Pseudonocardia antimicrobica sp. nov., a novel endophytic actinomycete associated with Artemisia annua L. (sweet wormwood).

A Gram-reaction-positive, non-motile, endophytic actinomycete, designated strain YIM 63235(T), was isolated from the surface-sterilized stems of Artemisia annua L., and characterized to determine its taxonomic position. The strain YIM 63235(T) formed well-differentiated aerial and substrate mycelia on media tested. The phylogenetic tree based on 16S rRNA gene sequences showed that the new isolate formed a distinct lineage within the genus Pseudonocardia, and the strain YIM 63235(T) was closely related to Pseudonocardia parietis 04-St-002(T) (99.1%). However, DNA-DNA relatedness demonstrated that strain YIM 63235(T) was distinct from the closest phylogenetic neighbor. The chemotaxonomic properties of strain YIM 63235(T) were consistent with those of the genus Pseudonocardia: the diagnostic diamino acid of the cell-wall peptidoglycan was meso-diaminopimelic acid and MK-8(H(4)) was the predominant menaquinone. The major fatty acids were iso-C(16:0) and iso-C(16:1) H. The DNA G+C content of strain YIM 63235(T) was 71.0 mol%. On the basis of the phenotypic and phylogenetic distinctiveness, the novel isolate was identified as representing a novel species of the genus Pseudonocardia, for which the name Pseudonocardia antimicrobica sp. nov. (type strain YIM 63235(T) =CCTCC AA 208080(T)=DSM 45303(T)) is proposed.