When the first genetically modified (GM) organisms were being developed for the farm, says Anastasia Bodnar, “we were promised rocket jet packs” — futuristic, ultra-nutritious crops that would bring exotic produce to the supermarket and help to feed a hungry world.
Yet so far, she says, the technology has shown most of its benefits on agribusiness — almost always through crops modified to withstand weed-killing chemicals or resist insect pests. This has allowed farmers to increase yields and spray less pesticide than they might have otherwise.
At best, such advances have been almost invisible to ordinary consumers, says Bodnar, a biotechnologist with Biology Fortified, a non-profit GM-organism advocacy organization in Middleton, Wisconsin. And at worst, they have helped to fuel the rage of opponents of genetic modification, who say that transgenic crops have concentrated power and profits in the hands of a few large corporations, and are a prime example of scientists meddling in nature, regardless of the dangers.
But that could soon change, thanks to a whole new generation of GM crops now making their way from laboratory to market. Some of these crops will tackle new problems, from apples that stave off discolouration to 'Golden Rice' and bright-orange bananas fortified with nutrients to improve the diets of people in the poorest countries.
Other next-generation crops will be created using advanced genetic-manipulation techniques that allow high-precision editing of the plant's own genome. Such approaches could reduce the need to modify commercial crops with genes imported from other species — one of the practices that most disturbs critics of genetic modification. And that, in turn, could conceivably reduce the public disquiet over GM foods.
Or maybe not. Whatever promise these crops may show in the laboratory, they will still have to demonstrate their benefits in painstaking, expensive and detailed field trials; jump through multiple regulatory hoops; and reassure an often sceptical public. That last part will not be easy, says Philip Bereano, who studies the political and social aspects of new technologies at the University of Washington, Seattle. He points out that the arguments over GM organisms run the gamut from concerns about safety and labelling to ethical issues with the patenting of life. “People are concerned about what they're feeding their kids,” he says, “and that is not going to change.”
Nevertheless, most GM-organism researchers seem convinced that the worst of the technology's problems are over, and that its future is bright. If you are looking for the jet-pack era of GM organisms, says Bodnar, “it is happening now.”
The first wave of GM crops was marketed mainly to farmers, with the goal of making their jobs easier, more productive and more profitable. In 1996, for example, biotechnology firm Monsanto of St Louis, Missouri, introduced the first of its popular 'Roundup Ready' products: a soya bean equipped with a bacterial gene that allows it to tolerate a Monsanto-made glyphosphate herbicide known as Roundup. This meant that farmers could kill off the majority of weeds with one herbicide rather than several, without damaging the crop. Other GM crops soon followed, including Monsanto's Bt cotton: a plant modified to produce a bacterial toxin that discourages destructive bollworms and cuts down on the need for pesticides.
Farmers will continue to be a core market for the coming generation of GM organisms. At Rothamsted Research in Harpenden, UK, for example, scientists are working on GM plants that will need even less pesticide than Bt cotton, and maybe none at all. The key is an 'alarm pheromone' that some species of wild plant have evolved to mimic the chemical warning signals put out by aphids — a major crop pest in the temperate zones — when they are under attack. Putting the genes for this defence into wheat has created a crop that could trick the insects into thinking that they are in peril and drive them away. Unlike Bt cotton and other existing GM organisms, such a crop would need no insect-killing chemical for protection from pests.
Field trials are currently under way, says Maurice Moloney, director and chief executive of the Rothamsted centre. “In the greenhouse it's been very successful,” he says. “If we can get it to work in the field, we'll be able to optimize it to make it a robust trait” suitable for large-scale deployment. From there, says Maloney, the team hopes to expand its efforts, searching for naturally evolved protections and deterrents in other crops, and working out how these might be enhanced or modified to fight particular pests. “For example, you could have a volatile chemical that also is a deterrent for caterpillars, stem borers and the like,” says Maloney. “Potentially, if we can get this to work, the range of applications is phenomenal.”
Many GM-organism researchers are pushing work on crops sometimes neglected by the big agricultural companies. In the plant biotechnology group at the Swiss Federal Institute of Technology in Zurich, for example, Herve Vanderschuren leads a team working on cassava (Manihot esculenta), a tropical shrub with a tuber that is a staple food in the developing world. “There is not major investment in breeding or improvement of this crop,” he says.
Vanderschuren and his team are genetically engineering cassava to be resistant to two particularly damaging viruses, by starting with a variety that is naturally resistant to cassava mosaic virus, and then inserting genes that confer resistance to cassava brown streak virus. The naturally resistant strain was already tailored to local needs and markets. That kind of local adaptation is a “very important part of the research we do here”, says Vanderschuren — and something that is rarely embraced by huge agribusinesses that want to sell products worldwide. Vanderschuren and his team have successfully made the plants, and are now collaborating with colleagues in Africa to arrange tests to confirm that the cassava can be grown in the field.
Much of the work on crops in developing nations focuses on nutritional enhancement. The most famous example of this effort is Golden Rice, a modified version of the staple food of half the world. Its distinct yellow hue comes from the addition of β-carotene, a precursor to vitamin A that is deficient in many East Asian diets. After much painstaking development and many objections from opponents of GM organisms — the original version of Golden Rice was announced in 2000 — the crop is currently undergoing field trials in the Philippines. It could clear the final regulatory hurdles and reach farmers by 2014.
edytowany przez urodzona13: 17 maj 2015