Label-free quantitative proteomics to investigate the response of strawberry fruit after controlled ozone treatment

To elucidate postharvest senescence in strawberry (Fragaria ananassa Duch. var. 'JingTaoXiang') fruit in response to ozone treatment at different concentrations (0, 2.144, 6.432, and 10.72 mg m^-3), a label-free quantitative proteomic investigation was performed. Postharvest physiological quality traits including respiration rate, firmness, titratable acid, and anthocyanin content were characterized. The observed protein expression profile after storage was related to delayed senescence in strawberries. A total of 2413 proteins were identified in differentially treated strawberry fruits, and 382 proteins were differentially expressed between the four treatments on day 7 and the initial value (blank 0). Proteins related to carbohydrate and energy metabolism and anthocyanin biosynthesis, cell stress response, and fruit firmness were characterized and quantified. Ozone treatment at the concentration of 10.72 mg m^-3 effectively delayed the senescence of the strawberry. The proteomic profiles were linked to physiological traits of strawberry fruit senescence to provide new insights into possible molecular mechanisms.