1. Department of Plant Physiology, Ruhr University Bochum, D-44801 Bochum, Germany
2. Department of Molecular, Cell, and Developmental Biology, University of California, Los Angeles, California 90095-1606
3. Institute of Genomics and Proteomics, University of California, Los Angeles, California 90095
4. Department of Biological Sciences, University of South Carolina, Columbia, South Carolina 29208
5. Max Planck Institute for Plant Breeding Research, D-50829 Cologne, Germany
6. Department of Chemistry and the Howard Hughes Medical Institute, University of California, Berkeley, California 94720-1460
7. Department of Chemistry and Biochemistry, University of California, Los Angeles, California 90095-1569