Ruegeria profundi sp. nov. and Ruegeria marisrubri sp. nov., isolated from the brine-seawater interface at Erba Deep in the Red Sea.

Two moderately halophilic marine bacterial strains of the family Rhodobacteraceae, designated ZGT108 and ZGT118, were isolated from the brine-seawater interface at Erba Deep in the Red Sea (Saudi Arabia). Cells of both strains were aerobic, rod-shaped, non-motile, and Gram-stain-negative. The sequence similarity of the 16S rRNA genes of strains ZGT108 and ZGT118 was 94.9 %. The highest 16S rRNA gene sequence similarity of strain ZGT108 to its closest relative, Ruegeria conchae JCM 17315, was 98.9 %, while the 16S rRNA gene of ZGT118 was most closely related to that of Ruegeria intermedia LMG 25539 (97.7 % similarity). The sizes of the draft genomes as presented here are 4 258 055 bp (strain ZGT108) and 4 012 109 bp (strain ZGT118), and the G+C contents of the draft genomes are 56.68 mol% (ZGT108) and 62.94 mol% (ZGT108). The combined physiological, biochemical, phylogenetic and genotypic data supported placement of both strains in the genus Ruegeria and indicated that the two strains are distinct from each other as well as from all other members in the genus Ruegeria. This was also confirmed by low DNA-DNA hybridization values (<43.6 %) and low ANI values (<91.8 %) between both strains and the most closely related Ruegeria species. Therefore, we propose two novel species in the genus Ruegeria to accommodate these novel isolates: Ruegeriaprofundi sp. nov. (type strain ZGT108=JCM 19518=ACCC 19861) and Ruegeriamarisrubri sp. nov. (type strain ZGT118=JCM 19519=ACCC 19862).