Most plant–microbe interactions are facultative, with microbes experiencing temporally and spatially variable selection. How this variation affects microbial evolution is poorly understood. Given its tractability and ecological and agricultural importance, the legume–rhizobia nitrogen-fixing symbiosis is a powerful model for identifying traits and genes underlying bacterial fitness. New technologies allow high-throughput measurement of the relative fitness of bacterial mutants, strains and species in mixed inocula in the host, rhizosphere and soil environments. I consider how host genetic variation (G × G), other environmental factors (G × E), and host life-cycle variation may contribute to the maintenance of genetic variation and adaptive trajectories of rhizobia – and, potentially, other facultative symbionts. Lastly, I place these findings in the context of developing beneficial inoculants in a changing climate.

Biography

Liana is an evolutionary ecologist broadly interested in how the environment shapes the evolution of organisms (primarily plants and microbes). Prior to starting my lab in the Dept. of Plant Science at PSU, I was a postdoc at the University of Minnesota in the lab of Peter Tiffin, a graduate student at Duke University in the lab of Kathleen Donohue, and a postbac in Johanna Schmitt’s lab at Brown University. When I am not in the lab, I’m an avid gardener, mountain biker, and cross-country skier, participating in the 29K Korte in WI each year.