Abstract: The aim of this study is to provide theoretical support for reducing the loss of grapes caused by Botrytis cinerea during storage. Botrytis cinerea was exposed to ozone at different concentrations (0, 30, 60 and 90 μL/L) for different times (5, 10 and 15 min), and then stored at (20 ± 1) ℃. The mycelial diameter, the formation of Botrytis cinerea spores and plasma membrane integrity were analyzed to explore the inhibitory effect of ozone on Botrytis cinerea. In a second experiment, postharvest ‘Red Globe’ grapes were inoculated with Botrytis cinerea and exposed to four different concentrations of ozone for 15 min, and then stored at (20 ± 1) ℃ for 5 days. The incidence, lesion size and related enzymes activities were measured to evaluate the inhibitory effect of ozone on controlling gray mold in postharvest grapes. The results indicated that compared with the control group, the growth of Botrytis cinerea was inhibited by ozone but the effect decreased gradually over storage time. Ozone could concentration-dependently and time-dependently damage the integrity of the plasma membrane of Botrytis cinerea and reduce conidia germination. On the other hand, the growth of Botrytis cinerea in grapes was strongly inhibited by ozone at concentrations of 60 and 90 μL/L. Meanwhile, ozone could inhibit the accumulation of malondialdehyde (MDA) content and help maintain higher levels of antioxidant enzyme activities. Taken together, this study suggested that ozone was effective against gray mold in postharvest ‘Red Globe’ grapes by inhibiting the growth of the pathogen and inducing host resistance and the best effect was observed at a concentration of 90 μL/L and 15 min treatment.

Key words: ozone, ‘Red Globe’ grapes, gray mold, storage and preservation