Ethylene-induced MdDof1.2 activates MdAMY1 to promote starch degradation in post-harvest apple fruit

Abstract

Starch degradation is a critical physiological change that occurs during the postharvest storage of apples, significantly affecting fruit quality. Ethylene, a key hormone in climacteric fruits, is known to promote this process. However, the underlying mechanism remains poorly understood. This study aimed to elucidate how ethylene mediates starch degradation in apples by focusing on its role in regulating specific gene expression. Using ethylene treatment and gene expression analysis, we identified two key genes, MdAMY1 and MdBAM8, that are upregulated during apple storage. In addition, we discovered a DOF-type transcription factor, MdDof1.2, whose expression is induced by ethylene. Functional assays demonstrated that MdDof1.2 directly binds to the promoter of MdAMY1, enhancing its transcription. Overexpression of MdDof1.2 in apple fruits significantly increased MdAMY1 expression and accelerated starch degradation during storage. These findings reveal a novel gene regulatory network in which ethylene regulates starch metabolism through transcriptional activation of key genes. This study provides new insights into the molecular mechanisms underlying postharvest fruit metabolism, with potential applications for improving storage strategies and extending fruit shelf life.