Wheat with Improved Powdery Mildew Resistance (University of Zurich)

Weizen mit verbesserter Mehltauresistez kaur

Contact University of Zurich

Prof. Beat Keller, Project Head University of Zurich
Institute for Plant Biology
Zollikerstrasse 107
8008 Zurich
Tel.: 044 634 82 11

Contact Agroscope

Project Status

The permit for the field trial submitted by the University of Zurich was granted by the Federal Office for the Environment (FOEN) on 15 August 2013. The first field season began in March 2014.

Proposed period of release

2014-2018, March to August of each year

Which genes were introduced into the wheat lines?


The introduced gene comes from other wheat lines. Known as Pm3, it provides resistance to powdery mildew disease. This resistance gene is only present in a few wheat lines, and different wheat lines carry different variants - referred to as alleles - of Pm3. The Pm3 gene and its various alleles were molecularly isolated (cloned) at the University of Zurich, and have been intensively researched since then. Wheat lines to which one of seven different Pm3 alleles was transferred by means of genetic engineering are being used in the field trials. Furthermore, two different Pm3 alleles were stably combined in a single plant by crossing these wheat lines. Four such crosses are also being studied in the field.

Moreover, all genetically modified wheat lines carry the manA gene that serves as a selection marker. The manA gene occurs naturally in bacteria, soya beans and several other legumes. In the tissue culture, an early stage of production of the wheat lines, it helps to distinguish the small percentage of genetically modified plants from non-genetically modified plants. The manA gene has no influence on resistance to powdery mildew.

Why are powdery mildew-resistance genes researched?

Wieso werden Resistenzgene gegen Mehltau erforscht

For a good wheat yield, healthy plants are essential. However, wheat is threatened by diseases, the majority of which are caused by fungi. For nearly 15 years now, researchers from the University of Zurich have been investigating how plants protect themselves against such fungal diseases. Here, they focus inter alia on the wheat gene Pm3, which confers resistance to the powdery mildew pathogen (Blumeria graminis f. sp. tritici). Powdery mildew is a significant disease of wheat worldwide. Since the Pm3 alleles belong to the largest class of plant resistance genes, the results will also be applicable to other plant diseases and their control.

Have the genetically modified plants already been tested in the field?

Yes, to an extent. Collaborating with other researchers from Swiss universities and Agroscope, the team from the University of Zurich conducted field trials at the Agroscope sites in Zurich-Reckenholz and in Pully from 2008 to 2010 (wheat-cluster.ch). Twelve of the 19 wheat lines that are being tested in the new trials were investigated in these previous field trials. They each carry one of six different Pm3 alleles. In these NRP 59-financed projects, studies were carried out on the benefits and biosafety of these wheat lines. In its final report, the Federal Office for the Environment, which authorised the trials, stated that the safety of humans, animals and the environment was always ensured.

What will be studied in the new trials?

Research continued after the 2008-2010 field trials. The Zurich researchers produced new genetically modified (GM) wheat lines by introducing another Pm3 allele, and by crossing the aforementioned GM Pm3 wheat lines. All of the new wheat lines were investigated in both the laboratory and greenhouse. In the convertible greenhouse, which provides light and weather conditions similar to the outdoors, some of the GM Pm3 wheat plants were fully mildew-resistant. Following this encouraging result, all wheat lines are now to be tested in field trials.
As was the case with the 2008-2010 field trials, the aim of these new trials is to gain knowledge about how resistance genes work. For example, the wheat lines with the new Pm3 allele are compared with the wheat lines already tested in the field. Another intention is to determine whether the wheat lines carrying two Pm3 alleles each are more mildew-resistant than their parent plants, each of which carries just one Pm3 allele.

Are the genetically modified wheat lines a health risk?

No. One of the reasons for this is that the introduced genes come from other wheat lines, all of which are already used agriculturally. The allergy potential is therefore the same as for currently cultivated wheat varieties.
The product of the introduced genes is not toxic for the fungus that produces powdery mildew, but it does give the plant the ability to detect the presence of this fungus. After detection occurs, the plants use their immune system to fight off the fungus.
The manA selection marker has already been very intensively researched, since in other countries it is present in maize varieties approved as food for humans. There are no indications of manA having a harmful effect.

How is the project funded?

The project is funded by the University of Zurich.

What happens after the trials?

The research results will be published. The wheat lines will be kept for potential further research activities, and propagated from time to time in the greenhouse for this purpose. Further development of the wheat lines for commercial applications is not planned.

Summary of the Permit Application