'Engineered' Plants Are Put to Field Tests
British researchers try to determine if transgenic crop strains present risks when released in a natural environment
| ASCOT, ENGLAND
'PROSAMO" may sound like some sort of Japanese martial art or a pasta dish, but it's far from any such thing. It is a large-scale scientific program set up in Britain to assess certain risks that may - or may not - attend the release of genetically engineered organisms, such as crop plants like potatoes, maize, or oil-seed rape (canola).PROSAMO, which stands for Planned Release of Selected and Manipulated Organisms, is a four-year study, half funded by the British government and half by a consortium of interested companies, including Dupont and Imperial Chemical Industries (ICI). Some 60,000 seeds of canola, engineered to include a marker gene to render them resistant to Basta, a herbicide, and kanomycin, an antibiotic, have been sown by hand in four different British locations with a wide variety of conditions. The attention to detail is remarkable: In 25 meter-square sites, nine seeds are sown in each 25-centimeter square, each of which has two metal tags. "What's different about this experiment," says Jonathan Thomas, project coordinator, "is that it is released into a natural environment, as opposed to released onto a farm field." Other field studies of transgenic crop plants - and there have been many in the United States and Europe - are designed "to check that products worked - that they were disease-resistant for instance. Our study ignores that," Mr. Thomas says. The PROSAMO sites where the plants are being grown are woodland, marsh, downs grassland, and so on, sometimes cultivated, sometimes fenced, but not farm fields. At each site, four kinds of habitat are used - wet, dry, shady, and sunny. Some of the plants have received fungicide treatment, some insecticide. "The experiment is to check that the transgenic plants don't become persistent" in the wild, Thomas says. There has to date been no similar assessment experiment, certainly not on such a scale. Halfway through the experiment (though the plots will continue to be watched for a total of seven years), results so far, says Michael Crawley, "have given us no cause for concern." Dr. Crawley, who is in charge of the assessment, is a plant ecologist of London's Imperial College. Results at the end of the first year showed that "the transgenic rape plants behaved exactly the same as the nontransgenic ones.... In no case did the transgenics produce, for example, more seed or survive better or germinate more freely. There has been no trend in a direction of them being more of a nuisance." Interviewed at Imperial College's outpost at Ascot, Berkshire (where one of the sites is - the other two are in Cornwall and Scotland), Crawley discussed his PROSAMO project at length. The risks being examined, he points out, are "conjectural." He names three: that transgenic plants might be a nuisance - more unruly - as crops. That they might become invasive of natural habitats in a way that nontransgenics do not. That they might transfer, through pollen, their transgenic attributes, to a related specie s that might then become more of a nuisance than it currently is (this is being assessed in another part of the PROSAMO program). Crawley is certain that only experiments outdoors can tell you what the relative size of such risks might be. "To do the work in the field is the only serious way to test these ecological questions," he says. "Not to do it in one place in one year, but to do it in many places over many years." What is being followed is a "step-by-step approach." The next question will be "to what extent you can generalize ... from a limited number of study sites to a wider geographic realm." Once such transgenic seeds have been let out on the commercial market, they are, according to Crawley, "going to get into far more places than they have ever got, even in the most thorough, comprehensive risk-assessment experiments." But the specific ones being tested, according to Keith Pike, spokesman for ICI's seeds division, have little or no commercial potential as such: They have been chosen simply because they were readily available in large numbers. Rigorous forms of legislation are being enacted in Britain to ensure caution, though in fact the European Community (EC) is the larger deciding body in this part of the world. Whether or not tests made in the British climate would be considered adequate to determine the behavior o f plants in, for example, a Mediterranean climate like Spain's, remains an important and unanswered question. "What is needed," Crawley argues, "is world legislation. Once a seed is released, it will go everywhere. One country releasing transgenic seed could be responsible for problems in another country where tests have not been made." Though public fears can be characterized as "the triffid syndrome" (a fictional fantasy of plants getting grotesquely out of hand), Crawley nevertheless does acknowledge that "the environmental consequences are potentially very great if anything did go wrong with transgenic plants. When plants get out of hand, they do so in a big way." He cites strawberry guava on Hawaii, for example. It was introduced as a crop and is now seriously invasive of natural habitats. In other words, "we should be very cautiou s about plant introductions of all sorts. Not only transgenic plants.... When plants do get out of hand, there is no cost-effective way of controlling them. People always imagine that because plants are big, you just go around and pull them up! People can be naive and have quite the wrong impression of what a serious weed problem is like." On the other hand, says Crawley, "the scientists who are making the products certainly don't think they are in any way hazardous, and they argue from evolutionary grounds." He refers to "the genetic baggage hypothesis." This means that "all changes in an organism that are caused by genetic changes have a cost: Organisms only have a certain number of resources. And if you put them into something new, it means you are taking them out of something else. For example, if you made a plant more herbicide resist ant, this would tend to make it less competitive in other ways. The only conditions in which it will be more competitive will be those very special ones that you have modified." Herbicide resistance is certainly one aim of transgenic-plant production. "That's got a lot of publicity," Crawley observes. "It's a commercial fact of life," he agrees, "that some chemical companies that make the seeds will also sell the herbicide." The companies argue, however, that such seeds available to farmers would mean they will not need to use so much herbicide. But the gains may be modest. Keith Pike of ICI does not think there will be dramatic reductions in herbicide use because of transgenic- plant production. Crawley says that the real environmental benefits from genetic engineering "come in the much longer term. When, for example, you make a transgenic crop plant which requires virtually no chemical inputs." And "drought resistance would be a tremendous environmental benefit. And more complicated things like nitrogen fixation." Legumes can fix nitrogen by having a symbiosis in their roots with bacteria. "Now it would be wonderful if you could take that biochemical machinery and put it, say, into maize. Then third-world farmers could grow crops of maize without fertilizers. That's a worthy aim. But it's turned out to be much more difficult to move whole suites of genes from one thing to another" (as would be required in this case). "So that's many, many years away." All the same, by the phrase "many, many years," he confesses, he might mean "perhaps five years. In terms of the pace of technology, that's a very long time."