Streptomyces radiopugnans sp. nov., a radiation-resistant actinomycete isolated from radiation-polluted soil in China.

The taxonomic position of an actinomycete isolated from radiation-polluted soil collected in Xinjiang Province, north-west China, was determined by using a polyphasic approach. The isolate, designated strain R97T, had chemical and morphological properties characteristic of streptomycetes. An almost-complete 16S rRNA gene sequence of the isolate was generated and compared with corresponding sequences of representative streptomycetes. The 16S rRNA data not only supported the classification of the strain in the genus Streptomyces but also showed that it represented a distinct phyletic line that was most closely, albeit loosely, associated with three other thermotolerant organisms, namely Streptomyces macrosporus NBRC 14748T, Streptomyces megasporus NBRC 14749T and Streptomyces thermolineatus NBRC 14750T. Strain R97T could be distinguished from these organisms based on a range of phenotypic properties. It is proposed that R97T (=CGMCC 4.3519T=DSM 41901T) be classified as the type strain of a novel species in the genus Streptomyces, Streptomyces radiopugnans sp. nov. The organism was shown to be resistant to 60Co gamma radiation at a dose of 15 kGy.