Sphingomonas silvisoli sp. nov., isolated from forest soil.

A novel Gram-stain-negative, aerobic, non-motile and short-rod-shaped bacterium, designated RP18T, was isolated from forest soil in Gwang-ju, Republic of Korea. Growth occurred at 15-30 °C (optimum 30 °C), pH 6.0-7.0 (optimum pH 7.0), and was inhibited in the presence of normal saline. According to the 16S rRNA gene sequence, strain RP18T showed the highest sequence similarity to Sphingomonas kyeonggiensis THG-DT81T (96.0 %), followed by Sphingomonas pituitosa EDIVT (95.4 %) and Sphingomonas dokdonensis DS-4T (95.2 %). Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain RP18T was clustered with Sphingomonas gimensis 9PNM-6T and Sphingomonas jejuensis MS-31T under the genus Sphingomonas. The G+C content of the genomic DNA of strain RP18T was 61.5 mol%. The major cellular fatty acids (>6 % of the total) were C16 : 0, C14 : 0 2-OH, C17 : 1ω6с, summed feature 3 (C16 : 1ω7с and/or C16 : 1ω6с) and summed feature 8 (C18 : 1ω7с and/or C18 : 1ω6с). Ubiquinone-10 (Q-10) and sym-homospermidine were detected as the predominant respiratory quinone and major compound in the polyamine pattern, respectively. The major polar lipids of the isolate consisted of diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phospholipid and sphingoglycolipid. Based on phylogenetic analysis and physiological and biochemical characterization, strain RP18T represents a novel species of the genus Sphingomonas, for which the name Sphingomonas silvisoli sp. nov. is proposed. The type strain is RP18T (=KACC 18914T=JCM 31801T).