Isolation and Characterisation of Rhizosphere-Associated Streptomycetes

A total of 607 isolates were obtained and chosen to represent the different colonial types of presumptive streptomycetes isolated from suspensions of two extraction methods. Five hundred and fifty- six isolates obtained using the DDC method were assigned to 37 multi-membered (451 isolates) and 105 single-membered colour groups. In addition, 51 isolates derived from tumble shaking procedure were assigned to 7 multi-membered (42 isolates) and 9 single-membered colour groups. The properties of these multi-membered colour groups were identical to those shown by corresponding colour groups that encompassed strains derived from the DDC procedure. Representatives of 31 out of 37 multi-membered had chemical and morphological properties consistent with their classification in the genus Streptomyces. The generic assignment of these organisms was underpinned by 16S rDNA sequence data which also suggested that most of the strains represented new centres of taxonomic variation. The taxonomic data indicate that diverse populations of streptomycetes are associated with the roots of Paraserianthes falcataria.