Introduction: Genes and Agriculture

In February, a discovery at the University of Kiel in Germany could potentially affect farmers around the world. German scientists found, in the genome (DNA) of a wild beet, a gene that makes the plant resistant to nematodes, tiny worms that destroy the root systems of such crops as sugar beets, cauliflower, and oilseed rape. This taste of nematodes for plant roots is a particularly expensive one for farmers, costing them an estimated $100 billion in worldwide crop losses each year, and there is little they can do to fight the worms except rotate their crops and spray them or the soil with pesticides. Now, however, the discovery of the nematode-resistance gene offers hope for an alternative. Classical breeding techniques can be used to transfer that gene into beets, but to get resistance to nematodes into unrelated crops such as corn or soybeans will require the isolation of the gene followed by genetic engineering of these other crops.

Those nematode-resistant crops will be just one member of a coming generation of ''supercrops'' and "superlivestock," genetically engineered plants and animals that promise to transform agriculture as profoundly as anything since our distant ancestors learned to save seeds from one year to plant the next. With their toolkits of genetic engineering techniques, agricultural researchers can modify organisms to improve quality and convenience, lower the cost of production, and add a variety of useful traits. Some such products are already on the market. The FlavrSavrTM; tomato, for instance, is genetically modified to ripen more slowly so that it can be picked closer to peak ripeness. And Roundup-readyTM; soybeans have been altered to be immune to the herbicide RoundupTM;. Farmers who pay the extra $5 a bag for seeds of this type can spray their entire field with Roundup and kill only the weeds.



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--> Introduction: Genes and Agriculture In February, a discovery at the University of Kiel in Germany could potentially affect farmers around the world. German scientists found, in the genome (DNA) of a wild beet, a gene that makes the plant resistant to nematodes, tiny worms that destroy the root systems of such crops as sugar beets, cauliflower, and oilseed rape. This taste of nematodes for plant roots is a particularly expensive one for farmers, costing them an estimated $100 billion in worldwide crop losses each year, and there is little they can do to fight the worms except rotate their crops and spray them or the soil with pesticides. Now, however, the discovery of the nematode-resistance gene offers hope for an alternative. Classical breeding techniques can be used to transfer that gene into beets, but to get resistance to nematodes into unrelated crops such as corn or soybeans will require the isolation of the gene followed by genetic engineering of these other crops. Those nematode-resistant crops will be just one member of a coming generation of ''supercrops'' and "superlivestock," genetically engineered plants and animals that promise to transform agriculture as profoundly as anything since our distant ancestors learned to save seeds from one year to plant the next. With their toolkits of genetic engineering techniques, agricultural researchers can modify organisms to improve quality and convenience, lower the cost of production, and add a variety of useful traits. Some such products are already on the market. The FlavrSavrTM; tomato, for instance, is genetically modified to ripen more slowly so that it can be picked closer to peak ripeness. And Roundup-readyTM; soybeans have been altered to be immune to the herbicide RoundupTM;. Farmers who pay the extra $5 a bag for seeds of this type can spray their entire field with Roundup and kill only the weeds.

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--> How quickly this transformation of crop production and animal husbandry takes place will depend in large part on how much effort—and what type of effort—is put into basic research on the genetics of crops and livestock. Although plenty of research has already been done, among dozens of different species there has been no overall plan or coordination. Not surprisingly, then, progress toward genetically improved crops and livestock has been slower than many would hope. The gene for resistance to nematodes, for example, took eight years to discover. It was found only because of a lucky recombination of chromosomes when domestic sugar beets were cross-bred with wild beets that have a natural nematode resistance. Even now, although we know that wild beets have a nematode resistance gene we have no idea where it is located in the genome or how to isolate it. Last fall, three government agencies took an important first step toward a more focused agricultural research effort. The National Science Foundation and the Departments of Agriculture and Energy established a program to track down the entire genetic code, including an estimated 20,000 genes, of Arabidopsis thaliana, a member of the mustard family. Although Arabidopsis itself has no commercial value—it is a weed—delineating its entire genome will give researchers working on other plants an important foundation for their own studies. It was chosen because working from what is known about the genes of Arabidopsis, they will be able to answer genetic questions about other species, such as the location of a particular gene, much more quickly. Now members of the agricultural research community believe it is time to start a broader project: an agricultural genome program. Building from the base provided by the Arabidopsis effort and using expertise and technology developed in other ventures, such as the Human Genome Project, it should be possible to generate a huge—and hugely valuable—amount of information on the genetics of agricultural species in a relatively short time. With that in mind, the National Research Council (NRC) held a workshop on April 26, "Designing an Agricultural Genome Program." Catherine Woteki, Acting Under Secretary for Research, Education and Economics at the Department of Agriculture, summarized the purpose of the workshop this way: "We in the scientific community need to provide our best estimates of the scientific gain to be made from these investments [in agricultural genome studies]. Over the last decade we have been making a very major investment in genomic activities of importance to agriculture. We have taken the approach of not setting priorities among the major commodities of interest to agriculture. We have a decade's worth of experience with that approach." But now, she noted, the Department of Agriculture has taken a different tack by joining with the National Science Foundation and the Department of Energy to fund the Arabidopsis program. "Having made that decision, let's take the time to go back and examine what we have learned scientifically from the 40 or 50 different species that we have invested in over this past decade in genome-mapping related activities. Can that help us to define a more focused agenda for

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--> the next five to ten years? Or should we continue with the approach that the USDA has taken, which is investing in the Arabidopsis mapping activity and then continuing the across-the-board approach in other plant species?" Or, as Dale Bauman, chair of NRC's Board on Agriculture, put it: "What are the lessons we have learned to date, and how can we use them?" In particular, the participants in the workshop were asked to assume that an agricultural genome project will be established and to discuss what features such a project should have in light of experience with the Human Genome Project and other genetic research over the past decade or so. How should resources be allocated among the dozens of commercially important species? Which scientific strategies will give the greatest return on investment? Would it be useful, for instance, to develop target organisms besides Arabidopsis, delineating their genomes completely? How should an agricultural genome project be organized and coordinated? And are there other issues, such as ethical or social concerns, that should be considered? By talking about such issues ahead of time, it should be possible to avoid some of the mistakes of the past and to make the most of research in the future. By the end of the workshop, several concepts and lessons from the past had emerged that were significant. No one disagreed that now is a good time to launch a broad, coordinated agricultural genome project A number of participants believed it should, for instance, be "multi-tiered," with the genomes of some organisms deciphered totally and others done to various degrees of completeness. Many participants also seemed to believe that the project should be planned in great detail before much money is spent on it, since timing and coordination among the different components will be a key factor in its effectiveness. The following is a summary and synthesis of the discussions that took place during the workshop and of the recommendations offered by the various participants.