Proteomics Approach to Uncover Key Signalling Pathways in Brassica juncea in Abiotic and Biotic Stress

Abstract

AbstractBrassica juncea (Indian mustard) is an important oil yielding crop. Total and sub-organelle proteome of B. juncea is analyzed by SDS-PAGE, two-dimensional gel electrophoresis (2-DE), 2-D DIGE, iTRAQ, gel free/in-gel trypsin digestion, MALDI-ToF/ToF and nLC-MS/MS. For sub-organelle proteome (cuticle, apoplast and nucleus) purity of samples was assessed by checking the presence of a cytosolic marker, glucose-6-phosphate dehydrogenase and a chloroplastic marker, RuBisCO. Enzymes associated with “mustard oil bomb” (myrosinase and its associating proteins) are common in apoplast and cuticle. S-nitrosylation (a post-translational modification) analyzed in the apoplast and nucleus showed the importance of sub-organelle proteomics in identifying regulation of Brassicaceae specific, defence (glucosinolate-hydrolysis pathway), stress and signalling pathway. Proteome analysis of Cadmium (Cd) treated Brassica plants showed the importance of peptide methionine sulfoxide reductase, 2-nitropropane dioxygenase, O-acetyl serine sulfhydrylase and glutathione S-transferase in the Cd hyperaccumulation and tolerance. Functional categorization of the mass spectrometry (MS) identified proteins suggested that during both abiotic and biotic stress, pathways of cellular detoxification (including enzymes of ascorbate glutathione cycle, superoxide dismutase and glutathione S-transferase), redox homeostasis, defence and photosynthesis are modulated. Interestingly, no detailed study has been reported on other PTMs except S-nitrosylation in B. juncea. To have an overview of B. juncea proteomics, collective information on the proteome based studies are presented.KeywordsSub-organelleMass spectrometry2-DEStressPost-translational modifications