作者单位:Biological Chemistry and Crop Protection Department, Rothamsted Research, Harpenden AL5 2JQ, U.K.[1]Centre for Plant Sciences, School of Biology, University of Leeds, Leeds LS2 9JT, U.K.[2]Institut für Biochemie der Pflanzen, Heinrich-Heine Universitat Düsseldorf, D-40225 Düsseldorf, Germany[3]