Haloparvum Sedimenti Gen. Nov., Sp. Nov., a Member of the Family Haloferacaceae

Two extremely halophilic archaeal strains, DYS4T and Y2, were isolated from rock salt of the Jiangcheng Salt Mine, Yunnan province, China. Cells of the two strains were non-motile, pleomorphic rods and Gram-stain-negative. The cells produced light red-pigmented colonies. Strains DYS4T and Y2 required 2.6-3.4 M NaCl, pH 7.5- 8.0 and 42 ºC in aerobic conditions for optimal growth. Mg2+ was required for growth. The major polar lipids of both strains were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and sulfated mannosyl glucosyl diether. An unidentified minor glycolipid spot was present for strains DYS4T and Y2, which differentiates them from the closely related species of the genera Halorubrum and Halopenitus. The lipid core of the glycolipid was sn-2,3-diphytanylglycerol (C20C20). The sequence similarity of the 16S rRNA gene demonstrated that the closest relatives of strains DYS4T and Y2 were Halorubrum aidingense 31-hongT (94.1 % and 93.6 % 16S rRNA gene sequence similarity to DYS4T and Y2, respectively) and Halopenitus salinus SKJ47T (93.4% and 93.1%). Phylogenetic analysis of the 16S rRNA gene and the rpoB' gene revealed that strains DYS4T and Y2 formed an independent lineage closely related to the genera Halorubrum and Halopenitus. The DNA G+C contents of strains DYS4T and Y2 were 68.2 and 67.0 mol%, respectively. The DNA-DNA relatedness value between strains DYS4T and Y2 was 90.0 ± 0.5%, while that between strain DYS4T and other closest relatives was less than 26 % (19 ± 0.7 % for Halorubrum aidingense 31-hongT and 25 ± 0.3% for Halopenitus salinus SKJ47T). The phenotypic, chemotaxonomic and phylogenetic properties suggest that strains DYS4T and Y2 (=CGMCC 1.15000=JCM 30892) represent a novel species of a new genus within the family Haloferacaceae, for which the name Haloparvum sedimenti gen. nov., sp. nov. is proposed. The type strain of the type species is DYS4T (=CGMCC 1.14998T=JCM 30891T).