Rheinheimera tuosuensis sp. nov., isolated from a saline lake.

ABSTRACT

A Gram-staining-negative bacterium, strain TS-T4(T), was isolated from Tuosu Lake, a saline lake (salinity 5.4 %, w/w) in Qaidam basin, Qinghai, China. Its taxonomic position was determined by using a polyphasic approach. Cells of strain TS-T4(T) were non-spore-forming rods, 0.4-0.8 µm wide and 1.7-2.3 µm long, and motile by means of a single polar flagellum. Strain TS-T4(T) was strictly heterotrophic, aerobic and catalase- and oxidase-positive. Growth was observed in the presence of 0-7.0 % (w/v) NaCl (optimum, 3.0-4.0 %) and at 4-40 °C (optimum, 30-35 °C) and pH 7.0-10.5 (optimum, pH 8.5-9.0). Strain TS-T4(T) contained Q-8 as the sole respiratory quinone and phosphatidylethanolamine and phosphatidylglycerol as the major polar lipids, as for other members of the genus Rheinheimera. The predominant fatty acids (>10 %) were summed feature 3 (C16  1ω7c and/or C16  1ω6c), C16  0, C17  1ω8c and C18  1ω7c. The DNA G+C content was 50.2 mol% (Tm). Phylogenetic trees based on sequences of the 16S rRNA gene and a conserved portion of the gyrase B gene (gyrB) showed that strain TS-T4(T) was associated with the genus Rheinheimera; the strain showed the highest 16S rRNA gene sequence similarity to Rheinheimera longhuensis LH2-2(T) (97.1 %) and then to Rheinheimera pacifica KMM 1406(T) (97.0 %). DNA-DNA relatedness of strain TS-T4(T) with R. longhuensis LH2-2(T) and R. pacifica NBRC 103167 was 53±2.5 and 48±2 %, respectively. Based on the data presented, it is concluded that TS-T4(T) represents a novel species of the genus Rheinheimera, for which the name Rheinheimera tuosuensis sp. nov. is proposed. The type strain is TS-T4(T) ( = CGMCC 1.12461(T) = JCM 19264(T)).