Ecological and evolutionary consequences of climate warming for fungal pathogens

Washington University, Saint Louis MO

Investigators

Abstract

Environmental change is expected to impact the risk of disease for plants and wildlife worldwide. Predicting those impacts requires understanding the role of climate in determining when and where diseases can occur. Understanding how climate affects pathogen evolution is also essential for improving disease prediction and management. Fungal pathogens cause many diseases that threaten hosts of agricultural and conservation concern. However, effects of environmental change on fungal pathogens are poorly understood. This is largely because fungi have complex life cycles that are challenging to study with respect to climate. For example, many fungi reproduce in different ways under different climate conditions. The researchers will determine effects of warming on fungal pathogens using mathematical models, field studies, and experiments. The models will simulate spread of infections by several types of pathogens under different climate scenarios. Data collection and analysis will focus on common plants and their fungal pathogens. These will be studied over a wide range of climate conditions. Undergraduates will contribute to the project through an introductory biology course at Truman State University. In that course, students will analyze images of diseased plants that were collected by citizen scientists around the world. Students will also be recruited to participate in field and laboratory research through the Tyson Undergraduate Fellows program at Washington University in St. Louis. The central goal of this project is to determine how climate warming changes the ecology and evolution of fungal pathogens. Most fungi are capable of both asexual and sexual reproduction, and each phase of the life cycle can be temperature dependent. In temperate regions, many fungal pathogens produce asexual (clonal) spores from spring through early fall seasons and then undergo sexual production of an overwintering stage when temperatures cool in later fall. Warming should alter the production, survival, and dispersal of clonal spores as well as the frequency of sexual reproduction and genetic recombination. In Aim 1, the researchers will develop a general metapopulation model to evaluate how effects of temperature on pathogen life-history traits lead to changes in pathogen prevalence and genotypic diversity under different climate scenarios. They will resolve how model outcomes depend on pathogen thermal biology, mating system, and other parameters. In Aim 2, the researchers will experimentally quantify thermal performance curves for life history traits of a fungal plant pathogen collected along a climatic gradient. They will test for pathogen local adaptation to thermal regimes and wild host plant populations. In Aim 3, the researchers will assess relationships between climate and the occurrence and genotypic diversity of the focal pathogen. This aim will be accomplished through field surveys, genotyping, and a citizen science project coupled with a course-based undergraduate research experience. Those data will be compared to predictions from a version of the metapopulation model parameterized for the focal study system. The project will integrate student training in a course-based undergraduate research experience class with data management and communication training to undergraduate students. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.