Halorientalis pallida sp. nov., an extremely halophilic archaeon isolated from a marine saltern.

An extremely halophilic archaeon, strain F13-25T, was isolated from a marine saltern located in Isla Cristina, Huelva, on the south-west coast of Spain. The novel strain had pink-pigmented, non-motile, coccoid cells. Optimal growth was achieved at 25 % (w/v) NaCl, pH 7.5 and 37 °C. Strain F13-25T possessed two heterogeneous 16S rRNA genes (rrnA and rrnB) most closely related to Halorientalis persicus D108T (97.6-99.2 % sequence similarity) and Halorientalis regularis TNN28T (95.9-98.8 %). On the basis of the results of rpoB' gene sequence analysis, strain F13-25T was also closely related to Halorientalis persicus IBRC-M 10043T (89.9 %) and Halorientalis regularis TNN28T (92.3 %). Relatedness values, computed using the Genome-to-Genome Distance Calculator, between strain F13-25T and Halorientalis persicus IBRC-M 10043T and Halorientalis regularis IBRC-M 10760T were 34.6 and 36.2 %, respectively. Average nucleotide identity values based on orthoANI, ANIb and ANIm of strain F13-25T and Halorientalis persicus IBRC-M 10043T and Halorientalisregularis IBRC-M 10760T were 88.0 and 88.8, 87.1 and 87.6 %, and 89.2 and 89.6 %, respectively. All values were far below the threshold accepted for prokaryotic species delineation. The major polar lipids were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester and one glycolipid chromatographically identical to sulfated diglycosyl diether. The DNA G+C content was 65.7 mol% (genome). The results of phylogenetic, phenotypic and chemotaxonomic analyses indicated that strain F13-25T represents a novel species of the genus Halorientalis, for which the name Halorientalis pallida sp. nov., with type strain F13-25T (=CECT 9384T=IBRC-M 11176T), is proposed.