1. Institute for Microbiology Cluster of Excellence on Plant Sciences Heinrich‐Heine University Building 26.12.01, Universitätsstr. 1 Düsseldorf 40225 Germany
2. Max Planck Institute for Plant Breeding Research Carl‐von‐Linné‐Weg 10 Cologne 50829 Germany
3. Department of Plant, Soil, and Microbial Sciences Michigan State University East Lansing MI 48824‐6254 USA
4. Unit of Botany and Molecular Genetics Institute for Biology I BioSC RWTH Aachen University 52074 Aachen Germany
5. The Sainsbury Laboratory Norwich NR4 7UH UK
6. Faculty of Biology, Genetics Ludwig‐Maximilians‐Universität München Großhaderner Str. 2‐4 Planegg‐Martinsried 82152 Germany