The molecular basis of superficial scald development related to ethylene perception and α-farnesene metabolism in ‘Wujiuxiang’ pear

Abstract

Superficial scald is a major disorder that may occur in pear fruits following long-term cold storage. In this study, harvested ‘Wujiuxiang’ pears (Pyrus communis L.) were treated with 1.0μL/L 1-methylcyclopropene (1-MCP), stored at 0°C for 120days, and transferred to 25±2°C for seven days to simulate shelf life. The effects of 1-MCP on scald development, the expression of ethylene perception genes, and α-farnesene metabolism and the expression of its associated genes were investigated. Compared with the control, 1-MCP reduced the scald index after 120days of cold storage and during shelf life, suppressed the accumulation of α-farnesene and conjugated trienols (CTols), inhibited the expression of PcETR2, PcERS1, PcHMGR2, PcAFS1, PcGPX5, PcGSTU7, and PcGSTU17, and delayed the maximum expression of PcETR1, PcERS2, PcHMGR1, and PcGPX6. These results indicate that 1-MCP regulates the expression of target genes to inhibit ethylene action and α-farnesene metabolism, which contributes to slower scald development. These findings suggest that PcGPX5, PcGPX6, PcGSTU7, and PcGSTU17 are involved in CTol accumulation and scald development in ‘Wujiuxiang’ pear fruit.