Plant adaptation to soil physical and chemical environments, or edaphic factors, is known to influence plant distribution, diversification, and speciation. However, the mechanisms of plant adaptation to edaphic factors are not fully understood. Traditionally, the study of edaphic adaptation has focused on the direct effects of soil conditions on plant growth and reproduction. A new theoretical and experimental framework will be explored, in which plant adaptation to edaphic factors is mediated through arbuscular mycorrhizal (AM) fungi. The goals of this research are to determine if adapted plant ecotypes require specific AM fungal taxa, if serpentine soils shape AM fungal assemblages, and if AM fungi impact plant growth and fitness in serpentine soil. Findings thus far show that the plant ecotypes associate with distinct AM fungal assemblages in the field. This project uses serpentine, a naturally toxic soil, to test the role of common root symbionts, arbuscular mycorrhizal fungi, in plant adaptation to extremely stressful soil environments. Broader impacts include contributions to taxonomy and education, and potential applications to conservation and bioremediation. Previously unknown fungal species are likely to be found associated with plants on serpentine soils. Undergraduate students and a PhD student will be trained in an important area of microbial biology. Collection and identification of fungi that are key components of a fragile, botanically important ecosystem could dramatically improve success of restoration efforts of locally endangered or rare species. Fungal species with unique physiological capabilities may be useful for bioremediation of toxic sites.
