title: Rhizobium tubonense sp. nov., isolated from root nodules of Oxytropis glabra.
abstract: Four rhizobial strains, designated CCBAU 85046(T), CCBAU 85051, CCBAU 85048 and CCBAU 85049, isolated from root nodules of Oxytropis glabra grown in Tibet, China, were previously defined, using amplified 16S rRNA gene restriction analysis, as a novel group within the genus Rhizobium. To clarify their taxonomic position, these strains were further analysed and compared with reference strains of related bacteria using a polyphasic approach. The 16S rRNA gene analysis showed that the four isolates formed a distinct phylogenetic lineage in the genus Rhizobium. The isolates showed highest sequence similarity (97.8  %) to Rhizobium indigoferae CCBAU 71042(T). Phenotypic and physiological tests, DNA-DNA hybridization, phylogenetic analyses of housekeeping genes recA, atpD and glnII and fatty acid profiles also indicated that these four strains constitute a novel group distinct from recognized species of the genus Rhizobium. Based on this evidence, strains CCBAU 85046(T), CCBAU 85051, CCBAU 85048 and CCBAU 85049 represent a novel species in the genus Rhizobium, for which the name Rhizobium tubonense sp. nov. is proposed. The type strain is CCBAU 85046(T) (=LMG 25225(T) =HAMBI 3066(T)) and its DNA G+C content is 59.52 % (T(m)). Strain CCBAU 85046(T) could form effective nodules on plant species Vigna unguiculata and Medicago sativa but not on its host of origin Oxytropis glabra.
authors.affiliation: State Key Laboratories for Agro-Biotechnology, Ministry of Agriculture/College of Biological Sciences, China Agricultural University, Beijing 100193, PR China.
authors.forename: Rong Juan
authors.initials: RJ
authors.lastname: Zhang
authors.affiliation: State Key Laboratories for Agro-Biotechnology, Ministry of Agriculture/College of Biological Sciences, China Agricultural University, Beijing 100193, PR China.
authors.forename: Bao Chao
authors.initials: BC
authors.lastname: Hou
authors.affiliation: Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, 11340 México D. F., Mexico.
authors.forename: En Tao
authors.initials: ET
authors.lastname: Wang
authors.affiliation: State Key Laboratories for Agro-Biotechnology, Ministry of Agriculture/College of Biological Sciences, China Agricultural University, Beijing 100193, PR China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.affiliation: Agricultural Cultural Collection of China, Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081, PR China.
authors.forename: Xiao Xia
authors.initials: XX
authors.lastname: Zhang
authors.affiliation: State Key Laboratories for Agro-Biotechnology, Ministry of Agriculture/College of Biological Sciences, China Agricultural University, Beijing 100193, PR China.
authors.forename: Wen Xin
authors.initials: WX
authors.lastname: Chen
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics; D015373:Bacterial Typing Techniques; D001482:Base Composition; D016000:Cluster Analysis; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D005227:Fatty Acids / Q000032:analysis; D008969:Molecular Sequence Data; D009693:Nucleic Acid Hybridization; D033021:Oxytropis / Q000382:microbiology*; D010802:Phylogeny; D018517:Plant Roots / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012231:Rhizobium / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D017422:Sequence Analysis, DNA; D018609:Tibet
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D005227:Fatty Acids; D012336:RNA, Ribosomal, 16S