title: The hierarchical system of the 'Alphaproteobacteria': description of Hyphomonadaceae fam. nov., Xanthobacteraceae fam. nov. and Erythrobacteraceae fam. nov.
abstract: Phylogenetic analysis of the class 'Alphaproteobacteria', including physiologically diverse species, was conducted by using small-subunit rRNA gene sequences. The 16S rRNA gene sequences of 261 species in the class 'Alphaproteobacteria' were obtained from GenBank/EMBL/DDBJ for constructing a phylogenetic tree by using maximum-likelihood analysis. In the resulting tree, members of the class 'Alphaproteobacteria' were subdivided into five major clusters, which were compared with the taxonomic outline of Bergey's Manual of Systematic Biology and the arb tree. Based on this phylogenetic tree, three novel families are proposed: Hyphomonadaceae fam. nov. to accommodate the bacterial genera Hyphomonas, Hirschia, Maricaulis and Oceanicaulis, Xanthobacteraceae fam. nov. to include the genera Xanthobacter, Azorhizobium, Ancylobacter, Labrys and Starkeya, and Erythrobacteraceae fam. nov. to accommodate the genera Erythrobacter, Porphyrobacter and Erythromicrobium. The phylogenetic tree of 16S rRNA gene sequences established in this study may provide a sound basis for future taxonomic reconstruction of the class 'Alphaproteobacteria'.
authors.affiliation: Department of Plant Biotechnology, Biotechnology Research Center, University of Tokyo, 1-1-1 Yayoi Bunkyo-ku, Tokyo, Japan.
authors.forename: Kyung-Bum
authors.initials: KB
authors.lastname: Lee
authors.affiliation: Department of Plant Biotechnology, Biotechnology Research Center, University of Tokyo, 1-1-1 Yayoi Bunkyo-ku, Tokyo, Japan.
authors.forename: Chi-Te
authors.initials: CT
authors.lastname: Liu
authors.affiliation: School of Pharmaceutical Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan.
authors.forename: Yojiro
authors.initials: Y
authors.lastname: Anzai
authors.affiliation: Department of Plant Biotechnology, Biotechnology Research Center, University of Tokyo, 1-1-1 Yayoi Bunkyo-ku, Tokyo, Japan.
authors.forename: Hongik
authors.initials: H
authors.lastname: Kim
authors.affiliation: Department of Plant Biotechnology, Biotechnology Research Center, University of Tokyo, 1-1-1 Yayoi Bunkyo-ku, Tokyo, Japan.
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Aono
authors.affiliation: Department of Plant Biotechnology, Biotechnology Research Center, University of Tokyo, 1-1-1 Yayoi Bunkyo-ku, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Oyaizu
mesh_terms: D020561:Alphaproteobacteria / Q000145:classification* / Q000235:genetics; D015373:Bacterial Typing Techniques; D001483:Base Sequence; D004269:DNA, Bacterial / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D020459:Genes, rRNA; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics*
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S