Wheat from a new breeding method: Agroscope searches for fungal resistances in field trial

Agroscope is launching a field trial with winter wheat bred using a new method. Researchers are hoping to find new disease resistances that are useful for further breeding. The Federal Office for the Environment has given the go-ahead for the trial, for which approval is compulsory.

Plant breeding uses the natural genetic diversity within a plant species or in closely related species to breed improved varieties. The aim is to find new and useful qualities for the cultivation and processing sectors as well as consumers. For decades, conventional breeding has used mutagenesis for this.

New method is a Swiss innovation

For this project, Agroscope used the new ‘TEgenesis’ mutagenesis method with the old Swiss winter-wheat variety ‘Arina’. The method was developed at the University of Basel to speed up the natural adaptation process of plants. With TEgenesis, no foreign DNA from other organisms is added. The plants are treated with two substances and simultaneously subjected to stress, causing so-called transposons to become mobile. Transposons are DNA sequences that change their location within and/or add copies of themselves to the genome. As a result, new desirable qualities can be created, or undesirable ones can be eliminated.

Wanted: natural defence mechanisms under field conditions

In TEgenesis wheat, researchers are looking for disease resistances that previously lay dormant in the genome. There is a particular focus on natural defence mechanisms against major fungal diseases such as Septoria, yellow rust, leaf rust and powdery mildew. Plants with increased resistance to mildew have already been identified in the greenhouse. Because such resistances seldom arise, however, researchers need to study a great many plants under conditions that are as natural as possible in field trials.

First field trial approved

All mutations caused by TEgenesis could also occur in nature, as they are triggered by a process inherent to the plant. Because the breeding method is new, however, the Swiss Federal Office for the Environment (FOEN) has classified plants created with TEgenesis as genetically modified organisms (GMOs). In order to conduct field trials despite this, Agroscope submitted the relevant release application to the FOEN, which has now been approved. The winter wheat will be sown on the Protected Site in Zurich-Reckenholz as soon as possible. The trial will run for a maximum of five years.

‘TEgenesis’ – A New Mutagenesis Method

The word ‘mutagenesis’ describes processes in which the DNA of a plant is altered without introducing additional genes. This occurs, for example, as a result of intensive UV radiation, radioactive radiation or exposure to certain chemical substances. Mutagenesis happens in nature due to stressors such as heat or drought. Transposons play a key role in this process. Nearly all living creatures have one or more transposons in their DNA. In wheat, they account for over 85% of the DNA. Normally, however, they are not very active. TEgenesis causes this blocade to be lifted briefly. The transposons become mobile and help the plant adapt to stress. Because it involves the activation of a natural mechanism in the plant, this gentle type of mutagenesis leads to fewer changes in the DNA than previous mutagenesis methods.

Wheat from an EU research project

The wheat used for the field trial was bred in an EU-funded research project at Agroscope. The head researcher is also the founder of epibreed, the company holding the exclusive patent rights for TEgenesis. However, the company is not involved in the trial and in fact ceased operations at the start of 2021. Since we are dealing with a research project here, the technique may be used freely by Agroscope (research privilege).