Applications of nitric oxide and melatonin in improving postharvest fruit quality and the separate and crosstalk biochemical mechanisms

Background: Due to the perishability of most fruits during post-harvest storage, it is necessary to look for environmental friendly chemical treatments to improve the quality of postharvest fruits. Most recent studies have found that exogenous MT and NO applications can effectively improve the quality of postharvest fruit. Scope and approach: This article reviews recent applications of NO and MT in postharvest fruits including the effect on delaying senescence, alleviating chilling injury and controlling disease, summaries the potential biochemical mechanisms of the applications of NO and MT in improving postharvest fruit quality. In addition, the potential crosstalk biochemical mechanism of MT and NO is also discussed. Key findings and conclusions: This review mainly concluded that exogenous NO treatment improved quality in postharvest fruit which was attributed to follows (1) Inhibition of ethylene biosynthesis. (2) Enhancement of antioxidant system. (3) Induced defense system. (4) Activated CBFs pathway. (5) Regulated sugar and energy metabolisms, and the exogenous MT treatment was attributed to the followings (1) Induced endogenous NO biosynthesis. (2) Enhanced antioxidant system and endogenous MT biosynthesis. (3) Induced defense system. (4) Enhanced GABA shunt pathway, polyamine and proline biosynthesis. Particular finding is the crosstalk mechanism that existing in the applications of exogenous MT and NO in postharvest fruit preservation.