MeJA-induced bifunctional transcription factor PuMYC2 regulates reactive oxygen species homeostasis and aroma quality in cold-stored Nanguo pear fruit

During the postharvest period of fruits, the abnormal accumulation of reactive oxygen species (ROS) is closely associated with the deterioration of fruit quality, which severely impairs the market value and shelf life of fruits. Methyl jasmonate (MeJA) can alleviate the postharvest fruit quality deterioration caused by cold storage. In this study, PuMYC2 was identified as a positive regulator of ROS scavenging and aroma metabolism in cold-stored Nanguo pear fruit. Overexpression of PuMYC2 led to the upregulation of the antioxidant enzyme gene PuPOD12 and the aroma synthesis gene PuLOX3-1. When Nanguo pear fruits were subjected to cold stress, the fruits overexpressing PuMYC2 exhibited lower ROS levels and higher contents of aroma compounds. Yeast one-hybrid (Y1H), electrophoretic mobility shift assay (EMSA), and beta-glucuronidase (GUS) assays confirmed that PuMYC2 directly binds to the promoters of PuPOD12 and PuLOX3-1 to activate their transcription. These findings provide novel insights into strategies for preserving the quality of cold-stored fruits.