3.4.23
TRANSFORMATION OF DIFFERENT WHEAT VARIETIES

M CLAUSEN, J FUETTERER, C ZHANG, T ZHAO, I. POTRYKUS and C SAUTTER

Institute of Plant Sciences, ETH Zurich, Universitaetsstrasse 2, 8096 Zurich, Switzerland

Background and objectives
Genetic transformation is one powerful tool in plant molecular genetics and breeding. Among the monocotyledoneous plants, rice was the first species to be transformed. Over the past years more and more reports on transgenic wheat plants appeared. One of the major goals in the Swiss Priority Program 'Biotechnology on Wheat' is the improvement of endogenous resistance against fungal diseases in Swiss breeding lines of wheat (Triticum aestivum).

Results and conclusions
In our initial experiments we bombarded somatic embryos of the wheat model variety BobWhite with two different visible marker genes. Using the maize C1 and Bperu genes different transgenic lines were obtained. Only the co-ordinated expression of both genes results in the accumulation of anthocyanins. Transgenic plants were used to study the tissue specific expression of the CaMV35S promoter. A strong anthocyan accumulation was detected in roots, leaf tips, ligula and spikes of transgenic plants. Furthermore, these two independently transformed genes were segregating together. Three-quarters of the progeny had red hypocotyls. We concluded that co-bombardments results in co-integration, co-expression and co-inheritance.

Our second approach concerned the expression pattern of the maize ubiquitin promoter. Promoter-GUS fusions were used to analyse in detail the tissue specific expression pattern of the promoter. Analysing various transgenic BobWhite lines we obtained a strong GUS expression in fast diving cells. High levels of GUS expression were obtained in roots and young meristematic tissue like the vegetative and floral mersitems. Since mature leaves showed very little to no GUS expression, we are questioning its application with respect to foliage diseases.

During the course of these experiments we accelerated the transformation methods such that today's regenerating shoots can be obtained in less than three months, reducing the danger of somaclonal variation.

Finally, various Swiss breeding varieties including Frisal, Golin, Greina and Attila, which are particularly susceptible to different fungal diseases, were transformed. As agronomically important traits we used genes involved in horizontal resistance, for example the wheat thaumatin-like gene or genes which play an important role in more specific plant resistances. We will discuss in detail our results on some of these transgenic lines.