Apoplast proteomic analysis reveals drought stress-responsive protein datasets in chilli (Capsicum annuum L.)

Drought is one of the major environmental constrains that limit plant performance worldwide. Plant apoplast which acts as connecting link between environment and plant protoplast carries multiple functions in plant metabolism and signalling. To investigate the drought induced changes in apoplast, proteome analysis in conjunction with antioxidant enzyme activity changes were studied in chilli (Capsicum annuum L). Drought induced apoplast proteome revealed augmented phenyl alanine ammonia lyase, peroxidase activities and reduced catalase activity. LC-MS analysis of apoplast proteome revealed differential expression of proteins under water stress conditions. Up-regulation of 43 protein species which encompass stress related proteins such as defensins, peroxidises, polygalaturonase inhibitor proteins, superoxide dismutase proteins were observed. Unlike control, twenty unique protein species were identified to be present in proteome of drought treated plants. Qualitative and quantitative changes in apoplast proteome emphasize the dynamics of plant apoplast and its role in drought stress. This work would provide insights into drought induced proteomic changes in apoplast and also would prove to be useful for protein phenotyping.