Hoeflea algicola sp. nov. and Hoeflea ulvae sp. nov., isolated from phycosphere of marine algae

Two Gram-negative, moderately halophilic, and motile rod bacteria, strains G2-23^T and J2-29^T, showing catalase- and oxidase-positive activities were isolated from species of the marine algae Chondrus and Ulva, respectively. Both strains optimally grew at 30 °C, pH 7.0 and 2% (w/v) NaCl. Both strains contained ubiquinone-10 as the sole isoprenoid quinone. Strain G2-23^T contained summed feature 8 (C_18 : 1 ω7c and/or C_18 : 1 ω6c), C_16 : 0 and summed feature 3 (iso-C_15 : 0 2-OH and/or C_16 : 1 ω7c/ω6c) as major cellular fatty acids, and phosphatidylethanolamine (PE), phosphatidyl-N-monomethylethanolamine (PME), phosphatidylglycerol (PG), diphosphatidylglycerol and an unidentified phospholipid (PL) as major polar lipids. Strain J2-29^T contained summed feature 8, C_18 : 1 ω7c 11-methyl and C_16 : 0 as major cellular fatty acids and PE, PME, PG and PL as major polar lipids. The genomic DNA G+C contents of strains G2-23^T and J2-29^T were 59.5 and 62.2 mol%, respectively. Both strains shared 97.9 % 16S rRNA gene sequence similarity, 79.8 % average nucleotide identity (ANI) and 22.8 % digital DNA-DNA hybridization (dDDH) values, indicating that they represent different species. Phylogenetic and phylogenomic analyses by 16S rRNA gene and genome sequences, respectively, revealed that strains G2-23^T and J2-29^T formed different phylogenic lineages within the genus Hoeflea. ANI and dDDH values between strains G2-23^T and J2-29^T and other Hoeflea type strains were less than 79.0 and 22.1% and 80.5 and 23.3 %, respectively, suggesting that they represent novel species of the genus Hoeflea. In summary, based on their phenotypic, chemotaxonomic and molecular properties, strains G2-23^T and J2-29^T represent two different novel species of the genus Hoeflea, for which the names Hoeflea algicola sp. nov. (G2-23^T=KACC 22714^T=JCM 35548^T) and Hoeflea ulvae sp. nov. (J2-29^T=KACC 22715^T=JCM 35549^T), respectively, are proposed.