Evidence for the evolution of native plant response to mycorrhizal fungi in post-agricultural grasslands
C. S. DELAVAUX , J. D. BEVER
ETH Zurich (Swiss Federal Institute of Technology), Universitätstrasse 16, 8092 Zurich, Switzerland

Increasing anthropogenic disturbance will lead to novel plant-mycorrhizal interactions, altering the longstanding co-evolutionary trajectories between plants and mycorrhizal fungi. Although work shows that plant response to the dominant mycorrhizal symbiosis with arbuscular mycorrhizal fungi (AMF) can evolve over relatively short time scales in response to anthropogenic change, little work has evaluated how plant AMF response specificity – or response to differing mycorrhizal inocula – may evolve due to novel plant-mycorrhizal interactions. Therefore, we conducted a greenhouse experiment across four native plant species to examine changes in plant-AMF interactions in novel grassland systems. We compared the mycorrhizal response of plant populations from native prairies with populations from post-agricultural grasslands to inoculation with both native and non-native AMF. We found evidence for evolution of mycorrhizal response specificity, consistent with expectations of local adaptation. Plants from native populations grew best with native AMF, while plants from post-agricultural populations grew best with non-native AMF. We also found evolution of mycorrhizal response in two of the four plant species, as overall responsiveness to AMF changed from native to post-agricultural populations. Our results provide evidence that anthropogenic disturbance has impacts on native plant-AMF relationships, causing evolutionary change in the benefit native plant species gain from native symbioses.