Comparative proteomic and metabolomic analyses reveal mechanisms of improved cold stress tolerance in bermudagrass (Cynodon dactylon (L.) Pers.) by exogenous calcium

摘要

As an important second messenger, calcium is involved in plant cold stress response, including chil ing (<20 °C) and freezing (<0 °C). In this study, exogenous application of calcium chloride (CaCl2) improved both chil ing and freezing stress tolerances, while ethylene glycol‐bis‐(b‐aminoethyl) ether‐N,N,N,N‐tetraacetic acid (EGTA) reversed CaCl2 effects in bermudagrass (Cynodon dactylon (L.) Pers.). Pysiological analyses showed that CaCl2 treatment al eviated the reactive oxygen species (ROS) burst and cel damage triggered by chil ing stress, via activating antioxidant enzymes, non‐enzymatic glutathione antioxidant pool, while EGTA treatment had the opposite effects. Additional y, comparative proteomic analysis identified 51 differential y expressed proteins that were enriched in redox, tricarboxylicacid cycle, glycolysis, photosynthesis, oxidative pentose phosphate pathway, and amino acid metabolisms. Consistently, 42 metabolites including amino acids, organic acids, sugars, and sugar alcohols were regulated by CaCl2 treatment under control and cold stress conditions, further confirming the common modulation of CaCl2 treatment in carbon metabolites and amino acid metabolism. Taken together, this study reported first evidence of the essential and protective roles of endogenous and exogenous calcium in bermudagrass response to cold stress, partial y via activation of the antioxidants and modulation of several differential y expressed proteins and metabolic homeostasis in the process of cold acclimation.