PpWRKY65 mediates peach (Prunus persica) fruit lignification in both ambient temperature storage and chilling injury condition

Abstract

The lignification process exerts an adverse impact on the peach fruit quality. The identification of a texture-related gene module was achieved through weighted gene co-expression network analysis (WGCNA) based on transcriptomic analysis of two peach fruit varieties, ‘Baili’ and ‘Hongli’. Notably, the WRKY transcription factor PpWRKY65 played a crucial role in regulating lignin biosynthesis in peach fruit. Analyzing the correlation among the expression level of PpWRKY65, the expression level of genes related to lignin synthesis, and the lignin content of peach fruit both under ambient temperature and chilling injury condition, it was found that PpWRKY65 negatively regulated the accumulation of peach fruit lignin by inhibiting the expression of genes related to lignin synthesis. Moreover, the lignin content was significantly lower in transient PpWRKY65-overexpressing fruit, compared to the control. Concurrently, the expressions of lignin biosynthesis genes (Pp4CL7, PpCAD1, PpCOMT, PpF5H) were decreased in fruit overexpressing PpWRKY65.