Halocatena pleomorpha gen. nov. sp. nov., an extremely halophilic archaeon of family Halobacteriaceae isolated from saltpan soil.

A novel archaeal strain designated as SPP-AMP-1 ^T was isolated from saltpan soil, using the serial dilution method on a halophilic archaeal medium supplemented with ampicillin. Cells were both rod-shaped and pleomorphic in nature, non-motile, unable to produce acid from a variety of sugars or grow anaerobically with different substrates (l-arginine) and electron acceptors (DMSO, nitrate). Optimal growth was observed at 42 °C, 3.4-4.2 M NaCl and pH 7.2. Cells did not lyse in distilled water and grew in the absence of Mg ²⁺ ions. Phylogenetic analysis based on the sequences of 16S rRNA gene, amino acid sequence of β'-subunit of RNA polymerase and 400 conserved proteins retrieved from the whole genome assemblies showed that strain SPP-AMP-1 ^T was distantly related to any existing genera within the family Halobacteriaceae . MK-8 was the only quinone detected. Polar lipid analysis showed a unique combination of diethyl derivatives of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, glycosyl-mannosyl-glucosyl diether and sulphated glycosyl-mannosyl-glucosyl diether as the major lipids. The G+C content of genomic DNA is 57.7 mol%. The phenotypic, phylogenetic and genomic data supported the concept of the novel genus status of strain SPP-AMP-1 ^T in the family Halobacteriaceae for which the name Halocatena pleomorpha gen. nov., sp. nov., is proposed; the type strain is SPP-AMP-1 ^T (=JCM 31368 ^T =KCTC 4276 ^T =MTCC 12579 ^T ).