Halorubellus salinus gen. nov., sp. nov. and Halorubellus litoreus sp. nov., novel halophilic archaea isolated from a marine solar saltern.

Abstract: Two extremely halophilic archaeal strains GX3^T and GX26^T were isolated from the Gangxi marine solar saltern near the Weihai city of Shandong Province, China. Cells from the two strains were pleomorphic and stained Gram-negative, colonies were red-pigmented. Strains GX3^T and GX26^T were able to grow at 25–50°C (optimum 37°C), at 1.4–5.1M NaCl (optimum 3.1M), at pH 5.5–9.5 (optimum pH 7.0) and neither strain required Mg²⁺ for growth. Cells lyse in distilled water and the minimal NaCl concentration to prevent cell-lysis was 8% (w/v). The major polar lipids of the two strains were PA (phosphatidic acid), PG (phosphatidylglycerol), PGP-Me (phosphatidylglycerol phosphate methyl ester) and three major glycolipids (GL1, GL2 & GL3) chromatographically identical to S-TGD-1 (sulfated galactosyl mannosy glucosyl diether), S-DGD-1 (sulfated mannosyl glucosyl diether), and DGD-1 (mannosyl glucosyl diether) respectively, an unidentified lipid (GL4) was also detected in strain GX26^T. Phylogenetic analysis based on 16S rRNA gene revealed that strain GX3^T and strain GX26^T formed a distinct clade with the closest relative, Haladaptatus paucihalophilus (89.9–92.4% and 90.4–92.7, respectively). The rpoB′ gene similarities between strains GX3^T and GX26^T, and between the two strains and the closest relative, Halorussus rarus TBN4^T are 96.5%, 84.3% and 83.9%, respectively. The DNA G+C contents of strain GX3^T and strain GX26^T are 67.3mol% and 67.2mol%, respectively. The DNA–DNA hybridization value between strain GX3^T and strain GX26^T was 44%. The phenotypic, chemotaxonomic and phylogenetic properties suggest that strain GX3^T and strain GX26^T represent two novel species in a new genus within the family Halobacteriaceae, Halorubellus salinus gen. nov., sp. nov. (type strain GX3^T =CGMCC 1.10384^T =JCM 17115^T) and Halorubellus litoreus sp. nov. (type strain GX26^T =CGMCC 1.10386^T =JCM 17117^T). [Copyright &y& Elsevier]