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

A Gram-stain-negative bacterium, designated strain YJ09T, was isolated from spinach farming field soil at Shinan in the Republic of Korea. Cells of strain YJ09T were found to be strictly aerobic, non-motile, non-spore-forming creamy-yellow rods which can grow at 20–37 °C (optimum, 30 °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 YJ09T belongs to the genus Sphingomonas with high sequence similarities to Sphingomonas parvus GP20-2 T (98.0 %), Sphingomonas agri HKS-06T (97.7 %) and Sphingomonas lutea JS5T (97.4 %). The results of phylogenetic analysis indicated that strain YJ09T formed a distinct phyletic line in the genus Sphingomonas and the results of DNA–DNA relatedness studies demonstrated that strain YJ09T could be separated from its closest relatives in the genus Sphingomonas . The major polar lipids were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, unidentified glycolipids, an unidentified phospholipid and sphingoglycolipid. The predominant ubiquinone and polyamine components were Q-10 and spermidine, respectively. The major fatty acids were C18:1 ω7c, C16 : 0 and C16:1 ω7c and/or iso-C15 : 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 YJ09T 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 YJ09T (=KACC 19551T=NBRC 113247T).