Food issues: myths and reality

Researchers at the German University of Neuenburg have used genetic technology to restore to maize a scent that defends it from pests. The maize then attracts nematodes that kill harmful insects in the root area of the plant.

Maize plants release certain scents to combat a variety of insects such as the maize root borer. The larvae of this insect eat root hairs and bore into the root of the plant.

In North America, the maize or 'corn' root borer is responsible for enormous harvest losses, the value of which may reach more than a billion dollars per year. In collaboration with the Max Planck Institute for Chemical Ecology in Jena, Germany, researchers at the Neuenburg University discovered that many maize varieties in the USA no longer produce such chemical cries for help against the root borer.

Researchers transferred a gene from the oregano herb into a variety of maize. The gene controls the release of the scent molecules and, according to the scientists, this new strategy teams biological pest control with biotechnology. This genetically modified maize already has been tested in field trials in the USA. The maize attracted nematodes and displayed significantly less root damage from the corn root borer. The number of root borers was reduced by 60 per cent in comparison with conventional maize, which means that the effectiveness of the method is approximately as high as is the case with the application of insecticides. The researchers state that this new process provides novel possibilities in the battle against the corn root borer.

In European varieties of maize and in its forebears, the signal to attract the larva-killing nematodes still is present. Therefore, this trait also could be re-crossed into the American varieties through conventional breeding. However, according to the scientists, one achieves this goal more quickly through gene technology.

The goal of the scientists now is to improve the defense system of maize. They assume that this strategy also may be applied in the protection of other plants.

Original paper at : http://www.pnas.org/content/early/2009/07/31/0906365106