Genome-based reclassification of Bacillus plakortidis Borchert et al. 2007 and Bacillus lehensis Ghosh et al. 2007 as a later heterotypic synonym of Bacillus oshimensis Yumoto et al. 2005; Bacillus rhizosphaerae Madhaiyan et al. 2011 as a later heterotypic synonym of Bacillus clausii Nielsen et al. 1995.

In the present study, phylogenetic and genome-based comparison was carried out to clarify the taxonomic positions of alkaliphilic Bacillus species, Bacillus plakortidis, Bacillus lehensis, Bacillus oshimensis, Bacillus rhizosphaerae and Bacillus clausii. Phylogenetic trees based on 16S rRNA gene sequences and concatenated protein marker genes were constructed. Average nucleotide identity (ANI) values were calculated to compare genetic relatedness. In phylogenetic trees, B. plakortidis DSM 19153T, B. lehensis DSM 19099T, and B. oshimensis DSM 18940T; B. rhizosphaerae DSM 21911T and B. clausii DSM 8716T clade together. The average nucleotide identity (ANI) values between B. oshimensis DSM 18940T, B. plakortidis DSM 19153T and B. lehensis DSM 19099T ranged from 98.7-98.8%, while the ANI values between B. rhizosphaerae DSM 21911T and B. clausii DSM 8716T were 95.2-95.5%. The ANI values were higher than the recognized threshold value for bacterial species delineation. Based on phylogenetic and genome comparison we propose reclassification of B. plakortidis and B. lehensis as a later heterotypic synonym of B. oshimensis; B. rhizosphaerae as a later heterotypic synonym of B. clausii.