Roseovarius roseus sp. nov. and Roseovarius maritimus sp. nov., isolated from marine coastal sediment.

Abstract

Two novel Gram-stain-negative, rod-shaped, facultatively anaerobic and non-motile bacterial strains, designated as S1116L3^T and S4756^T, were isolated from the marine sediment of Jingzi Port, Weihai, China. Strain S1116L3^T grew at temperatures 15-37 ℃ within pH 5.5-9.0 and in the presence of 1.0%-10.0% (w/v) NaCl. Optimal growth required 3.0% (w/v) NaCl at 30 ℃ and pH 7.0. Strain S4756^T grew at 15-37 ℃, pH 6.0-9.0 and in the presence of 1.0%-10.0% (w/v) NaCl. Optimal growth appeared with 2.0% (w/v) NaCl at 30 ℃ and pH 7.0. Strains S1116L3^T and S4756^T had a major fatty acid of C_18 : 1 ω7ϲ. The predominant respiratory quinone of the two strains was Q10. The major polar lipids detected in the two strains were phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The phylogenetic analysis based on 16S rRNA gene sequences placed the strains S1116L3^T and S4756^T into the genus Roseovarius. The comparison of 16S rRNA gene sequence similarities revealed that strains S1116L3^T and S4756^T had the closest relative with Roseovarius aquimarinus KCTC 32014^T (98.4% and 97.9%, respectively). These values were below the species delineation threshold of 98.6%. The average nucleotide identity (ANI) values based on the genome similarity between strain S1116L3^T and species of the genus Roseovarius ranged from 74.6% to 82.8%, while the ANI values ranged from 74.3% to 82.5% for strain S4756^T, which is significantly lower than the species delineation threshold of 95%. The DNA G+C content of both strains is 63.0%. Based upon the results presented in this study, strains S1116L3^T and S4756^T represent two novel species of the genus Roseovarius, for which the names Roseovarius roseus sp. nov. and Roseovarius maritimus sp. nov. are proposed with the type strains S1116L3^T (=KCTC 8178^T=MCCC 1H01426^T=SDUM 031094^T) and S4756^T (=KCTC 8179^T=MCCC 1H01425^T=SDUM 031096^T), respectively.