Mesorhizobium hankyongi sp. nov. Isolated from Soil of Ginseng Cultivating Field.

A Gram-negative, non-spore-forming and rod-shaped, bacterium (designated Gsoil 531T) was isolated from soil of a ginseng field. On the basis of 16S rRNA gene sequence, strain Gsoil 531T clustered with species of the genus Mesorhizobium and was closely related to M. camelthorni CCNWXJ 40-4T (98.9%) and M. alhagi CCNWXJ12-2T (98.7%). The DNA G + C content was 62.9 mol% and the predominant quinone was ubiquinone-10 (Q-10). The major cellular fatty acids were C16:0, C19:0 cyclo ω8c and summed feature 8 (C18:1 ω7c/C18:1 ω6c). The DNA-DNA hybridization values were less than 35.0% between novel isolate and its closest reference strains M. camelthorni HAMBI 3020T, M. alhagi HAMBI 3019T and M tamadayense LMG 26736T. Physiological, biochemical and low values of DNA-DNA hybridization results enabled strain Gsoil 531T to be differentiated genotypically and phenotypically from all known species of the genus Mesorhizobium. Therefore, strain Gsoil 531T signifies a novel species of the genus Mesorhizobium, for which the name Mesorhizobium hankyongi sp. nov. is proposed. The type strain Gsoil 531T (= KACC 19443T = LMG 30463T).