NSF Postdoctoral Fellowship in Biology FY 2017: The genetic basis of host range and specificity in the fungal parasite Escovopsis

Conn Caitlin E, Port Royal PA

Investigators

Abstract

This is an NSF Postdoctoral Research Fellowship in Biology, under the program Research Using Biological Collections. The fellow, Caitlin Conn, is conducting research and receiving training that utilizes biological collections in innovative ways, and is being mentored by Nicole Gerardo at Emory University. The postdoctoral fellow is studying the genetic basis of host range in parasites. Parasitism is a type of symbiotic relationship in which one organism (the parasite) benefits at the expense of the other (the host). Over time, parasites often evolve a narrow host range, meaning they specialize on a single host or a group of closely related hosts. However, parasites sometimes evolve compatibility with new hosts, either switching hosts or expanding the number of hosts they can use. Many questions about host-parasite compatibility remain unanswered, especially regarding its genetic basis. To address these questions, the fellow has selected the parasitic fungal genus Escovopsis as a study system. Escovopsis and its fungal hosts have a long coevolutionary history, characterized by specialization of Escovopsis strains on narrow host ranges, and occasional host switching. The fellow will sample an extensive collection of Escovopsis and use cutting-edge tools to investigate the genetic basis of host utilization. The fellow will also design a course-based undergraduate research experience (CURE) in which introductory biology students will screen for host/parasite compatibility using Escovopsis and an associated collection of hosts. This research will uncover important information about host range, which may extend to parasites that affect humans, livestock, and wildlife. It will also train a postdoctoral fellow in diverse research techniques and provide undergraduates with hands-on research experience. The fellow will sequence and comparatively analyze the genomes and transcriptomes of Escovopsis strains with different host preferences to determine whether any genomic features or expression patterns are correlated with host range. Genomes will be scanned for positive selection, which may characterize regions that influence host range. Candidate genes will be phylogenetically analyzed and functionally tested by targeted mutation. Finally, an analysis of fine-scale host specificity will be conducted by introductory biology students, who will co-culture Escovopsis samples and potential hosts and observe the outcomes of the interaction. Through this fellowship, the fellow will gain new skills in bioinformatics, ecology, and population genomics by attending courses and seminars and by joining a lab that specializes in these areas. The fellow will also develop teaching skills through the design, implementation, and assessment of the CURE. Results from the studies will be published in peer-reviewed journals and presented at scientific meetings. 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.