Project description:Bacterial genomic plasticity and instability carry multiple functional genetic information in Streptomyces secondary metabolism. Our previously publication has reported an effective industrial Streptomyces strain, with a unique phenotype of the high clavulanic acid yield. The complete genome of strain F163-1 harboring a 136.9-kb giant region of plasticity (RGP) was sequenced. The chromosome and plasmid are densely packed by an exceptionally huge variety of potential secondary metabolic gene clusters, excluding production of putative antibiotics. Intriguingly, architecture and size differences of plasmid pSCL4 between F613-1 and ATCC 27064 suggest the pSCL4 plasmid evolving from pSCL4-like and pSCL2-like extrachromosomal replicons, in addition to the previously proposed ATCC 27064 mega-plasmid formation hypothesis through recombination between the smaller F613-1 pSCL4 plasmid arm regions and the linear chromosome. Comparative genomics systemically investigate secondary metabolism capacitates in this study indicates that frequent exchange of genetic materials between Streptomyces replicons may shape remarkable diversities of secondary metabolite repertoires. Consequently, the F613-1 strain seems to have evolved its specific genomic architectures and genetic patterns to meet the requirement in subsequent industrial processes.
Project description:The terminal compartments of Streptomyces are less prone to transcription than the rest of the chromosome. Indeed, the expression of the highly variable regions enriched in those compartments is generally conditional and often requires an empirical approach to characterize the inducing conditions. For instance, in the context of identifying adequate antibiotic production conditions, an OSMAC (“One Strain Many Compounds”) approach is frequently implemented, based on strain cultivation in different environmental conditions (composition of the medium, growth time, temperature, co-cultures, etc.). Likewise, to find the expression conditions of a complete prophage of Streptomyces ambofaciens ATCC 23877 (named 'Samy' phage/prophage), we conducted a similar approach by analyzing the transcriptomes in five solid media (HT, SAF, ONA, MMM, MMM+NAG). The terminal compartments of Streptomyces are less prone to transcription than the rest of the chromosome. Indeed, the expression of the highly variable regions enriched in those compartments is generally conditional and often requires an empirical approach to characterize the inducing conditions. For instance, in the context of identifying adequate antibiotic production conditions, an OSMAC (“One Strain Many Compounds”) approach is frequently implemented, based on strain cultivation in different environmental conditions (composition of the medium, growth time, temperature, co-cultures, etc.). Likewise, to find the expression conditions of a complete prophage of Streptomyces ambofaciens ATCC 23877 (named 'Samy' phage/prophage), we conducted a similar approach by analyzing the transcriptomes in five solid media (HT, SAF, ONA, MMM, MMM+NAG).