Antifungal volatile organic compounds from Burkholderia sp. BV6 control gray mold disease of cherry tomato

• Burkholderia sp. BV6 had antifungal activity against Botrytis cinerea . • Optimization of the strain BV6 inoculation protocol enhanced antifungal activity. • VOCs produced by strain BV6 showed broad-spectrum antifungal activity. • BV6 emitted 24 VOCs, and 2-nonanol was the most effective antifungal compound. • Both 2-Nonanol and BV6 could be promising tools to control gray mold. Botrytis cinerea is a fungal pathogen that acts as a necrotroph, causing gray mold disease and affecting over 1400 plants. The biocontrol effect of microbial volatile organic compounds (VOCs) in controlling postharvest diseases has gradually gained significant attention as a research hotspot. This study evaluated the biocontrol effects of VOCs produced by Burkholderia sp. BV6 on B. cinerea in vitro and in vivo . The results showed that the strain BV6 volatiles suppressed the mycelial growth of B. cinerea . The antifungal effect of strain BV6 volatiles against B. cinerea was enhanced by optimizing the inoculation method and inoculation quantity of strain BV6. The volatiles of strain BV6 showed wide-spectrum antifungal activity against several plant pathogenic fungi. Solid-phase microextraction gas chromatography-mass spectrometry (SPME-GC/MS) analysis identified 24 volatile compounds, the most abundant of which (2-nonanol, 2-nonanone, 2-tridecanol, and 2-undecanol) showed dose-dependent antifungal activity. Among them, 2-nonanol exhibited the strongest antifungal activity toward B. cinerea , with a minimum inhibitory volume (MIV) of 1.5 μL/plate (equal to 21.43 μL/L). Strain BV6 and 2-nonanol reduced the lesion diameter and disease severity of of gray mold in cherry tomatoes caused by B. cinerea . These results suggest that fumigation with 2-nonanol or strain BV6 is a promising method for protecting cherry tomatoes against gray mold disease. Furthermore, this study demonstrated the antifungal efficacy of both strain BV6 and 2-nonanol against B. cinerea and their biocontrol potential for postharvest cherry tomatoes.