ISIS Report 30/03/05
Syngenta's GM Maize Scandals
A trail of unstable GM maize varieties, dead cows,
cross-contamination and misinformation
Prof. Joe Cummins and
Dr. Mae-Wan Ho demand a full
disclosure of all available data for damage limitation
Farmers who bought Syngenta’s genetically modified (GM) maize Bt11
may, in fact have got more than they bargained for, because many received
another GM variety Bt10 that may be worse. The news broke in the science
journal Nature. Several hundred tonnes of the unapproved GM maize
variety Bt10 had been "inadvertently" distributed under the Bt11 label between
the years 2001 and 2004. Syngenta claimed that Bt11 and Bt10 are physically
identical [1], but this is impossible to achieve in the current state of the GM
technology, and is at odds with its own reports to USDA/APHIS in 1994.
Eleven years ago the Northrup-King company (later taken over by
Syngenta) reported that Bt10 produced several times less toxin than Bt11 even
though the two lines were modified with similar sets of transgenes; but the
transgenes had inserted at different sites in the maize genome.
Bt11 has been approved for consumption in Argentina, Australia, Canada,
China, European Union, Japan, Korea, Philippines, Russia, South Africa,
Switzerland, Taiwan, United Kingdom, United States and Uruguay [2].
Northrop-King Company consulted the US Food and Drug Agency (FDA), and provided
minimal evidence that the maize strain was substantially equivalent to
unmodified maize [3, 4]. It applied for non-regulated status in the US in 1995,
which USDA/APHIS granted a year later [5].
Substituting the unapproved GM maize Bt10 for Bt11 is a very serious
breach of safety. But Bt11 maize is already bad enough, and should never have
been approved ("Approval of Bt11 maize endangers humans and livestock",
SiS 23). The
European Commission gave it approval in May 2004 when expert committees
repeatedly failed to reach an agreement. French and Belgian government
scientists had reported "rearrangements, truncations and unexpected insertions"
in Bt11. The main insert appeared to have landed in what turns out to be a
suspected "megatransposon" involved in exchanging segments between chromosomes,
making the variety potentially very unstable. Bt11 was also contaminated with
another Syngenta GM maize, Bt176, also found to be unstable and misidentified
("Unstable transgenic lines illegal
SiS 21), and was
implicated in the death of at least a dozen dairy cows in Hesse Germany ("Cows
ate GM maize and died", SiS 21). Watch
this space.
According to the petition from Northup-King [6], Bt11 (and also Bt10)
was constructed using the Cry1Ab toxin gene from Bacillus thuringiensis
var kurstaki that had been altered extensively and the protein shortened to
enhance expression in maize, and controlled by a cauliflower mosaic virus 35S
promoter enhanced by a maize alcohol dehydrogenase intron, and the nos
transcription terminator from Agrobacterium. A second transgene coding
for phosphoinothricin acetyl transferase (PAT) from Streptomyces, also
altered extensively and controlled by the same promoter and terminator, confers
resistance to the herbicide glufosinate; although the GM maize was not marketed
as herbicide resistance. The two structural genes were inserted into the long
arm of maize chromosome 8, it was claimed.
An appendix [7] to the Northrup King petition compared the production
of the events Bt11 and Bt10. The Bt10 event was not characterized as to the
chromosomal site of integration nor was there extensive analysis of the gene
inserts and their protein products. The study showed that Bt11 produced about
seven times more toxin protein than Bt10, indicating a clear difference between
the two events. Farmers unknowingly planting Bt10 in place of Bt11 would be
prone to experience insect resistance in the low toxin maize.
An advice on Bt11 from UK’s ACRE (Advisory Committee on Releases to
the Environment) [8], made reference to data provided by Syngenta to support
its claim that the ampicillin resistance marker gene was absent from Bt11, in
which Bt10 was used as a positive control. This implies that the
antibiotic resistance marker gene is indeed present in Bt10. Syngenta has now
admitted to this [9], but a spokesperson from the company downplayed the
significance of the antibiotic resistance marker gene. Ampicillin is a widely
used clinical antibiotic, and the European Food Safety Authority, the Codex
Alimentarius, and many medical and scientific experts have recommended against
using antibiotic resistance genes in GM foods, hence Bt10 is unlikely to have
received regulatory approval in Europe.
There are also as yet unconfirmed reports that the Bt10 inserts have a
promoter different from Bt11 and that the enhancer has been altered.
The Australia-New Zealand Food Authority reported that the Bt11 PAT
gene is driven by the 35S figwort mosaic virus [10] instead of the 35SCaMV
promoter reported to USDA/APHIS and the European regulatory authorities. The
Canadian Food Inspection Agency reported more than one Cry1Ab toxin protein
produced in Bt11, these included proteins of 69kDa, 65kDa and two minor ones of
40kDa and 15kDa [11]; suggesting that the toxin is processed or degraded in
Bt11 maize. The toxins produced in event Bt10 have not been reported to public
and this information should be made available immediately.
There was a long delay between the discovery of large plantings of Bt10
and the report to the public. Syngenta, the FDA [12] and UK DEFRA (Department
of the Environment, Food and Rural Affairs) [13] have all initially claimed
that Bt10 and Bt11 are identical. This claim was made in the face of clear
evidence that the two events were different, according to information available
to UK’s ACRE at least since 2003 [14].
There must now be a full disclosure of all available data to limit the
damages being done.
Reference
1. Macilwain C. US launches probe into sales of unapproved transgenic
corn, Nature 2005, 434, 424.
2. Agbios Bt11 approvals http://www.agbios.com/
3. US Food and Drug Administration Biotechnology Consultation Agency
Response Letter BNF No.000017 1996 http://www.cfscan.fda.gov/
4. US Food and Drug Administration Biotechnology Consultation Note on
the File BNF No.000017 1996 http://www.cfscan.fda.gov/
5. Payne J. USDA/APHIS Petition 95-195-01 for Determination of
Nonregulated Status for Bt11 Corn 1996.
6. Pilacinski W and Williams D. Petition for Determination of
Nonreguloated Status for: Insect protection corn expressing the Cry1Ab gene
from Bacillus thuringiensis var. kurstaki 1995.
7. Hanten J and Meeusen R. Petition for Determination of Nonreguloated
Status for: Insect protection corn expressing the Cry1Ab gene from Bacillus
thuringiensis var. kurstaki Appendix G Determination of levels of plant
produced Bacillus thuringiensis kuastaki HD-1 proteins in transgenic maize.
1994.
8. Advisory Committee on Releases to the Environment. Advice on a
notification for marketing of insect resistant and herbicide tolerant GM maize.
http://www.defra.gov.uk/environment/acre/advice/pdf/acre_advice35.pdf
9. "Stray seeds had antibiotic-resistance genes" Colin Macilwain,
Nature online, 29 March 2005.
http://www.nature.com/news/2005/050328/full/434548a.html
10. Australia-NewZealand Food Authority Draft Risk Analysis Report
Application A386 Food derived from insect protected herbicide tolerant Bt11
corn 2000.
11.Canadian Food Inspection Agency Decision Document DD96-12:
determination of environment safety of Northrup King Seeds European corn borer
resistant corn 1996.
12. Press Release: Following Syngenta-initiated investigation of
unintended corn release, EPA and USDA conclude existing food safety clearance
applies, no human health or environmental concerns, Washington, DC (USA), 21
March 2005, Syngenta web site.
http://www.nature.com/news/2005/050321/full/nature03570.html
http://www.syngenta.com
13. DEFRA Press Release, 23 March 2005 (see below)
http://www.gnn.gov.uk/Content/Detail.asp?ReleaseID=153346&NewsAreaID=2
14. "DEFRA accused of key role in GM contamination cover-up", Press
Notice from GM Free Cymru 30 March 2005
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