Description of Cohnella rhizoplanae sp. nov., isolated from the root surface of soybean (Glycine max)

Abstract

A Gram-staining-positive, aerobic bacterium, designated strain JJ-181^T, was isolated from the root surface of soybean. Based on the 16S rRNA gene sequence similarities, strain JJ-181^T was grouped into the genus Cohnella, most closely related to Cohnella hashimotonis F6_2S_P_1^T (98.85%) and C. ginsengisoli GR21-5^T (98.3%). The pairwise average nucleotide identity and digital DNA-DNA hybridisation values of the JJ-181^T genome assembly against publicly available Cohnella type strain genomes were below 84% and 28%, respectively. The fatty acid profile from whole cell hydrolysates, the cell wall diaminoacid, the quinone system, the polar lipid profile, and the polyamine pattern supported the allocation of strain JJ-181^T to the genus Cohnella. In addition, the results of physiological and biochemical tests also allowed phenotypic differentiation of strain JJ-181^T from its closely-related Cohnella species. Functional analysis revealed that strain JJ-181^T has different gene clusters related to swarming motility, chemotaxis ability, and endospore and biofilm formations. The gene content also suggests the ability of strain JJ-181^T to synthesise biotin and riboflavin, as well as indole-3-acetic acid, an important phytohormone for plant growth. Based on polyphasic analyses, strain JJ-181^T can be classified as a new species of the genus Cohnella, for which we propose the name Cohnella rhizoplanae sp. nov., with strain JJ-181^T (= LMG 31678^T= CIP 112018^T = CCM 9031^T = DSM 110650^T) as the type strain.