Streptomyces cathayae sp. nov., an endophytic actinobacterium from the root tissue of Cathaya argyrophylla

Abstract

An endophytic actinobacterium, designated strain HUAS 5^T, was isolated from the root tissue of Cathaya argyrophylla collected in Chenzhou city of Hunan Province, PR China. This strain produced grey aerial mycelium that differentiated into spiral spore chains with spiny-surfaced ellipsoidal spores on Gause's synthetic No. 1 medium. Strain HUAS 5^T grew well on Gause's synthetic No. 1, Reasoner'2 and ISP serial media. This strain grew at 15-40 °C (optimum, 28 °C), pH 6.0-9.0 (optimum, pH 7.0) and in presence of 0-5.0% (w/v) NaCl. The predominant cellular fatty acids of strain HUAS 5^T (> 5.0%) were iso-C_16:0, iso-C_14:0, anteiso-C_15:0, iso-C_15:0, C_16:0, iso-C_16:1 H and Sum in Feature 3 (C_16:1 ω7c/C_16:1 ω6c). Sequence analysis of the 16S rRNA gene indicated that this strain belonged to the genus Streptomyces and exhibited highest sequence similarity to Streptomyces hirsutus NRRL B-2713^T (97.3%), which is much less than 98.7% cut-off point of species definitions for bacteria and archaea. Phylogenetic analysis of 16S rRNA gene sequence and whole genome indicated that strain HUAS 5^T formed an independent lineage, which suggested that it belonged to a potential novel species. Based on the morphological, cultural, physio-biochemical properties and chemotaxonomy, strain HUAS 5^T (= MCCC 1K08552^T = JCM 36055^T) is deemed to represent a novel Streptomyces species, for which we put forward the name Streptomyces cathayae sp. nov.

Keywords: Cathaya argyrophylla; Polyphasic taxonomy; Streptomyces cathayae sp. nov..