Revision of the taxonomic status of the species Rhizobium lupini and reclassification as Bradyrhizobium lupini comb. nov.

• DOI: 10.1099/ijs.0.000082
• Publication Date: 2015-01-22T05:04:51Z
• Authors: Alvaro Peix; Martha Helena Ram...; José David Flores...; Pablo Alonso de l...; Raúl Rivas; Pedro F. Mateos; José M. Igual; Eustoquio Martíne...; Martha E. Trujillo; Encarna Velázquez
• Keywords: DNA, Bacterial; 0301 basic medicine; Molecular Sequence Data; Nucleic Acid Hybridization; Sequence Analysis, DNA; Bacterial Typing Techniques; Lupinus; 03 medical and health sciences; RNA, Ribosomal, 16S; Bradyrhizobium; Symbiosis; Phylogeny; Rhizobium

The species

Rhizobium lupini

was isolated from Lupinus nodules and included in the Approved Lists of Bacterial Names in 1980. Nevertheless, on the basis of the analysis of the type strain of this species available in DSMZ, DSM 30140T, whose 16S rRNA gene was identical to that of the type strain of

Bradyrhizobium japonicum

,

R. lupini

was considered a later synonym of this species. In this study we confirmed that the strain DSM 30140T belongs to the species

B. japonicum

, but also that it cannot be the original strain of

R. lupini

because this species effectively nodulated Lupinus whereas strain DSM 30140T was able to nodulate soybean but not Lupinus. Since the original type strain of

R. lupini

was deposited into the USDA collection by L. W. Erdman under the accession number USDA 3051T we analysed the taxonomic status of this strain showing that although it belongs to the genus

Bradyrhizobium

instead of genus

Rhizobium

, it is phylogenetically distant from

B. japonicum

and closely related to

Bradyrhizobium canariense

. The type strains

R. lupini

USDA 3051T and

B. canariense

BTA-1T share 16S rRNA, recA and glnII gene sequences with similarities of 99.8 %, 96.5 % and 97.1 %, respectively. They presented a DNA–DNA hybridization value of 36 % and also differed in phenotypic characteristics and slightly in the proportions of some fatty acids. Therefore we propose the reclassification of the species

Rhizobium lupini

as Bradyrhizobium lupini comb. nov. The type strain is USDA 3051T ( = CECT 8630T = LMG 28514T).