Abstract
An actinomycetes strain A-T 1946(T) that developed spherical sporangia containing non-motile spores on aerial mycelia was isolated from dry deciduous forest soil in Thailand. 16S rRNA gene sequence analysis indicated that strain A-T 1946(T) belongs to the genus Sinosporangium, being closely related to Sinosporangium album 6014(T) (98.8% sequence similarity). The DNA-DNA relatedness values were 43.7-50.9%, which were significantly below 70% and differentiated strain A-T 1946(T) from the closest species. The cell-wall peptidoglycan contained meso-diaminopimelic acid. The whole-cell sugars contained rhamnose, ribose, madurose and glucose. The predominant nnenaquinone was MK-9(H-2). The diagnostic phospholipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmethylethanolamine, lysophosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, phosphatidylinositol-mannoside, N-acetylglucosamine-containing phospholipids, two unknown phosphoglycolipids and two unknown phospholipids. The predominant cellular fatty acids were unsaturated C-16:1 and C-17:1, and saturated C-16:0 and 10-methyl-C-17:0. Following an evaluation of phenotypic, chemotaxonomic and genotypic characteristics, the isolate is proposed to represent a novel species of genus Sinosporangium to be named Sinosporangium siamense sp. nov. The type strain is A-T 1946(T) (=BCC 29081(T)=NBRC 109515(T)). An emended description of the genus Sinosporangium is also provided.
