Race Is On to Test 1st Engineered Bacteria
Now that the federal government has suspended Advanced Genetic Sciences’ license to field-test a genetically engineered bacterium, an informal race has developed between a British and an American group to conduct the first such test.
Both teams expect to perform the experiments this summer.
One of the groups, in England, has already received permission from the appropriate authorities to release an engineered variant of a virus that controls the spread of a moth that infests pine trees.
The other group, Calgene Inc., of Davis, Calif., expects to receive approval from the U.S. Department of Agriculture within two months to grow tobacco plants that have been engineered to make them more resistant to a commercial herbicide.
Safer Than Oakland Firm’s
Both projects are considered safer than that proposed by Oakland’s Advanced Genetic Sciences--even though that company’s experiment also is generally regarded by scientists as very safe.
Advanced Genetic Sciences had proposed to release into a small strawberry plot a mixture of two genetically engineered bacteria, trade-named Frostban, that would protect the plants from frost damage.
The U.S. Environmental Protection Agency had approved the company’s plans, but the work was delayed when the Monterey County Board of Supervisors refused to issue a permit for the tests. Opponents of such experiments fear that release of the engineered organism might adversely affect weather and have other unknown effects on the environment.
The EPA this week withdrew its permission after it was discovered that the firm had tested the engineered bacterium on its rooftop trees 15 months ago. The EPA also fined the firm $20,000.
British Project
The proposed British project “contrasts very clearly” with the Advanced Genetic Sciences project, said molecular biologist David Bishop of the Natural Environmental Research Council’s Institute of Virology at Oxford. His work combines a very minor piece of genetic engineering with a major project in biological control of pests.
The pest is a moth that damages lodgepole pine trees, which are planted in large numbers on the hills of Scotland by the British Forestry Commission.
In many areas of Britain, the caterpillar stage of the moth is controlled by a virus that infects and kills it. Unfortunately, the virus is not present in the lodgepole pine plantations. Several hundred acres of the plantations will thus be sprayed this summer to introduce the virus.
Bishop hopes eventually to engineer the virus to improve the efficiency with which it kills the caterpillars. “Before we change the virus, however, we want to understand the nature of the environmental impact,” he said in a telephone interview. “To do that, we want to release small quantities of a marked virus.”
Bishop and his colleagues have thus inserted a short piece of DNA into the genes of the virus. The DNA has no function and does not change any characteristics of the virus. It does, however, serve as a marker that will allow the scientists to determine how far the virus has spread from the site where it is applied.
The marked virus, Bishop said, will be applied to 100 trees in an area of about one-tenth of an acre.
Unlike those proposed in the United States, Bishop’s proposed experiments have met with virtually no opposition. Calgene plans to test its modified tobacco plants in a 1.5-acre plot in northern Yolo County in the Sacramento Valley. The USDA regulates genetically engineered plants, while the EPA regulates bacteria because they are classified as a pesticide.
Resistance to Herbicide
The plants, which are not a commercial variety, have been modified to give them resistance to the widely used herbicide glyphosphate. Glyphosphate kills plants by blocking their ability to produce certain amino acids that are essential to plant growth.
The Calgene scientists have modified the tobacco by inserting genes from a glyphosphate-resistant strain of the bacterium Salmonella . The new genes produce the amino acids even in the presence of glyphosphate.
Herbicide-tolerant plants are of great potential value and are the subject of study at many genetic engineering companies. Combining tolerant seeds with powerful herbicides would effectively control weeds in commercial fields, reducing the need for tillage to control weeds. Reducing tillage cuts soil erosion and the costs of energy, fertilizer and water.
According to biochemist Robert Goodman of Calgene, the use of glyphosphate-resistant tomatoes in California’s Central Valley could save farmers $30 per acre.
‘Close to Risk-Free’
The proposed Calgene project “is designed to be as close to risk-free as we can make it,” Goodman said in a telephone interview. Because plants are involved rather than microorganisms, it will be fairly easy to prevent their dispersal in the environment.
A prime consideration is that there are no tobacco-growing areas anywhere near the test site, so that even if pollen from the plants should escape from the site, there is nothing for them to pollinate. To further ensure safety, Calgene will snip off flower buds before they bloom.
If the experiment is successful, Calgene hopes to build glyphosphate tolerance into several other species, including tomatoes, cotton and poplar trees, which are important in the paper industry.
