Pathogenesis related proteins and genes

Plants respond to pathogens by defence strategies leading to the synthesis of several compounds such as the pathogenesis-related (PR) proteins; these compounds were first described in tobacco plants infected with TMV and then in a variety of species submitted to various kinds of injury. In the last years, a large number of PR-proteins have been characterised and grouped into 11 classes. Most of them show antifungal activity against specific pathogens, while just few of them possess a known enzymatic activity (chitinases. glucanases, pero:tidases and ribonucleases). The structural and functional characterisation of PR-proteins from wheat and other plants of commercial interest is currently quite uncompleted. We isolated from wheat kernel two homologous proteins, coded wheatwinl and wheatwin2, showing a strong antifungal activity against both specific (Fusarium culmorum and F. graminea:rum) and wide range pathogens (Borrytis cinerea). The synthesis of wheatwins is induced in the early stages of development of seedlings infected with F. culmorum. More recently, the corresponding PR-4 genes have been isolated and experiments leading to the production of recombinant proteins in E. coli are in progress. Both PR4 genes have been cloned in binary vectors (e.g. pBI 12 t, pXYLX71) and are being transferred to A. tumefaciens (strains LBA4404 and EfL:\105) for their use in genetic transformation.