Bacillus silvicola sp. nov, a new species within the Bacillus cereus group isolated from hardwood forest soil in Maryland, USA

Authors: Bartholomew, Holly; Sparks, Michael; KUHAR, DANIEL - Former ARS Employee; Mitchell, Ashaki; FARRAR, ROBERT - Retired ARS Employee; Gundersen, Dawn; BLACKBURN, MICHAEL - Retired ARS Employee

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/6/2026
Publication Date: 5/13/2026
Citation: Bartholomew, H.P., Sparks, M., Kuhar, D., Mitchell, A.D., Farrar, R., Gundersen-Rindal, D.E., Blackburn, M. 2026. Bacillus silvicola sp. nov, a new species within the Bacillus cereus group isolated from hardwood forest soil in Maryland, USA. Scientific Reports. https://doi.org/10.1038/s41598-026-52504-9.
DOI: https://doi.org/10.1038/s41598-026-52504-9

Interpretive Summary: There is an ongoing need for microbial biopesticide research and development to reduce use of chemical pesticides and improve agricultural yields and quality. Several species of Bacillus bacteria have been shown to be beneficial as biopesticides, and therefore, discovery of novel species are of interest. Here, we describe a novel Bacillus species that was originally isolated from a hardwood forest floor in Maryland, USA. Comparisons of the genome sequence and other physiological and biochemical characteristics with other Bacillus species shows it belongs to a subgroup with the closest relative identified as Bacillus proteolyticus. We propose to name this novel species Bacillus silvicola. This new species represents a novel microbial and genomic resource to scientists and industry. Furthermore, as this species is closely related to the heavily utilized biopesticial species Bacillus thuringiensis, it may also have biocontrol applications. Therefore, future examination of this novel species through comparisons with existing pesticidal strains could add interest to both scientists and the biocontrol industry.

Technical Abstract: A single bacterial isolate, IBL03679T, from forest soil in Maryland, USA in 2009 was originally identified as belonging to the Bacillus cereus senso lato group through multi-locus sequence typing. Here, further identification efforts with genomic and phenotypic methods demonstrate that this isolate belongs to a new species. Phylogenetic analysis using 16S rRNA gene and whole genome sequencing suggest the most closely related species is Bacillus proteolyticus. ANIb and dDDH values confirmed species differentiation with values below conventional 96% and 70% thresholds, respectively. It is a Gram-positive, facultative anaerobe, endospore and parasporal crystal forming rod-shaped bacterium. Physiological characteristics, such as casein hydrolysis and lecithinase production, and major fatty acids identified (C16:0, iso-C15:0, and iso-C17:0), support affiliation with other Bacillus species. The polar lipid profile was primarily diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), and phosphatidylglyercol (PG), the peptidoglycan type was A1' meso-Dpm – direct (A31), and the sole respiratory quinone was menaquinone-7 . API50 biochemical testing revealed distinguishing test results for IBL03679T through negative acid production for D-cellobiose and D-saccharose and positive for potassium gluconate. Collectively, the genotypic and phenotypic data demonstrate that IBL03679T belongs to a novel species. We propose the name Bacillus silvicola sp. nov for this taxon with the type strain IBL03679T (=NRRL B-65743).