Effects of melatonin treatment on ethanol fermenation and ERF expression in kiwifruit cv. Bruno during postharvest

Kiwifruit (Actinidia deliciosa) cv. Bruno is easy to accumulate ethanol during postharvest, which seriously affects fruit quality. In this study, the effects of melatonin (MT) treatment on ethanol accumulation and AdERF genes relative expression in kiwifruit were investigated. The main results were as follows: MT treatment slowed down the fruit softening by inhibiting the rates of respiration and ethylene release, and significantly reduced the acetaldehyde and ethanol contents in kiwifruit during the later storage. Correspondingly, MT treatment significantly down-regulated the relative expressions of AdADH1, AdPDC1 and AdPDC2, and inhibited the activities of pyruvate carboxylase (PDC) and alcohol dehydrogenase (ADH) in kiwifruit during the later storage period. Also, MT treatment down-regulated the expressions of AdERF4, AdERF74, AdERF75 and Achn226291 during the later storage, while the relative expressions of AdERF5, AdERF6, AdERF15, Achn164421 and Achn330401 were not significantly changed. These results indicated that MT treatment could affect the ethanol metabolism in kiwifruit by regulating the expressions of ADH1, PDC1 and PDC2 as well as the activities of ADH and PDC, thereby contributing to the quality maintenance and the shelf-life extension of kiwifruit. AdERF4, AdERF74, AdERF75 and Achn226291 might be implicated in the process. This study provided a theoretical basis for the MT application in maintaining fruit quality associated with control of alcoholic off-flavor via regulation of ethanol fermentation in kiwifruit during postharvest.