Functional diversity within arbuscular mycorrhizal symbioses

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The majority of plants are dependent on a specialized group of fungi to aid in their growth, reproduction, and survival. These are called mycorrhizal fungi, and they act as extensions of the root system, living in the root tips and extending out into the soil. Mycorrhizal fungi offer a number of benefits to the plant including improved nutrient and water uptake, protection from environmental stresses such as drought, contaminants, and attack from pathogens. Because these fungi are so important to plants, scientists have spent a lot of time exploring ways of using mycorrhizal fungi to improve the growth and health of crops and trees. However, few researchers have tried to understand how these fungi work under natural conditions. Until mycorrhizal fungi are understood in their natural habitat, we cannot expect to successfully manipulate them for our uses, whether we want to improve crop performance or restore a degraded ecosystem. In that vein, the objective of this research program is to better understand the functional diversity that exists among mycorrhizal fungi and to identify factors that determine their distribution and abundance in natural and disturbed ecosystems. We are planning to study, in detail, the distribution and abundance of mycorrhizal fungi in Long-Term Research Sites in Canada (an old-field meadow, a hardwood forest, and a semi-arid shrub/grassland). Life-history strategies will be studied for fungi isolated from these sites to determine which characteristics explain their abundance and functioning in the field. This approach will provide useful information on the roles of mycorrhizal fungi in ecosystems, and on how we may be better able to manipulate them.