Characterization of expression and enzyme activity of lipoxygenases during fruit softening and superficial scald development in ‘Wujiuxiang’ pear

Abstract

Lipoxygenases (LOXs; EC 1.13.11.12) have been implicated in fruit ripening and senescence; however, little is known regarding the specific LOX genes involved in fruit softening and scald develop- ment in pear. In this study, two 9-lipoxygenase genes, PcLOX1 and PcLOX7 , were characterized in silico in the Pyrus communis draft genome. The expression pattern of PcLOX1 and PcLOX7 , LOX ac-tivity, respiration rate and ethylene production were analyzed during fruit softening and superficial scald development in ‘Wujiuxiang’ pear with or without 1-MCP treatment. The results demonstrated that PcLOX1 and PcLOX7 belong to the type-1 LOX subfamily, and their expression levels, enzyme activity, respiration rate and ethy-lene production were increased during fruit softening and scald de­velopment. In contrast, 1-MCP treatment could effectively suppress respiration rate and ethylene production and inhibit expression of PcLOX1 and PcLOX7 and LOX enzyme activity, resulting in de- layed fruit softening and scald development. These findings indicate that PcLOX1 and PcLOX7 are involved in fruit ripening and scald development in ‘Wujiuxiang’ pear.