Sphingomonas segetis sp. nov., isolated from spinach farming field soil

A Gram-stain-negative bacterium, designated strain YJ09(T), was isolated from spinach farming field soil at Shinan in the Republic of Korea. Cells of strain YJ09(T) were found to be strictly aerobic, non-motile, non-spore-forming creamy-yellow rods which can grow at 20-37 degrees C (optimum, 30 degrees C), at pH 6.0-9.0 (optimum, pH 7.0-8.0) and at salinities of 0-0.5 % (w/v) NaCl (optimum, 0 % NaCl). The 16S rRNA gene sequence analysis showed that strain YJ09(T) belongs to the genus Sphingomonas with high sequence similarities to Sphingomonas parvus GP20-2(T) (98.0 %), Sphingomonas agri HKS-06(T) (97.7 %) and Sphingomonas lutea JS5(T) (97.4 %). The results of phylogenetic analysis indicated that strain YJ09(T) formed a distinct phyletic line in the genus Sphin-gomonas and the results of DNA-DNA relatedness studies demonstrated that strain YJ09(T) could be separated from its closest relatives in the genus Sphingomonas. The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidy-lethanolamine, unidentified glycolipids, an unidentified phospholipid and sphingoglycolipid. The predominant ubiquinone and polyamine components were Q-10 and spermidine, respectively. The major fatty acids were C-18:1 omega 7c, C-16:0 and C-16:1 omega 7c and/or iso-C-15:0 2-OH. The DNA G+C content of this novel isolate was 65.9 mol%. On the basis of phenotypic, chemotaxonomic properties and phylogenetic analyses in this study, strain YJ09(T) is considered to represent a novel species in the genus Sphingomonas, for which the name Sphingomonas segetis sp. nov. is proposed. The type strain is YJ09(T) (=KACC 19551(T)=NBRC 113247(T)).