Post-harvest 1-methylcyclopropene and ethephon treatments differently modify protein profiles of peach fruit during ripening

摘要

A proteomic approach based on two-dimensional polyacrylamide gel electrophoresis (2-DE) and MALDI TOF/TOF techniques has been used in this work to study the effect of 1-methylcyclopropene (1-MCP) and 2-chloroethylphosphonic acid (ethephon) on the protein profiles of melting peach fruit (cv. Huiyulu) during ripening. The extracted proteins from the 1-MCP-treated and ethephon-treated peach fruit were used. More than 600 protein spots were detected by means of 2-DE and 38 differently expressed spots (P<0.05) were selected to be excised and analyzed using MALDI-TOF/TOF, and 35 were finally confidently identified according to the peach EST database downloaded from Genome Database for Rosaceae and NCBI database. Among the 35 successfully identified protein regulated by 1-MCP and ethephon, 26 proteins were modulated by 1-MCP and 27 proteins were regulated by ethephon. Meanwhile, 8 proteins were down-regulated by 1-MCP and up-regulated by ethephon, and 5 proteins down-regulated by ethephon but up-regulated by 1-MCP. Differently expressed proteins belonged to different metabolic pathways including energy and me tabolism (34.29%), cell structure (22.83%), protein fate (17.14%), stress response and defense (14.29%) and ripening and senescence (8.57%). All these indicated that the regulation patterns by 1-MCP and ethephon at proteomic level are complicated, involving various metabolic pathways. Ethephon could induce the ex pressions of 1-aminocyclopropane-1 -carboxylic acid oxidase (ACO), abscisic acid stress ripening-like protein (ASR) and cell structure-related proteins, such as tubulin and actin, accelerate the glycolytic metabolisms, regulate the galactose and glutamine metabolism, and modulate the methionine metabolism. 1-MCP could inhibit the degradation of starch, weaken the metabolism of glycolytic pathway, strongly depresses the ex pression of ACO and ASR, and induce the expression of chaperonin 60 and HSPs in ripening peach fruit. Taken together, the present study will be informative for exploring the exact roles of ethylene in peach fruit ripening and explaining the molecular mechanism of peach ripening.