Halorubrum amylolyticum sp. nov., a novel halophilic archaeon isolated from a salt mine.

A pleomorphic and non-motile halophilic archaeon forming light-red pigmented colonies, strain ZC67, was isolated from the Yuanyongjing Salt Mine, Yunnan, China. Based on similarity search and phylogenetic analysis of the 16S rRNA gene sequence, strain ZC67 belongs to the genus Halorubrum and is closely related to the species of Halorubrum (Hrr.) saccharovorum JCM 8865, Hrr. persicum C49, Hrr. halophilum B8, Hrr. lipolyticum 9-3, Hrr. salsamenti Y69 and Hrr. depositum Y78 with 16S rRNA gene sequence similarities of 99.0%, 98.7%, 98.5%, 98.4%, 98.1% and 97.7%, respectively. The values of average nucleotide identity (ANI) and average amino-acid identity (AAI) between strain ZC67 and its close relatives were less than 90.5% and 89.3%, respectively. In silico DNA-DNA hybridization (DDH) analysis showed that DNA-DNA relatedness between strain ZC67 and its relatives is less than 45%. Values of ANI, AAI and in silico DDH were clearly below the thresholds used for the delineation of a new species. The major polar lipids of strain ZC67 were similar to other neutrophilic members in the genus Halorubrum containing phosphatidylglycerol, phosphatidylglycerolphosphate methyl ester, phosphatidylglycerol sulfate and sulfated mannosyl-glucosyl-glycerol diether-1. The DNA G+C content was determined to be 66.3 mol% (based on the draft genome). Combined with other diagnostic characteristics, e.g. phenotypic and chemotaxonomic differences, strain ZC67 is concluded to represent a novel species in the genus Halorubrum, for which the name Halorubrum amylolyticum sp. nov. is proposed. The type strain is ZC67 (=CGMCC 1.15718 = JCM 31850).