Marinomonas algae sp. nov. and Marinomonas phycocola sp. nov., two novel bacteria isolated from marine algae

Two novel bacterial strains, designated as 2405UD66-6^T and 2405UD68-3^T, were isolated from marine algae collected in the Republic of Korea. Both strains were Gram-stain-negative, strictly aerobic, motile, rod-shaped and oxidase-positive. Optimal growth occurred at 28 °C and pH 7.0, with NaCl concentrations of 3.0-4.0% (w/v) for strain 2405UD66-6^T and 2.0-3.0% (w/v) for strain 2405UD68-3^T. Phylogenetic analysis based on 16S rRNA gene sequences and phylogenomic analysis based on draft genome sequences revealed that strains 2405UD66-6ᵀ and 2405UD68-3ᵀ belong to the genus Marinomonas. Phylogenomic analysis revealed that strain 2405UD66-6^T was most closely related to Marinomonas colpomeniae SM2066^T, while strain 2405UD68-3^T was most closely related to Marinomonas phaeophyticola 15G1-11^T. Average nucleotide identity and digital DNA-DNA hybridization values between strain 2405UD66-6^T and its closest relative were 77.4 and 20.6%, respectively, whereas those between strain 2405UD68-3^T and its closest relative were 75.8 and 19.7%, respectively. These values are well below the accepted species delineation thresholds, indicating that both strains represent novel species within the genus Marinomonas. The genomic G+C contents for strains 2405UD66-6^T and 2405UD68-3^T were 42.5 and 40.5 mol%, respectively. The major polar lipids of both strains were phosphatidylglycerol and phosphatidylethanolamine, and the sole respiratory quinone was ubiquinone-8. The predominant fatty acids (>10.0%) in both strains were C_16 : 0, summed feature 3 (C_16 : 1  ω6c and/or C_16 : 1  ω7c) and summed feature 8 (C_18 : 1  ω7c and/or C_18 : 1  ω6c). Based on a polyphasic taxonomic approach, the names Marinomonas algae sp. nov. and Marinomonas phycocola sp. nov. are proposed, respectively. The type strain is 2405UD66-6^T (KACC 24016^T=MCCC 1K09776^T) for M. algae and 2405UD68-3^T (KACC 24017^T=MCCC 1K09819^T) for M. phycocola.