NSF Postdoctoral Fellowship in Biology FY 2018

Petipas Renee H, Ithaca NY

Investigators

Abstract

This action funds an NSF Postdoctoral Research Fellowship in Biology for FY 2018, Research Using Biological Collections. The fellowship supports research and training of the fellow that will utilize biological collections in innovative ways. Biological nitrogen fixation is the process of converting nitrogen gas to nitrogen that is used by the majority of organisms on Earth. Nitrogen fixation is accomplished by bacteria. Plant-associated bacteria (called rhizobia) are responsible for fixing 100 million metric tons of nitrogen in nature, and provide a critical ecosystem service. However, anthropogenic nitrogen inputs have the potential to change this bacteria-plant relationship. The fellow will use historical museum specimens to understand how increases in environmental nitrogen have changed the relationship between plants andplant-associated nitrogen fixation bacteria. The fellow will focus on Legumes and their rhizobia because these plants are important for ecosystem health and function. In areas with high nitrogen deposition, legumes decrease in frequency and are at risk for extinction. This project will better describe the legume-rhizobia relationship in environments with high nitrogen conditions and potentially illuminate conservation strategies and ways to preserve critical ecosystem functions. This project will incorporate biological collections to achieve two main objectives: 1) To conduct population genomic analyses across space and time to identify regions of host and symbiont genomes under selection and test whether anthropogenic nitrogen increase alters these patterns. 2) To use revived historical germplasm to experimentally test if there is evidence for antagonistic coevolution between host and symbiont in high nitrogen environments. This work will be done using contemporary and historical collections of legume species, Medicago lupulina and their rhizobial symbionts, Ensifer meliloti, that will be isolated from the roots of contemporary and historical plant specimens. Biological collections are an untapped resource for studying historical patterns of coevolution and as a source of material to perform manipulative experiments to better understand coevolutionary patterns. Collections can effectively act as a "time machine" allowing us a glimpse at the trajectory of coevolution in the Anthropocene. Broader impacts of this project include the development of protocols that allow researchers to revive historical bacteria. These protocols will be made publicly available and revolutionize the types of questions researchers can ask about mutualistic coevolution. The fellow will also develop active learning exercises about coevolution. Active learning is an incredibly effective pedagogical technique and one that leads to better learning outcomes for women and underrepresented groups in the classroom, and thus is one force that can be employed to level the playing field in academics. 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.