sp. nov., an Endophytic Actinomycete Isolated from the Roots of Acacia mangium Willd. and Its Genome Analysis.

A novel endophytic actinomycete strain GKU 173 isolated from the roots of Willd. showed potential plant growth promoting (PGP) activity. Phylogenetic analysis, based on 16S rRNA gene, indicated that strain GKU 173 was the most closely related to HKI 0501-the only species in the genus . Morphology and chemotaxonomy of strain GKU 173 indicated that it belongs to the genus by having meso-diaminopimelic acid in the cell wall and xylose as the characteristic cell-wall sugars. The cellular fatty acid profile mainly comprised iso-C, anteiso-C, iso-C, and iso-C. The major menaquinones were MK-9(H), MK-9(H), and MK-9(H). The main polar phospholipids contained diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), and phosphatidylinositol (PI). Genome analysis signified DNA G+C content of 67.81 mol%. The level of digital DNA-DNA relatedness between strain GKU 173 and the type strain was 21.30%. On the basis of polyphasic characteristics, strain GKU 173 clearly represents a novel species of the genus , for which the name sp. nov. (= TBRC 10620 = NBRC 114213) is proposed. Furthermore, genome analysis of both strains suggested that members of the genus are promising sources of beneficial PGP-actinomycetes and novel secondary metabolites.