Hydrogenophaga soli sp nov., isolated from rice field soil

A novel Gram-stain-negative bacterial strain, designated strain S10(T), was isolated from soil collected in a rice field in Goyang, South Korea. Cells of strain S10(T) were strictly aerobic, motile and rod-shaped. Colonies were round, convex, smooth and white. The strain grew optimally at 37 degrees C, pH 7.0 and 0% (w/v) NaCl. Phylogenetic analysis of the 16S rRNA gene sequence of strain S10(T) revealed that the bacterium belongs to the family Comamonadaceae and is related to members of the genus Hydrogenophaga, with Hydrogenophaga caeni EMB71(T) being its closest relative (97.9% sequence similarity). The DNA G+C content of strain S10(T) was 68.2 mol%. Strain S10(T) contained phosphatidylethanolamine and diphosphatidylglycerol as the major polar lipids. The major fatty acids were C-16:0 and summed feature 3 (C-16:1 omega 7c and/or iso-C-15:0 2-OH). The predominant respiratory quinone was ubiquinone Q-8. DNA-DNA hybridization values of strain S10(T) with Hydrogenophaga caeni KCTC 12613(T), Hydrogenophaga atypica DSM 15342(T) and Hydrogenophaga defluvii DSM 15341(T) were 16.1 +/- 4.8, 49.0 +/- 3.2 and 21.9 +/- 8.8 %, respectively. Based on phylogenetic distinctiveness, DNA-DNA hybridization and specific physiological and biochemical characteristics, strain S10(T) (=KCTC 52520(T)=JCM 31711(T)) is classified as a novel species of the genus Hydrogenophaga, for which the name Hydrogenophaga soli sp. nov. is proposed.