| Abstract |
Two Gram-positive, aerobic actinomycete strains, designated YIM 48771(T) and YIM 48782(T), were isolated from virgin forest soil samples collected in Hunan Province, China. 16S rRNA gene sequence similarities of the two novel isolates ranged from 96.3 to 97.6 % with species of the genus Sphaerisporangium with validly published names but, in the tree based on 16S rRNA gene sequences, the isolates formed distinct phyletic lines. The level of 16S rRNA gene sequence similarity between the two novel isolates was 97.1 %. DNA-DNA hybridization of strains YIM 48771(T) and YIM 48782(T) with recognized species of the genus Sphaerisporangium revealed that the level of DNA-DNA relatedness was below 70 %. The DNA G+C contents of strains YIM 48771(T) and YIM 48782(T) were 67.1 and 71 mol%, respectively. Chemotaxonomic data [major menaquinone, MK-9(H(4)); major polar lipids, diphosphatidylglycerol, phosphatidylinositol mannoside, phosphatidylethanolamine and phosphoglycolipids; major fatty acids, iso-C(16 : 0) and 10-methyl C(17 : 0)] supported the affiliation of the two isolates with the genus Sphaerisporangium. The results of DNA-DNA hybridization and physiological and biochemical tests allowed genotypic and phenotypic differentiation of the two isolates from recognized Sphaerisporangium species. Based on morphological, chemotaxonomical and phylogenetic data, strains YIM 48771(T) and YIM 48782(T) are considered to represent two novel species of the genus Sphaerisporangium, for which the names Sphaerisporangium flaviroseum sp. nov. (type strain, YIM 48771(T)=DSM 45170(T)=KCTC 19393(T)) and Sphaerisporangium album sp. nov. (type strain, YIM 48782(T)=DSM 45172(T)=CCTCC AA 208026(T)) are proposed.
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