Pseudooceanicola aquaeponti sp. nov. and Pseudooceanicola profundi sp. nov., two novel species isolated from seawater samples of the western Pacific Ocean.

Abstract

Two Gram-stain-negative, rod-shaped, aerobic bacterial strains, designated 200-1SWT and C21-150M6T, were isolated from seawater samples of the western Pacific Ocean. Both strains were able to grow in the presence of 1-10% NaCl, at pH 6-9 and at 10-37 °C. Phylogenetic analysis based on 16S rRNA gene sequences indicated that both strains belong to the genus Pseudooceanicola, with strain 200-1SWT closest to Pseudooceanicola marinus CECT 7751T (97.6% sequence similarity) and C21-150M6T to Pseudooceanicola flagellatus DY470T (97.8%). Genome sizes were 4.77 Mb (G+C content: 67.1 mol%) for 200-1SWT and 4.32 Mb (G+C content: 63.4 mol%) for C21-150M6T, with average nucleotide identity and digital DNA-DNA hybridization values with other Pseudooceanicola species below 86.5 and 32.0%, respectively. In silico genome mining identified several putative secondary metabolite biosynthetic gene clusters, suggesting that the strain possesses unexplored biosynthetic potential. Cellular fatty acid profiles identified summed feature 8 (C18 : 1  ω7c and/or C18 : 1  ω6c), C19 : 0 cyclo ω8c and C16 : 0 as the predominant fatty acids for 200-1SWT, as well as C18 : 1  ω7c 11-methyl, C16 : 0, C18 : 0 and summed feature 8 as the major fatty acids for C21-150M6T. The only respiratory quinone detected was ubiquinone 10 for both strains. The major polar lipids of both strains were phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol and phosphatidylmonomethylethanolamine. Based on phenotypic, chemotaxonomic and genomic characteristics, strains 200-1SWT and C21-150M6T represent two novel species within the genus Pseudooceanicola, for which the names Pseudooceanicola aquaeponti sp. nov. and Pseudooceanicola profundi sp. nov. are proposed; the type strains are 200-1SWT (=MCCC 1A12849T=NBRC 117448T) and C21-150M6T (=MCCC M22851T=NBRC 117449T), respectively.