SGM Journals
Proteobacteria

Microvirga lupini sp. nov., Microvirga lotononidis sp. nov. and Microvirga zambiensis sp. nov. are alphaproteobacterial root-nodule bacteria that specifically nodulate and fix nitrogen with geographically and taxonomically separate legume hosts

Julie K. Ardley, Matthew A. Parker, Sofie E. De Meyer, Robert D. Trengove, Graham W. O’Hara, Wayne G. Reeve, Ron J. Yates, Michael J. Dilworth, Anne Willems, John G. Howieson

  • 1Centre for Rhizobium Studies, Murdoch University, 90 South Street, Murdoch, WA 6150, Australia
  • 2Department of Biological Sciences, State University of New York, Binghamton, 4400 Vestal Parkway, Vestal, NY 13850, USA
  • 3Microbiology Laboratory, University of Gent, Sint-Pietersnieuwstraat 25, B-9000 Ghent, Belgium
  • 4Separation Science and Metabolomics Laboratory, Murdoch University, 90 South Street, Murdoch, WA 6150, Australia
  • 5Department of Agriculture Western Australia, 3 Baron Hay Court, South Perth, WA 6151, Australia
  • Correspondence
    Julie K. Ardley J.Ardley{at}murdoch.edu.au

    • International Journal of Systematic and Evolutionary Microbiology 2012; 62(Pt 11):2579–2588 · https://doi.org/10.1099/ijs.0.035097-0

    View at publisher PubMed

    Abstract

    Strains of Gram-negative, rod-shaped, non-spore-forming bacteria were isolated from nitrogen-fixing nodules of the native legumes Listia angolensis (from Zambia) and Lupinus texensis (from Texas, USA). Phylogenetic analysis of the 16S rRNA gene showed that the novel strains belong to the genus Microvirga, with ≥96.1 % sequence similarity with type strains of this genus. The closest relative of the representative strains Lut6T and WSM3557T was Microvirga flocculans TFBT, with 97.6–98.0 % similarity, while WSM3693T was most closely related to Microvirga aerilata 5420S-16T, with 98.8 % similarity. Analysis of the concatenated sequences of four housekeeping gene loci (dnaK, gyrB, recA and rpoB) and cellular fatty acid profiles confirmed the placement of Lut6T, WSM3557T and WSM3693T within the genus Microvirga. DNA–DNA relatedness values, and physiological and biochemical tests allowed genotypic and phenotypic differentiation of Lut6T, WSM3557T and WSM3693T from each other and from other Microvirga species with validly published names. The nodA sequence of Lut6T was placed in a clade that contained strains of Rhizobium, Mesorhizobium and Sinorhizobium, while the 100 % identical nodA sequences of WSM3557T and WSM3693T clustered with Bradyrhizobium, Burkholderia and Methylobacterium strains. Concatenated sequences for nifD and nifH show that the sequences of Lut6T, WSM3557T and WSM3693T were most closely related to that of Rhizobium etli CFN42T nifDH. On the basis of genotypic, phenotypic and DNA relatedness data, three novel species of Microvirga are proposed: Microvirga lupini sp. nov. (type strain Lut6T  = LMG 26460T  = HAMBI 3236T), Microvirga lotononidis sp. nov. (type strain WSM3557T  = LMG 26455T  = HAMBI 3237T) and Microvirga zambiensis sp. nov. (type strain WSM3693T  = LMG 26454T  = HAMBI 3238T).

    • The GenBank/EMBL/DDBJ accession numbers for the 16S rRNA gene sequences of strains WSM3557T and WSM3693T are HM362432 and HM362433, respectively. Accession numbers for the dnaK, gyrB, recA and rpoB sequences of strains Llb5, Lut5, Lut6T, WSM3557T, WSM3693T, M. flocculans TFBT and M. subterranea DSM 14364T, for the nifD sequences of strains Llb5, WSM3557T and WSM3693T and for the nifH sequences of strains Llb5, Lut5, WSM3557T, WSM3693T and Mesorhizobium sp. Lo5-9 are JF428144–JF428179. Accession numbers for the nodA sequences of strains WSM3557T and WSM3693T are HQ435534 and HQ435535, respectively.

    • Five supplementary tables and five supplementary figures are available with the online version of this paper.