|Non-GM wheat kernels|
Photo by David Shand
Strangely however, the message never seems to have reached biotech scientists, nor their funders. The development of GM wheat has continued behind lab doors regardless of public or commercial desires. At least two strains of a novel wheat are now ready for field testing in the UK.
The Department of the Environment, Food and Rural Affairs (DEFRA) has received an application from Rothamsted Research to carry out a two-year field trial of aphid-resistant GM wheat, to run during 2012 and 2013.
Aphids are sap-sucking insects which weaken the plants they are feeding on, and can transmit disease. They rapidly form dense colonies on their host plants due to their ability to produce large numbers of daughters without sexual reproduction. In a natural ecosystem, aphid numbers are controlled by insect predators and parasites.
The mechanisms by which aphids find their host plants to start with, and by which plants defend themselves against aphids, and by which aphids defend themselves against their enemies, all seem to be based on volatile chemicals. On release, these chemicals become gaseous and their presence in the air acts as a signal. Both plants and aphids produce such signals.
The most common amongst the volatile chemicals has been identified as E-β-farnesene (EBF). Scientists have found that some aphids release EBF into the air around them when they're attacked. This release signals to the rest of the colony to leave the area of danger, the host plant. EBF can also be detected by some of the aphids' predators which then know there's a colony of food nearby.
Genetic engineers plan to use a GM version of this mechanism to protect wheat against aphids.
Because wheat has an existing metabolic pathway which can be tweaked to divert it into EBF production, a single gene has been concocted which produces a single extra enzyme to achieve this. Levels of artificial EBF can also be boosted by a second gene whose enzyme feeds the EBF-producing pathway.
Rothamsted scientists have created two experimental GM wheat lines: one has four copies of the EBF gene; the other has one copy of the EBF gene plus one booster gene; the latter generates over sixty times the EBF of the other line. The research has reached the stage when actual effects on real aphids and their enemies in the field require to be assessed.
Like all GM ideas, EBF-generating wheat is simplistic. Real plants and aphids don't produce just one chemical in standard amounts. They release varying profiles of a range of interactive volatile substances, some of which may not even be produced by them in the first place, but which may well be part of a sophisticated detection and communication system. There are hundreds of aphid species (e.g. over 300 have been counted in Belgium alone). Each aphid species will produce unique spectra of volatile chemicals.
In the short-term, the GM wheat may well have the desired, beneficial effect. In the long-term, the large-scale, high-volume, continuous and unintelligent generation of a single, artificial form of EBF could cause very harmful ecological upsets; for example, a shift in the distribution of aphids or their enemies in neighbouring areas, evolving aphid species which switch hosts, or evolving predators which switch prey.
The cost and time required for a meaningful assessment of such ecological effects, which would necessarily be long-term, are prohibitive.
Rothamsted's consideration of humans health effects is dismissive due to the ubiquitous nature of EBF and its natural instability. Side-effects arising from the metabolic alterations induced in the plant, or from the uncontrolled artificial generation of EBF or its booster precursor in the plant are not considered. Wheat intolerance is a severely debilitating condition which is on the increase. The cost and time required for meaningful assessment of human health effects, which would necessarily include long-term clinical studies, are prohibitive.
The constructed genes, are both entirely artificial, while the enzymes they produce have some degree of superficial resemblance to enzymes found in peppermint plants and cows. Any notion of 'substantial equivalence' to anything natural is untenable.
Rothamsted acknowledges the risk of horizontal gene transfer due to the inclusion of DNA from soil bacteria in their construct. However, they limit the concern this might raise to the spread of antibiotic resistance from the marker gene. Other, more sinister, DNA movements or pathogen stimulation facilitated by the inserted qualities from foreign plant DNA, animal DNA and/or human pathogen DNA are not considered.
The GM wheat was produced by micro-projectile bombardment of wheat embryo cells with DNA-coated pellets. This technique is the original, and most primitive, one. It is notorious for causing genome disruption.
Studies have shown that aphid-resistance was present in some older wheat-types, but has become entirely absent in the newer high-yielding ones. Modern gene technology could, more profitably, be employed in the breeding of new aphid-resistant strains using native aphid-resistant wheat.
The UK is pouring £1.28 million of public funds into GM wheat when much faster, cheaper, more certain, non-GM techniques are available. Add to this the probability that novel crop will never have a market.
Needless to say, the GM wheat application was accompanied by a splurge of spin from the usual quarters. The NFU
What you can do
Before 19th August 2011
Send an e-mail to DEFRA objecting to Rothamsted Research's application to trial GM wheat.
The e-mail address to write to is: email@example.com
Quote application reference 11/R8/01
Grounds for your objection could include any or all of the points mentioned above e.g.
- lack of any market for GM wheat
- mis-use of public funds
- the prohibitive cost and time needed to assess environmental harm prior to any approval for the use or marketing the GM wheat
- the prohibitive cost and time to ensure no harm to human health prior to any approval for the use or marketing the GM wheat
- the extent of the risk of horizontal gene transfer
DEFRA assures objectors that their “comments and concerns ... raised will be collated along with all representions received”. Every little bit helps.
- Application for Consent to Release a GMO – Higher Plants Part A1 Information required under Schedule 1 of the Genetically Modified Organisms Deliberate Release) Regulation 2002
- Defra Should Reject G Wheat, GM Freeze Press Release, 7.07.11
- Ruth Gordon-Weeks et al., Project Report No. PR473, The role of the benzoxazinone pathway in aphid resistance in wheat, HGCA, October 2010
- F. Francis et al., 2005, Is the (E)-β-farnesene only volatile terpenoid in aphids? JEN 129(1)
- R. Almohamad et al., 2008, Emission of alarm pheromone by non-preyed aphid colonies, Journal of Applied Entomology 132
- J. A. Byers, 2005, A cost of alarm pheronome production in cotton aphids, Aphis gossypii, Naturewissenschaften 92
- Alistair Driver, Application submitted for UK GM wheat trial, Farmers Guardian, 23.06.11
- DEFRA acknowledgement 19.07.11