Preharvest methyl jasmonate maintain the shelf quality of kiwifruit after cold storage by regulating the antioxidant system

Abstract

Soft rot is an important postharvest disease of kiwifruit, and MeJA can induce kiwifruit to resist soft rot. However, the treatment timing of preharvest MeJA and the mechanism of inducing kiwifruit resistance are still unclear. In this study, we compared the effects of preharvest MeJA and postharvest MeJA on the shelf quality of kiwifruit after cold storage. We investigated the impact of soaked in MeJA for 10 s at 32 d after full bloom (DAFB) and/or sprayed with MeJA at 141 DAFB alone or simultaneously on the shelf quality of kiwifruit after cold storage, also the resistance of kiwifruit to B. dothidea. The results showed that both preharvest and postharvest MeJA inhibited the incidence of soft rot in postharvest kiwifruit by regulating antioxidant capacity, while preharvest MeJA was more effective compared to postharvest MeJA. Compared to the control, both preharvest MeJA at 32D or/and 141S kept the shelf quality of kiwifruit after cold storage, and the preharvest MeJA at 32D and 141S is optimal. Preharvest MeJA at 32D and 141S maintained the volatile aroma in kiwifruit during shelf quality by regulating the enzyme related to aroma metabolism, kept shelf quality by regulating the ROS homeostasis and glutathione-ascorbic acid (GSH-ASA) cycle, and improving the activities of disease-resistant enzymes. Further data from the kiwifruit inoculated with B. dothidea indicate that preharvest MeJA keeps the kiwifruit quality and induces its disease resistance during shelf life after cold storage by regulating the antioxidant system. Overall, these findings showed that preharvest MeJA kept the kiwifruit shelf quality after cold storage by regulating the antioxidant system.