Dongia sedimenti sp. nov., isolated from river sediment

A Gram-stain-negative, non-spore-forming and strictly aerobic bacterial strain, designated R-7(T), was isolated from river sediment in Wuxi, Jiangsu, PR China. Cells (1.6-3.8 mu m long and 0.6-0.8 mu m wide) were slightly curved to straight rods and motile by means of a polar flagellum. The strain grew optimally on Reasoner's 2A medium at 30 degrees C, pH 7.0 and with 1.0% (w/v) NaCl. Strain R-7(T) exhibited closest 16S rRNA gene sequence similarities to Dongia mobilis CGMCC 1.7660(T) (95.4%), D. rigui 04SU4-P-T (94.6%) and D. soli D78(T) (93.8%). The phylogenetic trees based on genomic and 16S rRNA gene sequences showed that strain R-7(T) was clustered in the genus Dongia. The obtained average nucleotide identity and digital DNA-DNA hybridization values between R-7(T) and the three type strains of the genus Dongia were 73.4, 72.8 and 72.4% and 19.5, 19.0 and 18.7%, respectively. The major respiratory quinone was Q-10. The major polar lipids were phosphatidylethanolamine, phosphatidylglycerol, three unidentified aminolipids, two unidentified aminophospholipids and nine unidentified polar lipids. The major cellular fatty acids (>5% of the total) were cyclo-C-19 : 0 omega 8c, C(16 : )0 and C-16 : 0 2-OH. The DNA G+C content was 65.5 mol%. On the basis of the evidence presented in this study, strain R-7(T) represents a novel species of the genus Dongia, for which the name Dongia sedimenti sp. nov. is proposed, with strain R-7(T) (=KCTC 8082(T)=MCCC 1K08805(T)) as the type strain.