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Liberty Link rice raises specter of tightened regulations

The discovery of traces of unapproved genetically modified rice in United States exports has once again put the spotlight on biotech companies’ failure to fully contain field trials and on governments’ inability to keep the food supply free of unapproved traits. Although public reaction to the latest escape has been restrained, the LLRICE-601 case will further increase pressure to tighten regulation of field trials and screen imported crops for ‘unknown’ genetic modifications.

On August 18, 2006, the US Department of Agriculture (USDA) announced that LLRICE601, an unapproved genetically modified (GM) rice variant developed by what is now a subsidiary of chemical company Bayer of Leverkusen, Germany, had been found in US rice export storage bins as far back as January of this year. During the weeks following, in European countries such as Germany, Italy, Switzerland and The Netherlands, many loads of US long-grain rice shipments tested positive for traces of the strain.

LLRICE601 is engineered to tolerate glufosinate, an herbicide sold under the brand name Liberty Link. The tolerance was introduced through a Streptomyces hygroscopicus gene that codes for phospinothricin acetyl transferase (PAT), a glufosinate-inactivating enzyme. PAT is also expressed in LLRICE06 and LLRICE62, two other Bayer rice strains approved by the US in 1999. The latter of the two strains is currently undergoing safety assessments in the EU. According to both US and EU regulators, trace amounts of LLRICE601 in food do not warrant immediate safety concerns.

The discovery of unapproved GM rice in food triggered a fall in rice export prices, prompting a string of lawsuits from angry growers. US rice growers had rejected GM rice thus far for fear of market rejection in the US and abroad. “The rice industry has long opposed the commercialization of genetically engineered rice until such time as there is consumer acceptance…,” says David Coia, spokesman for the USA Rice Federation, a Washington-based trade organization. “The discovery of trace amounts of…LLRICE601 in commercial supplies came as a surprise to rice growers, millers and merchants,” Coia says. Bayer CropScience of Monheim am Rhein, Germany, declined to comment.

In addition, the event elicited strongly worded statements from anti-GM groups such as Greenpeace and Friends of the Earth. “This…incident highlights that the biotechnology industry is unable to keep its crops under control,” Helen Holder, a campaigner at Brussels-based Friends of the Earth Europe, said in a statement.

What exactly caused the escape of LLRICE601 was still the subject of a USDA investigation by the time Nature Biotechnology went to press, and people close to the case refuse to speculate about the outcome. It could have been anything from gene-flow out of field trial plots to the inadvertent mixing of seeds during transport or processing (Box 1, see below).

For the USDA, the contamination case has revived the debate over a scathing audit report by its inspector general for the Southwest region, issued last December. The report slammed the USDA’s Animal and Plant Health Inspection Service (APHIS) for sloppy oversight of field trials with GM crops. In some cases, the report said, the agency didn’t even know the location of trial plots, although it was supposed to monitor them several times a year. Despite many precedents in contamination (Box 2, see below), APHIS still does not require companies to describe beforehand how they will contain their GM crops. In its response to the inspector general’s criticism, the USDA says it has started or completed implementation of 23 of his 28 recommendations. Yet the agency says it will not require companies to submit protocols for the containment of field trials.

On the other side of the Atlantic, the European Commission is already turning up the heat in response to the incident. Health and Consumer Safety Commissioner Markos Kyprianou has recently asked his staff to come up with better tools to prevent future contaminations. Testing for GM crops that haven’t yet been approved elsewhere is problematic, but researchers in the Co-Extra project—an EU research program on coexistence and traceability of GM and non-GM crops—are exploring ways to detect such ‘unknown events’, possibly through the use of DNA microarrays and algorithms that can flag unusual DNA arrangements.

Another way to simplify testing for unapproved strains would be to ask companies for detailed information on GM crops before they start field trials rather than when they seek market approval. In the US, the government has signaled it is willing to travel that route. According to APHIS spokesperson Rachel Iadicicco, the USDA plans to publish a programmatic environmental impact statement within the next half year. The document will outline safety criteria for allowing small amounts of unapproved materials. “Companies will be strongly encouraged to address safety issues very early on in the field trial process,” Iadicicco says. Having good data on the safety of new proteins will make it easier to immediately reassure consumers should ‘contamination’ occur. Michael Phillips, a vice president at Washington, DC-based Biotechnology Industry Organization, a US biotech trade organization, says his organization is ready to discuss such ideas with the USDA. “After all, we are talking about proteins that are meant to go into the food chain,” he adds.

The EU could also decide to add requirements to field trial regulation. “I believe we will see changes in legislation, requiring companies to submit more information at the time of applying for field trial permits,” says Arne Holst-Jensen, a researcher at the National Veterinary Institute in Oslo, Norway, who coordinates the work on ‘technical challenges of GMO detection’ at Co-Extra. In Europe, such adjustments could have much more far-reaching effects.

Unlike the US, which prefers to target its testing at proteins, EU scientists prefer DNA-based tests because they can distinguish between approved and unapproved strains carrying the same gene constructs and are better able to detect traces in processed foods. In the LLRICE601 case, for instance, protein-based tests would not necessarily raise red flags when other PAT-containing rice strains or crops have been approved. DNA-targeting tests, on the other hand, can detect unapproved LLRICE601 seeds in shipments of approved varieties containing the same tolerance gene. The same would be true for the many different seed lines that are still being tested in the field.

Requiring companies to present precise sequence information, PCR tests and reference material for every GM event that is tried out in the field, however, will make doing field tests close to impossible, says Simon Barber, director of the plant biotech unit of EuropaBio, a European biotech trade organization based in Brussels. “Breeders typically put out many seed lines before selecting the best ones,” Barber says. “It would take enormous amounts of money and work to create validated tests for all those separate lines. Companies would be severely limited in their ability to perform field trials.”

How did unapproved rice get mixed up with the food supply?

The US Department of Agriculture is investigating the mix-up, but whether the agency will be able to solve the puzzle remains to be seen. But one theory that is attracting particular attention was triggered by the discovery of LLRICE601-contaminated foundation seeds at the Louisiana State University (LSU) Agricultural Center in Crowley.

Between 1999 and 2001, LSU field tested LLRICE601 for Aventis CropScience of Research Triangle Park, in North Carolina, the company that was later acquired by Bayer, and became Bayer CropScience. During the same period, LSU was also developing new rice varieties through conventional breeding. The 2003 seed stock of one of them, Cheniere, tested positive for LLRICE601 last August. Seeds derived from this stock have been grown across the rice-growing areas of the southern US, says Steve Linscombe, director of the LSU AgCenter Rice Research Station.

How GM rice could have spilled into LSU’s Cheniere foundation seed stocks is still unclear, however. According to Linscombe, nowhere had the Cheniere and LLRICE test plots been less than 160 feet (48 meters) apart, much more than the 30 feet (9 meters) required by the USDA. Mix-ups during or after harvest seem equally unlikely, says Linscombe, because the research center is zealous when it comes to cleaning its equipment. “Keeping seeds apart is what we do every day,” Linscombe says.

Field trials other than those at LSU could also have contributed to the escape. Between 1996 and 2001, Bayer CropScience and its predecessors had permits to test LLRICE varieties on thousands of acres in Arkansas, California, Louisiana, Missouri, Texas, Florida, Haiti, Puerto Rico and Mississippi. The company will not speculate on what may have happened.

Incidents when unapproved biotech crops reached food chain

2001 A GM corn variety called Starlink, developed by Aventis CropScience, was found in hundreds of food products despite being approved for use in animal feed only ( Nat. Biotechnol. 19, 11, 2001 ).

2002 Traces of corn containing an experimental pig vaccine developed by ProdiGene (College Station, Texas) were found in soy grown on former test plots in Nebraska. The USDA later imposed a $250,000 fine on the company because of its failure to contain the GM corn ( Nat. Biotechnol. 21, 3–4, 2003 ).

2005 The Basel-based agrochemical company Syngenta acknowledged that unapproved Bacillus thuringiensis (Bt)-10 corn had found its way into stocks of approved Bt-11 corn, leading the EU to temporarily halt corn shipments from the US ( Nat. Biotechnol. 23, 514–514, 2005 ).

2006 In the midst of the LLRICE601 case, German authorities confirmed claims by Greenpeace that an unapproved Bt rice strain had turned up in Asian food store products in Germany, one year after the environmental group claimed it had found the same Bt rice in food stores in China.


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