title: Phylogenetic analysis of the genera Bradyrhizobium, Mesorhizobium, Rhizobium and Sinorhizobium on the basis of 16S rRNA gene and internally transcribed spacer region sequences.
abstract: A total of 128 strains was isolated from more than 23 legume hosts in Korea. Phylogenetic relationships between these Korean isolates and reference strains of the genera Bradyrhizobium, Mesorhizobium, Rhizobium and Sinorhizobium were analysed using their 16S rRNA gene and internally transcribed spacer (ITS) region sequences. Among the Bradyrhizobium strains, dendrograms based on both the 16S rRNA gene and ITS region sequences produced two main groups. The ITS tree yielded at least two new clusters that were discernable from the seven previously delineated genospecies. Large discrepancies were revealed between phylogenetic dendrograms based on 16S rRNA gene and ITS region sequences for members of the genus Rhizobium, reflecting their taxonomic heterogeneity. The amalgamation of Rhizobium and former members of Agrobacterium was confirmed using the 16S rRNA tree. Phylogenetic analysis of ITS region sequences showed that the Rhizobium giardinii clade (group II) and the Rhizobium radiobacter/Rhizobium rubi clade (group III) could be tentatively recognized as groups that are separable from the core group (group I), which includes Rhizobium leguminosarum. Dendrograms based on the 16S rRNA gene and ITS region sequences of Mesorhizobium strains were highly conflicting due to the poor taxonomic resolution of the 16S rRNA gene sequences and the low confidence in the ITS dendrogram. Several Korean isolates within the genus Mesorhizobium are thought to represent novel taxa when considering their relatively low ITS region sequence similarities (<80 %) to the reference strains.
authors.affiliation: Korean Agricultural Culture Collection (KACC), Genetic Resources Division, National Institute of Agricultural Biotechnology, Rural Development Administration (RDA), Suwon 441-707, Korea.
authors.forename: Soon-Wo
authors.initials: SW
authors.lastname: Kwon
authors.affiliation: Korean Agricultural Culture Collection (KACC), Genetic Resources Division, National Institute of Agricultural Biotechnology, Rural Development Administration (RDA), Suwon 441-707, Korea.
authors.forename: Jin-Young
authors.initials: JY
authors.lastname: Park
authors.affiliation: Department of Environmental Sciences, University of California, Riverside, CA 92521-0424, USA.
authors.forename: Jong-Shik
authors.initials: JS
authors.lastname: Kim
authors.affiliation: Department of Forest Resources, College of Agriculture and Life Sciences, Seoul National University, Suwon 441-744, Korea.
authors.forename: Jun-Won
authors.initials: JW
authors.lastname: Kang
authors.affiliation: Korean Agricultural Culture Collection (KACC), Genetic Resources Division, National Institute of Agricultural Biotechnology, Rural Development Administration (RDA), Suwon 441-707, Korea.
authors.forename: Yang-Hee
authors.initials: YH
authors.lastname: Cho
authors.affiliation: College of Agriculture and Life Sciences, Kangwon National University, Chunchon 200-701, Korea.
authors.forename: Chun-Keun
authors.initials: CK
authors.lastname: Lim
authors.affiliation: Department of Biological Sciences, State University of New York, Binghamton, NY 13902-6000, USA.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Parker
authors.affiliation: Korean Agricultural Culture Collection (KACC), Genetic Resources Division, National Institute of Agricultural Biotechnology, Rural Development Administration (RDA), Suwon 441-707, Korea.
authors.forename: Gil-Bok
authors.initials: GB
authors.lastname: Lee
mesh_terms: D020561:Alphaproteobacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D020369:Bradyrhizobium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D004269:DNA, Bacterial / Q000032:analysis; D021903:DNA, Ribosomal Spacer / Q000032:analysis*; D007887:Fabaceae / Q000145:classification / Q000382:microbiology*; D020459:Genes, rRNA; D007723:Korea; D008969:Molecular Sequence Data; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012231:Rhizobium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D017422:Sequence Analysis, DNA; D020579:Sinorhizobium / Q000145:classification / Q000235:genetics / Q000302:isolation & purification
chemical_list: D004269:DNA, Bacterial; D021903:DNA, Ribosomal Spacer; D012336:RNA, Ribosomal, 16S