Researchers boost drought tolerance of grain crops


RIVERSIDE, Calif.- Researchers at the University of California, Riverside, report the development of technology that increases the tolerance of grains crops to drought by decreasing the amount of an enzyme that is responsible for producing the plant hormone ethylene.
Biochemist Daniel R. Gallie led the research, funded by the USDA, the National Science Foundation and the California Agricultural Experiment Station.
Stress response. Ethylene is vital in regulation of plant responses to environmental stresses, such as flooding and drought, and to attack by pathogens.
But often ethylene initiates leaf death in response to adverse conditions, sacrificing less essential parts of a plant to protect the growing tip, responsible for producing flowers, the reproductive organs of plants.
In the most recent study, conducted by university researchers and Pioneer Hi-Bred International, an Iowa-based developer and supplier of seed to farmers, the authors targeted ACC synthase, an enzyme required for the production of ethylene, screening thousands of plants for naturally occurring mutants that were deficient in the enzyme.
Remaining functional. The researchers isolated several such plants, and one in particular that produced substantially lower levels of the hormone.
Leaves from this mutated plant remained functional and maintained photosynthetic function longer than non-altered plants.
In addition, the plants were more resistant to the effects of adverse environmental conditions. Surprisingly, by reducing the level of ethylene, all the leaves of the altered plants contained higher levels of chlorophyll and leaf protein, and functioned better than control leaves.
From time immemorial. “Thus, they are better able to survive conditions of drought and remain productive,” said Gallie.
“Erratic rainfall and conditions of drought have plagued farmers from time immemorial, and are responsible for substantial losses in crop yield when they do occur.”
Gallie’s research with corn opens the door to producing crops better able to withstand periodic losses in rainfall, including grains, which are the most important direct source of food for livestock and for a majority of humans.
Increasing reliability. “Our discovery will assist farmers who depend on rainwater for their crops during those years when rainfall is low, particularly those who grow crops in arid areas, such as exists in many developing countries,” said Gallie.
“As global warming continues to change our own environment in the United States, our work will be important in helping U.S. farmers continue to produce the food we need even as our climate becomes unpredictable.”
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