Nocardiopsis changdeensis sp. nov., an endophytic actinomycete isolated from the roots of Eucommia ulmoides Oliv.

Abstract

Strain Mg02T was isolated from roots of Eucommia ulmoides Oliv. collected from Changde City, Hunan Province, China. Strain Mg02T, which exhibited distinct chemotaxonomic characteristics of the genus Nocardiopsis: cell-wall chemotype III/C, i.e., meso-diaminopimelic acid as diagnostic amino acid in whole-cell hydrolysates and menaquinone MK-10 with variable degrees of saturation in the side chain as the predominant isoprenoid quinone, was investigated by a polyphasic approach to determine their taxonomic position. Sequence analysis of the 16S rRNA gene indicated that strain Mg02T is affiliated to the genus Nocardiopsis, having highest sequence similarity to Nocardiopsis flavescens CGMCC 4.5723T (99.1%) and <98.7% to other species of the genus Nocardiopsis with validly published names. Phylogenetic analysis of 16S rRNA gene indicated strain Mg02T formed a separate evolutionary clade, suggesting that it could be a novel Nocardiopsis species. Phylogenomic analysis showed that strain Mg02T was closely related to N. flavescens CGMCC 4.5723T and distinct from the latter according to the clustering patterns. The Average Nucleotide Identity and digital DNA-DNA hybridization values between strain Mg02T and N. flavescens CGMCC 4.5723T were far below the species-level thresholds. Based on phenotypic, phylogenetic and chemotaxonomic characteristics, we think that strain Mg02T should represent a novel Nocardiopsis species, for which the name Nocardiopsis changdeensis sp. nov. is proposed. The type strain is Mg02T (=MCCC 1K06174T = JCM 34709T).