1. Department of Plant Molecular Biology, University of Lausanne, CH-1015 Lausanne, Switzerland
2. Max Planck Institut für Pflanzenzüchtungsforschung, D-50829 Cologne, Germany
3. Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
4. Department of Botany, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
5. Department of Biology, University of Fribourg, CH-1700 Fribourg, Switzerland