Genomics-guided isolation and identification of active secondary metabolites of Bacillus velezensisBA-26

AbstractHere we report the discovery and identification of antibacterial substances from the secondary metabolites of a new strain Bacillus velezensisBA-26. The whole genome of B. velezensisBA-26 was sequenced. Its genome data were annotated, and four potentially unknown gene clusters and nine known secondary metabolite synthetic gene clusters were analyzed and excavated by antiSMASH software. Based on the predicted secondary metabolites from the genome of strain BA-26, the material identification of isolated and purified extracellular secondary metabolites was conducted in combination with mass spectrometry data. A total of 24 antifungal compounds were identified, namely, iturin and various fengycins. The minimum inhibitory concentration (MIC) of iturin to Botrytis cinereawas 62.50 µg·mL−1. The MICs of C14fengycin A, C16fengycin A and C18fengycin A were 62.50, 31.25 and 0.49 µg·mL−1, respectively, indicating that the increase in the number of carbon atoms in side chain fatty acids of fengycin improves its biological activity. Two kinds of anti-disease fungal compounds from B. velezensisBA-26, namely, iturin and fengycin, were purified and identified; they were found to have antibacterial activities against common pathogenic fungi. Therefore, B. velezensisBA-26 may be potentially used as a biological control agent. This study enriches the genome information on B. velezensis, elucidates the active components of B. velezensisBA-26 antibacterial substances, and provides a useful reference for using strain BA-26 as a biological control agent.Supplemental data for this article is available online at https://doi.org/10.1080/13102818.2021.1934540 .