U.S. Department of Energy Office of Biological and Environmental Research

BER Research Highlights


Some Bacterial Metabolites Make a Big Difference in Semi-Arid Rhizospheres
Published: August 20, 2018
Posted: February 15, 2019

Even a single species of bacteria can positively affect soils and plants, improving and even enabling agriculture in semi-arid areas.

The Science
Microbes deep in the soil influence plant health by releasing potent natural antibiotics such as PCA (phenazine-1-carboxylic acid). PCA-producing bacteria thrive on roots of dryland wheat throughout the Columbia Plateau, a major wheat-producing region in central Washington and Oregon, but their role in this important ecosystem has been something of a mystery. Now the work of an international team of scientists provides direct evidence for the first time that bacterial metabolites increase the formation of root-associated bacteria that help the wheat grow, and may improve the characteristics of the soil.

The Impact
Dry areas like the Columbia Plateau suffer large soil losses from wind erosion and plants often struggle to survive droughts. The availability of PCA encourages development of a biofilm that could combat soil degradation by improving water retention. This biofilm also protects the roots from drying out in drought conditions. Most importantly, PCA-producing bacteria enhance long-term soil health by contributing to soil organic matter. Understanding how these bacteria support the ecosystem may prove key to improving agriculture not only in the Columbia Plateau, but in dryland areas around the world.

Summary
Researchers set out to discover the mechanisms that control the accumulation of PCA under dryland conditions. Led by Melissa LeTourneau, an Office of Science Graduate Student Research (SCGSR) Fellow at Washington State University, the team included researchers from Pacific Northwest National Laboratory, University of Southern Mississippi, India’s Institute of Bioresources and Sustainable Development, U.S. Department of Agriculture Agricultural Research Service, and EMSL, the Environmental Molecular Sciences Laboratory, a U.S. Department of Energy Office of Science user facility. The researchers compared the biofilms on roots inoculated with one strain of PCA-producing bacteria to biofilms on roots lacking PCA-producing bacteria. Examining the samples using a suite of highly advanced microscopes, including EMSL’s new-generation ion microprobe (NanoSIMS), helium ion microscope, and focused ion beam/scanning electron microscope, they found PCA promotes biofilm development in dryland root systems and likely influences crop nutrition and soil health in dryland wheat fields. The results fill the gaps in our understanding of dynamics and effect of PCA in dryland agricultural ecosystems.

BER PM Contact

Paul Bayer, SC-23.1

PI Contact
Linda S. Thomashow
U.S. Department of Agriculture - Agricultural Research Service
Thomashow@wsu.edu

Funding
This work was supported by the U.S. Department of Energy’s Office of Science (Office of Biological and Environmental Research), including support of the Environmental Molecular Sciences Laboratory (EMSL), a DOE Office of Science user facility. Additional support was provided by the Harry E. Goldsworthy Wheat Research Fund and the Otto and Doris Amen Dryland Research Endowment administered by Washington State University, the U.S. Department of Agriculture National Institute of Food and Agriculture, the SCGSR program, the DOE Office of Science Office of Workforce Development for Teachers and Scientists, and a DOE Office of Science Early Career Research Award.

Publication
LeTourneau, M.K., M.J. Marshall, J.B. Cliff, R.F. Bonsall, A.C. Dohnalkova, D.V. Mavrodi, S.I. Devi, O.V. Mavrodi, J.B. Harsh, D.M. Weller, and L.S. Thomashow. “Phenazine-1-carboxylic acid and soil moisture influence biofilm development and turnover of rhizobacterial biomass on wheat root surfaces.” Environmental Microbiology and Environmental Microbiology Reports 20(6), 2178-2194 (2018). [DOI: 10.1111/1462-2920.14244]

Related Links
Some Bacteria Make a Big Difference EMSL science highlight

Topic Areas:

  • Research Area: Carbon Cycle, Nutrient Cycling
  • Research Area: DOE Environmental Molecular Sciences Laboratory (EMSL)
  • Research Area: Plant Systems and Feedstocks, Plant-Microbe Interactions
  • Cross-Cutting: Early Career
  • Cross-Cutting: Education

Division: SC-23 BER

 

BER supports basic research and scientific user facilities to advance DOE missions in energy and environment. More about BER

Recent Highlights

May 10, 2019
Quantifying Decision Uncertainty in Water Management via a Coupled Agent-Based Model
Considering risk perception can improve the representation of human decision-making processes in age [more...]

May 09, 2019
Projecting Global Urban Area Growth Through 2100 Based on Historical Time Series Data and Future Scenarios
Study provides country-specific urban area growth models and the first dataset on country-level urba [more...]

May 05, 2019
Calibrating Building Energy Demand Models to Refine Long-Term Energy Planning
A new, flexible calibration approach improved model accuracy in capturing year-to-year changes in bu [more...]

May 03, 2019
Calibration and Uncertainty Analysis of Demeter for Better Downscaling of Global Land Use and Land Cover Projections
Researchers improved the Demeter model’s performance by calibrating key parameters and establi [more...]

Apr 22, 2019
Representation of U.S. Warm Temperature Extremes in Global Climate Model Ensembles
Representation of warm temperature events varies considerably among global climate models, which has [more...]

List all highlights (possible long download time)