Towards a predictable framework of mycorrhizal phenotypes under environmental stress

Abstract

The arbuscular mycorrhizal symbiosis evolved ~400 million years ago when plants first moved onto land and formed an intimate association with fungi belonging to the phylum Glomeromycota. The symbiosis is characterized by an exchange of photosynthetically derived carbon from the plant for soil resources such as nitrogen (N) and phosphorus (P) provided by the fungus. Currently, two conceptual models of mycorrhizal functioning have been proposed. First, the functional equilibrium model predicts that positive and negative plant growth responses to AM fungi are largely determined by nitrogen or phosphorus limitation within the plant. Second, the model of host sanctions predicts that the symbiotic partner that is better able to provide limiting resources (C from the plant, and N or P from the fungus) will receive more resources in return. However, a large amount mycorrhizal phenotypic variation has been found to be affected by plant genotype, fungal genotype, and variation in environmental stresses such as salinity. Within my PhD thesis, I attempt to reconcile some of these shortfalls by applying a trait based approach along with theories of biological stoichiometry.

Date of Award	2018
Original language	English