Pelagovum pacificum gen. nov., sp. nov., a novel member of the family Rhodobacteraceae isolated from surface seawater of the Mariana Trench

A Gram-stain-negative, aerobic, ovoid-rod-shaped bacterium, designated strain SM1903 T , was isolated from surface seawater of the Mariana Trench. The strain grew at 15–37 °C (optimum, 35 °C) and with 1–15 % (optimum, 4 %) NaCl. It hydrolysed aesculin but did not reduce nitrate to nitrite and hydrolyse Tween 80. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that strain SM1903 T formed a separate lineage within the family Rhodobacteraceae , sharing the highest 16S rRNA gene sequence similarity with type strains of Pseudooceanicola antarcticus (95.7 %) and Roseisalinus antarcticus (95.7 %). In phylogenetic trees based on single-copy OCs and whole proteins sequences, strain SM1903 T fell within a sub-cluster encompassed by Oceanicola granulosus , Roseisalinus antarcticus and Histidinibacterium lentulum and formed a branch adjacent to Oceanicola granulosus . The major cellular fatty acids were summed feature 8 (C 18 : 1  ω 7 c and/or C 18 : 1  ω 6 c ), C 16 : 0 and 11-methyl-C 18 : 1  ω 7 c . The polar lipids mainly comprised phosphatidylglycerol, phosphatidylcholine, one unidentified lipid, one unidentified aminolipid, and one unidentified glycolipid. The solo respiratory quinone was ubiquinone-10. The genomic DNA G+C content of strain SM1903 T was 66.0 mol%. Based on the results of phenotypic, chemotaxonomic, and phylogenetic characterization for strain SM1903 T , it is considered to represent a novel species of a novel genus in the family Rhodobacteraceae , for which the name Pelagovum pacificum gen. nov., sp. nov. is proposed. The type strain is SM1903 T (=MCCC 1K03608 T =KCTC 72046 T ).