EjLAC12 is involved in postharvest chilling injury in loquat fruits by regulating lignin polymerization

Loquat fruits are susceptible to chilling injury at low temperatures following harvest, and heat shock treatment (HT) effectively mitigates chilling-induced lignification in these fruits. Laccase (LAC) is involved in lignin deposition. In this study, 43 laccase genes were identified based on the loquat genome, and the expression patterns of laccases were analyzed during fruit development and postharvest storage. The expression pattern analysis and subcellular localization revealed that EjLAC12 is involved in the regulation of lignin biosynthesis. Furthermore, the overexpression of EjLAC12 in tomato plants resulted in increased lignin and flavonoid contents. Overall, EjLAC12 promotes the accumulation of lignin during low-temperature storage, whereas HT treatment can alleviate its transcription, thereby mitigating postharvest chilling-induced lignification in loquat fruits.