Volatile organic compounds produced by Lysinibacillus sp. FJAT-4748 possess antifungal activity against Colletotrichum acutatum

FJAT-4748 is a bacterial strain isolated from forest soil samples taken from Dongba Valley, Lijiang, Kunming, Yunnan Province, PR China. This strain was identified as Lysinibacillus sp. based on a 16S rRNA gene sequence analysis. FJAT-4748 has been shown to possess antifungal activity against different fungi, including Colletotrichum acutatum, Aspergillus niger, Fusarium solani, Fusarium moniliforme and Fusarium oxysporum. The results of the present study indicate that this antifungal activity results from volatile organic compounds (VOCs) produced by this strain. The observed inhibition rates of VOCs from FJAT-4748 against these fungi were 100%, 100%, 37.20%, 18.94% and 7.64%, respectively. GC-MS analysis identified 24 VOCs from FJAT-4748, which included different categories of compounds, such as aldehydes, ketones, alcohols, aromatic hydrocarbons and alkanes. Of these 24 VOCs, the most abundant compound was 2-ethyl-1-hexanol, which constituted 36.24% of the total VOCs based on the relative peak area. In the in vitro C. acutatum mycelial growth assay, 2-ethyl-1-hexanol exhibited the strongest activity, with an inhibitory rate of 100% using 10?µL/plate of this VOC. The activity of benzaldehyde was lower. 2-decanone showed the weakest activity among the compounds tested. The inhibitory activity of an artificial mixture of three VOCs against the C. acutatum increased with the amount of artificial mixture used. The inhibition rate reached 100% using 30?µL/plate of this artificial mixture in the plate test. Taken together, these results show that the antifungal VOCs produced by Lysinibacillus sp. FJAT-4748 are potentially useful as agents for controlling anthracnose caused by Colletotrichum acutatum.