A novel bacterial strain, XY-99T, was isolated from the epidermis of a marine invertebrate of the genus Onchidium from seawater of the South China Sea. The cells of the strain were aerobic, Gram-stain-negative, non-motile, and oval-shaped (0.8-1.0 µm wide and 1.0-1.5 µm long) without a flagellum. The strain grew at temperatures of 15-37 °C (optimum, 35-37 °C), at pH 5.5-9.5 (optimum 7.5), and at NaCl concentrations of 0-12.0 % (w/v) (optimum 1.5-3.0 %). The major fatty acids (>10 %) were summed feature 8 (comprising C18 : 1ω7c and/or C18 : 1ω6c), C16 : 0 and 11-methyl C18 : 1ω7c. The predominant polar lipid was diphosphatidylglycerol. The respiratory quinone was Q-10. The closet phylogenetic neighbours were Pseudooceanicola flagellatus DY470T and Pseudooceanicola nitratireducens JLT1210T, showing 97.5 and 97.3 % of 16 s rRNA gene sequence similarity. The genome size of XY-99T was 3 673 499 bp, with 64.5 % DNA G+C content. The average nucleotide identity and digital DNA-DNA hybridization values between XY-99T and Pseudooceanicola flagellatus DY470T were 72.8 and 14.0 %, respectively, while they were 79.3 and 22.3 % between XY-99T and Pseudooceanicola nitratireducens JLT1210T. Characterization based on phylogenetic, phenotypic, chemotaxonomic and genomic evidence demonstrated that XY-99T represents a novel species of the genus Pseudooceanicola, for which the name Pseudooceanicola onchidii sp. nov. is proposed. The type strain is XY-99T (=KCTC 72211T=MCCC 1K03607T).
Keywords: Dapeng Nature Reserve; Pseudooceanicola onchidii; marine invertebrate; taxonomy.