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

BER Research Highlights


Grasses Fight Drought by Squelching Root Growth
Published: August 02, 2016
Posted: October 05, 2016

Shoot-borne roots that normally start developing in grasses weeks after germination are suppressed under drought conditions.  

The Science
Using fluorescent imaging technologies and direct observation of green foxtail roots excavated from soil, researchers discovered that root growth normally initiated from the crown (belowground shoot-root joint) is inhibited when water is scarce.  

The Impact
Drought tolerance is an important trait needed in bioenergy crops to enable their cultivation in marginal lands. As roots are the main conduit for water acquisition, understanding their biology is critical to discovering ways to improve bioenergy crops. The root system of potential bioenergy crops in the Poaceae family, such as switchgrass and sorghum, and the model grass Setaria viridis (green foxtail) is composed mostly by crown roots that emerge days or weeks after germination. However, little is known about their development under drought conditions. The discovery of a widespread mechanism of crown root suppression in grass species opens new avenues for improving bioenergy crop performance in dry environments.

Summary
A detailed study of root growth using traditional and new fluorescent imaging technologies in the model bioenergy crop Setaria showed that the crown (shoot-root node found belowground) senses the level of water conditions immediately surrounding the plant. At low soil humidity, root growth is arrested shortly after initiation, while root growth is rapidly resumed when water availability increases. Researchers from the Carnegie Institution for Science and international collaborators observed that drought-induced inhibition of root growth is also present in several other grasses, including the bioenergy crops sorghum and switchgrass and corn wild relatives, but not in highly domesticated corn lines. Furthermore, a corn mutant that lacks crown roots retains more water in the stem. These results suggest that grasses are adapted to inhibit root growth to preserve water and to induce crown root growth in response to precipitation to maximize water absorption in wet conditions. Genetic and transcriptomics analyses showed that oxidative-stress response genes may be involved in the process. The identification of the genes responsible for this phenomenon will be critical targets for engineering drought tolerance in bioenergy grasses.

Contacts (BER PM)
Pablo Rabinowicz
Office of Biological and Environmental Research
pablo.rabinowicz@science.doe.gov

(PI Contact)
José Dinneny
Department of Plant Biology
Carnegie Institution for Science, Stanford, CA 94305
jdinneny@carnegiescience.edu

Funding
This work was supported by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research under award DE-SC0008769. Additional support was provided by the National Science Foundation.

Publications
Sebastian, J., M. Yee, W. Viana, R. Rellán-Álvarez, M. Feldman, H. Priest, C. Trontin, T. Lee, H. Jiang, I. Baxter, T. Mockler, F. Hochholdinger, T. Brutnell, and J. Dinneny. 2016. “Grasses Suppress Shoot-Borne Roots to Conserve Water During Drought,” Proceedings of the National Academy of Sciences (USA) 113(31), 8861-66. DOI: 10.1073/pnas.1604021113. (Reference link)

Topic Areas:

  • Research Area: Genomic Analysis and Systems Biology
  • Research Area: Plant Systems and Feedstocks, Plant-Microbe Interactions
  • Research Area: Sustainable Biofuels and Bioproducts
  • Research Area: Biosystems Design
  • Research Area: Research Technologies and Methodologies

Division: SC-23.2 Biological Systems Science Division, 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)