Sphingomonas dokdonensis sp. nov., isolated from soil.

A Gram-negative, rod-shaped, Sphingomonas-like bacterial strain, DS-4(T), was isolated from soil of Dokdo, Korea, and its taxonomic position was investigated using a polyphasic approach. Strain DS-4(T) grew optimally on trypticase soy agar medium without NaCl at pH 6.0-6.5 and 25 degrees C. It contained Q-10 as the predominant ubiquinone and C(18 : 1)omega7c, C(16 : 0), C(14 : 0) 2-OH and C(16 : 1)omega7c and/or iso-C(15 : 0) 2-OH as the major fatty acids. Sphingoglycolipid, phosphatidylcholine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and unidentified phospholipid were the major polar lipids. The DNA G+C content was 66.9 mol%. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain DS-4(T) fell within the evolutionary radiation comprising Sphingomonas species. Levels of 16S rRNA gene sequence similarity between strain DS-4(T) and the type strains of Sphingomonas species ranged from 93.0 to 97.6 %. DNA-DNA relatedness data and differential phenotypic properties, together with the phylogenetic distinctiveness, demonstrated that strain DS-4(T) differs from the recognized Sphingomonas species. On the basis of phenotypic, phylogenetic and genetic data, this strain represents a novel species of the genus Sphingomonas, for which the name Sphingomonas dokdonensis sp. nov. is proposed, with DS-4(T) (=KCTC 12541(T)=CIP 108841(T)) as the type strain.