AdERF14 forms a self-activating loop to promote ethylene biosynthesis in kiwifruit

As a commercially important fruit crop, kiwifruit releases a burst of ethylene production during ripening, which critically influences its postharvest storage life and quality. Understanding the regulatory mechanisms underlying ethylene biosynthesis is essential for reducing postharvest losses. In this study, we measured physiological indices of kiwifruit ( Actinidia deliciosa cv. Hayward) during ripening. Subsequently, transcriptomic data revealed that AdERF14 is strongly up-regulated during natural ripening and the transcriptional activity assay confirmed that AdERF14 functions as a transcriptional activator. To investigate the biological function of AdERF14 , we generated AdERF14 -overexpressing callus lines of kiwifruit ( Actinidia chinensis cv. Donghong). RNA-seq analysis and RT-qPCR revealed that AcACS1 (the A. chinensis homolog of AdACS1 ), a key ethylene biosynthesis gene , was significantly up-regulated in these lines. Dual-luciferase reporter assay and electrophoretic mobility shift assay (EMSA) confirmed that AdERF14 directly binds to and activates the promoter of AdACS1 . Moreover, the AdERF14 overexpression lines produced higher levels of ethylene. Additionally, AdERF14 also activates its own promoter, thereby establishing a self-regulatory feedback loop. Together, these findings support a model in which AdERF14 activates its own transcription and enhances AdACS1 promoter activity, contributing to ethylene biosynthesis in kiwifruit.