Halomicroarcula sauna sp nov., isolated from a marine solar saltern

Halophilic archaeal strain YGHS18(T) was isolated from the Yinggehai marine solar saltern near Shanya city of Hainan Province, China. Cells from the strain were observed to be pleomorphic rods, stained Gram-negative, and formed red-pigmented colonies on solid media. Strain YGHS18(T) was found to be able to grow at 20-50 degrees C (optimum 37 degrees C), with 0.9-4.8 M NaCl (optimum 2.1 M) and at pH 5.5-9.0 (optimum pH 7.0). The cells lysed in distilled water and the minimum NaCl concentration to prevent cell lysis was found to be 0.9 M. The major polar lipids of the strain were identified as phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, glucosyl mannosyl glucosyl diether and a diglycosyl diether (DGD-2). Strain YGHS18T possessed two heterogeneous 16S rRNA genes (rrnA and rrnB) and both were related to those of members of the genera Haloarcula (93.1-96.9% sequence similarity) and Halomicroarcula (92.7-96.1 To similarity). The rrnA gene (orthologous gene) of strain YGHS18(T) clustered phylogenetically with members of the genus Halomicroarcula while the rrnB gene formed a paraphyly with members of the genera Halomicroarcula and Haloarcula. The rpoB' gene of strain YGHS18(T) was related phylogenetically to species of the genera Halomicroarcula (91.6-92.7% sequence similarity) and Haloarcula (91.5-92.4% similarity). EF-2 gene analysis revealed that strain YGHS18(T) was related phylogenetically to species of the genus Halomicroarcula (92.2-92.9% sequence similarity) rather than to those of the genus Haloarcula (90.9-91.7% similarity). The DNA G+C content of strain YGHS18(T) was determined to be 64.5 mol%. The phenotypic, chemotaxonomic and phylogenetic properties suggested that strain YGHS18(T) (=CGMCC 1.12128(T)=JCM 18369(T)) represents a novel species of the genus Halomicroarcula, for which the name Halomicroarcula salina sp. nov. is proposed.