2.1. Pathogen inoculum
B. cinerea was isolated from a grape berry showing typical gray mold and stored on potato dextrose agar (PDA, 200mL extract of boiled potatoes, 20g dextrose and 20g agar in 1000mL distilled water) at 4◦C. Before use, B. cinerea was freshly cultured on PDA plates at 23◦C Spore suspensions were prepared by removing the spores from a 7-day old culture with a sterile inoculator and then suspending in sterile distilled water to the required concentration of1×105 sporesmL−1,which was estimated using a hemacytometer (XB-K-25; Shanghai, China).