bacillomycin-f and fengycin

Bacillus subtilis currently encompasses four subspecies, Bacillus subtilis subsp. subtilis, Bacillus subtilis subsp. inaquosorum, Bacillus subtilis subsp. spizizenii and Bacillus subtilis subsp. stercoris. Several studies based on genomic comparisons have suggested these subspecies should be promoted to species status. Previously, one of the main reasons for leaving them as subspecies was the lack of distinguishing phenotypes. In this study, we used comparative genomics to determine the genes unique to each subspecies and used these to lead us to the unique phenotypes. The results show that one difference among the subspecies is they produce different bioactive secondary metabolites. B. subtilis subsp. spizizenii is shown conserve the genes to produce mycosubtilin, bacillaene and 3,3'-neotrehalosadiamine. B. subtilis subsp. inaquosorum is shown conserve the genes to produce bacillomycin F, fengycin and an unknown PKS/NRPS cluster. B. subtilis subsp. stercoris is shown conserve the genes to produce fengycin and an unknown PKS/NRPS cluster. While B. subtilis subsp. subtilis is shown to conserve the genes to produce 3,3'-neotrehalosadiamine. In addition, we update the chemotaxonomy and phenotyping to support their promotion to species status.

Topics: Bacillus subtilis; Genome, Bacterial; Lipopeptides; Lipoproteins; Peptides, Cyclic; Polyenes

A strain of bacteria in the Bacillus subtilis species complex was isolated from a building's air vent in the Washington DC area, USA, and produced strong antifungal activity with in vitro assays. This strain, designated (HU Biol-II), showed pronounced inhibitory effects on mycelial growth of a wide spectrum of fungi. The objectives of this study were to use genome sequencing to confirm the taxonomy of HU Biol-II, evaluate its antifungal activity and implement genome mining and HPLC-MS/MS to characterize the bioactive secondary metabolites. The strain, as determined by multilocus sequence alignment analysis, was identified as a member of Bacillus subtilis subsp. inaquosorum clade. Core genome phylogeny showed that the isolate is most closely related to B. subtilis subsp. inaquosorum strain DE111, a commercially produced human probiotic. The investigation identified eight bioactive metabolite clusters in the genome. HPLC MS/MS was able to confirm the production of seven of the metabolites. This study is the first to report the production of two antifungal cyclic lipopeptides (bacillomycin F and fengycin) from a member of B. subtilis subsp. inaquosorum. The strain also produced the antibacterial aurantinin B, which confirms the biosynthetic cluster responsible for its production. Comparative genomics and metabolomics demonstrated the commercial probiotic strain DE111 produced the same metabolites, with the exception of aurantinin B. These findings are the first description of the secondary metabolites produced by a strain of B. subtilis subsp. inaquosorum.

Topics: Anti-Bacterial Agents; Antibiosis; Antifungal Agents; Bacillus subtilis; Base Sequence; DNA, Bacterial; Fungi; Lipopeptides; Multilocus Sequence Typing; Mycelium; Peptides, Cyclic; Phylogeny; Polyenes; Secondary Metabolism; Sequence Alignment