1. Howard Hughes Medical Institute, Ann Arbor, Michigan 48109, United States
2. Department of
Horticulture, University of Kentucky, Lexington, Kentucky 40546, United States
3. Department of Chemistry
and Biochemistry, Utah State University, Logan, Utah 84322, United States
4. Department of
Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, United States