Diversity of non-ribosomal peptide synthetases genes in terrestrial streptomycetes

Biotechnological potential of secondary metabolites from microorganisms are receiving much attention for the discovery of novel bioactive compounds. The present study was designed to assess the genetic potential of rhizosphere streptomycete communities by amplifying adenylation (A) domains of non-ribosomal peptide synthetase (NRPS) genes. Using degenerate PCR and the sequencing of cloned products, NRPSs were detected in all 26 isolates. Based on the BlastX analysis, most of the NRPS fragments showed below 70% identity to their closest relatives. Additionally, NRPS A domain sequences were constituted established chemistry based clades in the phylogenetic tree. Different A domains were determined in the sequences, but in some cases their substrate specifity failed to be predicted. This means that these domains can recognize novel amino acids as substrate. For the first time, an investigation was performed on the substrate specifity of NRPS A domains of rhizosphere streptomycetes and their phylogenetic relationship. Genomic screening studies such as the one presented here for NRPS genes; contribute to on-going efforts to characterize the potential of plant-associated microbiota for secondary metabolite biosynthesis.