Ruegeria marisflavi sp. nov. and Ruegeria aquimaris sp. nov., isolated from seawater of the Yellow Sea

Two novel Gram-stain-negative, aerobic, non-motile and rod-shaped bacteria, designated as WL0004 T and XHP0148 T , were isolated from seawater samples collected from the coastal areas of Nantong and Lianyungang, PR China, respectively. Both strains were found to grow at 10–42 °C (optimum, 37 °C) and with 2.0–5.0 % (w/v) NaCl (optimum, 3.0 %). Strain WL0004 T grew at pH 6.0–9.0 (optimum, pH 7.0–8.0), while XHP0148 T grew at pH 6.0–10.0 (optimum, pH 7.0–8.0). The major cellular fatty acids (>10 %) of both strains included summed feature 8 (C 18 : 1 ω 6 c and/or C 18 : 1 ω 7 c ). In addition, strain WL0004 T contained 11-methyl C 18 : 1 ω 7 c and strain XHP0148 T contained C 12 : 0 3-OH. The respiratory quinone of both strains was ubiquinone-10. The G+C content of genomic DNA of strains WL0004 T and XHP0148 T were 62.5 and 63.0 mol%, respectively. Strains WL0004 T and XHP0148 T showed the highest 16S rRNA gene sequence similarity to Ruegeria pomeroyi DSS-3 T (99.4 and 99.0 %, respectively), and the 16S rRNA gene-based phylogenetic analysis indicated that the two strains were closely related to members of the genus Ruegeria . The average nucleotide identity and digital DNA–DNA hybridization values among the two strains and type strains of the genus Ruegeria were all below 95 and 70 %, respectively, and the phylogenetic tree reconstructed from the bac120 gene set indicated that the two strains are distinct from each other and the members of the genus Ruegeria . Based on this phenotypic and genotypic characterization, strains WL0004 T (=MCCC 1K07523 T =JCM 35565 T =GDMCC 1.3083 T ) and XHP0148 T (=MCCC 1K07543 T =JCM 35569 T =GDMCC 1.3089 T ) should be recognized as representing two novel species of the genus Ruegeria and the names Ruegeria marisflavi sp. nov. and Ruegeria aquimaris sp. nov. are proposed, respectively.