MiERF023 positively regulates chlorophyll degradation in ethylene-mediated ‘Tainong no.1’ mango by targeting the promoters of MiPPH and MiPAO

(1) ETH accelerates peel chlorophyll degradation and coloration in postharvest mangoes. (2) ETH induces PPH and PAO activities while 1-MCP represses them in mango ripening. (4) 1-MCP suppressed MiERF23 , MiPPH and MiPAO expressions in mango fruit. (4) MiERF23 directly binds to MiPPH and MiPAO promoters to activate their transcription. (5) Overexpression of MiERF23 results in chlorophyll catabolism in mango fruit. Chlorophyll degradation occurs during mango fruit ripening, contributing to the color and commercial value of the fruit. Ethylene response factors (ERFs) are recognized as important regulators of chlorophyll degradation. This study investigated the regulatory effects of MiERF023 on mango coloration through ethylene (ETH) and 1-methylcyclopropene (1-MCP) treatments. ETH treatment increased the activities of chlorophyll degradation-related enzymes (Chlase, MDCase, PPH, and PAO), activated the expression of chlorophyll catabolism genes ( MiPPH and MiPAO ), accelerated chlorophyll degradation, and promoted coloration of mango. In contrast, the opposite effects were observed after 1-MCP treatment. Meanwhile, the expression of MiERF023 was greatly induced by ethylene and inhibited by 1-MCP, then MiERF023 was isolated and characterized. Yeast one-hybrid (Y1H) and dual luciferase reporter (DLR) assays demonstrated that MiERF023 binds to the promoters of MiPPH and MiPAO , upregulating their transcript levels. Transient overexpression of MiERF023 in tomato and mango fruits increased the transcript levels of MiPPH and MiPAO , accelerating chlorophyll degradation and promoting peel coloration. Collectively, these findings reveal a novel regulatory mechanism by which MiERF023 modulates ethylene-mediated pigment metabolism offering potential targets for improving sensory quality in postharvest mango fruits.