Promicromonospora endophytica sp. nov., an endophytic actinobacterium isolated from the root of an Australian native Grey Box tree

Abstract

A novel aerobic actinobacterium, strain EUM 273(T), was isolated from the root of a Grey Box tree (Eucalyptus microcarpa Maiden). Cells were Gram-staining-positive with well-developed substrate mycelia which were non-motile and rod-like, with coccoid elements. Phylogenetic evaluation based on 16S rRNA gene sequence analysis placed the isolate as a member of the family Promicromonosporaceae that was most closely related to Promicromonospora xylanilytica YIM 61515(T) (98.2%) and Promicromonospora vindobonensis V45(T) (98%). Chemotaxonomic data including cell wall components, major menaquinone and major fatty acids confirmed the affiliation of strain EUM 273(T) to the genus Promicromonospora. The results of the phylogenetic analysis, including physiological and biochemical studies in combination with DNA-DNA hybridization, allowed the genotypic and phenotypic differentiation of strain EUM 273(T) from the closest related species with validly published names. The name proposed for the novel species is Promicromonospora endophytica sp. nov. The type strain is EUM 273(T) (=DSM 23716(T)=NRRL B-24816(T)).