Part 1: Genetically Modified Organisms
What is the next wave in seed science? Some suggest progress means returning to the best practices of the past; others espouse genetic engineering (GE) and other methods currently being researched and employed to make U.S. growers efficient and competitive on a global scale.
As the practice of genetic engineering grows more commonplace, agricultural purists warn that genetically modified (GMO) seeds and crops will ultimately yield a dangerous harvest for the earth and for human health. Meanwhile, some research scientists hope their work in genetic engineering will help create a better climate for organic growers.
What is genetic engineering?
A plant has tens of thousands of genes that are active during different points of development and in response to stress. In a stress situation, those genes need to turn themselves on. “Helper” genes sense changes in the plant’s environment and help guide the expression of the major gene. The purpose of genetic engineering (GE) is to strengthen a plant’s ability to respond to a specific stressor.
Also known as DNA transfer, the basic process of genetic engineering is to insert foreign genes into places on a DNA strand where they wouldn’t naturally exist. When the gene for a particular trait, like herbicide tolerance, is identified, then that gene is copied many times and attached to strong promoter genes. This bit is then forced into the genome of the plant.
Genetically modified foods have received some negative press, due in part to early attempts to create a cold-tolerant tomato by injecting a gene from the arctic flounder, and reports suggesting that Bt corn, modified with the insecticide Bacillus thuringiensis, kills monarch butterflies. Bacillus thuringiensis has been engineered into corn to prevent damage from the European corn borer.
Who’s doing it and why
Agribusiness giants Monsanto and Syngenta dominate the world market in genetically engineered seeds. Their herbicide-tolerant canola seed, cotton and corn, as well as insect-resistant Bt corn, are available through seed distributors in the United States and overseas. Monsanto’s herbicide-tolerant seeds are sold as “Roundup Ready,” and Syngenta’s insect-resistant corn is sold under the name “Attribute.”
Research in genetic engineering is occurring at universities and in private and public labs throughout the world, with many locations in North America. In Asia and Africa, with support from Cornell University and the University of California at Davis, Collaboration on Insect Management for Brassicas in Asia and Africa has explored the insertion of Bt into various brassica DNA to create cabbage and cauliflower resistant to the diamondback moth. The USDA Agricultural Research Service operates sites and collaborates with researchers throughout the country. Current and recent genetic modification projects in the United States explore the following:
- Increasing the nutritional value in certain crops. (Ithaca & Tufts)
- Reducing aflatoxin contamination in peanuts. (Georgia Coastal Plain)
- Developing a pineapple resistant to major disease, insects and nematodes. (University of Hawaii)
- Determining how edible plants transport and store nutrients and metals, and thereby increase the nutrients and decrease the harmful metals in the edible portions of plants. (Baylor College of Medicine, Texas)
- Increasing heat tolerance in strawberries. (Beltsville, Md., Ag Research Center)
- Engineering plants to survive salt stress resulting from irrigation and overuse of fertilizers. (USDA ARS, Urbana, Ill.)
- Developing new raspberry cultivars with low chill and high heat tolerance for use in southern growing conditions. (Florida A&M University)
In December 2008, Pamela Ronald, professor of plant pathology at UC Davis, received the USDA NRI Discovery Award for her work in developing new rice varieties that can withstand flooding. Ronald and her research group isolated the rice genomic region that carries the submergence tolerance trait and demonstrated that one of the 13 genes in the region, called Sub1a, confers submergence tolerance. Her colleague’s team used this information to transfer Sub1a into popular high-yielding rice varieties of countries in South and Southeast Asia.
Since then, Ronald has introduced the gene into a California rice variety to make it easy to test in the United States, and she is seeking U.S. farmers willing to participate in trials that may reduce the usage of toxic weed killers on their fields. “It’s a completely different growing situation here,” she says. “There’s no issue in California with flooding, [but] we’re hoping that growers will test our plants to see if they can flood the fields longer to control weeds and therefore use less herbicide.”
Facts about GE seeds
Seed from genetically engineered crops can be saved like any seed from conventionally altered crops, because once the DNA is changed, it’s inheritable.
Although most geneticists use a naturally occurring soil bacterium called agribacterium to introduce new genes into a DNA strand, the bacterium does not remain in the DNA once the genes recombine.
Next month, this column will explore the pros and cons of genetically engineered seeds.
The author is a freelance writer based in Massachusetts and a frequent contributor to Moose River Media.