Roseovarius phycicola sp. nov. and Roseovarius rhodophyticola sp. nov., isolated from marine red algae

Two Gram-stain-negative, strictly aerobic, non-motile, rod-shaped bacteria, designated as strains S88^T and W115^T, exhibiting catalase- and oxidase-positive reactions, were isolated from marine red algae in South Korea. Strain S88^T exhibited growth at 20-30 °C, pH 6.0-9.0 and 2.0-5.0% (w/v) NaCl, while strain W115^T grew at 20-30 °C, pH 7.0-9.0 and 2.0-5.0% (w/v) NaCl. Strain S88^T contained summed feature 8 (C_{18 : 1} <i> ω</i>7<i>c</i> and/or C_{18 : 1} <i> ω</i>6<i>c</i>), C_{16 : 0} and C_{16 : 0} 2-OH as major fatty acids (>5%), with major polar lipids being phosphatidylglycerol, phosphatidylcholine, an unidentified phospholipid, an unidentified aminolipid and two unidentified lipids. Strain W115^T contained summed feature 8 (C_{18 : 1} <i> ω</i>7<i>c</i> and/or C_{18 : 1} <i> ω</i>6<i>c</i>) and C_{16 : 0} as major fatty acids (>5%), with major polar lipids including phosphatidylglycerol, phosphatidylcholine, an unidentified phospholipid, an unidentified aminolipid and unidentified lipids. Ubiquinone-10 was the sole respiratory quinone in both strains, and the genomic DNA G+C contents were 57.0% for strain S88^T and 56.5% for strain W115^T. Despite 99.86% 16S rRNA gene sequence similarity, strains S88^T and W115^T shared 88.8% average nucleotide identity (ANI) and 36.8% digital DNA-DNA hybridization (dDDH) value, indicating different species. Phylogenetic and phylogenomic analyses based on 16S rRNA gene and genome sequences, respectively, revealed that strains S88^T and W115^T formed a phylogenetic lineage within the genus <i>Roseovarius</i>. ANI and dDDH values of both strains with other type strains were less than 73.7 and 20.3%, respectively, confirming that they represent novel species. Based on phenotypic, chemotaxonomic and molecular characteristics, strains S88^T and W115^T represent two novel species of the genus <i>Roseovarius</i>, for which the names <i>Roseovarius phycicola</i> sp. nov. (S88^T =KACC 23423^T =JCM 36647^T) and <i>Roseovarius rhodophyticola</i> sp. nov. (W115^T =KACC 23690^T =JCM 36651^T) are proposed, respectively.