Genome analysis-based reclassification of Bacillus weihenstephanensis as a later heterotypic synonym of Bacillus mycoides

Abstract

The aim of this study was to clarify the taxonomic status of the species Bacillus weihenstephanensis. A complete genome sequence for the type strain of B. weihenstephanensis was compared against that of the closely related type strain of Bacillus mycoides. The digital DNA-DNA hybridization and average nucleotide identity values between the two type strains was greater than two recognized thresholds for bacterial species delineation, indicating that they should belong to the same genomospecies. The psychrotolerant characteristic and signature sequences of 16S rRNA and cspA genes were incapable of distinguishing B. weihenstephanensis from some non-B. weihenstephanensis strains. Meanwhile, the metabolic, physiological and chemotaxonomic features for the type strain of B. weihenstephanensis were shown to be congruent with those of B. mycoides. On this basis, the taxonomic affiliations of related strains from the Genbank database were determined using multilocus sequence typing and genomic analyses. Therefore, we propose Bacillus weihenstephanensis as a later heterotypic synonym of Bacillus mycoides and correction of erroneous species identifications for several strains.

Keywords: Bacillus mycoides; Bacillus weihenstephanensis; genome analysis; heterotypic synonym; multilocus sequence typing; reclassification.