College Station, Texas
December 13, 2005
New tomato research has its roots
in yielding more food to feed more people, according to Dr.
Kendal Hirschi about results announced today.
His team's study appears in today's
Proceedings of the National
Academy of Sciences.
The team made tomato plants over-express the gene, AVP1, which
resulted in stronger, larger root systems and that resulted in
roots making better use of limited water, said Hirschi, a
researcher at Texas A&M University's
Vegetable and Fruit Improvement Center and Baylor's College of
"The gene gave us a better root system, and the root system
could then take the adjustment to drought stress better and thus
grow better," Hirschi said of the paper which details "a
strategy to engineer drought-resistant crop plants."
For example, regular or control tomatoes used in the experiment
suffered irreversible damage after five days without water, as
opposed to the transgenic tomatoes, which began to show signs of
damage after 13 days but rebounded completely as soon as they
were watered, according to the study.
"This technology could ultimately be applied to all crops
because it involves the over-expression of a gene found in all
plants," said Dr.
Roberto Gaxiola, a plant biologist at the University of
Connecticut and the lead author of the study. "It has the
potential to revolutionize agriculture and improve food
production worldwide by addressing an increasing global concern:
Gaxiola's findings regarding the use of AVP1 in Arabidopsis to
create hardier, more drought resistant plants were published in
the journal Science in October, but the study described in the
proceedings marks the first time the enhanced gene has been
inserted in a commercially viable crop, he said.
The paper notes that drought conditions throughout the world
each year carve out a huge amount of food production.
To overcome food shortages, the authors suggest, "it will be
necessary to increase the productivity of land already under
cultivation and to regain the use of arable land lost to scarce
Hirschi and Gaxiola worked with Dr. Sunghun Park, also of the
Vegetable and Fruit Improvement Center.
"Our center is good at moving genes into the different plants,"
Hirschi said. "Dr. Park's job was to move this gene into the
Hirschi, who's main research focus is "boosting nutrients in
plants to make them more nutritional for children," said the
study now may be tried on other crops. Gaxiola said he already
has additional studies under way to demonstrate how this
technology applies to other commercial crops.
More information on this study can be found at
Up-regulation of a
H+-pyrophosphatase (H+-PPase) as a strategy to engineer
drought-resistant crop plants
Sunghun Park, Jisheng Li, Jon K. Pittman, Gerald A.
Berkowitz, Haibing Yang, Soledad Undurraga, Jay Morris, Kendal
D. Hirschi, and Roberto A. Gaxiola
Engineering drought-resistant crop
plants is a critically important objective.
Overexpression of the vacuolar H+-pyrophosphatase
(H+-PPase) AVP1 in the model plant
Arabidopsis thaliana results in enhanced
performance under soil water deficits. Recent work
demonstrates that AVP1 plays an important role in root
development through the facilitation of auxin fluxes.
With the objective of improving crop performance, we
expressed AVP1 in a commercial cultivar of tomato.
This approach resulted in (i) greater
pyrophosphate-driven cation transport into root
vacuolar fractions, (ii) increased root
biomass, and (iii) enhanced recovery of plants from an
episode of soil water deficit stress. More robust root
systems allowed transgenic tomato plants to take up
greater amounts of water during the imposed water
deficit stress, resulting in a more favorable plant
water status and less injury. This study documents a
general strategy for improving drought resistance of
PNAS published 16 December 2005,