Sphaerisporangium rufum sp nov., an endophytic actinomycete from roots of Oryza sativa L

An endophytic actinomycete, strain R10-82(T), isolated from surface-sterilized roots of rice (Oryza sativa L.) was studied using a polyphasic approach. Strain R10-82(T) produced branching substrate mycelia and developed spherical spore vesicles on aerial hyphae containing non-motile spores. The major cellular fatty acids were iso-C-16:0, iso-C-14:0 and 10-methyl C-17:0. The predominant menaquinones were MK-9, MK-9(H-2), MK-9(H-4) and MK-9(H-6). Rhamnose, ribose, madurose, mannose and glucose were detected in whole-cell hydrolysates. The diagnostic phospholipids were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylinositol mannosides, hydrarylphosphatidylethanolamine and ninhydrin-positive phosphoglycolipids. These morphological and chemotaxonomic data were similar to those of the genus Sphaerisporangium. Analysis of the 16S rRNA gene sequence revealed that strain R10-82(T) was related most closely to Sphaerisporangium cinnabarinum JCM 3291(T) (98.3% similarity). The DNA G + C content of strain R10-82(T) was 74 mol%. DNA DNA relatedness data in combination with differences in the biochemical and physiological properties suggested that strain R10-82(T) should be classified as representing a novel species of the genus Sphaerisporangium, for which the name Sphaerisporangium rufum is proposed. The type strain is R10-82(T) (=BCC 51287(T)=NBRC 109079(T)). An emended description of the genus Sphaerisporangium is also provided.