Exploring the Effects of Different 1-MCP Concentration Treatment on Chilling Injury of Postharvest Peach Fruit

Peach (Prunus persica (L.) Batsch) fruit are susceptible to chilling injury that is often manifested as browning of the internal flesh. As the ethylene antagonist, 1-methylcyclopropene (1-MCP) is an important contributor to resist chilling stress during peach (Prunus persica (L.) Batsch) storage at low temperatures, but the molecular mechanism of it is still elusive. The study examined in detail the effects of two concentrations (1 and 2 mu L center dot L-1) of 1-MCP on alleviating chilling injury (CI) of postharvest peach fruit stored at 4 +/- 0.5 degrees C. The results showed that although all treatments relieved CI, treatment with 1 mu L center dot L-1 more effectively alleviated CI symptoms of postharvest peach fruit than 2 mu L center dot L-1. The internal browning (IB) and weight loss were significantly inhibited by 1 mu L center dot L-1 1-MCP. Lower concentration of 1-MCP maintained normal softening by decreasing the gene expression of expansin (Exp) 1,3, polygalacturonase (PG) 3, and pectate lyase (PLY) 1, 2, 3 and increased the content of soluble sugar during the whole storage period. Meanwhile, the activities of polygalacturonase, pectinmethylesterase (PME), and endo-1,4-beta-glucanase (EGase) were reduced by lower concentration of 1-MCP. Our results demonstrate that 1-MCP inhibited CI by suppressing the degradation of cell wall. This study provides a theoretical basis for revealing that 1-MCP alleviates chilling injury in peach fruit.