The rationale of this part of our project was to assume that new genes expressed in the upper leaf of plants pretreated on the lower leaf with arachidonic acid might be causally involved in resistance. The product of such genes could either be proteins with antifungal functions or factors involved in the induction of the resistance syndrome. Changes in other proteins beside PR's were not detected using this method of analysis. Test the value of such HR-like genes for the improvment of resistance by expressing them in potato under an inducible promoter.
HR is a common reaction taking place in response to incompatible pathogens.
It is characterized macroscopically by localized cell death. During this reaction, local defence mechanisms are induced which lead to necrosis of the invaded cells thus preventing further spread of the disease. Thus genes expressed early during HR might either be linked causally to the process of cell death, or could potentially be involved in reactions leading to sytemic acquired resistance. Our rationale was to identify such genes and express them under an inducible promoter. This could lead to localized cell death or to induction of resistance mechanims.