Unique colony housing the coexisting Escherichia coli and Dictyostelium discoideum

Two well-characterized and phylogenetically diverse species, Escherichia coli and Dictyostelium discoideum, were used as the model organisms. When the two species were mixed and allowed to grow on minimal agar plates at 22 °C, instead of the predator Dictyostelium exterminating E. coli, the two species remarkably achieved a state of stable coexistence in about two weeks. In addition, the emerged colonies housing the coexisting species have a mucoidal nature that is distinctive from its origin. The simplicity of the system and the short time span for the two species to develop the coexistence state, that is proven stable and reproducible on laboratory conditions, hence, provides a new model system for the study of symbiosis, particularly with reference to the initial stages.