Aphid-resistant GM wheat trial awaits approval

Britain’s first field trial of genetically modified wheat could begin in March next year if the government gives permission for the crop to be planted.

Rothamsted Research has applied for government approval to begin a field trial of a wheat crop which is modified to resist aphid attacks.

Scientists at Rothamsted have incorporated a novel, non-toxic aphid resistance trait into the cultivar Cadenza. The resulting plant produces (E) beta-farnesene (EBF), which is a naturally occurring chemical found in more than 300 plant varieties, including common mint.

Toby Bruce, a senior research scientist at Rothamsted, says preliminary laboratory tests have shown positive results, but the “acid test” is to see how it performs under field conditions.

“We have developed wheat plants which naturally release this aphid repellent, strongly repelling the aphids under laboratory conditions,” says Dr Bruce.

“Not only that, but the chemical is also attractive to parasitoid wasps, which are key natural enemies of the aphid pests. The wasps lay their eggs inside the aphid and the larvae then develop and kill the aphid.”

The new genes are similar to those in peppermint. However, they were not taken directly from another species, but chemically synthesised to function like wheat genes. “We took small samples of wheat plants and physically inserted the genes into the cells,” explained Dr Bruce, a research team member.

Tests on the plants show they repel a range of wheat aphid pests, including the three main UK winter aphids, Sitobion avenae (grain aphid), Rhopalosiphium padi (bird cherry oat aphid), and Metopolophium dirhodum (rose-grain aphid).

Developing GM crops, such as wheats that can repel aphids, offered an alternative approach to crop protection rather than relying on pesticides, said Dr Bruce.

“Aphids are very good at evolving resistance to pesticides and fewer new chemical products are being developed, so we need to find other methods of crop protection,” explained Dr Bruce.

“This is a non-toxic approach relying on the crop genetics rather than applying a pesticide, which contains a positive mode of action to kill the insects.

Helen Ferrier, NFU chief science and regulatory affairs adviser, says genetic improvement, enabling the plants to be more resistant to aphid infestation, is one important way to reduce unsustainable crops losses and reliance on pesticides.

“Aphids are a serious problem for many UK crops, reducing both yield and quality,” she says. “There are over 20 different aphid species that attack many key UK crops, which therefore require protection using pesticides.”

If approved, the trial is scheduled to run from March 2012 to October 2013, with eight 6m x 6m plots. It would be only the third GM field trial running in Britain. Scientists are currently testing different varieties of GM potato at the John Innes Centre in Norfolk and at Leeds University.

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