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INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY logo - Volume 61, Issue 2, 2011

Volume 61, Issue 2

Volume 61, Issue 2, 2011

  • New Taxa
    • Proteobacteria

      • sp. nov., isolated from forest soil, and emended description of the genus

        https://doi.org/10.1099/ijs.0.021618-0

        A bacterial strain, designated VA24, was isolated from forest soil of the Changbai Mountains, Heilongjiang province, China. Cells of strain VA24 were Gram-reaction-negative, aerobic, non-spore-forming, long rods, 0.3–0.5×2.0–3.0 μm in size and were motile by means of a subpolar flagellum. Strain VA24 was oxidase-positive and catalase-negative. Growth occurred at 21–36 °C, pH 5–10 and in 0–2 % (w/v) NaCl but did not occur at 37 °C. The predominant respiratory quinone was Q-8, the major polar lipids were phosphatidylethanolamine and phosphatidylmonomethylethanolamine and the major cellular fatty acids were iso-C (14.9 %), iso-C 9 (14.1 %), iso-C (10.8 %) and iso-C (10.3 %). The DNA G+C content was 67.4 mol% ( ). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain VA24 was closely related to IFO 13300 with 96.9 % sequence similarity. DNA–DNA relatedness of strain VA24 to DSM 6220 was 15.8 %. Based on its phenotypic and genotypic features, strain VA24 represents a novel species of the genus , for which the name sp. nov. is proposed. The type strain is VA24 (=CGMCC 1.7053 =NBRC 104236).

  • Eukaryotic Micro-Organisms
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  • Evolution, Phylogeny And Biodiversity

      • Genetic characterization of root-nodule bacteria associated with and (Mimosaceae) across south-eastern Australia

        https://doi.org/10.1099/ijs.0.021014-0

        Symbiotic relationships between legumes and nitrogen-fixing soil micro-organisms are of ecological importance in plant communities worldwide. For example, nutrient-poor Australian soils are often dominated by shrubby legumes (e.g. species of ). However, relatively few studies have quantified patterns of diversity, host-specificity and effectiveness of these ecologically important plant–microbe interactions. In this study, 16S rRNA gene sequence and PCR-RFLP analyses were used to examine bacterial strains isolated from the root nodules of two widespread south-eastern Australian legumes, and , across nearly 60 sites. The results showed that there was extensive genetic diversity in microbial populations, including a broad range of novel genomic species. While previous studies have suggested that most native Australian legumes nodulate primarily with species of the genus , our results indicate significant associations with members of other root-nodule-forming bacterial genera, including , , , , and . Genetic analyses also revealed a diverse suite of non-nodulating bacterial endophytes, only a subset of which have been previously recorded. Although the ecological roles of these endosymbionts are not well understood, they may play both direct and indirect roles in promoting plant growth, nodulation and disease suppression.

    • Phylogenetic relationships and diversity of -rhizobia associated with species grown in Sishuangbanna, China

      https://doi.org/10.1099/ijs.0.020560-0

      In order to investigate the genetic diversity of rhizobia associated with various exotic and invasive species in tropical mainland China, 116 bacterial isolates were obtained from root nodules collected from Sishuangbanna and Yuanjiang districts of Yunnan province. Isolated rhizobia were characterized by RFLP analysis of 16S rRNA genes, SDS-PAGE of whole-cell proteins and BOX-PCR. Most of the isolated strains were identified as -rhizobia belonging to diverse populations of and , and the phylogenetic relationships of their 16S rRNA gene sequences showed that they were closely related to one of four -rhizobia species: , , or . Additionally, among the 116 isolates, 53 different whole-cell SDS-PAGE profiles and 30 distinct BOX-PCR genotypic patterns were detected, which demonstrated the genetic and phenotypic diversity found within these and strains. To the best of our knowledge, this is the first report that -rhizobia are extant and possibly widespread on the Chinese mainland and nodulate easily with plants. We also find it especially interesting that this appears to be the first report from mainland China of symbionts of . These records enrich our knowledge and understanding of the geographical distribution and diversity of these bacteria.

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