Rubrivirga aquatilis sp. nov. and Rubrivirga halophila sp. nov., isolated from Korean coastal surface seawater.

Abstract

Two Gram-stain-negative, obligately aerobic, non-motile, short rod-shaped bacteria, designated IMCC43871T and IMCC45206T, were isolated from coastal surface seawater collected from the Yellow Sea and the South Sea of Korea, respectively. The two strains shared 99.2% 16S rRNA gene sequence similarity with each other and exhibited ≤ 98.4% similarity to three described Rubrivirga species. Average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values between IMCC43871T and IMCC45206T were 88.5% and 36.3%, respectively, confirming that they represent two distinct species. Their ANI (≤ 77.7%) and dDDH (≤ 21.4%) values relative to the type strains of the genus Rubrivirga further supported the recognition of strains IMCC43871T and IMCC45206T as two novel species within the genus. The complete genomes of IMCC43871T (4.17 Mb, 71.8% G + C content) and IMCC45206T (4.17 Mb, 72.8% G + C content) fall within the known genomic range of the genus. Cellular fatty acid, quinone, and polar lipid profiles were consistent with the chemotaxonomic features of the genus Rubrivirga, supporting their affiliation with the genus. Based on phylogenetic, genomic, and phenotypic evidence, strains IMCC43871T and IMCC45206T are proposed as two novel species, Rubrivirga aquatilis sp. nov. and Rubrivirga halophila sp. nov., respectively. The type strains are IMCC43871T (= KCTC 102072T = NBRC 116463T) and IMCC45206T (= KCTC 92925T = NBRC 116172T = CCTCC AB 2023136T).