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

Abstract

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°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°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 ω7c and/or C18:1 ω6c), C18:0 and 11-methyl-C18:1 ω7c, and diphosphatidylglycerol and phosphatidylglycerol as the major respiratory isoprenoid quinone, cellular fatty acids and polar lipids, respectively. The genomic DNA G+C contents were 57.2mol% for strain G2-5T and 57.5mol% 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. © 2024 The Authors.