Glossary

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Glyphosate

An active ingredient used in herbicides to control weeds; used as a complementary herbicide in conjunction with genetically modified plants (brand name: Roundup)

Glyphosate is sprayed on the leaves, where it is absorbed and transported throughout the plant. It has only a minimal effect in the soil. Glyphosate inhibits a certain enzyme that is needed for biosynthesis in most plants (EPSP sythetase). This enzyme is needed to produce vital aromatic amino acids. If a plant is prevented by glyphosate from producing these amino acids, it stops growing and dies within three to seven days. Compared with other herbicides, glyphosate is regarded as environmentally friendly. It is biodegradable and non-toxic to humans.

Glyphosate has a toxic effect on almost all plants and has therefore been used as a broad-spectrum herbicide all over the world for around 25 years (e.g. to control weeds on railway embankments).

It was not possible to use glyphosate for weed control in crops (soya, oilseed rape and maize) until it became part of the new RoundupReady herbicide system. A number of crop plants are now available that have a genetically engineered tolerance to herbicides containing the active ingredient glyphosate.

To achieve this, a gene isolated from the soil bacterium Agrobacterium tumefaciens was transferred to the plants. This means that the plants produce a bacterial form of the enzyme (EPSP synthetase), which, in its plant variant, is inhibited by glyphosate. The bacterial enzyme is resistant to glyphosate, which means that the GM plants can be treated with glyphosate without suffering any harmful effects.