Desulfovibrio africanus subsp. uniflagellum subsp. nov., a sulfate-reducing bacterium from a uranium-contaminated subsurface aquifer

The bacterial strain SR-1^T was isolated from subsurface sediments of a uranium-contaminated site in Shiprock, New Mexico, USA. Cells are vibrioid and motile by means of a single polar flagellum. Strain SR-1 ^T grows on sulfate, oxidizing formate, lactate and H₂, but not malate, and ferments pyruvate. The DNA sequences of the 16S rRNA gene and the 16S-23S internal transcribed spacer of strain SR-1^T showed 99.9 and 99.4% similarity, respectively, to those of the type strain Desulfovibrio africanus DSM 2603^T. The DNA sequence of the ITS region is 300 bases in length and contains two tRNA genes (tRNA^Ile, tRNA^Ala). The partial DNA sequence of the dsrAB gene showed 94.6 % amino acid sequence similarity to that of D. africanus. The DNA G+C content of strain SR-1 ^T was 62.4 mol% and it showed 72% DNA-DNA similarity to D. africanus. DNA typing methods that target gene clusters and whole genomes revealed characteristic genomic fingerprints for strain SR-1^T. A small plasmid was detected by gel electrophoresis. On the basis of distinct phenotypic and genotypic characteristics, strain SR-1^T represents a novel subspecies of D. africanus, for which the name Desulfovibrio africanus subsp. uniflagellum subsp. nov. is proposed. The type strain is SR-1^T (=JCM 15510 ^T =LS KCTC 5649^T).