Halonotius aquaticus sp. nov., a new haloarchaeon isolated from a marine saltern.

ABSTRACT

A halophilic archaeon, strain F13-13T, was isolated from a marine saltern located in Isla Cristina, Huelva, on the south-west coast of Spain. It was a Gram-stain-negative, motile and aerobic haloarchaeon. It grew at 28-50 °C (optimum, 37 °C), pH 6.0-8.5 (pH 7.5) and in 15-30 % (w/v) total salts (25 %). Phylogenetic analyses based on the 16S rRNA gene sequences showed that strain F13-13T is a member of the genus Halonotius, the most closely related species being Halonotius pteroides 1.15.5T (96.7 % sequence similarity). The 16S rRNA gene sequence similarity to species of other genera is lower than 93.4 %. Strain F13-13T was also found to be closely related to Halonotius pteroides 1.15.5T (91.4 %) on the basis of rpoB' gene sequence analysis. The Genome-to-Genome Distance Calculator relatedness result between strain F13-13T and Halonotius pteroides CECT 7525T was 35 %, a value lower than the 70 % threshold accepted for species delineation. The average nucleotide identity values based on OrthoANI, ANIb and ANIm of strain F13-13T and Halonotius pteroides CECT 7525T were 88.7, 87.8 and 89.4 %, respectively, these values are also lower than the threshold accepted for species delineation. The DNA G+C content of this isolate was 61.2 mol%. The major lipids of strain F13-13T were phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, phosphatidylglycerol sulfate and sulphated diglycosyl diether. Based on the phylogenetic, phenotypic, genotypic and chemotaxonomic characterization, we propose the placement of strain F13-13T as a new species within the genus Halonotius, with the name Halonotius aquaticus sp. nov. The type strain is F13-13T (=CECT 9386T=IBRC-M 11204T).