Project: Can cultivar root-microbial interactions rescue wheat from drought-induced nitrogen limitation?

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Principal investigator: Cynthia Kallenbach, Colorado State University

Associated with: USDA-NIFA

Project Summary:

Soil nitrogen (N) limitations intensify drought-associated yield losses, yet resolving water and N co-limitation remains a challenge. Under low soil moisture, microbial-mediated N mineralization is constrained by reduced microbial access to carbon and nutrients required for microbial metabolic processes. Selecting cultivars with certain root exudation traits may alleviate microbial carbon and N constraints such that N mineralization can be relatively maintained under drought. Our project explores cultivar root exudate-microbial interactions as a potential mechanism for enhanced plant-available N under water stress conditions.

We are using a combination of metabolomics, metagenomics, microbial functional and nitrogen assays to:

  1. Characterize root exudation rates and chemistry across a spectrum of drought-tolerant and -susceptible wheat cultivars,
  2. Determine how root exudation rate and chemistry mediate the mechanisms that drive microbial N cycling and subsequently wheat N-uptake under drought vs. well-watered conditions and
  3. Evaluate if and how the microbial responses influencing N mineralization under drought tolerant root exudation are altered by prior exposure to long-term drought.

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