Two novel strains, J77-1T and J76-1, were isolated from farmland soil and were taxonomically characterized by a polyphasic approach. Both strains were yellow, Gram-stain-negative, strictly aerobic, non-motile and rod-shaped bacteria. These strains were non-sporulating, catalase-positive and oxidase-negative. J77-1T and J76-1 were able to grow at 15-40 °C, pH 5.0-10.0, and 0-1.0 % (w/v) NaCl concentration. Phylogenetic analyses revealed that both strains formed a distinct separate lineage within the family Cytophagaceae of the phylum Bacteroidetes. J77-1T and J76-1 showed low 16S rRNA gene sequence similarity to the most closely related type strain Dyadobacter koreensis WPCB159T (85.09 %) and exhibited less than 85.0 % sequence similarity with other members of the family Cytophagaceae. The pairwise sequence similarity between strains J77-1T and J76-1 was observed to be 99.86 %. In both strains, the only respiratory quinone was menaquinone-7 (MK-7); the major polar lipid was phosphatidylethanolamine; and the major fatty acids were summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C16 : 0, iso-C15 : 0, iso-C17 : 0 3-OH C16 : 1ω5c, and C16 : 0 3-OH. The genomic DNA G+C content values of J77-1T and J76-1 were 50.1 and 50.9 mol%, respectively. On the basis of the results of phenotypic, genotypic and phylogenetic analysis, J77-1T represents a novel species of a novel genus, for which the name Ravibacter arvi gen. nov., sp. nov. is proposed, within the family Cytophagaceae. The type strain of Ravibacter arvi is J77-1T (=KEMB 9005-548T=KACC 19172T=JCM 31920T), and J76-1 is an additional strain.
Keywords: Bacteroidetes; Cytophagaceae; Cytophagales; Ravibacter arvi; farmland soil; new culture techniques.