sp. nov. and sp. nov., isolated from a marine red alga.

Two Gram-stain-negative, obligately aerobic, motile rod bacteria, designated as G2-5 and G20-9, exhibiting catalase- and oxidase-positive activities, were isolated from the phycosphere of a species, a marine red alga. Strain G2-5 exhibited optimal growth at 30 °C and pH 5.0-6.0 and in the presence of 0.5-1.0% NaCl. In contrast, strain G20-9 demonstrated optimal growth at 25 °C and pH 6.0 and in the presence of 0.5-1.5% NaCl. Both strains contained ubiquinone-10, summed feature 8 (C 7 and/or C 6), C and 11-methyl-C 7, and diphosphatidylglycerol and phosphatidylglycerol as the major respiratory isoprenoid quinone, cellular fatty acids and polar lipids, respectively. The genomic DNA G+C contents were 57.2 mol% for strain G2-5 and 57.5 mol% for strain G20-9. Strains G2-5 and G20-9 exhibited 98.2 % 16S rRNA gene sequence similarity, along with 82.3 % average nucleotide identity (ANI) and 25.0 % digital DNA-DNA hybridization (dDDH) values, indicating that they represent different species. Phylogenetic analyses based on both 16S rRNA gene and genome sequences revealed that strains G2-5 and G20-9 formed distinct phylogenic lineages within the genus . Strains G2-5 and G20-9 were most closely related to DSM 17137 and S02 with 97.7 and 96.9 % 16S rRNA gene sequence similarities, respectively. The ANI and dDDH values between strains G2-5 and G20-9 and other species were lower than 73.9 and 19.2 %, respectively, suggesting that they constitute novel species within the genus . Based on their distinct phenotypic, chemotaxonomic, and molecular characteristics, strains G2-5 and G20-9 represent two novel species of the genus , for which the names sp. nov. (G2-5=KACC 22601=JCM 35404) and sp. nov. (G20-9=KACC 22650=JCM 35405) are proposed, respectively.