Volatile organic compounds of the solid fumigant prepared by strain Streptomyces setonii WY228 control gray mold disease in postharvest strawberries

Gray mold disease caused by Botrytis cinerea severely compromises postharvest strawberry quality. As an eco-friendly alternative to chemical fungicides, biological control agents based on microbial volatile organic compounds (VOCs) have emerged as promising candidates. This study developed a VOC-producing fumigant derived from wheat grain-cultured Streptomyces setonii WY228 to control gray mold in postharvest strawberries. Key parameters influencing the fumigant’s antifungal activity, including inoculation volume, culture temperature, incubation time, moisture content and dosage of wheat grains, were systematically optimized to establish a preparation strategy. Storage at 4 °C with vacuum maintained 70 % B. cinerea inhibition with sustained viability of fumigant for 90 d. Application of the fumigant at 26.7 g L −1 suppressed gray mold in postharvest strawberries. The firmness, ascorbic acid content, titratable acidity, and superoxide dismutase activity of fumigated strawberries were 42 %, 54 %, 24 %, and 160 % higher than those of the positive control group, respectively. Four main compounds in VOCs were identified as methyl 2-furoate, 2-methylbutyric acid, 4-methylpentanoic acid, and cyclopentanone, and exhibited antifungal activity and gray mold suppression in strawberries. The wheat grain solid fumigant prepared by S. setonii WY228 demonstrates potential as a biological control agent for gray mold suppression in postharvest strawberries.