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 Medicine.

"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: water scarcity."

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 water supplies."

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 tomato."

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 http://www.pnas.org/.

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

ABSTRACT

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 crops.

PNAS published 16 December 2005, 10.1073/pnas.0509512102
http://www.pnas.org/cgi/content/abstract/0509512102v1?etoc