Most species depend on other species for survival and reproduction. Thus, coevolution (reciprocal evolutionary change between species) arguably plays a dominant role in the origin and organization of biodiversity. The proposed research uses a novel model system to study coevolutionary dynamics: wild chili peppers and their fruit-associated fungal pathogens. The spiciness of chilies (caused by the antimicrobial chemical capsaicin) protects chili fruits from fungi that can destroy seeds. Fungal strains obtained from wild chilies in Bolivia are used in lab and field experiments to examine how the variation in chili spiciness selects for fungal tolerance to plant defenses and drives fungal local adaptation. Field experiments will be conducted in Bolivia to gain information about the ecology of fungal insect vectors and their impact on infection of fruits in the field.
The research examines the coevolutionary dynamics that are likely responsible for the major property of one of the most popular spice plants in the world: the spiciness of chilies. The ability of chilies to inhibit food borne pathogens is believed to be responsible for their domestication and use worldwide. Understanding the selective pressures that favored the evolution of capsaicinoids in wild plants may provide insight into our use of these chemicals and has applications for medicine, food storage, crop development, and the management of plant diseases and pests. In addition, undergraduate research assistants are mentored in association with this project both locally and in Bolivia.
