Reclassification of Pseudomonas boreopolis Gray and Thornton 1928 (Approved Lists 1980) as Xanthomonas boreopolis comb. nov. and Pseudomonas carboxydohydrogena (ex Sanjieva and Zavarzin 1971) Meyer et al. 1980 as Afipia carboxydohydrogena comb. nov.

In the present study, we conducted the whole-genome sequence analysis of <i>Pseudomonas boreopolis</i> JCM 13306^T and <i>Pseudomonas carboxydohydrogena</i> DSM 1083^T from the genus <i>Pseudomonas</i> for assigning taxonomic placement. Sequence analysis of the 16S rRNA gene revealed that <i>P. boreopolis</i> JCM 13306^T had the highest sequence similarity to <i>Xanthomonas</i> species, with sequence similarities ranging from 97.24% to 97.92% nucleotide identity. Likewise, sequence analysis of the 16S rRNA gene exhibited <i>P. carboxydohydrogena</i> DSM 1083^T with 99.36%, 99.00% and 98.93% similarity to <i>Afipia felis</i> ATCC 53690^T, <i>Afipia carboxidovorans</i> ATCC 49405^T and <i>Afipia clevelandensis</i> ATCC 49720^T, respectively. <i>P. boreopolis</i> JCM 13306^T and <i>P. carboxydohydrogena</i> DSM 1083^T have indicated a distinct position in the phylogenetic (based on concatenated sequences of 81 core proteins and 16S rRNA gene) and phylogenomic trees from some type strains of the <i>Pseudomonadaceae</i> family; however, <i>P. boreopolis</i> JCM 13306^T and <i>P. carboxydohydrogena</i> DSM 1083^T were strongly clustered with species of the <i>Xanthomonas</i> (family <i>Lysobacteraceae</i>) and <i>Afipia</i> (family <i>Nitrobacteraceae</i>), respectively. Besides, the amino acid identity values between <i>P. boreopolis</i> JCM 13306^T and the members of the <i>Pseudomonadaceae</i> family were 53.95-57.98%, as well as between <i>P. carboxydohydrogena</i> DSM 1083^T and this family which were 50.43-51.41%. These values were below the cut-off level for genus demarcation (60-85%). The scores of digital DNA-DNA hybridization (70%), average nucleotide identity by blast (95-96%) and average nucleotide identity using MUMmer (96%) between <i>P. boreopolis</i> JCM 13306^T and <i>P. carboxydohydrogena</i> DSM 1083^T, with the members of the <i>Pseudomonadaceae</i> family, were below the threshold value for bacterial species delineation. Therefore, based on genomic and phylogenomic analysis, we propose reclassifying <i>P. boreopolis</i> JCM 13306^T and <i>P. carboxydohydrogena</i> DSM 1083^T as <i>Xanthomonas boreopolis</i> comb. nov. in the <i>Lysobacteraceae</i> family and <i>Afipia carboxydohydrogena</i> comb. nov. in the <i>Nitrobacteraceae</i> family, respectively.