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Monsanto Company, St Louis, Missouri
Address reprint requests to: Maureen Mackey, PhD, Monsanto Company, 800N. Lindbergh Avenue, St Louis, MO 63167. E-mail: Maureen.a.Mackey{at}monsanto.com
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ABSTRACT |
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 TOP ABSTRACT CROP BIOTECHNOLOGY TO ENHANCE...CROP BIOTECHNOLOGY TO ENHANCE...CONCLUSIONSREFERENCES |
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Key words: genetically modified organism, crops, pest resistance, mustard seed oil, beta-carotene
Key teaching points:
• Crop biotechnology is being used to enhance the productivity of crops important for the developing world, with the aim of improving food security.
• The nutritional composition of crop foods can be improved via biotechnology; on-going projects include those involving carotenoid or oleic acid enhanced vegetable oils.
• Food crops can be genetically improved by reducing their allergens.
• Foods can become vehicles for vaccines against life-threatening diseases.
• Human milk proteins can be expressed in plants as a means to produce improved infant formulas.
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CROP BIOTECHNOLOGY TO ENHANCE GLOBAL FOOD SECURITY |
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TOPABSTRACTCROP BIOTECHNOLOGY TO ENHANCE...CROP BIOTECHNOLOGY TO ENHANCE...CONCLUSIONSREFERENCES |
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In 1991, a collaborative research project was launched to solve the SPFMV problem. The members of this coalition were the Kenya Agricultural Research Institute (KARI), the US Agency for International Development (USAID), the University of Missouri and the Monsanto Company. The basic research phase was conducted in Monsanto’s laboratories, where Monsanto scientists, Dr Florence Wambugu and a number of other scientists from KARI conducted the transformation and regenerated virus-resistant plants. Monsanto provided a royalty-free license so KARI could use its technology and share it with other African countries. Dr Wambugu then returned to Kenya to transfer the trait to locally grown varieties of sweet potato. Since Kenya had no regulatory biosafety process for review of genetically modified products in place at that time, scientists from KARI worked with the government of Kenya to establish a local system for review and acceptance of crops developed via biotechnology. Field trials of the genetically enhanced sweet potatoes started in Kenya in 2001 and will continue for a few more years. These trials represented the first field test of a genetically enhanced food crop in sub-Saharan Africa, outside of South Africa. The International Service for the Acquisition of Agri-biotech Applications (ISAAA) and the Agricultural Research Center of South Africa have also joined this research and development partnership. It is expected that instead of 20 to 80 percent losses/year, yields of virus-resistant sweet potatoes could increase by 15 percent. This net increase in production is expected to increase farmers’ income by $41 million annually and provide food security for one million Kenyans without additional production costs [2]. As other varieties of sweet potato are transformed and shared with sub-Saharan Africa, the increased production is estimated to result in an additional 1.8 million tons a year, valued at $495 million [2]. This is one of the best examples of the ability of biotechnology to enhance greatly the availability of foods in the developing world.
The Papaya In Hawaii And Southeast Asia
Another example of biotechnology’s improvement in yields is the papaya crop in Hawaii. Papayas are well known as highly nutritious fruits, especially rich in carotenoids. Less well known is the fact that several years ago the papaya crop in Hawaii was severely affected by the papaya ring-spot virus (PRSV). The crop was almost decimated, threatening the businesses of Hawaiian farmers [3]. However, researchers at Cornell University and the University of Hawaii genetically enhanced papaya to resist the ring-spot virus. Along with the USDA, the university researchers worked with local small- and large-scale papaya farmers to adapt the crop. The transgenic papaya was released for commercialization in 1998 and is the first genetically enhanced fruit crop on the market. Hawaiian papaya production, which had been falling since 1993 when the virus started severely affecting yields, increased for the first time in 1999.
Over the last two decades, PRSV invaded SE Asia, having a devastating effect on this major crop and on the small-scale, subsistence farmers who grew it. Virus-resistance technology similar to that in Hawaii is now being developed by several countries in SE Asia, including Indonesia, Malaysia, the Philippines, Thailand and Vietnam [4–6]. With the assistance of ISAAA and technology from Monsanto Company, the Papaya Biotechnology Network of SE Asia has been formed among the countries to enhance learning, establish the infrastructure needed to assess biosafety and to facilitate the transfer of proprietary technology from industry to these developing countries. The virus-resistance technology is being adapted to local cultivars, and field trials are expected to begin by 2003.
In addition to developing resistance to PRSV, efforts are also being directed toward the development of delayed ripening in papaya. This fruit ripens quickly, making it difficult to store and transfer to distant markets. With the help of technology supplied by the Syngenta Company and the University of Nottingham, the Network is now developing cultivars with delayed ripening traits as well as resistance to PRSV. Varieties suited to local preferences and the environment will be developed and made available to small-scale farmers [6].
High Carotene Mustard Seed Oil
"Golden Rice," the rice genetically enhanced to express carotenoids, has received much media attention because of its potential to supply a desperately needed nutrient, vitamin A, to millions of malnourished people [7]. Developed in the 1990s by researchers in Germany and Switzerland with financial support from the Rockefeller Foundation, the laboratory lines of Golden Rice must now be transferred to local rice varieties. Initial efforts are focused on India, but arrangements have also been established in SE Asia, China, Africa and Latin America to transfer the technology [8]. Although commercialization of Golden Rice is still several years in the future, a commitment has been made to make the product available free of charge to small-scale poor farmers of developing countries.
A similar project has been initiated by Monsanto Company, in cooperation with Michigan State University, USAID and the Tata Energy Research Institute in India. The project was developed in part to respond to a greater effort to enlist private sector collaboration in the Global Vitamin A partnership program, which was initiated by then First Lady Hillary Clinton. Monsanto developed the technology to insert the enzymes of the phytoene synthase pathway into Brassica napus (canola). Concentrations of 1000–1500 µg carotenoids/g fresh weight of seeds were achieved [9].
This technology now is being transferred into Brassica juncea (mustard), a relative of canola. Brassica juncea is grown in many parts of the world, including India, Nepal and Bangladesh, and it provides the second highest consumed oil in India. The resulting mustard seed oil is expected to contain adequate beta-carotene to have an impact on Vitamin A deficiency in the Indian population. And since it is in an oily medium, it is expected to have good bioavailability [10].
It is important to realize that the first crops developed via biotechnology appeared on the market only six years ago [11]. While these first products were intended to benefit primarily farmers and consumers in the developed world, the examples cited above show that biotechnology is being applied for the benefit of populations of the developing world. In the next several years, we will see the application of biotechnology to improve major global staples, such as rice, wheat, corn and cassava grown in Asia, Africa and Latin America, which will be needed to feed the expanding populations in these continents. A case in point is the application of Bt-based pest resistance technology to corn in Kenya. Kenyans consume 175–275 pounds per capita of corn, yet experience losses of 15% to 45% of the crop, equivalent to 400,000 tons and valued at $90 million. In 1999 the International Maize and Wheat Improvement Center (CIMMYT) and KARI launched a project to use Bt technology to develop corn adapted to Kenya’s agro-ecological zones and resistant to pests such as stem borers [12]. Similarly, in the Philippines, resistance to stem borers has been achieved in rice by inserting the Bt gene [13]. Since rice forms the basis of the Asian diet and the population is rapidly expanding, additional strategies such as Bt rice should help meet the increasing demand for this staple [13].
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CROP BIOTECHNOLOGY TO ENHANCE NUTRITIONAL QUALITY |
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TOPABSTRACTCROP BIOTECHNOLOGY TO ENHANCE...CROP BIOTECHNOLOGY TO ENHANCE...CONCLUSIONSREFERENCES |
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9 desaturase enzyme; the resulting vegetable oil requires little or no hydrogenation, has no trans-fatty acids and provides the food processing qualities of a hydrogenated oil without the hydrogenation process [16]. While such a product could provide a solution to the food processing industry, current fatty acid labeling regulations provide a disincentive to the use of such a product. Because the U.S. FDA requires that the stearic acid content of a product be reflected in the saturated fat declaration in labeling [17], the substitution of high stearic acid oil for a hydrogenated oil in a processed food product could result in an increase in saturated fat content of the product. Furthermore, the FDA has proposed that a "trans-free" claim cannot appear on the labeling of products that contain more than 0.5 g saturated fatty acids [18]. Since consumers understand that saturated fats have undesirable effects on blood lipids and should be limited in the diet, a product with more stearic acid, even though it does not elevate lipids, will be represented negatively in labeling.
Another approach to improve the functional properties of vegetable oils while avoiding hydrogenation and the generation of trans-fatty acids is to over-express oleic acid (18:1 n-9) at the expense of linoleic (18:2 n-6) and linolenic acids (18:3 n-6). The reduction of polyunsaturates makes the oil less susceptible to oxidative rancidity, an important consideration in food processing and food service applications. By silencing the gene for the 12 desaturase enzyme, oleic acid conversion to linoleic acid is minimal, and instead oleic acid accumulates in the oilseed. Soybean oil with 85% oleic acid and less than 5% total polyunsaturates has been produced via this transformation process [19], and the oxidative stability of the oil was shown to be similar to that of a fully hydrogenated frying shortening.
As of this writing, there are no commercialized food products of biotechnology containing animal or human genes. The technology is available, but public acceptance issues may be deterring their development. Nevertheless, researchers at the University of California at Davis have succeeded in inserting and expressing the genes for several human milk proteins—lactoferrin, lysozyme and the alpha-1 antitrypsin protein—in rice for the purpose of improving infant formulas [20]. Such a product could provide a test case for the debate over whether there are socially acceptable circumstances where human genes could be used in commercial, genetically enhanced food products. Such products also would necessitate the development of policies and practices to assure that rice (or any other vehicle) containing human proteins would be segregated from the general food supply and that pediatricians and consumers would be fully informed about the product.
There has been much concern in the media and among consumer activist groups about the possibility of inadvertently inserting an allergen into a genetically enhanced crop, causing it to be allergenic to certain people. Developers of genetically improved crops take several measures to assure the risk of such an inadvertent event is very small [21]. The "flip-side" of this situation is that genetic engineering techniques are being used to reduce, if not eliminate, allergens in food. For example, workers in Japan have reduced the content of an allergenic protein in rice by silencing the gene expressing the protein [22]. Other researchers are working to reduce the allergenicity of peanuts [23] and wheat [24].
Genetic engineering techniques are also being used to put vaccines in foods. Potatoes have been developed to contain vaccines against a variety of diseases, including cholera [25], Norwalk virus [26] and hepatitis B [27]. One draw back from the use of potatoes as the vehicle is that they must be eaten raw. Dr Charles Arntzen, a pioneer in this field, is now inserting a vaccine against hepatitis in bananas, a more palatable vehicle when eaten raw and a food that can be readily eaten by small children [28]. The benefits of food-borne vaccines are that they could be provided for a fraction of what it costs to develop and administer vaccines as injections. However, there are many questions about how these products would be controlled, so again new policies and procedures will need to be developed. Issues such as proper distribution, quality control and control of access will need to be resolved.
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CONCLUSIONS |
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TOPABSTRACTCROP BIOTECHNOLOGY TO ENHANCE...CROP BIOTECHNOLOGY TO ENHANCE...CONCLUSIONSREFERENCES |
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TOPABSTRACTCROP BIOTECHNOLOGY TO ENHANCE...CROP BIOTECHNOLOGY TO ENHANCE...CONCLUSIONSREFERENCES |
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