Pseudooceanicola onchidii sp. nov., isolated from a marine invertebrate from the South China Sea

Abstract

A novel bacterial strain, XY-99^T, was isolated from the epidermis of a marine invertebrate of the genus <i>Onchidium</i> 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 C_{18 : 1}ω7<i>c</i> and/or C_{18 : 1}ω6<i>c</i>), C_{16 : 0} and 11-methyl C_{18 : 1}ω7<i>c</i>. The predominant polar lipid was diphosphatidylglycerol. The respiratory quinone was Q-10. The closet phylogenetic neighbours were <i>Pseudooceanicola flagellatus</i> DY470^T and <i>Pseudooceanicola nitratireducens</i> JLT1210^T, showing 97.5 and 97.3 % of 16 s rRNA gene sequence similarity. The genome size of XY-99^T was 3 673 499 bp, with 64.5 % DNA G+C content. The average nucleotide identity and digital DNA-DNA hybridization values between XY-99^T and <i>Pseudooceanicola flagellatus</i> DY470^T were 72.8 and 14.0 %, respectively, while they were 79.3 and 22.3 % between XY-99^T and <i>Pseudooceanicola nitratireducens</i> JLT1210^T. Characterization based on phylogenetic, phenotypic, chemotaxonomic and genomic evidence demonstrated that XY-99^T represents a novel species of the genus <i>Pseudooceanicola</i>, for which the name <i>Pseudooceanicola onchidii</i> sp. nov. is proposed. The type strain is XY-99^T (=KCTC 72211^T=MCCC 1K03607^T).