Kaistella Yananensis Sp. Nov., a Novel Indoleacetic Acid-Producing Bacterium Isolated from the Root Nodules of Sophora Davidii (Franch.) Skeels

A novel endophytic bacterium, designated strain BT6-1-3, was isolated from the root nodules of a leguminous shrub named Sophora davidii (Franch.) Skeels, found growing wild in Yan'an, Shaanxi Province, China. Cells were Gram-staining-negative, non-motile, catalase-positive, oxidase-positive, and did not produce HS. Strain BT6-1-3 grew at 15-40 °C (optimum 30 °C), at pH 6.0-10.0 (optimum pH 9.0), and with 0-1% (w/v) NaCl (optimum 0.5%). The quinone system was menaquinone 6. The major fatty acids present in BT6-1-3 were iso-C, iso-C, and C. The G+C content of genomic DNA was 39.4 mol% by whole genome sequencing. According to the analysis of 16S rRNA gene sequence, the closest relative was Kaistella montana WG4 (nucleotide identity was 97.6%). The genome of strain BT6-1-3 was sequenced, and the genome similarity was calculated using average nucleotide identity and genome-to-genome distance analysis with the genomes of other strains of Kaistella. Both strongly supported that the strain BT6-1-3 belonged to the genus Kaistella as a representative of a new species. Based on phylogenetic analysis, chemotaxonomic data, and physiological and biochemical characteristics, strain BT6-1-3 represents a new species of the genus Kaistella and is named as Kaistella yananensis sp. nov. Type strain is BT6-1-3 (= NBRC 115452 = CGMCC 1.60032).