RHS Journals

The Garden
September 2001

Viewpoint

Feast or folly?

The dangers associated with genetic modification may have been overlooked in the rush to apply new techniques, claims Moyra Bremner

'It is very difficult to engineer a plant to make it better' John Fagan molecular biologist

Every gardener must be wondering how soon genetic engineering will affect home gardens. The answer is: quite soon - unless we oppose it. Some floristry flowers are already engineered and America grows many genetically modified vegetables. However, gardeners have benefited from F1 hybrids, so if genetic modification (GM) is 'just an extension of other plant breeding' - as bio-tech companies would have us believe - why not welcome it?

As a science lover I did - at first. But when I talked to independent geneticists worldwide I learned that GM is only an extension of other plant breeding in the sense that an atom bomb is an extension of other bombs. The purpose is the same, but the technology - and risks - are radically different. Just how different, and how potentially dangerous, has not been spelt out to the public and most other scientists.

Hearing that GM can force genes from a fish to work in a tomato, it is easy to imagine wonder-plants: I dream about digging-free perennial 'new potatoes' that grow on bushes and taste like Jerseys. But unfortunately, the trench between the promise and the reality is wide, and filled with barbed wire.
Few people know that to make genes enter and operate in a totally different species, scientists had to enlist nature's great invaders: germs. Every inserted gene is linked to, and guided by, pieces of bacteria and a fragment from a virus (usually cauliflower mosaic virus), and these inhabit every cell of the resulting plant, or other organism. If you think that this risks disease spreading to your garden, you are right - but maybe not quite the way you think.

These viral fragments are chosen for their power, and microbes are so promiscuous that such fragments could join forces with not only any plant viruses in the air, but with human or animal viruses too. Many scientists say it is just a matter of time before that gives some plant, animal or human disease new virulence. That could happen tomorrow, or not for a century,

or more, but nobody might link the epidemic with genetic engineering. Do we want to take that risk just to have orange seedlings bear fruit faster?

Meanwhile, there is the disruption to GM plants themselves. Plant genes are an interactive community; having strangers thrust among them is so stressful and disruptive that most GM plantlets malfunction immediately and are discarded. However, under the added stress of drought, heat or cold, even those that seem to be normal can prove unpredictable and may behave oddly. For example, in a heatwave the cotton bolls fell off thousands of acres of GM cotton (with resulting lawsuits), and the stems of other GM crops split open. GM plants can exude toxins that kill vital soil organisms or produce new allergens and poisons, or existing ones may be boosted to dangerous levels. Genetically modified crops may also change in ways that reduce pest or disease resistance, alter their food values, or the way they cook. At the very least the inserted genes may switch off - so you could pay for red petunias but end up with white ones, as has already happened during research.
For me the most crucial fact is that new allergens or poisons could be created, or the nutritional value of food crops fall, long after safety approval has been given. Some GM crops already seem to be causing allergic reactions, but a poison which builds up in the body, doing gradual harm, might be undetected until the level is fatal. Small wonder, then, that insurance companies refuse to cover GM crops.

What, then, of the promised benefits of lower pesticide use and higher yields? Long term that simply doesn't happen. Pests can rapidly develop resistance to engineered toxins - often in as little as three years - so more, and stronger, chemicals are needed. As to higher yields, hundreds of studies - including ones by the pro-GM US Department of Agriculture - show that in real life GM crops usually give lower yields.

Some say these are teething troubles and promise wonders soon. However, I doubt if most promises can be fulfilled. For the bigger the promised benefit, the more genes must be used to change the plant. As each gene needs its own viral and bacterial support, wonder-plants would endure a host of new genes and viral and bacterial support teams. As even one team can make a plant malfunction, the promised benefits may be impossible, or bring with them grave weaknesses.
Moreover, being driven by a desire to make money from patents, GM often offers complex, unreliable, solutions where better and cheaper natural ones exist. The much-vaunted 'golden rice' is a good example. It was engineered to contain more vitamins, but is more likely to increase vitamin A blindness than reduce it. Using GM to improve nutrition is absurd when geneticists have not even decoded the genes in the crops they seek to 'improve'. I would not let my car be 'improved' by a mechanic who did not know all the elements of an engine, or how it worked. Would you?

Finally, there is the risk of human error. GM crops have accidentally pollinated those in distant seed stations, and GM fodder maize has twice been sown for human consumption. So it is quite possible that toxic or indigestible plants, modified to produce new alternatives to fossil fuels or biodegradable plastics for example, could fatally enter the food chain.

I'm not suggesting all GM research should stop. But I believe it should remain totally confined to laboratories, and the billions of pounds currently wasted on it should go into other areas of science and technology that can help us feed humanity by understanding the natural world and working with it - from soil science to satellite crop surveillance.

Nonetheless genetic engineering has made us look at science with new eyes. The instinct to act first, observe later has served science well for millennia. However, by changing something as central as food, genetic modification invites us to acknowledge that - for the sake of those who live after us - we must put an end to trial-and-error science.

By opposing GM crops, both ordinary people and responsible scientists worldwide are saying science must proceed with caution, using every tool at its disposal to predict the consequences of any action. People have realised that calling for this is not anti-science but simply a loving and reasonable insistence that science 'grows up'. Indeed Nobel-Prize-winning physicist Sir Joseph Rotblat has gone further, saying, 'Scientists should have to take a Hippocratic oath that they will see that what they are doing does not harm humankind.' Who would not say 'amen' to that?

'I would not let my car engine be 'improved' by a mechanic who did not know all the elements of an engine, or how it worked. Would you?'

Moyra Bremner is the author of GE: Genetic Engineering and You, and broadcasts and speaks widely on this topic

Genetic modification is neither panacea nor inherently wrong, but should be examined cautiously on a case-by-case basis, argues Phil Gates

Plants, our most important natural renewable resource, provide us with food, fuel, fibre and drugs that we depend on for our well-being. They generate the oxygen we breathe, and maintain our planet in a habitable state.
In the century since the rediscovery of the laws of genetics first described by Mendel, plant breeders have used increasingly sophisticated techniques to make crops more productive or more desirable. Mutation breeding, species hybridisation, tissue and embryo culture techniques and chromosome doubling are technologies that became commonplace without arousing much controversy. Even switching chunks of chromosome containing unknown numbers of genes between species, such as when parts of barley chromosomes were transferred into bread wheat, passed into use without a murmur of public dissent.
Gardeners have accepted the sophisticated products of scientific plant breeding with alacrity. Our gardens contain mutant chrysanthemums produced with chemical mutagens or nuclear radiation; hyacinths whose cells are crammed with so many chromosomes that their flowers are completely sterile; and clonally propagated hostas that began life as a speck of cells
in sterile agar jelly. Gardeners have an insatiable appetite for botanical curiosities, and have always had an open-minded attitude to the products of modern plant science. Then along came genetically modified (GM) crops, and attitudes changed.
Emotive, meaningless terms such as 'Frankenstein foods' have been used to demonise a new science that may allow us to make better use of our plant resources. Antipathy towards genetic modification is in no small part due to the crude and premature attempts to exploit GM products by those whose vision does not extend beyond the bottom line of corporate balance sheets, but this should not blind us to the possibilities for applying the new knowledge for the common good.
Recently a group of researchers in Spain transferred the genes that make weedy Arabidopsis thaliana (thale cress) flower rapidly into orange plants. These make orange seedlings flower and bear fruit just a year after sowing. Citrus seedlings can take more than a decade to produce their first flower, but thale cress genes mean that we might soon be able to breed fruit or forest tree cultivars by conventional means as quickly as we can breed an annual crop such as wheat. This is important because, thanks to global climate change, growing conditions for plants are changing rapidly.
Genetic modification also allows us to use plants' solar energy-driven capacity to synthesise chemicals to make products that currently come from polluting fossil fuels. Vegetable oils for lubricants, paints, diesel fuel and feedstocks for the chemical industry could all be made by GM plants, as could biodegradable plastics. So GM not only allows us to breed plants more quickly in response to climate change, but also gives us the invaluable option of using solar energy instead of coal or oil to make industrial products.
Nor should we overlook the role GM technology can play in exploiting natural products from wild plants. Currently we use only a tiny proportion of the planet's estimated 250,000 flowering plant species. Many of these are in danger of extinction, and one of the best arguments for conserving them is based on the value of the natural medicines, pesticides and other products that they contain.
To extract these natural compounds, vast quantities of plant material must be processed to derive trace amounts of the active chemicals. For example, it takes the bark of a whole Taxus brevifolia (Pacific yew) to produce enough life-saving drug to treat a single cancer patient. This kind of crude extraction from wild plants is environmentally damaging, but if the genes for the products could be isolated, they could be transferred into existing crop plants. A research group in the United States recently devised a way to harvest valuable proteins from GM plants from the droplets of guttation fluid produced at night around the edges of leaves grown in humid conditions.
Vociferous protests from concerned environmental organisations have already done society a great service by forcing scientists to confront the risks associated with GM plants. The two most commonly expressed concerns are that breeders might accidentally create rampant weeds, and that GM genes could spread via pollen into wild plants. Both are important issues.
If we are really going to take a tough regulatory attitude towards invasive plants, however, we need to look at the problem in a wider context, scrutinising what we grow currently in our gardens and not merely focusing on fears about rampant 'new' GM plants. Horticulture introduces new plants from around the globe in a haphazard, unregulated fashion, and gardeners have a lamentable record for letting loose invasive alien plants that threaten ecosystems. There is real concern in Britain over the ecological damage inflicted by species such as Impatiens glandulifera (Himalayan balsam) and Rhododendron ponticum, as well as a host of alien aquatic plants threatening our wetlands. If more stringent rules for GM plants are imposed, then perhaps new garden plants should also undergo prolonged trials, to assess the ecological risks of them escaping into the wild.
The problem of genes carried in pollen from GM crops to wild plants and conventional crops is much more serious, but is beginning to be addressed. Many plants are able to set seeds without pollination - a natural process called apomixis, where a seed forms from a single cell of the mother plant. Apomixis could be genetically engineered into crop plants that also contain a gene which blocks pollen production, so they would set seed but would have no pollen to spread genes beyond the GM crop. Such a technique would also allow gardeners (and poor, developing-world farmers) to save apomictic seeds from expensive F1 hybrids, which would be identical to their parent.
There is a definite danger that in the current furore surrounding the present, controversial applications of GM, we are losing sight of the real long-term benefits such plants can offer. Some pressure groups are using the issue as a lever to loosen the grip of transnational corporations on world trade. Others, on both sides of the debate, have engineered a spurious confrontation between organic agriculture and GM technology, with both struggling to gain the moral high ground.
The long- and short-term risks and benefits of each specific application of GM technology need to be analysed, consulting not just scientists but everyone who cares about the ways in which plant resources are exploited. Only then will it be possible to make rational decisions based on the best available advice.

'Gardeners have an insatiable appetite for botanical curiosities and have always had an open-minded attitude to the products of modern plant science. Then along came genetically modified crops'

Phil Gates is Lecturer in Botany at the University of Durham, and gardens organically

Do you believe that the benefits of genetic modification outweigh the disadvantages? E-mail thegarden@rhs.org.uk

Images: David Banks

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