Selective isolation and characterisation of members of the Streptomyces violaceusniger clade associated with the roots of Paraserianthes falcataria

Large numbers of putatively novel streptomycetes were isolated from environmental samples collected from in and around the root system of the tropical angiosperm, Paraserianthes falcataria. Representative isolates were assigned to 37 multi-membered and 107 single membered colour groups based on their ability to form pigments on oatmeal and peptone yeast extract iron agars. The largest taxon, colour group 3, encompassed 94 isolates which had morphological properties typical of members of the Streptomyces violaceusniger clade. Twelve representatives of this taxon chosen on the basis of Curie-point pyrolysis mass spectrometric data were compared with representatives of the validly described species which constitute the Streptomyces violaceusniger clade. Six out of the twelve representative strains were readily distinguished from one another and from the marker strains using a combination of genotypic and phenotypic properties. These organisms were consequently considered to merit species status as Streptomyces asiaticus sp. nov., Streptomyces cangkringensis sp. nov., Streptomyces indonesiensis sp. nov., Streptomyces javensis sp. nov., Streptomyces rhizosphaerius sp. nov. and Streptomyces yogyakartensis sp. nov.