Halosimplex litoreum sp. nov., isolated from a marine solar saltern

Pan-Pan Yuan, Jia-Qi Xu, Wen-Mei Xu, Zhao Wang, Shuai Yin, Dong Han, Wen-Jiao Zhang, Heng-Lin Cui

A halophilic archaeal strain, YGH94(T), was isolated from the Yinggehai marine solar saltern near the Shanya city of Hainan Province, China. Cells of the strain were observed to be short rods, stain Gram-negative and to form red-pigmented colonies on solid media. Strain YGH94(T) was found to grow at 25-50 °C (optimum 40 °C), at 0.9-4.8 M NaCl (optimum 3.1 M), at 0-1.0 M MgCl2 (optimum 0.05 M) and at pH 5.0-9.0 (optimum pH 7.5). The cells were found to lyse in distilled water and the minimal NaCl concentration to prevent cell-lysis was determined to be 5 % (w/v). The major polar lipids were identified as phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and four major glycolipids (disulfated mannosyl glucosyl diether, sulfated mannosyl glucosyl diether and two unidentified glycolipids chromatographically identical to glycolipids in Halosimplex carlsbadense JCM 11222(T)). Strain YGH94(T) was found to possess two heterogeneous 16S rRNA genes (rrnA and rrnB) and both are related to those of Hsx. carlsbadense JCM 11222(T) (92.7-98.6 % similarities), Halosimplex pelagicum R2(T) (94.6-99.2 % similarities) and Halosimplex rubrum R27(T) (92.9-98.8 % similarities). The rpoB' gene similarity between strain YGH94(T) and Hsx. carlsbadense JCM 11222(T), Hsx. pelagicum R2(T) and Hsx. rubrum R27(T) are 95.4, 94.9 and 95.1 %, respectively. The DNA G+C content of strain YGH94(T) was determined to be 64.0 mol%. Strain YGH94(T) showed low DNA-DNA relatedness (35-39 %) with the current three members of the genus Halosimplex. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strain YGH94(T) (=CGMCC 1.12235(T) = JCM 18647(T)) represents a new species of the genus Halosimplex, for which the name Halosimplex litoreum sp. nov. is proposed.