Kribbella mirabilis sp. nov., isolated from rhizosphere soil of a herbaceous plant, Mirabilis jalapa L.

Strain XMU 706(T), isolated from the rhizosphere soil of a herbaceous plant, Mirabilis jalapa L., collected from Xiamen City, China, was characterized using a polyphasic approach to clarify its taxonomic position. Strain XMU 706(T) shared the highest 16S rRNA gene sequence similarity with Kribbella antibiotica YIM 31530(T) (97.2%), and formed a distinct branch in the subclade of the genus Kribbella in the 16S rRNA gene phylogenetic tree. The genetic distances of gyrase subunit B gene (gyrB) sequence between strain XMU 706(T) and other species of the genus Kribbella ranged from 0.045 to 0.116, greater than the threshold value of 0.014 for species delineation of this genus. DNA-DNA hybridization experiments gave a DNA-DNA relatedness value of 34.82 ± 6.31% between strain XMU 706(T) and K. antibiotica YIM 31530(T). The chemotaxonomic properties further supported the assignment of strain XMU 706(T) to the genus Kribbella. ll-Diaminopimelic acid was the diagnostic amino acid in the cell-wall peptidoglycan and cell hydrolysates contained ribose and glucose. The major menaquinone was MK-9(H4). The polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine and other unidentified phospholipids and lipids. The major fatty acids of the strain were anteiso-C15 : 0 and iso-C15 : 0, and the G+C content of the genomic DNA was 67.3 mol%. Based on the results of phylogenetic analysis, phenotypic and genotypic characterization, strain XMU 706(T) represents a novel species of the genus Kribbella, for which the name Kribbella mirabilis sp. nov. is proposed. The type strain is XMU 706(T) ( = KCTC 29676(T) = MCCC 1K00429(T)).