Halorientalis salina sp. nov., Halorientalis marina sp. nov., Halorientalis litorea sp. nov.: three extremely halophilic archaea isolated from a salt lake and coarse sea salt.

ABSTRACT

Three halophilic archaeal strains, NEN8T, GDY88T and ZY14T, were isolated from a salt lake in Tibet and coarse sea salt samples from Guangdong and Hebei, China, respectively. These strains formed three separate clades (showing 94.4-95.8% and 87.1-89.4% similarities, respectively) and then clustered with the current Halorientalis members (showing 90.7-97.6% and 87.0-91.2% similarities, respectively), as revealed by phylogenetic analyses based on 16S rRNA and rpoB' genes. The overall genome-related index, average nucleotide identity (ANI), in silico DNA-DNA hybridization (DDH), average amino acid identity (AAI) and the percentage of conserved proteins (POCP) values, among the three strains and members of the genus Halorientalis were 76.0-88.0%, 21.3-37.2%, 69.0-88.3% and 57.7-78.1%, clearly below the threshold values for species demarcation. Strains NEN8T, GDY88T and ZY14T could be distinguished from current Halorientalis species according to differential phenotypic characteristics. The major polar lipids of the three strains were phosphatidylglycerol (PG), phosphatidylglycerol phosphate methyl ester (PGP-Me), sulfated mannosyl glucosyl diether (S-DGD-1) and disulfated mannosyl glucosyl diether (S2-DGD). In addition, mannosyl glucosyl diether (DGD-1) was detected in strain NEN8T and phosphatidic acid (PA), posssulfated galactosyl mannosyl glucosyl diether (S-TGD-1) and sulfated mannosyl glucosyl diether-phosphatidic acid (S-DGD-PA) were observed in strain ZY14T. These results revealed that strains NEN8T (= CGMCC 1.17213T = JCM 34155T), GDY88T (= CGMCC 1.18548T = JCM 34481T) and ZY14T (= CGMCC 1.17178T = JCM 34154T) represent three novel species of the genus Halorientalis, for which the names Halorientalis salina sp. nov., Halorientalis marina sp. nov. and Halorientalis litorea sp. nov. are proposed.