Insight into microevolution of Streptomyces rimosus based on analysis of zwf and rex genes

Streptomyces rimosus has greatly influenced human history as a producer of many important secondary polyketide metabolites, such as oxytetracycline (OTC). The traditional screen and mutation program has resulted in a dramatic increase in OTC production. The availability of multiple semi-complete genome sequences of S. rimosus facilitates attempts to systematically address basic questions in genome evolution. We refer to such efforts as micro-evolutionary analysis. We report the results of comparative analysis of semi-complete genome sequences of three S. rimosus strains from the genealogy map (G7, M4018 and 23383) with different OTC production levels using genome comparison (single nucleotide polymorphisms, SNPs) method. These data were used to assess the influence of microevolution on the physiology, genetics and evolution of S. rimosus. Some SNPs were found in primary metabolism related genes which might affect the final OTC production. We further discussed the microevolution of primary metabolite genes (Glucose-6-phosphate dehydrogenase, zwf) and regulatory genes (redox regulator, rex) in S. rimosus. Using SOLEXA sequencing data, the phylogenetic trees of zwf and rex were constructed. The results indicate that S. rimosus is closely related with Streptomyces albus and represents a distinct evolutionary lineage compared with other Streptomyces. Our research cannot only provide important information for genotyping and evolutionary research of S. rimosus, but can also make possible the development of an informed view of genotype and phenotype.