Transgenic Plants Patented for Warming World

The researchers say their discovery offers hope for global agriculture challenged by limited and variable water supplies.

Research on the new drought-tolerant plants is reported in the November 26 online issue of the "Proceedings of the National Academy of Sciences." In this study, tobacco plants were used as a research model.

The University of California has filed a patent application on this technology. The patent application is pending in the United States and in a number of foreign countries.

The patent rights are covered by an exclusive arrangement between the University of California and Arcadia Biosciences, which has completed initial outdoor field trials with the drought-tolerance gene in tobacco.

"This is an exciting development because it opens the door, not only to producing plants that can survive periodic droughts, but also to reducing the amount of irrigation water routinely used to grow some of the world's most important food and fiber crops," said Eduardo Blumwald, a professor and Will W. Lester Endowed Chair in the Department of Plant Sciences.

Rosa Rivero and Eduardo Blumwald examine their transgenic tobacco plants. (Photo courtesy UC-Davis)

Scientists monitoring global climate change warn that warming trends will result in more frequent and widespread droughts, impacting agriculture and food security worldwide.

"Because climate change is altering rainfall patterns," Blumwald said, "agriculture must adapt by using strategies that range from changing traditional farming practices to developing genetically modified crops that can better tolerate drought and make more efficient use of irrigation water."

The National Center for Atmospheric Research has reported that the percentage of the Earth's land area impacted by serious drought has more than doubled during the past three decades.

In dry regions, annual plants avoid seasonal drought conditions by having relatively short life cycles and growing quickly during the wet season.

These plants increase their chances of survival by minimizing water loss through their leaves, increasing root growth while reducing leaf growth, and dropping their older leaves.

Blumwald and colleagues investigated enhancing the plants' tolerance to drought by delaying the shedding of leaves triggered by water shortage.

Tobacco was chosen as an experimental plant because it is big, fast growing and a good model for many other crop plants.

The researchers inserted a gene into the tobacco plants that interrupted the biochemical chain of events that causes loss of the plant's leaves during drought.

The genetically modified tobacco plants and the non-modified plants in the experiment's control group were all grown in a greenhouse under the same optimal conditions for 40 days.

Water was then withheld from all of the plants for 15 days, simulating extreme drought conditions.

During the dry days, the non-modified plants in the control group wilted, lost their green pigment and deteriorated. The genetically modified plants remained green and did not display signs of severe deterioration.

At the end of the 15 day induced drought, all of the plants were re-watered for one week. The plants in the control group all died, but the genetically modified plants recovered and resumed normal growth, with little reduction in seed yield.

"Surprisingly, although the genetically modified tobacco plants went more than two weeks without being watered, they maintained relatively high water content and continued their photosynthetic activity throughout the dry period," said researcher Rosa Rivera.

"With only minimal reduction in yield, these plants survived on just 30 percent of the normal irrigation water - severe drought conditions that killed all of the plants in the control group," she said.

The research team hopes that similar results will be found in crops such as tomatoes, rice, wheat, canola and cotton. Upon completion of greenhouse experiments, the researchers plan to carry the research to field trials.

Funding for this research was provided by the University of California's Will W. Lester Endowment and Arcadia Biosciences Inc, a private company headquartered in Davis.

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