Plantactinospora endophytica sp nov., an actinomycete isolated from Camptotheca acuminata Decne., reclassification of Actinaurispora siamensis as Plantactinospora siamensis comb. nov and emended descriptions of the genus Plantactinospora and Plantactinospora mayteni

A novel endophytic actinomycete, designated strain VIM 68255(T), was isolated from healthy leaves of Camptotheca acuminata Decne. collected in Yunnan province, south-west China and characterized by using a polyphasic approach. The strain formed well-developed substrate mycelium, but no aerial mycelium. It grew at 10-45 degrees C, at pH 5-10 (optimum pH 7) and in the presence of 0-3% (w/v) NaCl. The DNA G+C content was 73.0 mol%. Phylogenetic analyses showed that strain VIM 68255(T) belonged to the genus Plantactinospora. However, it exhibited some differences from Plantactinospora mayteni VIM 61359(T) and the level of DNA-DNA relatedness was 42.7 +/- 1.3%. Based on comparative analysis of physiological and chemotaxonomic data, it is proposed that strain VIM 68255(T) represents a novel species of the genus Plantactinospora, Plantactinospora endophytica sp. nov., with strain VIM 68255(T) (=DSM 45387(T)=CCTCC AA 209047(T)) as the type strain. In addition, it is also proposed that Actinaurispora siamensis Thawai et al. 2010 be transferred to the genus Plantactinospora as Plantactinospora siamensis comb. nov. [type strain CM2-8(T) (=JCM 15677(T)=BCC 34762(T))] based on chemotaxonomic characteristics and phylogenetic analysis. Emended descriptions of the genus Plantactinospora and Plantactinospora mayteni are also provided.