CAREER: Elucidating the Interaction Dynamics of Soil Metals with Flavonoids in the Plant Rhizosphere

University Of California-Davis, Davis CA

Investigators

Abstract

Plants must acquire metal micronutrients in trace amounts from the soil for their growth and survival. The levels of these metals must be regulated to prevent unwanted toxicity or deficiency. The goal of this project is to untangle how plants chemically shape the region of soil surrounding their roots, known as the rhizosphere, to regulate and properly utilize these metal micronutrients. This research specifically investigates both how interactions of soil copper with secondary metabolites impact copper availability as well as how copper may regulate the biochemical function of these metabolites. Central to the project objectives is the development of chemical strategies and tools that illuminate metal biochemistry in complex environments. In tandem with laboratory-based investigations, these studies will be enhanced by the development of a computer-based undergraduate research course platform aimed at enhancing community college STEM transfer pathways. Participating students will have the opportunity to make meaningful contributions to interdisciplinary research while establishing and building science identity. These combined studies will offer molecular insight into the metal-associated drivers for plant fitness, providing new opportunities to harness rhizosphere processes in meeting global challenges such as the increasing food demands of a growing population and detoxifying contaminated environments. This project centers on deciphering metal dynamics in the plant rhizosphere and its contribution to plant-biotic interactions and plant health. While present in soil matter, metal micronutrients primarily exist in non-available forms that the plant must mobilize to acquire and utilize. This project seeks to determine how molecular-level interactions between copper and flavonoids (secondary metabolites secreted by the roots) in the soil environment impact plant survival and growth via three objectives. (1) The first objective is to determine how metal binding to flavonoids impacts flavonoid function in plant-microbe signaling. A combination of reagent arrays and chemometric analysis will be used to profile flavonoids in terms of their copper reactivity. Application of this strategy to plant-microbe models will provide new insight on the influence of metals on flavonoid perception and specificity in the rhizosphere. (2) The second objective will probe how flavonoids impact metal bioavailability by developing and applying imaging systems that differentiate mobile and immobile forms of copper. (3) A computer-based course-based undergraduate research experience (CURE) platform will be established as a vehicle for improving the STEM transfer pathway for California community college students. CURE projects will utilize open-source data to identify pathways that link metal metabolism and rhizosphere signaling. Taken together, these studies will test the hypothesis that the metal-interacting capacity of a given flavonoid may define its function within plant-soil feedback processes. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.