Kosakonia calanthes sp. nov., a plant growth-promoting bacterium, isolated from Calanthe triplicata leaves in China.

A Gram-stain-negative, facultatively aerobic, rod-shaped and motile bacterium, designated as CCTCC AB 2023082^T, was isolated from leaves of Calanthe triplicata in China. Optimal growth occurred at 4-45 ℃ and pH 4.0-10.0 and in the presence of 0-7% (w/v) NaCl. The major fatty acids of the strain CCTCC AB 2023082^T were C16 : 0, sum of C16 : 1 ω7c/C16 : 1 ω6c, C17 : 0 cyclo and C18 : 1 ω7c. The polar lipids included unidentified lipids, phospholipids, phosphatidylethanolamine, phosphatidylglycerol and amino phospholipid. The DNA G+C content of strain CCTCC AB 2023082^T was 54.2 mol%. 16S rRNA gene sequence analysis indicated that strain CCTCC AB 2023082^T formed a distinct lineage within the genus Kosakonia and exhibited the highest similarity to Kosakonia quasisacchari, with a 97.9% 16S rRNA gene sequence similarity. Moreover, the preliminary analysis of the organism's genome suggested its potential as a biostimulant for augmenting plant growth. According to its genotypic, phenotypic, phylogenetic and chemotaxonomic characteristics, strain CCTCC AB 2023082^T should be categorized as a novel species in the genus Kosakonia. The novel species was named Kosakonia calanthes sp. nov., and its type strain is CCTCC AB 2023082^T (=JCM 36393^T).