Ajjamada C. Kushalappa, PhD
ajjamada [dot] kushalappa [at] mcgill [dot] ca (Email)
Website: McGill Metabolome Database
Satellite metabolic pathways: Satellite metabolic pathways
Plants synthesize thousands of biochemicals, and some of these are used to defend them against biotic and abiotic stresses. My current research program involves metabolomics and proteomics of crop plants to identify mechanisms of resistance in plants against biotic stress. We are also using plant-pathogen interaction volatile metabolites to detect and discriminate diseases of crops in storage. For mass spectra of metabolites visit: McGill Metabolome Database.
Metabolomics and proteomics of Plant Resistance against Pathogen Attack:
Plants defend against pathogen attack using biochemicals that are constitutively produced or induced following pathogen invasion. Based on gas chromatography and mass spectrometry (GC-TOF-MS) and liquid chromatography and hybrid mass spectrometry (LC-nESI-LTQ-Orbitrap) we have detected more than 5000 peaks in wheat/barley – Fusarium graminearum (fusarium head blight) and potato-Phytophthora infestans (late blight) interaction systems. We have identified more than 200 resistance related metabolites, which were linked in their metabolic pathways to explore their precursors and possible polymers or structural components. Several of these are known antimicrobials, toxin inhibitors/detoxifiers, signaling molecules, and cell wall apposition compounds. These can be used for gene/QTL function elucidation and also as biomarkers to screen genotypes for resistance, following validation. Currently, in progress are combined metabolomics and proteomics to better understand the mechanisms of resistance in plants against biotic stress.
Volatile Metabolite Profiling and Plant Disease Diagnosis:
Pathogens attack plants by producing enzymes and toxins to breakdown cells and feed on cell contents. During the metabolism both plants and pathogens release several volatile compounds. These volatile compounds have been used not only to detect disease within 24 h following pathogen invasion, but also to discriminate different diseases, mainly caused by bacterial and fungal pathogens. GC/MS has been used to identify chemical compounds and to generate volatile fingerprints. Neural network and multivariate models have been used to discriminate diseases. These metabolites can be used as biomarkers for the early detection of diseases of fruits and vegetables in storage.
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. DOI: 1007/s11103-011-9815-8.
Kumaraswamy GK, Kushalappa AC, Choo TM, Dion Y. and Rioux S. 2011. Differential metabolic response of barley genotypes, varying in resistance, to trichothecene-producing and nonproducing (tri5-) isolates of Fusarium graminearum. Plant Pathology DOI: 10.1111/j.1365-3059.2011.02528.x.
Bollina V, and Kushalappa AC. 2011. In vitro inhibition of trichothecene biosynthesis in Fusarium graminearum by resistance-related endogenous metabolites identified in barley. Mycology DOI:10.1080/21501203.2011.604354.
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;
Abu-Nada, Y., Kushalappa, A. C., Prasher, S., Al-Mughrabi, K. and Murphy, A. 2010. Metabolic profiling to phenotype potato cultivars varying in horizontal resistance to leaf infection by Phytophthora infestans. The Americas J. Plant Science and Biotechnology 4: 55-64.
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., Mamer, O. and Somers, D. 2008. Metabolic profiling to discriminate wheat near isogenic lines, with quantitative trait loci at chromosome 2DL, varying in resistance against fusarium head blight. Can. J. Plant Sci. 88:789-797.
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.
Abu-Nada, Y., Kushalappa, AC., Marshall, WD., Prasher, S. and Al-Mughrabi, K. 2007. Metabolic profiling horizontal resistance in potato leaves (cvs. Caesar and AC Novachip) against Phytophthora infestans. 269-286p. In: Nikolau, BJ and Wurtele, ES, Concepts in Plant Metabolomics, Springer, Netherlands.
Hamzehzarghani, H., Kushalappa, A. C., Dion, Y., Rioux, S., Comeau, A. Yaylayan, V., Marshall, W. D. and Mather, D. 2005. Metabolic profiling and factor analysis to discriminate quantitative resistance in wheat cultivars against fusarium head blight. Physiol. Molecular Plant Pathol. 66:119-133.
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.
Kushalappa, AC. and Eskes, AB. 1989. Advances in coffee rust research. Annu. Rev. Phytopahol. 27:503-531.
Kushalappa, AC. and Eskes, AB. (Edt.). 1989. Coffee Rust: Epidemiology, Resistance and Management. CRC Press, Florida, 345pp.