SlWRKY31 enhances chilling tolerance by interacting with SlSIZ1 in tomato fruit

Abstract

Refrigeration can extend the storage life of postharvest fruits and vegetables. However, tomato fruit are susceptible to chilling injury (CI) under low temperatures, leading to economic losses. In the present work, SlWRKY31 facilitated to reduce the reactive oxygen species (ROS) content by improving the activity of superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) and production of glutathione (GSH) and ascorbic acid (AsA), thus inhibiting the CI index in tomato fruit. SlWRKY31 promoted the SAP AND MIZ1 DOMAIN-CONTAINING LIGASE1 (SlSIZ1) expression. Moreover, SlWRKY31 transactivated the SlSIZ1 by binding to the W-box motif derived from its promoter. SlSIZ1 contributed to repress the ROS generation by promoting the activity of SOD, POD and CAT and accumulation of GSH and AsA, and thereby boosted the chilling tolerance in tomatoes. SlSIZ1 enhanced the SlWRKY31 expression. The protein-protein interaction between SlSIZ1 and SlWRKY31 was occurred. Thus, SlWRKY31 retarded the CI by interacting with SlSIZ1 in tomato fruit.