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 Sirinathsinghji

Rothamsted 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.
Despite 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.

What 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 [1]. 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.
The 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 [2].


The pheromone (E)-ß-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.


The 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 [2], “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 [3] Transgenic Lines Proven Unstable, SiS 20).


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 [4] 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.


Kanamycin is still in clinical use and also cross reacts with other new antibiotics (see [5] Kanamycin Still Used and Cross-Reacts with New Antibiotics, ISIS report).


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.


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