Condition-dependent competition in a synthetic Streptomyces albidoflavus community harboring a potent yet rare antibiotic gene cluster

This project contains amplicon sequencing data from a defined synthetic community of Streptomyces albidoflavus, designed to investigate the eco-evolutionary dynamics of a rare and potent antibiotic biosynthesis gene cluster (BGC). The sequencing targeted a ~700-nucleotide engineered genetic barcode unique to each strain, enabling high-resolution tracking of individual strain abundances within the S. albidoflavus population. The community includes a set of closely related set strains, among which a single "super-killer" strain produces the hybrid aromatic polyketide antibiotic kosinostatin (ksn), conferring exceptional antagonistic activity against conspecifics.The study tests the hypothesis that the rarity of the horizontally acquired ksn BGC is maintained by a balance of competitive advantages and metabolic trade-offs. Microcosm experiments were conducted to compare the fitness of the kosinostatin producer versus sensitive strains in two distinct environments: liquid culture and native soil. As predicted, the producer strain demonstrated a significant competitive advantage only in the liquid environment where antibiotic inhibition was effective, with no net benefit observed in the complex soil matrix.This data set captures the temporal dynamics of community assembly and strain abundance under these controlled conditions. The findings provide direct experimental evidence for environment-dependent selection acting on antibiotic production. They support a model where the current patchy distribution of the ksn BGC results from the dynamic interplay of recurrent horizontal gene transfer (HGT), vertical inheritance, and frequent loss, resolving the paradox of why potent antibiotic genes can remain rare within a population.