Abstract
Underground, mycorrhizal fungi form complex networks of filamentous hyphae that connect roots. The fungus mobilizes phosphorus and nitrogen, and trades these for host carbon in a market-like exchange. While the ubiquity and importance of underground networks is established, we have no mechanistic understanding of how a fungus evaluates its trade environment. Fungi must integrate a complex array of chemical, physical, and environmental stimuli. It is unknown how this is achieved. The project’s goal is to understand how symbiotic fungi process and share complex information across their bodies to execute trading strategies with their host plants. WP1: Using high-resolution video to track fluorescently-tagged nutrients across in-vitro networks, we will determine the factors meditating the speed/direction of nutrient flows within hyphae. WP2: Similar to neural networks in animals, fungi can use electrical activity to rapidly integrate information across their complex bodies. We will test how mycorrhizal networks modulate electrical activity (voltage changes across cell membranes) in response to nutrient stimuli. WP3: To map nutrient trade routes, we will use our automated-imaging robot to create time-lapse videos of intact-networks, linking fungal architecture to nutrient foraging and transport strategies. WP4: Scaling up to the rhizosphere, we will track symbiotic N2-fixing bacteria tagged with florescent-protein across fungal networks connecting roots. We will test how bacteria use the physical and chemical infrastructure of the trade network for their own benefit. WP5: Moving to real soils, we will use X-ray scans to build 3D reconstructs of intact plant-fungal networks. We will ask how structural complexity of networks affects plant productivity. By integrating high-throughput imaging and video, nanoprobe-tracking, high-resolution neural network mapping, and ecological manipulations, we will achieve a quantitative and predictive understanding of mycorrhizal trade – a globally ubiquitous partnership fundamental to agricultural and natural ecosystems.
Netherlands