[1] Max Planck Inst Plant Breeding Res, Dept Plant Microbe Interact, D-50829 Cologne, Germany
[2] John Innes Ctr Plant Sci Res, Sainsbury Lab, Norwich NR4 7UH, Norfolk, England
[3] Riso Natl Lab, Plant Res Dept, DK-4000 Roskilde, Denmark
[4] Univ Giessen, Inst Phytopathol & Appl Zool, D-35392 Giessen, Germany
[5] Carnegie Inst Washington, Dept Plant Biol, Stanford, CA 94305 USA