Haloplanus salinus sp. nov., an extremely halophilic archaeon from a Chinese marine solar saltern

Halophilic archaeal strain YGH66(T) was isolated from the Yinggehai marine solar saltern near the Sanya city of Hainan Province, China. Cells were pleomorphic, flat, stained Gram-negative, and produced pink-pigmented colonies. Strain YGH66(T) was able to grow at 20-50 °C (optimum 37 °C), at 0.9-4.8 M NaCl (optimum 3.1 M NaCl), at 0.005-1.0 M MgCl2 (optimum 0.05 M MgCl2), and at pH 6.0-8.0 (optimum pH 7.0). The cells of strain YGH66(T) were lysed in distilled water, and the minimum NaCl concentration that prevented cell lysis was 5 % (w/v). The major polar lipids of the strain were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate, one major glycolipid (GL1) chromatographically identical to sulfated mannosyl glucosyl diether and a minor unidentified lipid (GL2), respectively. On the basis of 16S rRNA gene sequence analysis, strain YGH66(T) was closely related to Haloplanus natans JCM 14081(T), Haloplanus aerogenes TBN37(T), and Haloplanus vescus RO5-8(T) with the similarities of 98.0, 97.6, and 96.9 %, respectively. The rpoB' gene similarity between strain YGH66(T) and the current three members of Haloplanus were 90.4-92.8 %. The DNA G+C content of strain YGH66(T) was 67.2 mol %. The DNA-DNA hybridization values between strain YGH66(T) and three members of Haloplanus, H. natans JCM 14081(T), H. aerogenes TBN37(T), H. vescus RO5-8(T) were 50, 46 and 39 %, respectively. It was concluded that strain YGH66(T) represents a novel species of the genus Haloplanus, for which the name Haloplanus salinus sp. nov. is proposed. The type strain is YGH66(T) (=CGMCC 1.12127(T) = JCM 18368(T)).