BACKGROUND: Melatonin (MT) is an endogenous indoleamine that regulates senescence progression and stress response in plants. OBJECTIVE: Here, we investigated the effect of MT on the shelf-life and postharvest quality of table grapes (Vitis labrusca L. cv. ‘Fengzao’). METHODS: After harvesting, ‘Fengzao’ grapes were immersed in MT solution at various concentrations (0 [as control], 0.05, 0.1, 0.5 and 1.0 mM for 2 h and stored at 24±1 for 15 days. Physiological indicators including weight loss rate, firmness, contents of total soluble solids (TSSs), ascorbic acid (AsA), malondialdehyde (MDA), hydrogen peroxide (H2O2), and activities of catalase (CAT), ascorbate peroxidase (APX), and superoxide dismutase (SOD) were investigated. Additionally, the DNA methylation rate of ‘Fengzao’ grapes were measured using the methylation-sensitive amplification polymorphism (MSAP) technique. RESULTS: Application of MT effectively delayed grape senescence in all treatment groups compared with the control, with the longest delay observed in the 0.5 mM treatment. Additionally, the rate of DNA methylation decreased in all the 0.5 mM MT treatment groups, indicating a potential role of MT in demethylation. CONCLUSIONS: Our results suggest that the exogenous application of MT can delay the senescence of grapes during postharvest.
Deciphering the Role of CBF/DREB Transcription Factors and Dehydrins in Maintaining the Quality of Table Grapes cv. Autumn Royal Treated with High CO2 Levels and Stored at 0°C