Diversity and Rate of Infection of Ericoid Mycorrhizal Fungi That Colonize Rhododendron Maximum Along an Elevational Gradient and Their Potential To Degrade Poly-Aromatic Hydrocarbons Using Lignin Degrading Enzymes

This study focuses on the dynamics of ericoid mycorrhizal (ErM) fungal colonization levels and diversity in R. maximum roots along elevational gradients in the southern Appalachian Mountains. First we hypothesized that overall ErM colonization levels in fine roots would increase with an increase in elevation due to an increased need for nutrient acquisition by the fungal symbionts for the plant. We also hypothesized that community composition of the fungi would change along an elevation gradient because some fungi are likely to be better adapted to potentially more xeric and nutrient poor conditions on the tops of mountains or other associated factors. To address this question we sampled roots and soils from three elevational transects at two locations. Root associated fungi were cultured and the DNA amplified from these cultures was typed by RFLP analysis of the ITS regions. Root colonization was quantified by counting mycorrhizal hyphae at random locations within the root using light microscopy. Colonization was shown to increase at both sites at higher elevations. Changes in abundance, frequency and species composition of the fungal communities tracked elevational differences at the two locations. Differences in species composition at Unaka Mountain were clearer, showing separation of fungal communities by elevation.