Understanding Arbuscular Mycorrhizal Fungi-Plant Interactions Using Dynamic Modeling and Genomics

Olivia Asher, University of Georgia

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400 million years ago land plants and arbuscular mycorrhizal fungi (AMF) developed a symbiotic relationship in which the plants provide the fungus with carbon in exchange for phosphorous and other elements, including nitrogen in some environments. This relationship has potential to be harnessed for agricultural purposes to increase plant yields while reducing fertilizer use and irrigation. However, not enough is known about the conditions required to facilitate the most beneficial symbiosis, and thus AMF remain underutilized in agriculture. Therefore, we will create a dynamic mathematical model of the nutrient exchange between multiple species of AMF and their plant host, as well as for competition between the fungal species. This model will allow us to make predictions about the success of the plant and fungi over time under varied starting conditions. These predictions will be used to test the model in the lab using AMF grown in root organ cultures. By fitting the model to time series molecular data in root organ cultures using a high-performance computing cluster with hybrid CPU/GPU nodes the model can be tested with a comparison between the predicted and observed time series. In addition to associating with plants, AMF form symbioses with bacteria. The endobacteria of AMF are suspected to play a key role in the development of the AMF-plant symbiosis. However, the genomes of these organisms remain poorly understood. I plan to sequence and analyze the genomes of the AMF and the endobacteria found inside of the AMF in a sorghum study system. We hope to use these sequencing data to potentially expand upon the model. Predictions from the dynamic model and information generated from the genomes of AMF and their endobacteria have potential to help future farmers understand the optimal field conditions to maximize beneficial symbioses and crop yields.

Abstract Author(s): Olivia A. Asher, Jonathan Arnold, Jeffery Bennetzen