CAREER: The developmental response of a parasitic chytrid fungus to amphibian mucus

University Of Massachusetts Amherst, Amherst MA

Investigators

Abstract

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117- 2). The chytrid fungus Batrachochytrium dendrobatidis engages in a parasitic interaction with frogs that is decimating hundreds of amphibian species around the world. B. dendrobatidis grows in amphibian skin that is coated in mucus. The goal of this project is to determine how B. dendrobatidis responds to exposure to molecules found in amphibian mucus. Establishing the molecular mechanism by which mucus induces changes in B. dendrobatidis may be used to develop remediation strategies to reverse the decline in amphibians caused by B. dendrobatidis infection. A hands-on laboratory course will be developed resulting in an authentic research experience for ~24 students per year for the duration of the project. These students will gain practical experience in designing, executing, and interpreting the results of their own experiments, preparing them to participate in the STEM workforce. The development, evaluation, and dissemination of a modular laboratory course framework will allow additional University of Massachusetts Amherst faculty, as well as extra-mural faculty, to develop new courses and/or quickly revise existing courses to improve scientific reasoning in undergraduate students. Finally, the adaptation of these materials into a workshop for middle school students will broaden participation in STEM fields. B. dendrobatidis is one of >1000 species of chytrid fungus, many of which form ecologically important symbioses with plants, animals, and microbes. Like all chytrids, the lifecyle of B. dendrobatidis comprises two stages: a dispersal form called a zoospore that swims through aquatic environments, and a growth form called a sporangium that grows and produces new zoospores. The transition between the dispersal and growth form is an essential developmental process called encystation. This project will test the central hypothesis that B. dendrobatidis zoospores sense their host by the presence of mucin, the bulk component of mucus, and respond by inducing a cellular response that results in encystation. To test this hypothesis, the project will combine quantitative microscopy, developmental assays, and chemical genetics in the following objectives: OBJECTIVE 1: Identify developmental and cellular alterations of B. dendrobatidis induced by mucin exposure. OBJECTIVE 2: Identify signaling pathways controlling mucin-induced encystation. OBJECTIVE 3: Develop, evaluate, and disseminate a modular lab course framework that teaches students to evaluate the quality of scientific information. This framework will be used to develop a course in which groups of students will identify environmental cues that could induce encystation in other symbiotic and free-living chytrid species. The successful completion of these objectives will fill a gap in the understanding of the developmental pathways and host interactions that mediate B. dendrobatidis infection. 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.