Saliphagus infecundisoli gen. nov., sp nov., an extremely halophilic archaeon isolated from a saline soil

Two extremely halophilic archaea, strains YIM 93745 T and YIM 93707, were isolated from a saline soil sample collected from Loulan, China. Cells of the two strains were coccus, non-motile and Gram-stain negative. The strains were aerobic and grew at 25-50 ffi C (optimum, 37 degrees C), in the presence of 5-35% (w/v) NaCl (optimum, 20 %), 0.01-0.1M Mg2+ (optimum, 0.03 M) and pH 6.0-8.5 (optimum, 7.0-7.5). Cells lysed in distilled water and with 0-5% NaCl. Major polar lipids were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, sulfated mannosyl glycosyl diether and two unidentified glycolipids. Phylogenetic analysis based on the 16S rRNA sequence revealed that the two strains were most closely related to Halovivax cerinus IC35(T) (95.1 and 95.2% sequence similarities, respectively). The two strains, however, shared highest rpoB' gene sequence identities with Natrinema pellirubrum JCM 10476(T) (87.8 and 87.7% respectively). Phylogenetic trees based on 16S rRNA and rpoB' gene sequences demonstrated a robust clade of the two strains with members of related genera of the family Natrialbaceae. The DNA G+C contents of the two strains were 64.6 and 64.4 mol%, respectively. DNA-DNA relatedness values between them were 95 +/- 2 %. Phenotypic, chemotaxonomic characteristics and phylogenetic properties suggested that the two strains YIM 93745 T and YIM 93707 represent a novel species in a new genus within the family Natrialbaceae, for which the name Saliphagus infecundisoli gen. nov., sp. nov. is proposed. The type strain is YIM 93745(T) (= KCTC 4228(T) = CGMCC 1.15824(T)).