sp. nov., a fibrillar matrix-producing bacterium isolated from the rhizosphere of rice plant.

A novel fibrillar matrix-producing, rod-shaped, red-orange, asporogenous, aerobic bacterium, designated DK36, was isolated from roots of a rice plant in the Ilsan region near Dongguk University, South Korea. Cells of strain DK36 were Gram-stain-negative and motile by means of gliding. The temperature and pH ranges for growth were 7-35 °C (optimum: 30 °C) and pH 5-10 (optimum: pH 7.0). The strain did not require NaCl for growth but tolerated up to 8 % (w/v) NaCl. Phylogenetic anlaysis of the 16S rRNA gene sequence revealed that DK36 formed a monophyletic clade with 6425 S-25, 6515 J-31 and 17mud1-7 with sequence similarities of 96.3, 95.5 and 95.2%, respectively. The average nucleotide identity and DNA-DNA hybridization values of strain DK36 with the most closely related strains whose whole genomes are publicly available were 72.5-83.6% and 19-28 %, respectively. The strain showed the typical chemotaxonomic characteristics of the genus , with the presence of menaquinone MK-7 as the respiratory quinone, and Cω5, iso-C and summed feature 4 (composed of iso-C I/anteiso-C B) as the major fatty acids. The polar lipid profile consisted of phosphatidylethanolamine, one unidentified aminophosphoglycolipid, one unidentified phospholipid, two unidentified aminolipids and five unidentified polar lipids. The genomic DNA G+C content based on the draft genome sequence was 43.4 mol%. The results of physiological and biochemical tests and 16S rRNA gene sequence analysis clearly revealed that strain DK36 represents a novel species of the genus , for which the name sp. nov. is proposed. The type strain is DK36 (=KACC 19902=NBRC 113689).