NSF Postdoctoral Fellowship in Biology: Identifying Mechanisms of Plant Symbiosis Control Through Virus Induced Mutant Stacking (VIMS)

Ellison, Evan E, Cambridge

Investigators

Abstract

The title of the research and training plan for this fellowship to Dr. Evan Ellison is “Identifying Mechanisms of Plant Symbiosis Control Through Virus Induced Mutant Stacking (VIMS)”. The host institution for the fellowship is the University of Cambridge and the sponsoring scientist is Prof. Giles E.D. Oldroyd. To sustain and expand food production in a growing global population, next generation crop varieties must be developed that take advantage of natural systems to improve nutrient capture rather than rely on excessive application of inorganic nutrients. Fortunately, most crop species can greatly improve their ability to capture and use essential nutrients through symbiotic relationships with beneficial soil fungi. This symbiosis, however, is restricted if high concentrations of nitrogen or phosphorus have been applied to the soil, limiting the utility. The goal of this research is to characterize unknown signals that regulate symbiosis under high nutrient conditions; thereby identifying crop genotypes that use less input while maintaining high productivity. This project also seeks to democratize and remove financial, geographic and time limitations of large-scale genome editing projects, which is critical for international molecular plant improvement. Broader impacts from this project include generating genetic and technological resources for the plant science community, educating citizen scientists interested in how gene editing contributes to reducing fertilizer use, and translating results for crop improvement and sustainable food production. Training objectives include obtaining hands-on expertise in applying genetic and genomic tools to address biologically important questions. Split root experiments suggest that nutrient suppression of arbuscular mycorrhizal symbiosis exists through largely unknown systemic process in addition to local mechanisms. Secreted peptides have been demonstrated to be a critical component of systemic symbiosis regulation and nutrient response. This research will characterize systemic peptides that regulate symbiosis with mycorrhizal fungi in response to differential nutrient conditions. Connecting multiple environmental conditions to their signaling response will be accomplished by developing a new method of Viral Induced Mutant Stacking to rapidly stack targeted mutations across a population. This novel genetic screening technique will be applied to create a combinatorial population of peptide mutants and isolate genetic backgrounds enabling symbiosis under nutrient suppressive conditions. Mutant populations and genetic engineering reagents generated during this project will be immediately available to researchers for independent investigations. New technology developed in this research can be used to study complex, integrated, phenotypic responses while providing valuable insight into the systemic regulation of symbiosis. Causal alleles identified using this approach can quickly be incorporated into agriculturally relevant species for rapid crop improvement. All data, genetic and molecular resources, and methodological advances will be made freely available to the general scientific community through public long-term repositories and upon request. 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.