related proteins. Temporal expression polymorphism of defense related genes could be used to distinguish the response of a lentil genotype as susceptible or resistant.
    Full-text · Article · Apr 2013 · BMC Genetics
  • [Show abstract] [Hide abstract]
    ABSTRACT: Chilli is one of the spices used to enhance the flavour and taste of cooked food. Fungal diseases are the main biological constraints in chilli production, and Alternaria leaf spot disease caused by Alternaria alternata is one of the most devastating diseases of chilli. One of the effective and environmentally friendly ways to control this disease is introgress resistance from wild relative/varieties to the cultivated one. The first step towards introgression of resistance genes is to screen the chill germplasm for leaf spot resistance. In the current study, we screened the chilly germplasm and identified the sources of leaf spot resistance, which can be harnessed in resistance breeding programmes.
    No preview · Article · Feb 2013 · Archives of Phytopathology and Plant Protection

  • No preview · Article · Jan 2013 · Plant Pathology Journal
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The hemibiotrophic fungus Colletotrichum truncatum causes anthracnose disease on lentils and a few other grain legumes. It shows initial symptomless intracellular growth, where colonized host cells remain viable (biotrophy), and then switches to necrotrophic growth, killing the colonized host plant tissues. Here, we report a novel effector gene, CtNUDIX, from C. truncatum that is exclusively expressed during the late biotrophic phase (before the switch to necrotrophy) and elicits a hypersensitive response (HR)-like cell death in tobacco leaves transiently expressing the effector. CtNUDIX homologs, which contain a signal peptide and a Nudix hydrolase domain, may be unique to hemibiotrophic fungal and fungus-like plant pathogens. CtNUDIX lacking a signal peptide or a Nudix motif failed to induce cell death in tobacco. Expression of CtNUDIX:eGFP in tobacco suggested that the fusion protein might act on the host cell plasma membrane. Overexpression of CtNUDIX in C. truncatum and the rice blast pathogen, Magnaporthe oryzae, resulted in incompatibility with the hosts lentil and barley, respectively, by causing an HR-like response in infected host cells associated with the biotrophic invasive hyphae. These results suggest that C. truncatum and possibly M. oryzae elicit cell death to signal the transition from biotrophy to necrotrophy.
    Full-text · Article · Sep 2012 · Eukaryotic Cell
  • Source
    Article: Alanine
    [Show abstract] [Hide abstract]
    ABSTRACT: The rice blast pathogen, Magnaporthe oryzae has been widely used as a model pathogen to study plant infection-related fungal morphogenesis, such as penetration via appressorium and plant-microbe interactions at the molecular level. Previously, we identified a gene encoding peroxisomal alanine: glyoxylate aminotransferase 1 (AGT1) in M. oryzae and demonstrated that the AGT1 was indispensable for pathogenicity. The AGT1 knockout mutants were unable to penetrate the host plants, such as rice and barley, and therefore were non-pathogenic. The inability of ∆Moagt1 mutants to penetrate the susceptible plants was likely due to the disruption in coordination of the β-oxidation and the glyoxylate cycle likely resulted from a blockage in lipid droplet mobilization and eventually utilization during conidial germination and appressorium morphogenesis, respectively. Here, we further demonstrate the role of AGT1 in lipid mobilization by in vitro germination assays and confocal microscopy.
    Full-text · Article · Sep 2012 · Plant signaling & behavior
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The role of β-oxidation and the glyoxylate cycle in fungal pathogenesis is well documented. However, an ambiguity still remains over their interaction in peroxisomes to facilitate fungal pathogenicity and virulence. In this report, we characterize a gene encoding an alanine, glyoxylate aminotransferase 1 (AGT1) in Magnaporthe oryzae, the causative agent of rice blast disease, and demonstrate that AGT1 is required for pathogenicity of M. oryzae. Targeted deletion of AGT1 resulted in the failure of penetration via appressoria; therefore, mutants lacking the gene were unable to induce blast symptoms on the hosts rice and barley. This penetration failure may be associated with a disruption in lipid mobilization during conidial germination as turgor generation in the appressorium requires mobilization of lipid reserves from the conidium. Analysis of enhanced green fluorescent protein expression using the transcriptional and translational fusion with the AGT1 promoter and open reading frame, respectively, revealed that AGT1 expressed constitutively in all in vitro grown cell types and during in planta colonization, and localized in peroxisomes. Peroxisomal localization was further confirmed by colocalization with red fluorescent protein fused with the peroxisomal targeting signal 1. Surprisingly, conidia produced by the Δagt1 mutant were unable to form appressoria on artificial inductive surfaces, even after prolonged incubation. When supplemented with nicotinamide adenine dinucleotide (NAD(+))+pyruvate, appressorium formation was restored on an artificial inductive surface. Taken together, our data indicate that AGT1-dependent pyruvate formation by transferring an amino group of alanine to glyoxylate, an intermediate of the glyoxylate cycle is required for lipid mobilization and utilization. This pyruvate can be converted to non-fermentable carbon sources, which may require reoxidation of NADH generated by the β-oxidation of fatty acids to NAD(+) in peroxisomes. Therefore, it may provide a means to maintain redox homeostasis in appressoria.
    Full-text · Article · Apr 2012 · PLoS ONE
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Hemibiotrophic phytopathogenic fungi cause devastating diseases in agronomically important crops. These fungal pathogens exploit a stealth bi-phasic infection strategy to colonize host plants. Their morphological and nutritional transition from biotrophy (characterized by voluminous intracellular primary hyphae) to necrotrophy (characterized by thin secondary hyphae) known as the biotrophy-necrotrophy switch (hemibiotrophy) is critical in symptom and disease development. To establish successful hemibiotrophic parasitism, pathogens likely secrete suites of proteins at the switch that constitute the biotrophy-necrotrophy switch secretome. To catalogue such proteins, a directional cDNA library was constructed from mRNA isolated from infected Lens culinaris leaflet tissues displaying the switch of Colletotrichum truncatum, and 5000 expressed sequence tags (ESTs) were generated. Four potential groups (hydrolytic enzymes, cell envelope-associated proteins [CEAPs], candidate effectors and proteins with diverse functions) were identified from pathogen-derived ESTs. Expression profiling of transcripts encoding CEAPs and candidate effectors in an infection time-course revealed that the majority of these transcripts were expressed or induced during the necrotrophic phase and repressed during the biotrophic phase of in planta colonization, indicating the massive accumulation of proteins at the switch. Taken together, our data suggest that the hemibiotrophic mode of fungal proliferation entails complex interactions of a pathogen with its host wherein the pathogen requires live host cells prior to switching to the necrotrophic phase. The microbial proteins employed during pathogenesis are likely to have defined roles at specific stages of pathogenesis.
    Full-text · Article · Oct 2011 · Plant signaling & behavior
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Colletotrichum truncatum is a haploid, hemibiotrophic, ascomycete fungal pathogen that causes anthracnose disease on many economically important leguminous crops. This pathogen exploits sequential biotrophic- and necrotrophic- infection strategies to colonize the host. Transition from biotrophy to a destructive necrotrophic phase called the biotrophy-necrotrophy switch is critical in symptom development. C. truncatum likely secretes an arsenal of proteins that are implicated in maintaining a compatible interaction with its host. Some of them might be transition specific. A directional cDNA library was constructed from mRNA isolated from infected Lens culinaris leaflet tissues displaying the biotrophy-necrotrophy switch of C. truncatum and 5000 expressed sequence tags (ESTs) with an average read of > 600 bp from the 5-prime end were generated. Nearly 39% of the ESTs were predicted to encode proteins of fungal origin and among these, 162 ESTs were predicted to contain N-terminal signal peptides (SPs) in their deduced open reading frames (ORFs). The 162 sequences could be assembled into 122 tentative unigenes comprising 32 contigs and 90 singletons. Sequence analyses of unigenes revealed four potential groups: hydrolases, cell envelope associated proteins (CEAPs), candidate effectors and other proteins. Eleven candidate effector genes were identified based on features common to characterized fungal effectors, i.e. they encode small, soluble (lack of transmembrane domain), cysteine-rich proteins with a putative SP. For a selected subset of CEAPs and candidate effectors, semiquantitative RT-PCR showed that these transcripts were either expressed constitutively in both in vitro and in planta or induced during plant infection. Using potato virus X (PVX) based transient expression assays, we showed that one of the candidate effectors, i. e. contig 8 that encodes a cerato-platanin (CP) domain containing protein, unlike CP proteins from other fungal pathogens was unable to elicit a hypersensitive response (HR). The current study catalogues proteins putatively secreted at the in planta biotrophy-necrotrophy transition of C. truncatum. Some of these proteins may have a role in establishing compatible interaction with the host plant.
    Full-text · Article · Jun 2011 · BMC Genomics
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Triglyceride lipases catalyze the reversible degradation of glycerol esters with long-chain fatty acids into fatty acids and glycerol. In silico analysis of 5'-end flanking sequence of the gene LIP1 encoding a triglyceride lipase from the wheat head blight pathogen Fusarium graminearum revealed the presence of several cis-regulatory elements. To delineate the function of these regulatory elements, we constructed a series of deletion mutants in the LIP1 promoter region fused to the open reading frame of a green fluorescent protein (GFP) and assayed the promoter activity. Analysis of GFP expression levels in mutants indicated that a 563-bp promoter sequence was sufficient to drive the expression of LIP1 and regulatory elements responsible for the gene induction were located within the 563-372bp region. To further investigate the regulatory elements, putative cis-acting elements spanned within the 563-372bp region were mutated using a targeted mutagenesis approach. A CCAAT box, a CreA binding site, and a fatty acid responsive element (FARE) were identified and confirmed to be required for the basal expression of LIP1, glucose suppression and fatty acid induction, respectively.
    Full-text · Article · Feb 2011 · Microbiological Research
  • Source
    Vijai Bhadauria · Li-Xia Wang · You-Liang Peng
    [Show abstract] [Hide abstract]
    ABSTRACT: The rice blast disease caused by Magnaporthe oryzae is a major constraint on world rice production. The conidia produced by this fungal pathogen are the main source of disease dissemination. The morphology of conidia may be a critical factor in the spore dispersal and virulence of M. oryzae in the field. Deletion of a conidial morphology regulating gene encoding putative transcriptional regulator COM1 in M. oryzae resulted in aberrant conidial shape, reduced conidiation and attenuated virulence. In this study, a two-dimensional gel electrophoresis/matrix assisted laser desorption ionization- time of flight mass spectrometry (2-DE/MALDI-TOF MS) based proteomics approach was employed to identify the cellular and molecular components regulated by the COM1 protein (COM1p) that might contribute to the aberrant phenotypes in M. oryzae. By comparing the conidial proteomes of COM1 deletion mutant and its isogenic wild-type strain P131, we identified a potpourri of 31 proteins that exhibited statistically significant alterations in their abundance levels. Of these differentially regulated proteins, the abundance levels of nine proteins were elevated and twelve were reduced in the Δcom1 mutant. Three proteins were detected only in the Δcom1 conidial proteome, whereas seven proteins were apparently undetectable. The data obtained in the study suggest that the COM1p plays a key role in transcriptional reprogramming of genes implicated in melanin biosynthesis, carbon and energy metabolism, structural organization of cell, lipid metabolism, amino acid metabolism, etc. Semi-quantitative RT-PCR analysis revealed the down-regulation of genes encoding enzymes involved in melanin biosynthesis in the COM1 mutant. Our results suggest that the COM1p may regulate the transcription of genes involved in various cellular processes indispensable for conidial development and appressorial penetration. These functions are likely to contribute to the effects of COM1p upon the aberrant phenotypes of M. oryzae.
    Full-text · Article · Nov 2010 · Biology Direct
  • Vijai Bhadauria · You-Liang Peng
    [Show abstract] [Hide abstract]
    ABSTRACT: Protein extraction is a critical step in any proteomics study. Since most fungi possess a robust cell wall, efficient isolation of total proteins has become challenge to fungal proteomics. To circumvent this bottleneck of fungal proteomics, we standardized a protocol named as Mg/CHAPS extraction by comparing with an established method of protein extraction (Tris/EDTA extraction), using 2-DE and MALDI-TOF MS. Total mycelial proteins were isolated using both protocols from Magnaporthe grisea (causal agent of rice blast disease). Six hundred forty two proteins were resolved on two 2-DE gels corresponding to mycelial proteomes isolated by Mg/CHAPS and Tris/EDTA. Mycelial proteome extracted by Mg/CHAPS showed higher number protein spots than to Tris/EDTA. Quantitative analysis of mycelial proteome, histogram and MS analyses of a protein spot suggested that Mg/CHAPS extraction is more effective than the widely used protocol i.e. Tris/EDTA. KeywordsFungal proteomics-Mg/CHAPS extraction-Tris-EDTA extraction-Protein extraction techniques-Mycelial proteome
    No preview · Article · Oct 2010 · Indian Journal of Microbiology
  • Vijai Bhadauria
    [Show abstract] [Hide abstract]
    ABSTRACT: Since genomes of rice and blast fungus are sequenced, global profiling of gene expression i.e. transcriptomics has become an important tool to decipher molecular mechanisms underlying rice-blast interaction and infection related morphogenesis (appressorium formation and maturation, formation of penetration peg). This article summarises transcriptomics studies conducted on rice blast fungus.
    No preview · Article · Apr 2010 · Archives of Phytopathology and Plant Protection
  • Vijai Bhadauria · You-Liang Peng
    [Show abstract] [Hide abstract]
    ABSTRACT: The rice blast fungus genome has been sequenced. Now the major task is to monitor the global changes in its proteome for dissecting the molecular mechanisms underlying rice-blast interaction, fungal development (conidial germination, appressorium morphogenesis and formation of penetration peg), pathogenesis. Proteome analysis of rice blast fungus can be instrumental in elucidating these mechanisms at protein level. This article summarises proteomics studies conducted on rice blast fungus and its interaction with rice.
    No preview · Article · Jan 2010 · Archives of Phytopathology and Plant Protection

Publication Stats

153 Citations
63.74 Total Impact Points

Institutions

  • 2009-2015
    • University of Saskatchewan
      • • Department of Plant Sciences
      • • Crop Development Centre
      • • Department of Biology
      Saskatoon, Saskatchewan, Canada
  • 2007-2010
    • China Agricultural University
      • • State Key Laboratory for Agrobiotechnology
      • • Department of Plant Pathology
      Peping, Beijing, China