Secretion and volatile components contribute to the antagonism of Bacillus velezensis 1-10 against fungal pathogens

Fungal pathogens widely infect plants and fruits, causing various diseases and reducing their yield and quality. Biological control provides a good strategy for improving crop productivity and quality as well as reducing the use of potentially environmentally hazardous chemical fertilizers and pesticides. In this study, antagonistic and functional components of Bacillus velezensis 1-10 (GenBank: JAJJCH000000000), isolated from the acidic soil of tea gardens were investigated. B. velezensis 1-10 inhibited the growth of four fungal pathogens based on dual culture bioassay and the counterpoint fumigation method, as well as inhibiting the diseases of tomato and grapes caused by Glomerella cingulata PTT and Athelia rolfsii DQ. Genomic analysis showed that B. velezensis 1-10 contained multiple gene clusters encoding lipopeptides and siderophore bacillibactin. Based on antimicrobial experiments and mass spectrometry analysis, B. velezensis 1-10 was found to produce 2 types of lipopeptides, iturin with four homologues, and fengycin with five homologues. Quality and quantity tests demonstrated that B. velezensis 1-10 produced siderophore baillibactin. Headspace solid-phase microextraction and GC-MS detection indicated that B. velezensis 1-10 produced 22 VOC components, including antifungal phenol, Nmethylacetamide and 2,4-di-tert-butylphenol. 2,4-di-tert-butylphenol was confirmed to inhibit three of the fungal pathogens. The various antifungal substances produced by B. velezensis 1-10, including secreted lipopeptides, siderophores and volatile compounds, collectively endow the strain with great potential in green agriculture and fruit preservation.