A polyphasic taxonomic approach was used to characterize 31 rhizobial isolates obtained from , a metallicolous legume species, growing close to a zinc mine in the south of France (Saint Laurent le Minier). Comparative analysis of nearly full-length 16S rRNA gene sequences showed that these Gram-negative bacteria belonged to the genus and that they were related most closely to ORS 2640. The phylogenetic relationships of these isolates with other species were confirmed by sequencing and analysis of the and genes, which were used as alternative chromosomal markers. These novel mesorhizobial strains tolerated high concentrations of heavy metals: 16–32 mM Zn and 0.3–0.5 mM Cd. DNA–DNA hybridizations revealed >73 % relatedness between the strains isolated from , but only 19–33 % relatedness between these and the type strains of and . These results, together with other phenotypic characteristics, support the conclusion that these isolates represent a single, novel species of the genus , for which the name sp. nov. is proposed. The type strain is STM 2683 (=CFBP 7147=LMG 24485).


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vol. , part 4, pp. 850 – 855

GenBank accession numbers for sequences determined in this study [ PDF] (75 KB)

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