Riverside, California
November 17, 2004
UC Riverside team finds that
lowering enzyme increases drought tolerance in corn
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.
UCR Biochemist
Daniel R. Gallie
led the research, funded by the U.S. Department of Agriculture,
the National Science Foundation and the California Agricultural
Experiment Station. The findings will be published in the
December issue of
The Plant Journal
in a paper titled ACC Synthase Expression Regulates Leaf
Performance and Drought Tolerance in Maize.
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. Gallie said that he
and his research team have examined the role of ethylene during
plant growth and development since 1997.
In the most recent study, conducted by UCR 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.
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.
“Thus, they are better able to survive conditions of drought and
remain productive,” said Professor Gallie, who led a research
team that included UCR Colleague Todd E. Young and Robert B.
Meeley, of Pioneer Hi-Bred. “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.”
For several years, Gallie said, a number of studies on global
climate have predicted an increase in global temperature, and
regional conditions of drought, which may have already begun.
“Increasing drought tolerance in crops is highly valuable to
U.S. and world agriculture now, and will be even more critical
as our environment continues to change as a consequence of
global warming,” said Gallie.
The findings by Gallie and his research team suggest that
ethylene controls the level of leaf function under normal growth
conditions, as well as during adverse environmental conditions.
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.
“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 [is he is okay with this change] countries,”
said Gallie. “As global warming continues to change our own
environment in the U.S., our work will be important in helping
U.S. farmers continue to produce the food we need even as our
climate becomes unpredictable.”
Future inquiries will most likely focus on how ethylene may
regulate other aspects of plant growth and development, such as
during flower development and root growth, Gallie added.
Related
Links:
U.S. Department of
Agriculture
National Science Foundation
UC California Agricultural
Experiment Station
The
University of California, Riverside is a major research
institution and a national center for the humanities. Key areas
of research include nanotechnology, genomics, environmental
studies, digital arts and sustainable growth and development.
With a current undergraduate and graduate enrollment of nearly
17,000, the campus is projected to grow to 21,000 students by
2010. Located in the heart of inland Southern California, the
nearly 1,200-acre, park-like campus is at the center of the
region's economic development. |
