AP2/ERF Transcription Factor MiRAP2.11 Mediates Ethylene-Induced Starch Degradation in Postharvest Mango Fruit

Starch degradation is a fundamental process underlying the development of key postharvest quality attributes in ripening mango fruit; however, its regulatory mechanisms remain incompletely understood. In this study, ethephon (ETH) and 1-methylcyclopropene (1-MCP) were used as ripening modulators to investigate the patterns of starch degradation and its transcriptional regulation in postharvest mango fruit. The results demonstrated that ETH fumigation accelerated the ripening process, while 1-MCP treatment effectively inhibited this process. Transcriptome and RT-qPCR analyses revealed and validated that six starch-degrading genes (MiAMY1.1, MiAMY3, MiBAM3, MiBAM9, MiGWD and MiPWD) were regulated in response to ETH. Furthermore, the transcription factor MiRAP2.11 was identified as a nucleus-localized transcriptional activator of MiBAM3 and MiPWD. Transient transformation assays demonstrated that MiRAP2.11 positively regulated starch degradation, thereby promoting development of ripening and quality attributes. The results indicate that MiRAP2.11 functions as a crucial regulator mediating ethylene-induced starch degradation during mango ripening.