Hydrogen Sulfide Alleviates Postharvest Senescence of Grape by Modulating the Antioxidant Defenses

Hydrogen sulfide (H(2)S) has been identified as an important gaseous signal in plants. Here, we investigated the mechanism of H(2)S in alleviating postharvest senescence and rotting of Kyoho grape. Exogenous application of H(2)S released from 1.0 mM NaHS remarkably decreased the rotting and threshing rate of grape berries. H(2)S application also prevented the weight loss in grape clusters and inhibited the decreases in firmness, soluble solids, and titratable acidity in grape pulp during postharvest storage. The data of chlorophyll and carotenoid content suggested the role of H(2)S in preventing chlorophyll breakdown and carotenoid accumulation in both grape rachis and pulp. In comparison to water control, exogenous H(2)S application maintained significantly higher levels of ascorbic acid and flavonoid and total phenolics and reducing sugar and soluble protein in grape pulp. Meanwhile, H(2)S significantly reduced the accumulation of malondialdehyde (MDA), hydrogen peroxide (H(2)O(2)), and superoxide anion (O(2) (∙−)) in grape pulp. Further investigations showed that H(2)S enhanced the activities of antioxidant enzymes ascorbate peroxidase (APX) and catalase (CAT) and decreased those of lipoxygenase (LOX) in both grape peels and pulp. In all, we provided strong evidence that H(2)S effectively alleviated postharvest senescence and rotting of Kyoho grape by modulating antioxidant enzymes and attenuating lipid peroxidation.