Oryzicola mucosus gen. nov., sp. nov., a novel slime producing bacterium belonging to the family Phyllobacteriaceae isolated from the rhizosphere of rice plants

A novel Gram-stain negative, asporogenous, slimy, rod-shaped, non-motile bacterium ROOL2^T was isolated from the root samples collected from a rice field located in Ilsan, South Korea. Phylogenetic analysis of the 16S rRNA sequence showed 96.5% similarity to Tianweitania sediminis Z8^T followed by species of genera Mesorhizobium (96.4–95.6%), Aquabacterium (95.9–95.7%), Rhizobium (95.8%) and Ochrobactrum (95.6%). Strain ROOL2^T grew optimally at 30 °C in the presence of 1–6% (w/v) NaCl and at pH 7.5. The major respiratory quinone was ubiquinone-10 and the major cellular fatty acids were C_18:1ω7c, summed feature 4 (comprising iso-C_17:1 I and/or anteiso-C_17:1 B) and summed feature 8 (comprising C_18:1ω6c and/or C_18:1ω7c). The polar lipid profile consisted of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, phosphatidylmethylethanolamine, phosphatidylglycerol, one unidentified aminolipid and two unidentified lipids. The assembled draft genome of strain ROOL2^T had 28 contigs with N50 value of 656,326 nt, total length of 4,894,583 bp and a DNA G?+?C content of 61.5%. The average amino acid identity (AAI) values of strain ROOL2^T against the genomes of related members belonging to the same family were below 68% and the ANI and dDDH values between the strain ROOL2^T and the type strains of phylogenetically related species were 61.8–76.3% and 19.4–21.1%, respectively. Strain ROOL2^T only produces carotenoid-type pigment when grown on LB agar and slime on R2A agar. In the presence of tryptophan, strain ROOL2^T produced indole acetic acid (IAA), a phytohormone in plant growth and development. Gene clusters for indole-3-glycerol phosphatase and tryptophan synthase were found in the genome of strain ROOL2^T. The genotypic and phenotypic characteristics indicated that strain ROOL2^T represents a novel genus belonging the family Phyllobacteriaceae, for which the name Oryzicola mucosus gen. nov., sp. nov. is proposed. The type strain is ROOL2^T (KCTC 82711 ^T?=?NBRC 114717 ^T).