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UC Riverside Researchers Improve Drought Tolerance in Plants

The Issue

UC Riverside Researchers Improve Drought Tolerance in Plants
Suppressing DHAR expression results in reduced transpiration and increased tolerance to water stress in the leaf to the left relative to the control leaf (center). Overexpression of DHAR in the leaf on the right increases the total open stomatal area, thus reducing its tolerance to water stress.
Diminishing water resources, climate changes brought about by global warming, and drought conditions in many arid and semi-arid regions of the world are making it increasingly difficult to grow viable crops. Rainfall in California has been below normal in recent years, raising concerns that the state may be experiencing another of its periodic droughts. And in the sub-Saharan area of Africa where many regions depend on rain-fed agricultural production, rain can be extremely scarce and the rainy season short. On top of this, there will be enormous needs for increased food production over the next 50 years. Current projections are that the global human population will increase from approximately 6 billion currently to between 8 and 12 billion around 2050.

What Has ANR Done?

UC Riverside Biochemist Daniel R. Gallie together with Zhong Chen of his research group, have developed technology that increases drought tolerance in plants by decreasing the amount of an enzyme that is responsible for recycling vitamin C. In the study, Drs. Gallie and Chen reasoned that decreasing the amount of the enzyme DHAR would reduce the ability of plants to recycle vitamin C, making them more drought tolerant. The researchers accomplished this by using the plant’s own gene to decrease the amount of the enzyme three fold. Vitamin C serves as an important antioxidant in plants as it does in humans and among its many functions in both, it destroys reactive oxygen species that can otherwise damage or even kill cells. Reactive oxygen species are produced in plants typically following exposure to environmental conditions such as drought, cold, or air pollution. Plants sense drought conditions by the buildup in reactive oxygen species and then respond by reducing the amount of water that escapes from their leaves. Reducing the amount of DHAR decreases the ability to eliminate the buildup of reactive oxygen species that occurs with the onset of a drought. This causes plants to be highly responsive to dry growing conditions by reducing the rate of water that escapes from their leaves. Thus, they are better able to grow with less water and survive a drought. The U.S. Department of Agriculture and California Agricultural Experiment Station funded the six years of research that led to the findings.

The Payoff

Potential for More Drought Tolerant Crops

This technology is expected to aid in the development of crops that conserve water resources. Assisting plants to be better water managers is important for crops growing in areas that experience erratic rainfall. This discovery will assist farmers who depend on rainwater for their crops during those years when rainfall is low. It will also assist farmers who irrigate their crops to conserve water, which is important in California where rapid population growth continues to increase the demand on this scare resource. Finally, this discovery should help farmers who grow crops in arid areas, such as exists in many developing countries.


Supporting Unit: CNAS Dean's Office at UCR

Dr. Daniel R. Gallie, Boyce Hall 3432
UC Riverside, P(951) 827-7298, F(951) 827-4434
daniel.gallie@ucr.edu, http://www.biochemistry.ucr.edu/faculty/gallie.html