Rubricoccus marinus gen. nov., sp. nov., of the family 'Rhodothermaceae', isolated from seawater

Abstract

A coccoid- and amorphous-shaped, non-gliding, reddish bacterium, designated SG-29(T), was isolated from seawater in the western North Pacific Ocean near Japan. The strain was Gram-stain-negative, obligately aerobic, heterotrophic and catalase-positive. Nitrate was reduced to nitrogen and acid was produced from aesculin, turanose, 2-keto-gluconate and arabinose. Growth occurred with 1-5 % NaCl (optimum 2 % NaCl) and at 5-37 °C (optimum 20-30 °C). The G+C content of genomic DNA was 68.9 mol% (HPLC). The predominant isoprenoid quinone was MK-7 and the major cellular fatty acids (>10 %) were iso-C₁₇:₁ω9c, C₁₇:₁ω8c and iso-C₁₇:₀. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain SG-29(T) belonged to the phylum Bacteroidetes. The most closely related strain was Rhodothermus obamensis JCM 9785(T), with which the isolate exhibited 86.1 % 16S rRNA gene sequence similarity. On the basis of phenotypic and phylogenetic features, strain SG-29(T) is classified in a novel genus and species within the family 'Rhodothermaceae', for which the name Rubricoccus marinus gen. nov., sp. nov. ( = NBRC 107124(T) = KCTC 23197(T)) is proposed.