Genome-Based Reclassification of Anoxybacillus geothermalis Filippidou et al. 2016 as a Later Heterotypic Synonym of Anoxybacillus rupiensis Derekova et al. 2007

In this study, our aim was to elucidate the relationship between Anoxybacillus rupiensis DSM 17127 T and Anoxybacillus geothermalis GSsed3 T through whole-genome phylogenetic analysis. The obtained 16S rRNA gene sequence from the genome of A. rupiensis DSM 17127 T exhibited a 99.8% similarity with A. geothermalis GSsed3 T . In the phylogenetic trees constructed using whole-genome sequences and 16S rRNA gene sequences, A. rupiensis DSM 17127 T and A. geothermalis GSsed3 T were observed to form a clade, indicating a close relationship between them. Moreover, the average amino acid identity, average nucleotide identity, and digital DNA–DNA hybridization values calculated between A. rupiensis DSM 17127 T and A. geothermalis GSsed3 T exceeded the threshold values typically used for species demarcation. Furthermore, the phylogenomic analysis based on the core genome of the strains in question provided additional support for the formation of a monophyletic clade by A. rupiensis DSM 17127 T and A. geothermalis GSsed3 T . Most phenotypic and chemotaxonomic features between both strains were almost identical except for a few exceptions. These findings suggest that both strains should be classified as belonging to the same species, and we propose that A. geothermalis GSsed3 T is a later heterotypic synonym of A. rupiensis DSM 17127 T .