5.4.8
CHITINASE OVER-EXPRESSION IN TRANSGENIC WHEAT CONFERS ENHANCED RESISTANCE TO POWDERY MILDEW

M BLIFFELD, S BIERI, I POTRYKUS, C SAUTTER and J FUTTERER

Institute of Plant Sciences, ETH, Zürich, Switzerland

Background and objectives
Fungal diseases are important constraints to wheat production. A large number of genes are known that seem to contribute to resistance against fungal infections. Genetic engineering can contribute to introducing such genes into wheat cultivars and can thus supplement classical breeding methods.

Material and methods
Wheat (cv. Bobwhite) was transformed by particle bombardment of scutellum-derived calli with genes coding for a barley seed chitinase and other supposedly antifungal proteins. Transgenic plants were regenerated under selection with phosphinotricin.

Results and conclusions
Plant lines stably expressing the barley seed chitinase under control of the maize ubiquitin 1 promoter were obtained. Inheritance of expression followed Mendelian rules and expression is stable so far over four generations. Leaves from transgenic plants showed increased resistance to infection by Erysiphe graminis. The reduction of colony formation varied from 40 to 95%, depending on the level of chitinase expression.

No transgenic plants expressing either a barley seed b-1,3 glucanase or a ribosome-inactivating protein, under control of a constitutive promoter, could be obtained.