Asanoa endophytica sp. nov., an endophytic actinomycete isolated from the rhizome of Boesenbergia rotunda

Abstract

A novel Gram-stain-positive, non-motile, endophytic actinomycete, designated strain BR3-1^T, which produced spore chains borne on the tips of short sporophores, was isolated from the rhizome of <i>Boesenbergia rotunda</i> collected from Udon Thani province, Thailand. This strain was investigated for its taxonomic position using a polyphasic approach. The strain contained 3-hydroxydiaminopimelic acid and <i>meso</i>-diaminopimelic acid in the cell-wall peptidoglycan. The whole-cell sugars comprised glucose, mannose, rhamnose, ribose and xylose. Phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides were found as the characteristic phospholipids. The predominant menaquinones were MK-10(H₈) and MK-10(H₆). The major cellular fatty acids were iso-C_{16 : 0}, iso-C_{15 : 0} and anteiso-C_{15 : 0}. The G+C content of the genomic DNA was 71.4 mol%. 16S rRNA gene sequence analysis revealed that strain BR3-1^T belonged to the genus <i>Asanoa</i> and was most closely related to <i>Asanoa ishikariensis</i> (99.39 %), <i>Asanoa iriomotensis</i> (99.31 %), <i>Asanoa siamensis</i> (99.17 %), <i>Asanoa ferruginea</i> (98.84 %) and <i>Asanoa hainanensis</i> (98.71 %). The DNA-DNA relatedness value between strain BR3-1^T and its phylogenetically closest relatives was in the range of 15.4 % ± 1.2 to 45.8 % ± 2.6. In addition, some physiological and biochemical properties indicated that strain BR3-1^T could be readily distinguished from all type strains in the genus <i>Asanoa</i>. Thus, strain BR3-1^T should be classified as a representative of a novel species, for which the name <i>Asanoa endophytica</i> sp. nov. is proposed. The type strain is BR3-1^T ( = BCC 66355^T = NBRC 110002^T).