Pseudonocardia serianimatus sp. nov., a novel actinomycete isolated from the surface-sterilized leaves of Artemisia annua L.

An aerobic, non-motile, catalase-positive, Gram-stain positive actinomycete designated YIM 63233(T) was isolated from the surface-sterilized leaves of Artemisia annua L. and characterized using a polyphasic taxonomic approach. Optimal growth occurred at 20-28°C, pH 6.0-7.0 and in the presence of 0-3% (w/v) NaCl. 16S rRNA gene sequence-based phylogenetic analysis showed that strain YIM 63233(T) clustered with species of the genus Pseudonocardia, displaying ≥1.2% sequence divergence with recognized species of this genus (from 98.8 to 94.0%). Relatively low levels of DNA-DNA relatedness were found between strain YIM 63233(T) and Pseudonocardia petroleophila IMSNU 22072(T), which supported the classification of strain YIM 63233(T) within a novel species of the genus Pseudonocardia. The G + C content of genomic DNA was 72.0 mol%. Strain YIM 63233(T) possessed chemotaxonomic markers that were consistent with classification in the genus Pseudonocardia, i.e. the predominant fatty acids were iso-C16:0 (32.27%), C16:0 10-methyl (8.73%) and C17:1ω8c (8.30%), whilst the predominant menaquinone was MK-8(H(4)). The diagnostic diamino acid of the cell-wall peptidoglycan was meso-diaminopimelic acid. The major cell wall sugars were glucose, arabinose, galactose, mannose and rhamnose. The results of physiological and biochemical tests and DNA-DNA hybridization allowed the phenotypic and genotypic differentiation of strain YIM 63233(T) from its closest phylogenetic neighbours. Therefore, the new isolate YIM 63233(T) represents a novel species of the genus Pseudonocardia, for which the name Pseudonocardia serianimatus sp. nov. is proposed. The type strain is YIM 63233(T) (=DSM 45302(T) = CCTCC AA 208079(T)).