Michael F. Thomashow, Ph.D.
Professor
Michigan State University
East Lansing, Michigan 48824

Before the U.S. House Science Subcommittee on Basic Research

October 5, 1999

Mr. Chairman, and distinguished members of the Subcommittee. My name is Michael Thomashow. I am a professor in the Department of Crop and Soil Sciences at Michigan State University. My statement today is supported by the American Society of Plant Physiologists, a non-profit science society representing more than 5,000 scientists. I have been actively engaged in plant biotechnology research since its incipient days some twenty years ago, and am honored by having the opportunity to speak today about the potential benefits of genetically engineered plants.

It is now possible to transfer genes from essentially any organism on our planet to a wide variety of plants including agronomic crop and horticultural species. Such "plant biotechnology" or "genetic engineering" techniques are enabling scientists to pursue exciting novel strategies for plant improvement, most of which would be impossible using traditional plant breeding methodologies.

These new lines of investigation have great potential to benefit farmers, consumers and societies worldwide. Indeed, first generation transgenic herbicide and pest resistant crops have already made it to the field. These engineered plants not only promise increased crop yields and better quality products, but also allow the use of chemicals that are more environmentally friendly and pose less hazards to human and animal health. Future generation transgenic crops will not only provide further advances in these areas, but in addition, will lead to the creation of foods that are nutritionally-enhanced to improve human health.

Through the power of genetic engineering, it should also be possible to dramatically increase the use of plants to produce "industrial feedstocks" such as specialty oils for lubricants, precursors of plastics and valuable health-related biomolecules. Such developments would not only directly benefit the consumer, but would also afford farmers greater opportunities in choosing what crops to grow.

My intent today is not to exhaustively enumerate the exciting advances that have already been made in plant genetic engineering or those that have the potential to "come on line" in the near future. Instead, what I would like to do is give a few examples of the range of activities that are in progress and to then give some added details about a few of these.

Most of the plant genetic engineering projects that are in progress fall under one of the following three general headings, each of which would include "value-added" traits: Engineering for Improved Crop Production and Quality, Engineering for Improved Health, [and] Engineering for Alternative Nonfood Uses.

Some examples of efforts in these areas include:

Genetic Engineering for Improved Crop Production and Quality

-- Herbicide Resistance (e.g.: glyphosate resistance)

-- Pest Resistance (e.g.: BT toxin for insect resistance)

-- Disease Resistance (e.g.: increase resistance to viral, fungal and bacterial diseases) -- Environmental Stress Tolerance (e.g.: increase freezing and drought tolerance) -- Modification of Post-Harvest Characteristics (e.g.: prevent potato sweetening) -- Altered Cell Wall Composition (e.g.: decrease lignin content)

Genetic Engineering for Improved Health

-- Edible Vaccines (e.g.: prevent infectious diseases)

-- Healthier Oil Profiles (e.g.: increased unsaturated fats)

-- Increase Vitamin and Mineral Contents (e.g.: increase iron and vitamins A and E) -- Decrease Food Allergies (e.g.: eliminate allergens in milk, nuts and cereals) -- Improve Protein Content (e.g. high lysine corn)

Genetic Engineering for Alternative Nonfood Uses

-- Specialty Oils (e.g.: jet engine lubricants)

-- Plastics (e.g.: biodegradable thermoplastics)

-- Pharmaceuticals (e.g.: anti-cancer drugs like taxol)

-- Hormones (e.g.: insulin and growth hormone)

-- "Plantibodies" (e.g.: human antibodies for treatment of infectious and autoimmune disease) -- Vaccines (e.g.: against infectious diseases like cholera and rabies) -- Phytoremediation (e.g.: remove heavy metals and toxic organics)

Clearly, genetic engineering offers a wide range of exciting possibilities for future crop improvement that were not only unthinkable, but actually impossible, before the advent of this powerful technology.

Now, let me touch on a few of these areas of genetic engineering in a bit more detail:

Herbicide Resistance

Weeds, if uncontrolled, have major negative effects on plant yield. Thus, farmers apply a variety of chemicals to prevent weed growth. Unfortunately, many of these chemicals are hazardous to human and animal health. In addition, many are environmentally unfriendly as they persist in the soil and can accumulate in ground water.

This overall situation has lead investigators to seek chemical herbicides that are less toxic and more environmentally friendly. Indeed, a number of such chemicals have been discovered such as glyphosate, commonly known as Roundup (produced by Monsanto). The chemical is quickly degraded in the soil, has low toxicity to humans and animals, and is very effective in killing plants. The initial problem, however, was that the chemical effectively kills a wide range of plants; it would kill the target weeds, but in addition, would kill the crop the farmer was trying to grow. Through the power of genetic engineering, however, genes have been isolated, modified and transformed back into crop species to make them resistant to the herbicide. This, then has made it possible for farmers to use the herbicide to kill weeds, but grow healthy crops.

Bottom line: Genetic engineering is leading to the development of herbicide resistant plants that allow for the use of much safer, highly effective and environmentally friendly herbicides.

Improved Stress Tolerance

Environmental stresses including extremes in temperature and drought have a major impact on crop production. It has been estimated that in the U.S., the average annual yield of the major row crops is only 20% of their genetic potential, with most of "missing" 80% being due to environmental stresses. In addition, environmental stresses greatly limit the locations where crops can be grown.

For instance, due to freezing temperatures, winter canola cannot be grown throughout the northern U.S. nor throughout most of Canada. Likewise, the forest industry would dearly like to grow eucalyptus throughout the southeast for paper production, but can't due to periodic springtime frosts. Last January in California, the citrus industry experienced some $600 Million in losses due to a couple of days of freezing temperatures. And we are all aware of the losses caused by drought this summer in parts of the Eastern U.S.

Given the importance of stress tolerance, one might think that plant breeding programs would include efforts to increase environmental stress tolerance. Indeed, this is the case. However, because of the physiological and genetic complexities involved in enhancing stress tolerance, traditional breeding efforts have met with little success. The most freezing tolerant wheat varieties today, for instance, are only marginally better than those developed in the early part of this century.

Upon moving to Michigan State University some ten years ago, I became interested in the general area of plant stress tolerance, and particularly became interested in freezing tolerance mechanisms. My goal has been to determine how certain plants sense low temperature and activate natural freezing tolerance mechanisms. This research, funded by the USDA, NSF and the state of Michigan, has led to the identification of the CBF "master switch" genes that control freezing tolerance.

Significantly, turning on the CBF "master switches" also leads to an enhancement of tolerance to drought and high salinity stress. "CBF technology" is now beginning to be tested for improving stress tolerance in a wide range of crop and horticultural species. Additional approaches, including the use of metabolic engineering, also hold great promise to improve plant stress tolerance.

Bottom line: Genetic engineering makes possible novel strategies to improve the environmental stress tolerance of plants which will have major positive impacts on food production worldwide.

Increase Vitamin and Mineral Content

As noted in a recent Science article by Trisha Gura, Vitamin A deficiency affects some 400 million people worldwide, leaving these individuals vulnerable to infections and blindness. Similarly, iron deficiency affects some 3.7 billion people, particularly women, leaving them weakened by anemia and susceptible to complications during childbirth. A question thus raised is whether it might be possible to use the power of genetic engineering to modify plants for correcting these common and serious nutritional deficiencies?

This question has interested a number of investigators including Dr. Ingo Potrykus and his colleagues at the Swiss Federal Institute of Technology in Zurich. The answer reached by Dr. Potrykus after 7 years of effort appears to be an exciting "Yes!" What Potrykus and his colleagues have accomplished is a colossal feat in plant genetic engineering.

By appropriately modifying a total of seven genes-genes that came for plants, bacteria and fungi-and introducing all of them into rice, they have been able to create lines that contain high amounts of b -carotene, the precursor to Vitamin A, and high amounts of iron. Dean DellaPenna at the University of Nevada, who himself has done pioneering research on elevating the vitamin E content of plants, notes that the work by Potrykus "is tremendously exciting and should have an enormous impact." Indeed, Potrykus estimates that as little as 300 grams a day of the cooked improved rice, an amount typical for an Asian diet, should provide almost the entire daily vitamin A requirement.

Bottom line: Genetic engineering offers a powerful tool to improve the nutritional content of plants through metabolic engineering and thereby improve the health of individuals throughout the world.

Edible Vaccines

The development of edible plant vaccines has the potential to provide more convenient, less costly immunization strategies and means for implementing universal vaccination programs worldwide. Indeed, vaccination programs remain problematic in many parts of the world, particularly in developing nations.

As noted by Dr. Charles Arntzen, "the dramatic impact of modern vaccines is not reaching the developing world where it is most needed." This is due in large part to a lack of equipment needed for making, storing and delivering vaccines, but in addition, includes cultural differences that impede acceptance of injection-based immunization.

However, what if people could eat foods that are part of their normal diet, but are enhanced with subunit vaccines that could immunize against diseases? As Dr. Arntzen wondered a number of years ago, what if bananas could be used to produce edible vaccines? There would be fewer problems with storage of the vaccine; the vaccine could be produced more economically compared to traditional vaccine production methods; and such a vaccine could potentially get around technical and cultural problems associated with injection-based immunization.

Such considerations have led a number of investigators to pursue the development of edible plant vaccines. Ones that Dr. Arntzen is particularly interested in are those that would protect individuals from enteric diseases including cholera and diarrhea, leading causes of infant deaths in the developing world. In his initial studies, Dr. Arntzen and colleagues produced transgenic potato plants (banana transformation requires further development) that were demonstrated to be effective in immunizing mice against bacteria that cause diarrhea. The potatoes were then used in the first-ever human clinical trails utilizing a genetically engineered food to deliver a pharmaceutical. And they proved successful! Further human clinical tests are now in planning.

Bottom line: The genetic engineering of plants has the potential to provide edible plant vaccines that could be used to immunize individuals against a wide variety of infectious diseases ranging from cholera to potentially AIDS. Such developments have profound implications for improving human health worldwide and save millions of lives.

In closing, I hope that my presentation today has conveyed the exciting promise and possibilities that genetic engineering, combined with plant genome research, has for improving agriculture and human health. None of these advances would be possible without the support of you and your colleagues in Congress.

Your efforts on behalf of basic plant research are deeply appreciated, and are helping provide for a more secure and safe food supply; are leading to the development of plants that provide "sun-driven factories" for the production of industrial chemicals and pharmaceuticals; and are leading to enhanced crops that will help conquer pervasive and debilitating diseases among people worldwide. Thank you, Mr. Chairman, for the opportunity to participate in today's hearing.

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