Roseovarius gaetbuli sp. nov., a novel alphaproteobacterium isolated from a tidal flat sediment.

A Gram-negative, aerobic, non-motile and ovoid or rod-shaped bacterial strain, designated YM-20(T), was isolated from a tidal flat of the Yellow Sea in South Korea. Strain YM-20(T) was found to grow optimally at 30 °C, at pH 7.0-8.0 and in the presence of 2.0-3.0 % (w/v) NaCl. Phylogenetic trees based on 16S rRNA gene sequences revealed that strain YM-20(T) clustered consistently with the type strains of 'Roseovarius marisflavi' and Roseovarius lutimaris, with which it exhibited 16S rRNA gene sequence similarities of 99.86 and 98.71 %, respectively. Strain YM-20(T) was found to contain Q-10 as the predominant ubiquinone and C18:1 ω7c as the predominant fatty acid. The major polar lipids of strain YM-20(T) were identified as phosphatidylcholine, phosphatidylglycerol, phosphatidylethanolamine, one unidentified aminolipid and one unidentified lipid. The DNA G+C content of strain YM-20(T) was determined to be 60.9 mol% and its DNA-DNA relatedness values with the type strains of 'R. marisflavi', R. lutimaris and Pelagicola litorisediminis were 53 ± 7.1, 22 ± 5.5 and 13 ± 4.7 %, respectively. The differential phenotypic properties, together with the phylogenetic and genetic distinctiveness, revealed that strain YM-20(T) is separated from 'R. marisflavi', R. lutimaris, the other Roseovarius species and P. litorisediminis. On the basis of the data presented, strain YM-20(T) is considered to represent a novel species of the genus Roseovarius, for which the name Roseovarius gaetbuli sp. nov. is proposed. The type strain is YM-20(T) (= KCTC 32428(T) = CECT 8370(T)).