LAUSR

ABSTRACT Volatile organic compounds (VOCs) from a biocontrol bacterium Paenibacillus polymyxa CF05 were evaluated for antifungal effects against Rhizopus stolonifer, an important pathogen causing postharvest fruit rot. The aerial mycelial growth and sporangia production of R. stolonifer was inhibited after exposure to the bacterial VOCs. Moreover, bacterial VOCs exhibited effective inhibition on Rhizopus rots of cherry, mango and nectarine, resulting 75.88%, 60.64% and 73.13% of suppression ratios at 96 h postinoculation (hpi), respectively. However, the suppression ratios were lower than chemical fungicide imazalil. The main volatile compounds from CF05 were analysed by solid-phase microextraction-gas chromatography tandem mass spectrometry (SPME-GC-MS) and 14 compounds were predominately identified. Among them, the volatile compounds benzothiazole and butylated hydroxytoluene exhibited the highest inhibitory effects on R. stolonifer, resulting 0.03 μL mL −1 headspace and 0.04 μL mL −1 headspace of 50% effective concentrations (EC50), respectively. Furthermore, the antagonistic effects of bacterial VOCs were dependent on the cultivation medium, which might be attributed to their various amounts and compositions. In conclusion, the antifungal VOCs from strain CF05 could be a promising agent in the integrated management of Rhizopus fruit rot.