Research PaperInduction of disease resistance providing new insight into sulfur dioxide preservation in Vitis vinifera L.

- SO2 could prolong the storage life and maintain a high quality of grape berries.
- Secondary Metabolities played crucial roles during SO2 preservation in Vitis vinifera L.
- Transcriptional levels of some defense-related genes were induced by SO2.

The effect of a postharvest treatment with sulfur dioxide (SO2) under commercial conditions on table grapes (Vitis vinifera L. 'Muscat Hamburg') quality and the possible action mechanisms were investigated. The results indicated that SO2 treatment resulted in an improved control of infections in grapes during storage. The fresh fruit rate of SO2 treatment group was significantly higher than that of the control group. Furthermore, SO2 markedly enhanced activity of phenylalanine ammonia lyase (PAL), promoted the accumulation of phenolic compounds including total phenol, flavonoid and lignin, and improved the polyphenol oxidase (PPO) activity. Moreover, SO2 significantly elevated transcription levels of pathogenesis-related (PR) proteins genes chitinase3 (CHI3), CHI1b and β-1,3-glucanase (PR2). Consistently, the activities of chitinase and β-1,3-glucanase remarkably increased in SO2 treatment group. Our founding indicates that SO2 activates defense responses associated with secondary metabolism and PR proteins for enhanced disease resistance and thereby thus extending the storage life of table grapes.

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