Fontisubflavum oceani gen. nov., sp. nov., isolated from the deep-sea cold seep water of South China Sea

In this study, we report a Gram-stain-negative, rod-shaped, atrichous and aerobic bacterial strain named CSW1921 T , which was isolated from the deep-sea water of a cold seep in South China Sea. Growth of strain CSW1921 T occurred at 10.0–35.0 °C (optimum, 30 °C), pH 5.0–10.0 (optimum, pH 8.0–9.0) and with 0–9.0 % (w/v) NaCl (optimum, 1.0–2.0 %). Phylogenetic tree analysis based on 16S rRNA gene sequence or the genomic sequence indicated that strain CSW1921 T belonged to the family Rhodobacteraceae and was closely related to Rhodophyticola porphyridii MA-7-27 T (97.5 % sequence similarity). Genomic analysis indicated that strain CSW1921 T contains a circular chromosome of 3 592 879 bp with G+C content of 60.5 mol%. The predominant respiratory quinone of CSW1921 T was ubiquinone-10. The polar lipids of CSW1921 T contained phosphatidylglycerol, three unidentified aminolipids, two unidentified phospholipids and two unidentified lipids. The major fatty acids of strain CSW1921 T contained C 16 : 0 , C 18 : 1 ω7c 11-methyl and summed feature 8 (C 18 : 1 ω7c). The average nucleotide identity, DNA–DNA hybridization and average amino acid identity values between strain CSW1921 T and members of its related species were 68.02–69.08 %, 12.7–12.9 % and 46.87–48.08 %, respectively, which were lower than the recommended threshold values for bacterial species or genus delineation. Phylogenetic, physiological, biochemical and morphological analyses suggested that strain CSW1921 T represents a novel genus and a novel species of the family Rhodobacteraceae , and the name Fontisubflavum oceani gen. nov., sp. nov. is proposed with the type strain CSW1921 T (=MCCC 1K08371 T =KCTC 92834 T ).