BSc, MSc (Bangalore)
Ajjamada C. Kushalappa obtained his Ph. D. from University of Florida (USA), M.Sc (Plant Pathology) and B. Sc. (Agri) from University of Agricultural Sciences (Bengaluru, India). From 1977-1985 he was a Professor Titular Visitante, at Universidade Federal de Vicosa (Brazil). In 1985 he joined McGill University as an Assistant Professor in the Department of Plant Science, in 1991 he became an Associate Professor and in 2019 a Full Professor. He is a recipient of CPS sponsored Dr. and Mrs D. L. Bailey award for an exception and distinguished contribution to plant pathology. He was an invited speaker on ‘Plant biotic stress resistance genes and genome editing’ at 16 national and international conferences in the past six years.
As a Plant Pathologist, Dr. Kushalappa 's current research focus is the identification plant biotic stress resistance genes through forward and reverse genetics (systems biology), and the use these genes to replace the mutated genes in commercial cultivars, based on transgene free genome editing, using CRISPR-Cas9 systems, to enhance multiple disease resistance in plants.
Awards and Recognitions
1990: Dr. and Mrs. DL Bailey Award, for an exceptional and distinguished contribution to plant pathology
Canada grows hundreds of cultivars for each crop. They are mainly bred for yield and often have poor disease resistance. The fusarium head blight of wheat and barley not only causes heavy loss in yield but also produces mycotoxins in grains, which causes vomiting and hemorrhage in animals and humans. Late blight and scab are serious diseases of potato, the former requires weekly applications of fungicides to reduce loss. We are developing transgene free cisgenic cultivars (gene transfer from sexually compatible plants) to enhance resistance to fusarium head blight in wheat and barley, and to late blight and scab in potato. Each transgene free cultivar we produce is expected to have 10% increase in yield due to reduced disease, in addition to reducing production costs and environmental impacts, amounting to millions of dollars income to Canada per year.
Dr. Kushalappa is a Plant Pathologist. His current research focus is to identify plant biotic stress resistance genes through forward and reverse genetics (systems biology), and use these genes to replace the mutated genes in commercial cultivars, based on cis gene stacking (gene transfer between sexually compatible plants), using CRISPR-Cas9 systems, to increase the genetic composition for biotic stress resistance in crop plants.
Plants defend against pathogen attack using metabolites and proteins that are constitutively produced or induced following pathogen invasion. Based on metabolomics and proteomics, using liquid chromatography and high resolution mass spectrometry (LC-ESI-LTQ-Orbitrap), we have detected thousands of metabolites and proteins in wheat/barley – Fusarium graminearum (fusarium head blight) and potato-Phytophthora infestans (late blight) interaction systems. The resistance metabolites were mapped in their metabolic pathways to explore their precursors and possible polymers and plant structural components that explained the mechanisms of resistance. Several of these metabolites are known phytoalexins, toxin inhibitors, and cell wall reinforcing compounds. The proteins identified were mainly regulatory and catalytic enzymes that biosynthesize these metabolites. The metabolites with high fold change in abundance in resistant genotypes than in susceptible were searched in metabolomics network and genomic databases to identify candidate genes. Resistance gene regulation by receptors, phytohormones, MAP kinases and transcription factors also have been identified based on RNA sequencing combined with metabolomics. The putative resistance genes were sequenced in both resistant genotypes and commercial cultivars to identify polymorphisms. The candidate genes were then silenced (VIGS) in resistant genotypes to validate gene functions. The biotic stress resistance is due to hierarchies of genes, regulatory and resistance metabolite and protein biosynthetic genes, which eventually produce phytoalexins and cell wall reinforcing metabolites and proteins to resist the pathogen. The non-functional or mutated genes in commercial cultivars are being replaced with resistance R gene segments to improve resistance against biotic stress. The transgene free cisgenic commercial cultivars developed with high biotic stress resistance should not only increase grower incomes but also reduce environment impacts, through reduced application of fungicides.
Current Graduate Students and Visiting Scientists
Mr. Russiachand Singh (PhD): RNA sequencing and metabolomics to identify resistance genes in Sumai3 and mutated genes in Pasteur wheat cultivars against FHB.
Mr. Krishna Kumar (PhD): Genome editing to enhance FHB resistance in durum wheat.
Mr. Bikram Poudel (PhD): Genome editing to enhance FHB resistance in hexaploidy wheat.
Miss Chaithra Nagaraju (PhD): Genome editing to enhance FHB resistance in barley.
Dr. Niranjan Hegde (Postdoctoral Researcher): Transgene free genome editing potato to enhance multiple disease resistance.
Hegde N., Joshi S., Soni N. and Kushalappa AC. 2020. The caffeoyl-CoA O-methyltransferase gene SNP replacement in Russet Burbank potato variety enhances late blight resistance through cell wall reinforcement. https://doi.org/10.1007/s00299-020-02629-6.
Hegde N., Doddamani D. and Kushalappa AC. 2020. Identification and functional characterization of late blight resistance polymorphic genes in Russet Burbank potato cultivar. Functional Plant Biology. https://doi.org/10.1071/FP19327 .
Soni N., Altartouri B., Hegde N., Duggavathi R. and Kushalappa AC. 2020. TaNAC032 transcription factor regulates lignin-biosynthetic genes to combat Fusarium head blight in wheat. Plant Science. doi: https://doi.org/10.1016/j.plantsci.2021.110820.
Soni N., Hegde N., Dhariwal A. and Kushalappa AC. 2020. Role of laccase gene in wheat NILs differing at QTL-Fhb1 for resistance against Fusarium head blight. https://doi.org/10.1016/j.plantsci.2020.110574.
Nazarien F, Joshi S, Xue H, and Kushalappa AC. 2019. Genome-wide identification of LysM-RLK genes in potato (Solanum tuberosum L). Molecular Biology Reports. https://doi.org/10.1007/s11033-019-04951-z.
Karre S, *Kumar A, *Yogendra KN, *Kage U, Kushalappa AC, Charron JB. (2019) HvWRKY23 regulates the biosynthesis of flavonoid glycosides and hydroxycinnamic acid amides in barley to resist fusarium head blight. Plant Molecular Biology http://doi.org/10.1007/s11103-019-00882-2.
Kage U, *Hukkeri S, Kushalappa AC. 2017. Liquid chromatography and high resolution mass spectrometry‐based metabolomics to identify quantitative resistance‐related metabolites and genes in wheat QTL-2DL against Fusarium head blight. European J. Plant Pathology. https://doi.org/10.1007/s10658-017-1362-y.
Yogendra KN, *Sarkar K, Kage U, Kushalappa AC. 2017. Potato NAC43 and MYB8 Mediated Transcriptional Regulation of Secondary Cell Wall Biosynthesis to Contain Phytophthora infestans Infection. Plant Mol. Biol. Rep. 35:519–533; http://doi.org/10.1007/s11105-017-1043-1.
Yogendra KN, *Dhokane D, Kushalappa AC, Sarmiento F, Rodriguez E, Mosquera T. 2017. StWRKY8 transcription factor in potato regulates benzylisoquinoline alkaloid pathway to reinforce cell walls to contain Phytophthora infestans, confirming high level of resistance to late blight. Plant Science http://dx.doi.org/10.1016/j.plantsci.2016.12.014.
Kage U, *Yogendra KN, Kushalappa AC. 2017. TaWRKY70 transcription factor in wheat QTL-2DL regulates downstream genes biosynthesizing metabolites that enforce cell wall to contain Fusarium graminearum. Nature Sci. Report 7:42596, http://doi.org/10.1038/srep42596
Karre S, *Kumar A, *Dhokane D, Kushalappa AC. 2017. Metabolo-transcriptome profiling of barley reveals induction of a chitin elicitor receptor kinase gene (HvCERK1) conferring resistance against Fusarium graminearum. Plant Molecular Biol. DOI: http://dx.doi.org/10.1007/s11103-016-0559-3
Dhokane D, Karre S, Kushalappa AC, McCartney C. 2016. Integrated Metabolo-transcriptomics reveals fusarium head blight resistance genes in wheat QTL-Fhb2. PLoS ONE 11(5): e0155851; http://dx.doi.org/10.1371/journal.pone.0155851
Yogendra KN and Kushalappa AC. 2016. Integrated transcriptomics and metabolomics reveal induction of hierarchies of resistance genes in potato against late blight. Functional Plant Biology http://dx.doi.org/10.1071/FP16028.
Kumar A, Yogendra KN, Karre S, Kushalappa AC, Dion Y, Choo TM. 2016. WAX INDUCER1 (HvWIN1) transcription factor regulates free fatty acid biosynthetic genes to enforce cuticle to resist fusarium head blight in barley spikelets. J. Expt. Bot. http://dx.doi.org/10.1093/jxb/erw187
Kushalappa AC, *Yogendra KN, *Karee S. 2016. Plant innate immune response: qualitative and quantitative resistance. Invited Review: Critical Rev. in Plant Science 35:38–55. http://dx.doi.org/10.1080/07352689.2016.1148980
Yogendra KL, Kumar A, Sarkar K, Li y, Pushpa D, Mosa K, Duggavathi R and Kushalappa A. (2015). Transcription factor StWRKY1 regulates phenylpropanoid metabolites conferring late blight resistance in potato. The Journal of Experimental Botany http://dx.doi.org/10.1093/jxb/erv434
Kage U, Kumar A, Dhokane D, Karre S, Kushalappa AC. (2015). Functional Molecular Markers for Crop Improvement. Critical Reviews in Biotechnology http://dx.doi.org/10.3109/07388551.2015.1062743
Kumar A, Karre S, Dhokane D, Kage U, Hukkeri S, Kushalappa AC.(2015). Real-time quantitative PCR based method for the quantification of fungal biomass to discriminate quantitative resistance in barley and wheat genotypes to fusarium head blight. Journal of Cereal Science 64: 16-22. 64: 16-22.
Gunnaiah R, Kushalappa AC. 2014. Metabolomics deciphers the host resistance mechanisms in wheat cultivar Sumai-3, against trichothecene producing and non-producing isolates of Fusarium graminearum. Plant Physiol Biochem. 83:40-50.
Yogendra KN, Pushpa D, Mosa K, Kushalappa AC, Murphy A and Mosquera T. 2014. Quantitative resistance in potato leaves to late blight associated with induced hydroxycinnamic acid amides. Functional and Integrative Genomics. 14:285–298.
Pushpa D, Yogendra K, Gunnaiah R, Kushalappa AC and Murphy A. 2014. Identification of late blight resistance related metabolites and genes in potato through non-targeted metabolomics. Plant Molecular Biology Reporter. 32:584-595.
Chamarthi S, Kundan K, Gunnaiah R, Kushalappa AC, Dion Y, Choo TM. 2014. Identification of fusarium head blight resistance related metabolites specific to doubled-haploid lines in barley. European J. Plant Pathology. 138: 67-78.
Kushalappa AC and Gunnaiah R. 2013. Metabolo-proteomics to discover plant biotic stress resistance genes. INVITED REVIEW: Trends in Plant Science. 18: 522-531.
Gunnaiah R, Kushalappa AC, Duggavathi R, Fox S and Somers DJ. 2012. Integrated Metabolo-proteomic approach to decipher the mechanisms by which wheat QTL (Fhb1) contributes to resistance against Fusarium graminearum. PLoS ONE 7:e40695.
Kumaraswamy GK, Kushalappa AC, Choo TM, Dion Y. and Rioux S. 2012. Differential metabolic response of barley genotypes, varying in resistance, to trichothecene-producing and nonproducing (tri5-) isolates of Fusarium graminearum. Plant Pathology 61, 509–521.
Bollina V, and Kushalappa AC. 2011. In vitro inhibition of trichothecene biosynthesis in Fusarium graminearum by resistance-related endogenous metabolites identified in barley. Mycology 2:291-296.
Bollina V, Kushalappa AC, Choo TM, Dion Y and Rioux S. 2011. Identification of metabolites related to mechanisms of resistance in barley against Fusarium graminearum, based on mass spectrometry. Plant Molecular Biology. 77:355-370.
Kumaraswamy GK, Kushalappa AC, Choo TM, Dion Y. and Rioux S. 2011. Mass spectrometry based metabolomics to identify potential biomarkers for resistance in barley against fusarium head blight (Fusarium graminearum). Journal of Chemical Ecology 37:846-856.
Kumaraswamy GK, Bollina V, Kushalappa AC, Choo TM, Dion Y., Rioux S., and Faubert D. 2011. Metabolomics technology to phenotype resistance in barley against Gibberella zeae.. European J. Plant Pathology 130:29-43.
Bollina, V., Kumaraswamy, KG., Kushalappa, AC., Choo TM., Dion Y., Rioux S., Faubert D. and Hamzehzarghani H. 2010. Mass spectrometry based metabolomics application to identify quantitative resistance related metabolites in barley against fusarium head blight. Molecular Plant Pathology 11:769-782.
Kushalappa, AC., Vikram, A. and Raghavan, GSV. 2008. Metabolomics of headspace gas for diagnosing diseases of fruits and vegetables after harvest. Stewart Posthar. Tech. 4:1-7.
Paranidharan, V., Abu-Nada, Y., Hamzehzarghani, H., Kushalappa, A. C., Dion, Y., Rioux, S., and Comeau, A. 2008. Resistance related metabolites in wheat against Fusarium graminearum and the virulence factor, DON. Botany 86: 1168-1179.
Hamzehzarghani, H., Paranidharan, V., Abu-Nada, Y., Kushalappa, A. C., Dion, Y., Rioux, S., Comeau, A. Yaylayan, V. and Marshall, W. D. 2008. Development of metabolic profiling technology for potential high throughput screening of quantitative resistance in wheat cultivars against fusarium head blight. Can. J. Plant Path. 30:24-36.
Abu-Nada, Y., Kushalappa, A. C., Marshall, W., Yaylayan, V., Al-Mughrabi, K. and Murphy, A. 2007. Temporal dynamics of pathogenesis related metabolites and their plausible pathways of induction in potato leaves following inoculation with Phytophthora infestans. European J. Plant Path. 118:375-391.