Flavobacterium oryzagri sp. nov. and Flavobacterium oryzicola sp. nov., isolated from paddy soil.

Two bacterial strains, designated M3-11T and M6-14T, were isolated from paddy field soils in the Republic of Korea. Cells were aerobic, Gram-stain-negative, rod-shaped and non-flagellated but motile. The strains exhibited optimal growth at 28 °C and pH 7.0 and in the absence of NaCl. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strains M3-11T and M6-14T were placed within the genus Flavobacterium, showing the highest similarity to Flavobacterium zhairuonense A5.7T (97.98%) and Flavobacterium nitrogenifigens NXU-44T (98.23 %), respectively. The genomic similarity between two strains and their closely related strains was 39.3 and 51.1 % for digital DNA-DNA hybridization and 90.0 and 93.2 % for orthologous average nucleotide identity, both of which were lower than the thresholds recommended for species delineation. The respiratory quinone was menaquinone-6, and the major polar lipids were phosphatidylethanolamine and aminolipid. The major fatty acids (>10 %) were iso-C15 : 0 and summed feature 3. The phenotypic, chemotaxonomic and genotypic data obtained in this study showed that strains M3-11T and M6-14T represent novel species of the genus Flavobacterium, for which the names Flavobacterium oryzagri sp. nov. (type strain M3-11T=KACC 22761T=JCM 35942T) and Flavobacterium oryzicola sp. nov. (type strain M6-14T=KACC 22763T=JCM 35943T) are proposed.