Haloterrigena salina sp. nov., an extremely halophilic archaeon isolated from a salt lake

A novel extremely halophilic strain, designated XH-65(T), isolated from the salt lake Xilinhot in Inner Mongolia, PR China, was subjected to a polyphasic taxonomic characterization. Strain XH-65(T) is neutrophilic, non-motile and requires at least 2.5 M NaCl for growth, with an optimum at 3.4 M NaCl, and grows at pH 6.0-9.0, with optimum growth at pH 7.5. Strain XH-65(T) grows at 25-50 degrees C, with optimal growth at 37 degrees C. Magnesium is not required for growth. On the basis of 16S rRNA gene sequence analysis, strain XH-65(T) was shown to belong to the genus Haloterrigena and was related to Haloterrigena turkmenica VKM B-1734(T) (98.1 % sequence similarity), Haloterrigena saccharevitans AB14(T) (96.9 %), Haloterrigena thermotolerans PR5(T) (96.3 %), Haloterrigena limicola AX-7(T) (95.8 %) and Haloterrigena hispanica FP1(T) (95.7 %). DNA-DNA hybridization revealed 37 % relatedness between strain XH-65(T) and Htg. turkmenica VKM B-1734(T). The polar lipid composition revealed the presence of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and mannose-2,6-disulfate (1-->2)-glucose glycerol diether (S(2)-DGD). The results of the DNA-DNA hybridization and physiological and biochemical tests allowed genotypic and phenotypic differentiation of strain XH-65(T) from the six Haloterrigena species with validly published names. Therefore, strain XH-65(T) represents a novel species, for which the name Haloterrigena salina sp. nov. is proposed, with the type strain XH-65(T) (=CGMCC 1.6203(T) =JCM 13891(T)).