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$4.4 million NSF grant funds plant genetics research at Dartmouth

Posted 09/26/00

A research group led by Dartmouth researcher Mary Lou Guerinot has received a $4.4 million National Science Foundation grant to investigate the genetic processes that allow plants to absorb minerals from soil. The project, which will include collaborations with researchers at four other universities, could provide new approaches to problems ranging from malnutrition to pollution, said Guerinot.

"Plants with an enhanced ability to acquire and store minerals could help feed the world, prevent further degradation of our environment and begin to reverse the damage caused by our increasingly industrialized society," she said.

"For example, crop plants with a greater capacity to accumulate minerals could promote sustainable agriculture and improve human health through balanced mineral nutrition. We can also use plants to clean up toxic metals from polluted soils and waters. Each of these goals requires understanding how plants accumulate and store minerals," Guerinot added.

Understanding the way plants take up metals, particularly iron, from the soil has been a long-time research interest for Guerinot. In this newest project, she and her colleagues will analyze 100,000 mutant plants, looking for unusually high or low levels of 72 different elements. Plants with abnormal levels of these elements will then be used to identify the genes whose mutation affects the plant's absorption of various minerals.

Through this process, the researchers hope to learn more about which genes control the uptake of minerals from soil, and how that process works. Then, the individual scientists in the project can begin to study in more depth the particular nutrients or metals that interest them. The research group's results will be made available online to other scientists interested in the uptake of minerals.

If they can determine the genetic processes involved in nutrient uptake, the scientists might be able to breed plants that will absorb more, or less, of particular minerals. For example, iron deficiency is a significant world hunger issue, and if Guerinot's team can deduce how to help plants absorb more iron from the soil, more nutritionally rich crops could result. This could potentially alleviate the world's iron deficiency problem because most of the world's population gets its iron from eating plants.

Also, if plants can be bred to draw nutrients from the soil more efficiently, plant growth on otherwise marginal soil could be improved, thus improving yields while decreasing the need for fertilizer.

Plants--which already metabolize air pollution--might also be bred to absorb toxic metals from the soil, allowing plants to clean polluted fields and rendering them safer for crop production. Conversely, food crops might be bred to not take up harmful toxic metals from the soil.

While many people have reacted negatively to crops that are genetically altered to increase their resistance to pests or herbicides, Guerinot believes that increasing nutritional content of crops through genetic processes will be more acceptable to the general public.

"Crops that would make the biggest difference for the largest number of people in the world are those that would serve as better sources of essential nutrients. Most of the genetically engineered plants on the market today provide no direct benefit to the people who consume them, whereas plants with improved nutritional properties definitely would," she said. The best example of such a modified crop is golden rice, engineered to produce beta-carotene, a substance the body metabolizes into vitamin A, when ingested. Usually found in yellow or orange plant foods like carrots, Vitamin A contributes to good eyesight, the development of healthy teeth and gums, and resistance to disease. By improving the provitamin A content of rice, researchers have taken a step toward alleviating the worldwide problem of vitamin A deficiency, which experts say could affect as many as 70 percent of children under the age of 5 in Southeast Asia.

Guerinot's group will do their initial work on the Arabidopsis plant, a common weed whose genome has been completely sequenced. They also hope to study either maize or rice and do comparative work with yeast.

Four other institutions will have researchers involved with the project besides Dartmouth. Most of the initial screening will take place at Northern Arizona University and the Scripps Research Institute. The focus at Dartmouth will be to analyze the data as it becomes available and to start working on the plants with altered profiles. Researchers at the University of San Diego and the University of Missouri-Columbia also will participate in the project.

In addition to profiling plants to uncover gene functions and working with particular minerals, one of the project's goals is to help train undergraduate and graduate students in genomics, informatics and molecular biology techniques. The research group will also work with the Montshire Museum of Science and the Dartmouth Toxic Metals Research program to help develop science curricula about metals in the environment.

"This investigation will provide the first integrated picture of the genes involved in the selective accumulation of essential minerals, which is a fundamental feature of all living systems," Guerinot said.

Guerinot's project is one of 16 projects to receive awards from the NSF's Plant Genome Research Program this year. In recent years, the NSF has had particular interest in functional genomics, or the study of gene functions.

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