Location: Crop Bioprotection ResearchTitle: Promotion of Bacillus subtilis subsp. inaquosorum, Bacillus subtilis subsp. spizizenii and Bacillus subtilis subsp. stercoris to species status
Submitted to: Antonie Van Leeuwenhoek
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/27/2019
Publication Date: 1/1/2020
Citation: Dunlap, C.A., Bowman, M.J., Zeigler, D.R. 2020. Promotion of Bacillus subtilis subsp. inaquosorum, Bacillus subtilis subsp. spizizenii and Bacillus subtilis subsp. stercoris to species status. Antonie Van Leeuwenhoek. 113:1-12. https://doi.org/10.1007/s10482-019-01354-9.
Interpretive Summary: ARS researchers from Peoria, IL collaborated with a researcher at a university in Ohio to evaluate an important class of bacteria and determine their taxonomic position under the most advanced methods of taxonomy. These bacteria are from an important genus of bacteria, Bacillus, which is found and utilized in many food and agricultural products. The results showed changes were necessary with species nomenclature, since they were inconsistent with current bacterial taxonomy. This study will allow us to better understand these beneficial microbes through the consistent use of nomenclature. This research benefits U.S. farmers and consumers that rely on these products for food and agriculture applications.
Technical Abstract: 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.