Maren L. Friesen
maren dot l dot friesen at gmail dot com
Mutualistic symbioses are both ancient and wide-spread, from the merger of lineages resulting in the eukaryotic cell to looser associations between microbes that alternate between free-living and symbiotic forms. I am interested in how these associations evolve, in particular how they remain mutualistic and what evolutionary forces shape their diversity. I aim to combine theoretical and empirical work, focussing on the legume-rhizobia interaction as a model system to attain a mechanistic understanding of coevolutionary patterns and processes.
In my PhD work at UC Davis, I experimentally evolved the model rhizobium Sinorhizobium meliloti (Rm1021) on its model legume host Medicago truncatula (Jemalong A17). The goal of this experiment was to determine whether mutations that increased the fitness of the rhizobium had a positive or negative effect on plant performance. Multiple populations adapted in this experiment by dramatically increasing their relative infection ability, but this did not impact host fitness.
In collaboration with Andrea Mathias,Regis Ferriere, and James Stegen at the University of Arizona, I am analyzing mathematical models of the adaptive dynamics of host and symbiont strategies.
For my post-doctoral work, I am involved in a project investigating the genetic basis of salinity adaptation in Tunisian populations of Medicago. This is a collaboration between Mounawer Badri and Elarbi Aouani (CBBC, Tunisia), Laurent Gentzbittel, Cecile Ben and Thierry Huguet (ENSAT, France), and Doug Cook, Eric von Wettberg, Stef Porter,and Sharon Strauss (UC Davis). Community Genomics of Local Adaptation in Medicago truncatula
R. Ford Denison (UMN) Will Ratcliff (UMN)