Diversification of Interactions in Multi-species Laboratory Communities

University Of Wisconsin-Madison, Madison WI

Investigators

Abstract

This project will explore how species interactions evolve by using bacteria in controlled laboratory conditions as a model. It will result in a greater understanding of the mechanisms by which initially simple communities can grow in complexity over time due to changes in species interactions. Most natural environments harbor diverse microbial communities within which microbes live in close proximity and interact via secreted chemicals. Such interactions are not static but constantly and rapidly evolve over time. This evolution happens because the optimal amounts and types of chemicals secreted, and the optimal microbial responses to these chemicals, depend on the other species in the community, that in turn changes as the interactions change. Given society's growing interest in predicting, manipulating and engineering microbial communities, it is essential to develop approaches for measuring and understanding these fundamental processes. In addition, bacterial strains, protocols and suggested activities will be put together as part of a toolkit for high school teachers. This project also features field trips for middle-school students and hands-on workshops for high-school students focusing on rapid microbial evolution and its implications for society. While microcosm experiments have demonstrated that microbes can evolve rapidly, they have usually focused on single-species communities, which often show diversification due to adaptation to available abiotic niches. In complex multi-species communities, the eco-evolutionary dynamics may be driven by dynamic biotic factors. The project will test the hypothesis that bacteria experiencing a novel and interaction-rich multi-species context are under strong selection to evolve and diversify their ecological interactions. The project will utilize bacteria from the genus Streptomyces, which are prolific producers of bioactive small molecules. Multi-species communities of various numbers and complexities will be established on agar, allowed to evolve for several weeks, and then measured for changes in their interactions. Laboratory evolution studies in such contexts have been limited by the lack of suitable model systems and monitoring tools. To address this gap, a novel high-throughput approach is introduced that allows systematic investigation of changes in interactions as they arise in multi-species laboratory communities.