Devosia rhodophyticola sp. nov. and Devosia algicola sp. nov., isolated from a marine red alga

Two Gram- stain- negative, obligately aerobic, motile rod bacteria, designated as G2- 5T and G20- 9T, exhibiting catalase- and oxidase- positive activities, were isolated from the phycosphere of a Chondrus species, a marine red alga. Strain G2- 5T exhibited optimal growth at 30 degrees C and pH 5.0-6.0 and in the presence of 0.5-1.0% NaCl. In contrast, strain G20- 9T demonstrated optimal growth at 25 degrees C and pH 6.0 and in the presence of 0.5-1.5% NaCl. Both strains contained ubiquinone- 10, summed feature 8 (C18:1 w7c and/or C18: 1 w6c), C18:0 and 11-methyl-C18:1 w7c, 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- 5T and 57.5 mol% for strain G20- 9T. Strains G2- 5T and G20- 9T 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 G2-5T and G20- 9T formed distinct phylogenic lineages within the genus Devosia. Strains G2- 5T and G20- 9T were most closely related to Devosia limi DSM 17137T and Devosia beringensis S02T with 97.7 and 96.9 % 16S rRNA gene sequence similarities, respectively. The ANI and dDDH values between strains G2- 5T and G20- 9T and other Devosia species were lower than 73.9 and 19.2 %, respectively, suggesting that they constitute novel species within the genus Devosia. Based on their distinct phenotypic, chemotaxonomic, and molecular characteristics, strains G2- 5T and G20- 9T represent two novel species of the genus Devosia, for which the names Devosia rhodophyticola sp. nov. (G2- 5T=KACC 22601T=JCM 35404T) and Devosia algicola sp. nov. (G20- 9T=KACC 22650T=JCM 35405T) are proposed, respectively.