GENE FLOW FROM CULTIVATED RICE: ECOLOGICAL CONSEQUENCES
Bao-Rong Lu

Introduction
Rice (Oryza sativa) is one of the world's most important cereal crops, providing staple food for nearly one half of the population. In many developing countries, rice is the main source of food security and is intimately associated with local lifestyles and culture. With the rapid increase of global population, much greater rice production is demanded, leading to wide application of transgenic biotechnology to rice for genetic improvement¹. Although no GM rice has been officially approved yet for extensive commercial cultivation in the world, genes conferring traits, such as high amounts of beta-carotene, high protein content, disease and insect resistance, herbicide resistance, and salt tolerance, have been successfully transferred into different rice varieties through transgenic techniques^{2, 3}. Some of these GM rice breeding lines or varieties have been released into the environment for testing. It is apparent that as an important world cereal crop, transgenic rice varieties will inevitably be released into environments for commercial production in the near future.

Undoubtedly, biotechnology and GM crops will provide new opportunities for global food security and development in life sciences. However, the uses of GM crops have also aroused tremendous concerns about their biosafety world wide. The potential ecological risks associated with transgene escape through gene flow are the foremost among these concerns⁴.

When alien transgenes escape to and express in weedy or wild relatives of GM rice, transgenes may persist and disseminate within the weedy or wild populations through sexual reproduction and/or vegetative propagation. Transgenes that are responsible for resistance to biotic and abiotic stresses (such as disease and insect resistance, drought and salt tolerance, and herbicide resistance) can significantly enhance the ecological fitness of weedy and wild populations. The escape of these transgenes may cause ecological problems, for instance, by producing aggressive weeds, the spread of which might result in unpredictable consequences to local ecosystems. On the other hand, when transgenes escape to and persist in wild rice populations, the rapid dissemination of transgenic hybrid individuals (or progeny) might change the original wild rice populations. In some cases, the aggressive spreading of hybrid swarms with better ecological fitness could even lead to the extinction of endangered wild species populations locally⁵. Therefore, knowledge of the likelihood of gene flow from rice to its weedy and wild relatives will help to predict the magnitude of the potential ecological consequences caused by transgene escape. This knowledge will also facilitate the effective management and safe use of the transgenic crops.

Cultivated rice and its weedy and wild relatives
The first step in the assessment of gene flow and its consequences is to determine which weedy and wild species can hybridize with the crop to produce fertile offspring. Cultivated rice is included in the genus Oryza of the grass family (Poaceae). This genus includes two cultivated species (Asian rice Oryza sativa, and African rice O. glaberrima) and more than 20 wild species with ten different genome types, i.e., AA, BB, CC, BBCC, CCDD, EE, FF, GG, JJHH, and JJKK. The wild relatives of rice with different genome types usually have significant reproductive isolation, making them unlikely to hybridize under natural conditions. Therefore, the wild species of concern for transgene escape are only those containing the AA genome.

As close relatives of cultivated rice, some wild rice species such as O. rufipogon, O. nivara, O. longistaminata, and O. glumaepatula are commonly found or coexist in rice farming systems of many Asian, African, and American countries. The weedy rice (also referred to as red rice, Oryza spontanea) is frequently observed in rice fields as an accompanying weed, particularly in the rice fields with direct-seeding cultivation practices. These AA-genome weedy and wild relatives are highly compatible sexually with cultivated rice. Their interspecific F₁ hybrids could form complete chromosome pairing in meiosis and have relatively high pollen and seed fertility to produce viable offspring. Thus, studying gene flow from rice to its weedy and wild relatives becomes an important component for the potential ecological risk assessment of GM rice, because gene flow is the primary step from which potential ecological consequences of transgene escape may follow.

Gene flow from cultivated rice to its weedy and wild relatives
In order to estimate the pollen-mediated gene flow from cultivated rice to its weedy and wild relatives, experiments were conducted at two sites in Kyongsan of South Korea and Chaling of Hunan Province, China, respectively, under special field conditions mimicking the natural occurrence of weedy and wild relatives in Asia. Two types of experimental designs were established by constructing different populations to examine gene flow from cultivated rice to weedy and wild rice species.

Gene flow from transgenic rice to weedy rice was measured using a transgenic rice variety (Nam29/TR18, as a pollen donor) with herbicide resistance (bar) and 13 accessions of weedy rice collected from Asia and America. The experimental plot was designed as complete random blocks where Nam29/TR18 was planted and mixed with one of the 13 weedy rice accessions in each block, respectively (Fig. 1). Each block consisted of eight weedy rice plants. For identification of hybrids between Nam29/TR18 and weedy rice, seedlings generated from different weedy rice plants were sprayed with herbicide Basta at the 3—4-leaf stage. The surviving seedlings with resistance to herbicide Basta were considered hybrids and were subject to PCR detection of the herbicide resistance bar gene to confirm their hybridity. Gene flow frequencies were estimated by calculating the number of hybrids against the total number of seedlings germinated. The average frequencies of weedy rice seedlings with herbicide resistance were very low and varied among different blocks, but with no significant differences among the replications. The experimental results indicated that the detectable rate of herbicide resistance gene flow from the transgenic rice to weedy rice plants varied between 0.011~0.046%.

Gene flow from cultivated rice to perennial common wild rice was measured using the Minghui-63 rice variety, and wild rice O. rufipogon (as pollen recipient) was planted in different models to allow outcrossing to occur naturally. Co-dominant simple sequence repeats (SSRs) were used as molecular markers for accurate identification of hybrids between cultivated rice and O. rufipogon. The selected SSR primer pair amplified polymorphic alleles from the two species, which were easily distinguishable with electrophoresis in agarose gels. O. rufipogon presented a consistent fast-migrating allele (F) and Minghui-63 a slow-migrating allele (S) in the gels. The hybrids between the two species displayed stable heterozygous (FS) alleles. Leaf samples of germinated seeds from O. rufipogon populations were collected from individual seedlings for SSR examination. Gene flow frequencies were estimated by calculating the number of seedlings with the FS heterozygote SSR pattern against the total number of seedlings examined. As a result, the frequencies of detected interspecific hybrids varied from 1.21~2.94% in different planting models. Gene flow frequency from cultivated rice to O. rufipogon was therefore expectedly high, up to ca. 3%, although humidity and wind strength and direction significantly affected the rate of gene flow.

Potential consequences of transgene escape from GM rice to its weedy and wild relatives
With current concerns over weed problems caused by wild rice, and particularly the weedy rice in rice farming ecosystems, one of the major fears is whether the transgenes in GM rice varieties will escape to their wild and weedy relatives through gene flow, and enhance the fitness of the wild relatives. This could increase the weediness of wild and weedy rice that invade rice fields, causing serious weed problems. Our experimental data clearly indicate the likelihood of gene flow from cultivated rice to its wild and weedy species, although with different frequencies. The gene flow frequency from cultivated Minghui-63 to wild O. rufipogon in different planting models varied between 1.1~2.94%. These frequencies are significantly high in terms of transgene escape if the cultivated GM rice varieties are grown in the vicinity of wild rice species. Therefore, for the purpose of preventing or minimizing transgene escape to wild relatives, it is recommended that isolation zones with a sufficient space or with trap plants between GM rice and O. rufipogon should be established, until more effective methods are available. Effective isolation from GM rice will benefit the genetic integrity of in situ conserved wild rice populations.

The detected gene flow frequencies from GM rice line Nam29/TR18 to various weedy rice accessions were very low, ranging from 0.011~0.046% in one generation, when a weedy rice strain occurred simultaneously in a rice field. However, the gene flow frequency from cultivated to weedy rice in large populations might be more significant than the data observed in this experiment. Actually, rice cultivars cross easily with their related weedy forms (red rice) found in direct-seeded paddy fields and produce viable and fertile hybrids with a reasonable rate. In addition, when weedy rice consistently occurs simultaneously with a cultivated rice variety in the same field, the number of hybrids resulting from gene flow could accumulate and increase through generations. If GM rice varieties are released to environments where weedy rice occurs abundantly, the transferred alien genes could spread and accumulate in weedy populations. This may pose a severe problem for weedy rice control and management in rice production. Therefore, release of transgenic rice with genes that can significantly increase weediness and can resist weed control measures is not recommended in regions where weedy rice is already a serious weed problem.

1. Huang JK, Rozelle S, Pray C, and Wang QF. (2002) Plant Biotechnology in China. Science 295: 674-677.

2. Matsuda T. (1998) Application of transgenic techniques for hypo-allergenic rice. Proc. Intern. Symp. on Novel Foods Regulation in The European Union — Integrity of The Process of Safety Evaluation. Berlin, Germany 1998, p. 311-314.

3. Potrykus I. (2002) Golden rice: concept, development, and its availability in developing countries. In: Abstracts of International Rice Congress, Beijing, China, p. 46.

4. Snow A. (2002) Transgenic crops—why gene flow matters. Nature Biotechnology 20: 542.

5. Kiang YT, Antonvics J, and Wu L. (1979) The extinction of wild rice (Oryza perennis formosa) in Taiwan. Journal of Asian Ecology 1: 1-9.

To heterologously express the C. elegans n-3 fatty acid desaturase in mice, the fat-1 gene encoding this protein was modified from the original by optimization of codon usage for mammalian cells and coupled to a chicken beta-actin promoter and cytomegalovirus enhancer, which are highly active in a wide range of cell types and therefore allow high-level and broad expression of the transgene in mice⁶.

The expression of the fat-1 in F1 pups from transgenic founder mice and their offspring was examined by Real-Time PCR of tail DNA and by analysis of tail lipids. The transgenic mice appear to be normal and healthy. Both transgenic and wild type mice are maintained on a diet high in omega-6 fatty acids (mainly linoleic acid) with very little omega-3 fatty acids (~0.1% of total fat supplied). Feeding this n-3 fatty acid-deficient diet allows us to identify the phenotype readily. Under this dietary regime, wild type mice have little or no n-3 fatty acid in their tissues because the animals naturally cannot produce n-3 from n-6 fatty acids, whereas the fat-1 transgenic mice should have appreciable amounts of n-3 fatty acids (derived from n-6 fatty acids) in their tissues if the transgene is functional in vivo⁷.

Since the phenotype of the transgenic mouse lines is mainly reflected by lipid profiles, we analyzed the fatty acid composition of various organs of the transgenic mice at different ages by gas chromatography—mass spectrometer. Figure 1 shows the differential fatty acid profiles of total lipids extracted from skeletal muscles of age- and sex-matched wild type and transgenic mice. In the wild type animals, the polyunsaturated fatty acids found in the tissues are mainly (98%) n-6 linoleic acid (LA, 18:n-6) and arachidonic acid (AA, 20:4n-6) with a trace (or undetectable) amount of n-3 fatty acids.

Fig. 1. Partial gas chromatograph traces showing the polyunsaturated fatty acid profiles of total lipids extracted from skeletal muscles of a wild-type mouse (WT, upper panel) and a fat-1 transgenic mouse (TM, lower panel). Both the wild type and transgenic mice were 8 weeks old female and fed with the same diet. Note, the levels of n-6 polyunsaturated acids (18:2n-6, 20:4n-6, 22:4n-6 and 22:5n-6) are remarkably lower whereas n-3 fatty acids (marked with *) are abundant in the transgenic muscle (lower panel) compared with the wild type muscle in which there is very little n-3 fatty acid (upper panel).

In contrast, there are large amounts of n-3 polyunsaturated fatty acids, including linolenic acid (ALA, 18:3n-3), eicosapentaenoic acid (EPA, 20:5n-3), docosapentaenoic acid (DPA, 22:5n-3) and docosahexaenoic acid (DHA, 22:6n-3), in the tissues of transgenic mice. Accordingly, the levels of the n-6 fatty acids LA and AA in the transgenic tissues are significantly reduced, indicating a conversion of n-6 to n-3 fatty acids. The resulting ratio of n-6 to n-3 fatty acids in the tissues of transgenic animals is close to 1. This n-3 rich lipid profile with a balanced ratio of n-6 to n-3 and an even more balanced AA/(EPA+DPA+DHA) ratio can be observed in all the organs/tissues, including muscle and milk. The muscle of the transgenic animals has the most significant change in these ratios, indicating the highest enzyme activity in this tissue. To date, four generations (homozygotes or heterozygotes) of transgenic mouse lines have been examined and their tissue fatty acid profiles show consistently high levels of n-3 fatty acids, indicating the transgene is functionally active in vivo and transmittable. Our data clearly show that the transgenic mice expressing the fat-1 gene are capable of producing n-3 fatty acids from n-6 fatty acids, resulting in enrichment of n-3 fatty acids in their organs/tissues without the need of dietary n-3 supply, which is impossible in wild type mammals⁷.

The available sources of n-3 fatty acids in our diets are from marine vertebrates, but stem from the ability of single cell phytoplankton and algae to convert the parent n-6 fatty acid, linoleic acid, to the parent n-3 fatty acid, α-linolenic acid, which enters the food chain of marine life and is further elongated and desaturated to produce the fish oil fatty acids EPA and DHA. As sources of edible fish in the oceans are being depleted by over-fishing and the market price of fish keeps rising, the continued supply of dietary n-3 PUFAs in the future is a concern.

Our findings provide a new strategy for producing n-3 PUFA-enriched foodstuff (e.g., meat, milk, and eggs) by generating large transgenic animals (e.g., cow, pig, sheep, and chicken) with the n-3 desaturase gene. In recognition of the health benefits of omega-3 fatty acids and the deficiency of these fatty acids in Western diets, a great effort has now been made to return omega-3 fatty acids to the food supply³. Since most animals cannot produce omega-3 fatty acids themselves, what the food industry is currently doing in order to enrich animal food products with n-3 fatty acids is to feed animals flax seed, fish meal, or other marine products. This feeding procedure is not only time consuming and costly, but source-limited. Thus, the feeding strategy seems to be an unsustainable method of producing omega-3 rich foodstuff. With the use of our gene transfer strategy, transgenic animals genetically capable of producing n-3 fatty acids themselves can be created. We could thus achieve an n-6/n-3 ratio approximating 1.0 by consuming foods with such a ratio without the public having to make stringent changes in their diets.

In addition, availability of the "Omega-3" mice will provide a unique model and new opportunities for elucidation of the biological functions of the n-3 fatty acids as well as the importance of supplementation with these fatty acids and the balance of n-6/n-3 ratio in disease-prevention and treatment. As interest in n-3 fatty acids is growing, the significance and impact of the availability of the unique transgenic mice for n-3 research are obvious.

1. Simopoulos AP and Cleland LG. (eds) (2003) Omega-6/omega-3 essential fatty acids ratio: The scientific evidence. World Rev. Nutr. Diet. (Basel, Karger) vol. 92.

2. Leaf A and Weber PC. (1987) A new era for science in nutrition. Am. J. Clin. Nutr. 45: 1048-1053.

3. Simopoulos AP et al. (eds) (1998) The Return of Omega-3 Fatty Acids into the Food Supply: Land-based Animal Food Products and Their Health Effects. World Rev. Nutr. Diet. (Basel, Karger) vol. 83.

4. Spychalla JP, Kinney AJ and Browse J. (1997) Identification of an animal omega-3 fatty acid desaturase by heterologous expression in Arabidopsis. Proc. Natl. Acad. Sci. USA. 94: 1142-1147.

5. Kang ZB, Ge Y, Chen ZH, Brown J, Laposata M, Leaf A and Kang JX. (2001) Adenoviral gene transfer of C. elegans n-3 fatty acid desaturase optimizes fatty acid composition in mammalian cells. Proc. Natl. Acad. Sci. USA 98: 4050-4054.

6. Niwa H, Yamamura K, and Miyazaki J. (1991) Efficient selection for high-expression transfectants with a novel eukaryotic vector. Gene 108: 193-199.

7. Kang JX, Wang J, Wu L, Kang ZB. (2004) Fat-1 transgenic mice convert n-6 to n-3 fatty acids. Nature 427: 504.

TRANSGENIC FISH BY ELECTROPORATION
Heather A. Hostetler

In the field of transgenics, there have been numerous methods employed in the transfer of foreign DNA to target organisms, and each has had varying success depending upon the recipient animal. To date, microinjection is still the preferred method for aquatic species, and many of the techniques are modified versions of those used in mammalian microinjection. However, significant differences in fish egg physiology (i.e., a large yolk, an impenetrable outer membrane, and overall opaqueness) make it impossible to inject DNA directly into the nucleus, which renders this method time consuming, labor intensive, and technically challenging.

Electroporation is an alternative that alleviates some of these difficulties and could greatly facilitate research and commercial development of transgenic animals. However, techniques for electroporation have not been standardized, and considerable variation exists among methods. Initial studies involving electroporation in aquatic species used a direct current (DC) with either a pulse of exponential decay or multiple rectangular pulses; however, levels of transfer were low, and expression questionable¹. As a modification to cell culture electrotransfection techniques, Chang combined the properties of a DC field and an oscillating field to produce a new waveform, called DC-shifted radio frequency (RF) pulses². The idea is that this new waveform would be gentler to the membrane and therefore increase the probability of the membrane resealing. We recently tested the efficacy of DC-shifted RF pulses to improve gene transfer in fish embryos and to determine if transgene expression could be achieved³.

The Japanese medaka (Oryzias latipes) was chosen as the study organism. Medaka offer several advantages as model organisms. For example, the medaka is a small, egg-laying freshwater teleost with a rapid generation time, large number of offspring, and external fertilization. Many aspects of this species have been well characterized, including physiology, genetics, and development. Medaka are easy to maintain in a laboratory setting, fertilization time can be predicted, and the fertilized embryos develop externally.

We used the commercially available Gene Pulser II and RF module (Bio-Rad Laboratories, Hercules, CA) with the reporter gene constructs pCMV-SPORT-ß-gal (Invitrogen, Carlsbad, CA) and the pEGFP-1 promoterless plasmid linked to a gene of agricultural importance. The pCMV-SPORT-ß-gal plasmid contains the ß-galactosidase gene from E. coli driven by the CMV promoter and followed by the SV40 polyadenylation signal. The EGFP construct consisted of the CMV promoter driving expression of both the egfp gene and the phyA phytase gene from Aspergillus niger. Plasmid DNA was purified using a commercial kit. Following fertilization, embryos were collected as quickly as possible. Embryos were rinsed with deionized water, separated into groups, and placed into a 0.4cm gap-width cuvette with supercoiled plasmid DNA resuspended in buffer.

Over 15,000 embryos were electroporated with pCMV-SPORT-ß-gal in order to determine how each parameter (buffer choice, buffer volume, quantity of DNA, total voltage, percent modulation of the wave, the radio frequency of the wave, number of bursts, length of bursts, time between bursts, and number of embryos) affected gene transfer. Following electroporation, embryos were rinsed with deionized water, placed within a homemade hatchery, and allowed to develop. At two weeks of age, fry were sacrificed, fixed, and stained overnight to detect ß-galactosidase activity. Transgenic fry were compared to wild type controls, and blue tissue staining was used as an indicator of transgene expression. Total voltage significantly affected survival of electroporated embryos, and this effect was influenced by buffer choice and volume. The radio frequency significantly affected the number of transgenics obtained, and this effect was most significant with 100% modulation of the wave. The length of the bursts as well as the amount of time between bursts also significantly affected the number of transgenic fry obtained.

Based upon these results, we concentrated on the effects of voltage, radio frequency, burst duration, and burst interval on gene transfer in embryos electroporated in groups of 50 with 4mg of plasmid DNA resuspended in 400ml of HEPES buffered saline solution. From these results, it is evident that voltage will not only affect survival, but in turn will also affect the probability of surviving fry being transgenic. For the most part, survival decreased as voltage increased, yet the percentage of fish with transgene expression increased as voltage increased up to 20-25V and then decreased. Similarly, as burst duration increased, survival decreased. However, the effect of burst duration on the production of transgenic fish was dependent upon the radio frequency. When the radio frequency was between 35 and 45KHz, the highest percentage of transgenics was obtained with a burst duration of 10msec; for a radio frequency of 30 or 50KHz, the highest percentage of transgenics occurred with a burst duration of 50msec. In contrast, the effect of the burst interval on the production of transgenic fish was linear and did not appear to be influenced by any other factor. As the burst interval increased, the efficiency of gene transfer decreased.

Since the expression patterns in the ß-galactosidase stained fish displayed a high level of mosaicism, we decided to test for germ-line integration, transmission, and expression of the transgene in subsequent generations. The EGFP construct was utilized because its expression can be observed in living organisms with minimal discomfort to the fish. Following analysis of the above parameters and their effects, we decided to use the same DNA concentration resuspended as above, 25V, 100% wave modulation with a radio frequency of 35KHz, and 3 bursts for 10msec each with a 1.0sec pause between bursts. These fish were grown to sexual maturity and a double back-cross performed. Approximately 85% of the founders that survived to sexual maturity demonstrated germ-line transmission to their offspring³. The observance of green fluorescent protein indicated transgene expression, and Southern blots demonstrated heritability of both the copy number and junction fragments of the transgene in a Mendelian fashion.

It is evident that electroporation has the potential to increase greatly the efficacy of transgenic fish production. We were able to use an electroporation device based upon the principle of a direct current with an oscillating field, called DC-shifted RF pulses, to produce effectively and efficiently germ-line transgenic medaka. Unlike microinjection, this technique is very rapid and easy to use, allowing for as many embryos as can be collected to be electro-porated in a day. Although some time is required to optimize the electroporation condition, once a set of conditions has been determined, it can be used repeatedly to produce transgenic fish with varying transgenes. The high percentage of transgenic fish obtained should allow for an abundant number of founders to be screened for proper or ideal expression, as well as to decrease the number of embryos needing to be sacrificed in order to obtain one transgenic one. Unfortunately, the RF module from Bio-Rad Laboratories is no longer commercially available.

1. Sin FYT. (1997) Rev. Fish Biol. 7: 417-441.

2. Chang DC. (1989) Biophys. J. 56: 641-652.

3. Hostetler HA, Peck SL, and Muir WM (2003) Transgenic Res. 12: 413-424.

The UK Copes with a Controversial Technology
On March 9 Margaret Beckett, Secretary of State for the Department for Environment, Food and Rural Affairs (Defra), advised Parliament of the government's policy on GM crops and gave a conditional approval for the cultivation of a GM maize variety. Mrs. Beckett declared that "[n]o other country has undertaken such a comprehensive and rigorous assessment of the case for and against GM crops." So far, nobody has disputed this claim.

During the latter years of the UK's investigation of GM food and crops, English Nature, the nature conservation and wildlife protection adviser, informed the government about its concerns regarding the effects of GM herbicide-resistant crops on biodiversity. The government responded by authorizing the Farm-Scale Evaluations, a three-year bio- diversity study of GM maize, beet, and oilseed rape crops.

Meanwhile, the Agriculture and Environment Biotechnology Commission, a strategic advisory body, suggested that the government fund an independently-run public debate on GM issues. The government agreed. In May 2002, Margaret Beckett announced that Defra and the Devolved Administrations in Scotland, Wales, and Northern Ireland would sponsor a dialog with three strands: a public debate called "GM Nation?," a cost-benefit study performed by the Prime Minister's Strategy Unit, and a review of the scientific issues relating to GM crops and food, conducted by a panel of independent scientists.

The three strands converged during the summer of 2003, producing a tightrope for the future of UK's GM technology. The public debate registered a general unease about GM food, and the participants gave little support for commercialization of GM crops in the near future. While the costs and benefits study concluded that currently available GM crops offer only limited benefits to UK farmers, the government suggested that future developments might provide benefits of greater value. The Science Review concluded that GM methodology is not a homogeneous technology, and that applications for GM crop approval should be assessed on a case-by-case basis. The science committee also found no evidence to suggest that current GM foods pose a greater risk to human health than their conventional counterparts. The main environmental risk with current GM crops, said the committee, is their potential impact on farmland biodiversity. And this is where the Farm-Scale Evaluations come in.

A consortium of research institutions performed the FSE project, in which about 60 fields each were planted with beet, maize, and spring oilseed rape. Each field was split, one half sown with a conventional variety managed according to farmers' normal practices, and the other half sown with a GM herbicide-tolerant variety. Researchers evaluated biodiversity effects by looking at the levels of weeds and insects in the fields. The results were published in October 2003 as a series of eight peer-reviewed scientific papers in the Royal Society's journal, Philosophical Transactions: Biological Sciences.

Margaret Beckett commissioned the UK's Advisory Committee on Releases to the Environment (ACRE)to assess the results of the FSEs. In January 2004, ACRE presented its findings and the Science Review published its second and final report. Both groups concluded that if GM herbicide-tolerant beet and oilseed rape were managed as in the FSEs then a significant reduction would be expected in weed biomass and weed seed return, and this would result in fewer nectar resources for pollinators and fewer weed seed resources for granivorous birds. That is, cultivation of the GM crops could present a danger to farmland wildlife. The maize study yielded opposite results: fields sown with GM maize produced more weeds and seeds than those planted with conventional maize.

The completion of the FSE study and the three strands of the public debate set the stage for a policy decision. Beckett's March statement to Parliament described the government's guidelines on GM agriculture. The government will assess GM crops on a case-by-case basis, taking an evidence-based approach to decision-making; institute mandatory labeling of GM food products; and consult on measures to facilitate the co-existence of GM and non-GM crops and on options to provide compensation to farmers of conventional and organic crops who suffer financial loss due to GM crop contamination.

Noting the results of the FSEs, Mrs. Beckett said that the government will oppose EU approval for the commercial cultivation of the GM beet and oilseed rape varieties as grown in the trials. But the government would allow the commercial cultivation of the GM corn selected for the FSEs, Bayer CropScience's Chardon LL (T25) forage maize. Farmers would have to cultivate the maize under the same conditions used in the trials or under other environmentally-safe conditions.

Beckett also addressed concerns that a GM crop could affect wild type relatives. She observed that maize has no wild type counterparts in the United Kingdom and suggested that it is highly unlikely that any stray remaining plant or seed would survive a UK winter to initiate a subsequent crop. These characteristics of maize cultivation in the United Kingdom, she said, reinforce the value of a case-by-case approach to GM crop approval.

Despite these reassurances, the government offered only a conditional approval for Chardon LL; there would be many hurdles to go.

Bufferin' Zones, Provisos, and Mounting Tensions
Before any business commercially cultivates a GM crop, the UK government may require placement of coexistence measures. A new public consultation exercise, scheduled for the summer, will focus on separation distances between crops necessary to prevent cross-pollination. The government plans to announce the results of scientific and public consultation on separation schemes by the end of the year. In early 2005, legislation should be progressing to give statutory backing to a regime for growing GM crops that incorporates a separation system.

The government will also develop a compensation program for conventional or organic farmers who experience GM crop contamination. Like the buffering zone issue, the compensation plan options will emerge from a public consultation before formulating legislation. In her Parliament address, Margaret Beckett emphasized that any compensation scheme must be funded by the biotechnology industry, rather than by the government or producers of non-GM crops. Paul Rylott, head of BioScience UK at Bayer CropScience, predicted that the industry would never agree to the suggestion that biotech companies must foot the bill to compensate farmers for GM crop contamination.

Another prerequisite for commercial cultivation of Chardon LL is that the maize must be added to the UK National List of Varieties as suitable for growing. In the post-devolution United Kingdom, ministers in England, Wales, Scotland, and Northern Ireland must agree to add a seed to the List. However, Carwyn Jones, the Welsh Assembly's Environment Minister, announced on March 24 that he will not add Chardon LL to the List without the authorization of the Assembly through a free vote on the issue. Dr. Brian John of GM Free Cymru asserted that it is highly unlikely that the Assembly would approve the listing.

These additional hurdles promised more than a simple delay in cultivating Chardon LL: they narrowed a window of opportunity. Bayer CropScience's EU marketing consent for the maize expires in October 2006. And Margaret Beckett warned the company that an application for a new license would have to include data comparing the cultivation of the GM maize with whatever herbicide practice is in operation with conventional maize at that time. In the FSE's, farmers had sprayed conventional maize with the weed killer atrazine, a herbicide that will be banned across the European Union by April 2005.

Bayer Cures its GM Maize Headache
On March 31, Bayer CropScience announced that it would discontinue further efforts to commercialize Chardon LL in the United Kingdom. Dr. Julian Little, a company spokesman, told the BBC News that uncertainties and undefined timelines associated with the UK's conditional approval "makes an already ageing variety old and essentially economically unviable." The withdrawal of Chardon LL may end Britain's commercialization of GM crops until at least 2008 when Bayer CropScience, Monsanto and Syngenta will attempt approval for GM sugar beets and oilseed rape.

Bayer deals blow to UK GM crops. (2004) BBC News. March 31, 2004.

Brown P. (2004) Green light for GM crop, but rift threatens planting. The Guardian (Manchester), 2, March 10, 2004.

It was not mentioned that Alexander Sorokin of Sainsbury Laboratory has patented the rhamnolipid expression system through Plant Bioscience Limited, Norwich, UK. UK Priority Patent Application No. GB 0228444.6 and International Priority Patent Application No. PCT/GB2003/005322 were both filed in December 2003 by Sorokin, AP, Brychkova, GG, Kartel, NA and Jones, JJ. A paper describing the expression system will also be appearing in Nature Biotechnology.

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