Crucial information omitted from public discussion discredits the
public-funded research institute: it has close ties to industry, the GM crop has
not been molecularly characterized or tested for potential risks to health or
the environment, it carries genes for antibiotic resistance and tolerance to
glufosinate, a herbicide banned in Europe, and the anti-aphid trait on trial is
very likely to be ineffective Dr Eva
Institute in Hertfordshire, UK, has begun an open-air GM wheat trial that is
re-energising the country’s debate on genetically modified (GM) crops. The crop
has been engineered to produce an aphid ‘alarm’ pheromone that aims to repel
the aphid pests from the crop and/or attract aphid predators.
the media hype, there has been no critical analysis
of the scientific or political rationale behind the project. The huge PR
campaign headed by the lobby group Sense About Science has successfully
confused the public and obscured the facts. Meanwhile, Rothamsted is pressing
for debates with GM sceptics in an attempt to convince the public that the GM technology
is based on environmental principles, and is needed to feed a starving world.
But evidence of the technology’s effectiveness, safety and potential non-private
beneficiaries is conspicuously lacking. The inclusion of a herbicide tolerance
(see below) trait in the crop – not disclosed to the
public - also discredits the institute’s claims of being “environmentalists” with
aims to promote sustainable agricultural practices and reduce chemical use.
is the GM wheat?
According to Rothamsted, these new GM crops are “designed to
‘emulate’ a plant’s natural defence system” and have been shrewdly dubbed “second
generation” GM crops, distinguishing them from the herbicide-tolerant crops
that currently dominate the market . Herbicide-tolerant crops promote the
use of chemical herbicides, as GM plants made tolerant to them will not die
after application. The scientists claim that their new strategy will reduce
pesticide use, as aphids will be deterred from the crop, and the pheromone may
also attract aphid predators to the plant.
GM spring wheat allegedly contains a modified version of an ‘alarm’ pheromone
normally produced by aphids to alert them of danger. Currently, there is no
published data on this GM crop, so there is little scientific information on
the genetic modification or the GM plants themselves to justify the project. What
little information there is has come from press releases and from the institute’s
application for consent to release the GM crop available on the internet .
pheromone (E)-β-farnesene (EBF) is produced by some plants such as
peppermint as a natural defence against aphids. The experiment will test two
different varieties of pheromone-producing wheat. One expresses the alarm
pheromone alone, and the second expresses the pheromone and an additional
enzyme that increases the levels of pheromone substrate, and therefore levels
of the pheromone itself.
DNA sequences put into the wheat include chimeric versions of the peppermint
gene encoding EBF synthase, expressed under the maize ubiquitin promoter 1. EBF
synthase converts substrates including farnesyl diphosphate (FPP) into EBF. The
Ubiquitin promoter is expected to express the enzyme
everywhere in the plant. The second GM wheat produces in addition FPP synthase,
the enzyme that makes FPP. The theory is that more substrate will be available to
increase pheromone production. The first line carries 4 copies of the EBF
synthase transgene, while the second line contains one copy of both the
EPF synthase and FPP synthase transgenes. As stated in Rothamsted’s application
, “the nucleotide sequences of these genes are synthetic and chimeric and
not found naturally”. They have not analysed the genome of the GM wheat to determine the structure or location of the
inserted DNA. The transgenes were judged to be stably inherited according to
the PCR experiments. But without thorough molecular genetic characterization, transgene
instability cannot be ruled out, and this is a notorious limitation of
genetic modification of crop plants (see  Transgenic Lines
Apart from the pheromone-related genes, there are extra DNA
elements including neomycin and kanamycin antibiotic resistance, and both DNA constructs also
contain a gene conferring resistance to glufosinate ammonium herbicides. These
can be used as selectable markers for transgenic plants  but are surplus to
requirement in protecting plants against aphid attack; and should have
been removed from the transgenic plants to prevent the genes from spreading to
other crops and indeed to bacterial pathogens in the environment.
The only information published by Rothamsted on any aphid-repelling
GM crops refers to kanamycin resistance for selection, so the herbicide
resistance trait is not even used. But there is a clear intention to benefit
from this trait once the crop is commercialised. As stated in their
application, “these plants possess the ability to tolerate glufosinate-based
herbicides which would increase their survivability in environments where these
herbicides were the only ones used”.
It also transpires that Bayer, the major producer of glufosinate
and glufosinate-tolerant crops including canola, soybean, cotton and corn, is a
partner of Rothamsted.
The fact that glufosinate herbicides have been banned in the EU since 2009 due
to their high toxicity in mammals (including
reproductive problems) raises the question – is this product really
aimed for the UK market? The fact that the wheat is also the spring and not
winter variety adds further weight to this question, as
the overwhelming majority grown in the UK is of the winter variety.
regards to general plant health, no physiological or morphological analyses of the plants were performed on the grounds that  “no other changes
to the plant morphology or development are apparent”.
experiments with alarm pheromone
There have been no publications on the new GM wheat. The
institute, did however, publish results of a flowering plant, A. thaliana
also expressing the pheromone . The study looked at acute effects on aphid
behaviour but did not test any long-term impacts on aphids or beneficial
insects. Aphids were exposed to the pheromone either in droplet form or
through exposure to air space above the plants for 1 minute or 15 minutes. They
recorded a near 80 % behavioural response to EBF-containing droplets after one
minute that was reduced to around 40 % after 15 minutes. Exposure to air space
above the transgenic plants elicited a near 15 % response after 1 minute that
was also reduced to below 10 % after 15 minutes. The
length of time the predator species D. rapae spent on the GM plants was
also increased from 10 to 15 minutes.
trend for a reduction of aphid response from 1 to 15 minutes exposes a
limitation in the technology that has been highlighted in other studies - the
potential habituation of aphids to the pheromone. Ordinarily, aphids release
these signals in acute pulses, which differ significantly to the continual
expression in GM crops.
A follow up study performed in Germany using the same GM A.
thaliana plants made by Rothamsed, found that the aphids no longer
responded at all in the long term . An experiment allowing aphids to choose
between GM and control non-GM plants over a period of 2 weeks found no
significant difference. They also analysed the numbers of winged morph
offspring that were produced. EBF is thought to increase the numbers of winged
aphids that can then escape potential danger. There were no differences in the
total numbers of offspring or the percentage of winged offspring produced.
study, again using Rothamsted’s GM A. thaliana found habituation to the pheromone with no significant difference in response to GM
versus non-GM plants after only 3 generations . There was a fitness
cost to the habituation, with more being predated after 24 hours of
co-habitation with beetles. It would have been interesting to see the effects
on predators over a longer period of time. The rapid habituation to the
pheromone suggests that the GM wheat will not have any long-lasting effects,
and simple laboratory experiments prior to field release would have provided
answers to these basic questions.
Risks of genetic contamination
The researchers are claiming risks of genetic contamination to be
negligible, although possible. However, genetic contamination of wheat has been
documented in the past, and widespread contamination by other GM crops
including corn and canola has been well documented.
Wheat is predominantly self-pollinating, but can also cross-pollinate,
the level depending on many factors including weather conditions, wild-life,
and size and densities of both GM fields and donor plant fields. Insect
pollination can also occur in hot conditions during seed set. As stated in the application
 “Dispersal of seed prior to harvest by wind is unlikely, but possible by
wildlife”. They also admit that: “Under certain growing
conditions individual genotypes may have out-crossing rates of up to 4-5%”.
Further, the trial report does not deal with seed transfer by birds and small
four-footed animals both in faeces and by sticking to feet and feathers or
coats. It is very difficult to prevent small animals from spreading
wheat grains. The sucking nature of aphid feeding can also enable the transfer
of transgenic DNA to other plants.
grain obtained will be disposed of in a deep landfill using an approved
contractor, however there is no discussion of the predictable spread of seed
along roadways from truck wheel, wells etc. This has already led to the
contamination of seed stocks, roadsides and rail tracks with
herbicide-resistant rapeseed (called canola in the US) in Japan and Canada that
has all but decimated Western Canada’s organic trade of the crop (see Transgenic
Contamination of Certified Seed Stocks, SiS19). Coincidentally, Maurice Maloney,
current director of Rothamsted Institute, had developed glyphosate-tolerant rapeseed.
GM wheat has already contaminated non-GM seed stocks in wheat samples obtained from certified seed producers in Colorado, USA .
GM wheat trials with a 200 metre buffer zone of pollen receptor plots did not
prevent pollen-mediated genetic outflow in Switzerland . The buffer zone
proposed by Rothamsted Institute, is for cereals not to be grown at less than
80 metres surrounding the trial field.
gene transfer is an alternative form of genetic contamination whereby transgenic DNA can be taken up by unrelated species such as
microorganisms in the soil or on the plant surface. Horizontal gene transfer
and recombination is the main route for generating new pathogens and spreading
antibiotic and drug resistance, and genetic engineering is nothing if
not greatly facilitated horizontal gene transfer and recombination. Transgenic
DNA is different from natural DNA; not only does it contain new combinations of
genes, but also new synthetic genes that have never existed in billions of years
of evolution: new coding sequences, promoters and other non-coding regulatory
sequences that boost gene expression to abnormally high levels (see  Horizontal Gene
Transfer Does Happen,
SiS 38,  Scientists Discover
New Route for GM-gene 'Escape', SiS 50).
use of the bacterial vector Agrobacterium tumefaciens which is capable
of infecting bacterial cells that exist in the soil and gut, as well as human cells can cause DNA
mutations and possible cancer development. The application states : “The
plasmid backbone sequences, nptI gene [antibiotic resistance], origins of
replication, border sequences etc. come originally from E. coli and Agrobacterium
tumefaciens, two common gut and soil bacteria respectively and these
sequences are already widespread in the soil metagenome”. They further state
that “These elements may increase the rates of horizontal gene transfer and
establishment in soil bacteria because they provide a theoretical mechanism for
homologous recombination and selection.” Despite this admission, risks during
the trial are estimated “negligible”, and such elements are already “common” in
bacterial species anyway.
research at Rothamsted
of the media attention surrounding the Institute has aimed to distinguish it
from the private corporations that have commercialised most GM crops. Although
Rothamsted is a public institution with research money awarded by the
government’s BBSRC (Biotechnology and Biological Sciences Research Council), it
has a long history of chemical agriculture and has
commercialised herbicides in the past, including 2,4-D which is a component of
the notorious Agent Orange pesticide used in the Vietnam war. They also
invented pyrethroid insecticides, which are the most common insecticides today.
Indeed, the Institute was founded in 1843 by John Bennett Lawes, who a year
earlier had opened up a chemical fertilizer company that marked the beginnings
of the chemical fertilizer industry. Rothamsted was set up to investigate the
differences between inorganic and organic farming. Their links to chemical
agriculture is not new or unusual. A recent publication supporting the use of
paraquat herbicides for sustainable agriculture was timed with the EU-wide
re-introduction in 2003 after individual nations had banned it due to health
concerns. In 2007, an EU-wide ban was put in place with links to Parkinson’s
disease amongst the major concerns.
That is not all.
links to corporate agribusiness
As proudly stated on Rothamsted Institute’s website:
“Our portfolio of industrial partners includes global agri-biotech
companies such as Syngenta, Dow Agrosciences, Bayer Agriculture, BASF and
Monsanto and multinational organisations such as British Sugar and Novozymes
Biologicals Inc. Examples of collaboration with Small and Medium-Size
Enterprises include work done with VSN International, BioForsk and ADAS. We
also have projects funded by industrial organisations such as the National
Farmers Union and the British Beet Research Organisation. The quality and
impact of our input is such that we have been very successful in building
long-term relationships with our partners.”
Can one still believe Rothamsted’s GM wheat is a
mere experiment with no commercial objectives in mind? Should taxpayer’s money
be hijacked to support GM development for corporate agribusiness without regard
for potential damage to health and environment?
MH, Birkett MA, Bruce TJ, Chamberlain K, Field LM, Huttly AK, Martin JL, Parker
R, Phillips AL, Pickett JA, Prosser IM, Shewry PR, Smart LE, Wadhams LJ,
Woodcock CM, Zhang Y. Proc Natl Acad Sci U S A 2006, 103, 10509-13.
G, Reinhold C, Gershenzon J. Constitutive emission of the aphid alarm pheromone,
(E)-β-farnesene, from plants does not serve as a direct defense against
aphids. BMC Ecology 2010, 10, 23-35.
Vos M, Cheng WY, Summers HE, Raguso RA, Jander G. Alarm pheromone habituation
in Myzus persicae has fitness consequences and causes extensive gene expression
changes. Proc Natl Acad Sci U S A 2010, 107, 14673-8.
Gaines T, Preston C, Byrne P, WB
Henry, Westra P. Adventitious Presence of Herbicide Resistant Wheat in
Certified and Farm-Saved Seed Lots.
A, Quijano CD, Moullet O, Fammartino A, Kneubuehler Y, Mascher F, Sautter
C, Bigler F. Surveying of pollen-mediated crop-to-crop gene flow from a wheat
field trial as a biosafety measure. GM Crops Food 2012, 3 [Epub ahead of