16S Ribosomal DNA Sequence Analysis Confirms the Close Relationship between the Genera Xanthobacter, Azorhizobium, and Aquabacter and Reveals a Lack of Phylogenetic Coherence among Xanthobacter Species
A comparative 16S ribosomal DNA (rDNA) sequence analysis was used to investigate the phylogenetic position of members of the genus Xanthobacter. We determined 16S rDNA sequence data for the type strains of the three Xanthobacter species and five additional Xanthobacter strains. The close relationship between the genera Xanthobacter, Azorhizobium, and Aquabacter previously demonstrated by DNA-rRNA hybridization studies was confirmed. The results of our phylogenetic analysis indicate that members of the genera Xanthobacter, Azorhizobium, and Aquabacter are intermixed and that there is no clear generic cluster consisting of the Xanthobacter species. A comparison of the Xanthobacter sequences with the 16S rDNA sequences available from environmental clone studies indicated that members of this genus have not been detected by nonculturing approaches.
DreyfusB., GarciaJ. L., GillisM.1988; Characterization of Azorhizobium caulinodans gen. nov., sp. nov., a stem-nodulating nitrogenfixing bacterium isolated from Sesbania rostrata. Int. J. Syst. Bacteriol 38:89–98
GillisM., GarciaJ. L., DreyfusB.1989 Phenotypic and genotypic studies on tropical rhizobia leading to the characterization of Azorhizobium caulinodans,. 19–22Proceedings of the International Congress on Sesbania rostrata Technical Centre for Agricultural and Rural Cooperation ACP/EEC; Wageningen, The Netherlands:
JenniB., AragnoM., WiegelJ. K. W.1987; Numerical analysis and DNA-DNA hybridization studies on Xanthobacter and emendation of Xanthobacter flavus. Syst. Appl. Microbiol 9:247–253
Lidstrom-O’onnorM. E., FultonG. L., WopatA. E.1983; “Methylobacterium ethanolicum”: a syntrophic association of two methylotrophic bacteria. J. Gen. Microbiol 129:3139–3148
MurrayR. G. E., BrennerD. J., ColwellR. R., De VosP., GoodfellowM., GrimontP. A. D., PfennigN., StackebrandtE., ZavarzinG. A.1990; Report of the Ad Hoc Committee on Approaches to Taxonomy within the Proteobacteria. Int. J. Syst. Bacteriol 40:213–215
RaineyF. A., DorschM., MorganH. W., StackebrandtE.1992; 16S rDNA analysis of Spirochaeta thermophila: its phylogenetic position and implications for the systematics of the order Spirochaetales. Syst. Appl. Microbiol 15:197–202
RedingH. K., HartelP. G., WiegelJ.1991; Effect of Xanthobacter, isolated and characterized from rice roots, on growth of wetland rice. Plant Soil 138:221–229
WardN., RaineyF. A., GoebelB., StackebrandtE.1995 Identifying and culturing the “unculturables”-a challenge for microbiologists. 89–110AllsoppD., HawksworthD. L., ColwellR. R.edMicrobial diversity and ecosystem function CAB International; Wallingford, United Kingdom:
WiegelJ.1992 The genus Xanthobacter,. 2365–2383BalowsA., TriiperH. G., DworkinM., HarderW., SchleiferK.-H.edThe prokaiyotes, 2nd. Springer-Verlag; New York:
WiegelJ., WilkeD., BaumgartenJ., OpitzR., SchlegelH. G.1978; Transfer of the nitrogen-fixing hydrogen bacterium Coiynebacterium autotrophicum Baumgarten et al. to Xanthobacter gen. nov. Int, J. Syst. Bacteriol 28:573–581
16S Ribosomal DNA Sequence Analysis Confirms the Close Relationship between the Genera Xanthobacter, Azorhizobium, and Aquabacter and Reveals a Lack of Phylogenetic Coherence among Xanthobacter Species