Identification of differentially expressed proteins in bermudagrass response to cold stress in the presence of ethylene

Low temperature is considered to be a key environmental factor that limits broad application of bermudagrass (Cynodon dactylon). The phytohormone ethylene has been confirmed to be involved in plant response to cold stress. However, there is limited knowledge concerning the proteomic alterations of ethylene-regulated cold stress response in plant. To explore the possible molecular mechanism, a proteomic approach was performed by using iTRAQ (isobaric tags for relative and absolute quantitation) system. Bermudagrass leaves were treated with the ethylene precursor 1-aminocyclopropane-1-carboxylic acid (ACC) or water (as control) at 4 degrees C for 24 h. Among 3990 quantified proteins, 201 differentially expressed proteins by ethylene and cold stress were identified. To better understand the possible mechanism involved in the ethylene-regulated cold response in bemudagrass, eleven groups of differentially expressed proteins were further analyzed. These proteins were mainly related to lipid stability, antioxidant enzymes and antioxidants, ribosome pathway, as well as protein synthesis and degradation. Therefore, the process of ethylene-regulated cold response maybe mainly related to lipid peroxidation, stress response and denfence and protein metabolism. Taken together, this study provides some novel insights into the molecular mechanisms of ethylene in bermudagrass responses to cold stress.