Physiological and proteomic analyses reveals that brassinosteroids application improves the chilling stress tolerance of pepper seedlings

Brassinosteroids (BRs) are important in plant resistance to chilling stress. However, limited information is available regarding the specific mechanisms involved at proteomic level. We utilized iTRAQ approach, physiological assays and obtained from cellular ultrastructure clarify underlying molecular mechanism of BRs alleviate stress pepper (Capsicum annuum L.). Foliar application 24-epibrassinolide (EBR) improved photosynthesis cell structure by presenting a distinct mesophyll chloroplast with well-developed thylakoid membranes leaves seedlings. identified 346 differentially expressed proteins (DEPs), including 217 up-regulated 129 down-regulated plants under (Chill) Chill + EBR treated plants. Most DEPs were related multiple pathways, photosynthesis, carbohydrate metabolism, energy protein biosynthesis, amino acid synthesis, redox defence (ascorbate peroxidase, glutathione peroxidase superoxide dismutase). Up-regulated associated photosynthetic electron transfer chain, oxidative phosphorylation, GSH metabolism pathway, Calvin cycle signaling pathway. The physiochemical analysis showed that treatment tolerance seedlings