Physiological and iTRAQ-Based Quantitative Proteomics Analysis of Methyl Jasmonate-Induced Tolerance in Brassica napus Under Arsenic Stress.

Brassica napus plants exposed to 200 μM arsenic (As) exhibited high-level of stress condition, which led to inhibited growth, enhanced lipid peroxidation, and disrupted cellular ultrastructures. Exogenous application of methyl jasmonate (MeJA) alleviated the As-induced oxidative stress and improved the plant growth and photosynthesis. In this study, changes in the B. napus leaf proteome are investigated in order to identify molecular mechanisms involved in MeJA-induced As tolerance. The study identifies 177 proteins that are differentially expressed in cultivar ZS 758; while 200 differentially expressed proteins are accumulated in Zheda 622, when exposed to As alone and MeJA+As treatments, respectively. The main objective was to identify the MeJA-regulated protein under As stress. Consistent with this, iTRAQ detected 61 proteins which are significantly accumulated in ZS 758 leaves treated with MeJA under As stress. While in Zheda 622, iTRAQ detected 49 MeJA-induced proteins under As stress. These significantly expressed proteins are further divided into five groups on the base of their function, that is, stress and defense, photosynthesis, carbohydrates and energy production, protein metabolism, and secondary metabolites. Taken together, this study sheds light on the molecular mechanisms involved in MeJA-induced As tolerance in B. napus leaves and suggests a more active involvement of MeJA in plant physiological processes.