1. Laboratory for Phytopathology and Plant Protection, Katholieke Universiteit Leuven, 3001 Leuven, Belgium (E.J.M.V.D., J.H., W.J.P.);
2. Institute of Plant Biochemistry, D–06018 Halle, Germany (B.H.);
3. Institut de Pharmacologie et Biologie Structurale, Unité Mixte Recherche-Centre National de la Recherche Scientifique 5089, 31077 Toulouse cedex, France (A.B., P.R.); and
4. Rega Institute, Laboratory of Molecular Immunology, Katholieke Universiteit Leuven, 3000 Leuven, Belgium (P.P.)