Zobellia roscoffensis sp. nov. and Zobellia nedashkovskayae sp. nov. two flavobacteria from the microbiome of the brown alga Ascophyllum nodosum. Zobellia roscoffensis sp. nov. and Zobellia nedashkovskayae sp. nov.

Four marine bacterial strains, were isolated from the thallus of the brown algae Ascophyllum nodosum collected in Roscoff, France. Cells were Gram-stain-negative, strictly aerobic, non-flagellated, gliding, rod-shaped and grew optimally at 25-30 °C, at pH 7-8 and with 2-4 % NaCl. Phylogenetic analyses of their 16S rRNA gene sequences showed that the bacteria were affiliated to the genus Zobellia (family Flavobacteriaceae, Phylum Bacteroidetes). The four strains exhibited 16S rRNA gene sequence similarity values between 97.8 and 100% themselves and between 97.9 and 99.1 % to the type strains of Zobellia amurskyensis KMM 3526T and Z. laminariae KMM 3676T, and less than 99% to other species of the genus Zobellia. The DNA G+C content of four strains was determined to be 36.7-38.1 mol%. Digital DNA-DNA hybridization predictions by the ANI and GGDC methods between the new strains and other members of the genus Zobellia showed values of 76.4-88.9 %, and below 38.5 %, respectively. The phenotypic, phylogenetic and genomic analyses show that the four strains are distinct from species of the genus Zobellia with validly published names and that they represent two novel species of the genus Zobellia, for which the names Zobellia roscoffensis sp. nov. and Zobellia nedashkovskayae sp. nov. are proposed.