H2S treatment alleviates postharvest chilling injury in green pepper by regulating antioxidant capacity, osmotic regulation and lipid metabolism to maintain cell membrane integrity.

Green pepper is prone to chilling injury (CI) under low temperature stress, resulting in quality deterioration. This study aimed to investigate the effect of hydrogen sulfide (H2S) treatment on green peppers during cold storage. The results showed that H2S treatment inhibited the CI, maintained a high chlorophyll content, improved antioxidant capacity and promoted proline and polyamines accumulation in green pepper. Meanwhile, H2S treatment could support a higher unsaturated fatty acids content and inhibit the activity of lipid metabolism-related enzymes, thereby maintaining the stability of cell membranes in green pepper. Moreover, the correlation analysis suggested that green pepper fruit CI was highly negatively correlated with antioxidant enzymes and the unsaturation degree of fatty acids. Molecular docking and enzyme activity assay results showed that H2S might regulate enzyme activity through S-sulfhydration. Together, the results reveal the mechanism of H2S inducing cold tolerance in postharvest green pepper.