| Summary: | The present study focuses on the inhibitory effect of volatile metabolites released by <i>Bacillus velezensis</i> CT32 on <i>Verticillium dahliae</i> and <i>Fusarium oxysporum</i>, the causal agents of strawberry vascular wilt. The CT32 strain was isolated from maize straw compost tea and identified as <i>B. velezensis</i> based on 16S rRNA gene sequence analysis. Bioassays conducted in sealed plates revealed that the volatile organic compounds (VOCs) produced by the strain CT32 possessed broad-spectrum antifungal activity against eight phytopathogenic fungi. The volatile profile of strain CT32 was obtained by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). A total of 30 volatile compounds were identified, six of which have not previously been detected in bacteria or fungi: (Z)-5-undecene, decyl formate, 2,4-dimethyl-6-tert-butylphenol, dodecanenitrile, 2-methylpentadecane and 2,2’,5,5’-tetramethyl-1,1’-biphenyl. Pure compounds were tested in vitro for their inhibitory effect on the mycelial growth of <i>V. dahliae</i> and <i>F. oxysporum</i>. Decanal, benzothiazole, 3-undecanone, 2-undecanone, 2-undecanol, undecanal and 2,4-dimethyl-6-tert-butylphenol showed high antifungal activity, with benzothiazole and 2,4-dimethyl-6-tert-butylphenol being the most potent compounds. These results indicate that the VOCs produced by <i>B. velezensis</i> CT32 have the potential to be used as a biofumigant for management of vascular wilt pathogens.
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