1. Department of Forest Genetics and Plant Physiology, Umeå Plant Science Center, Swedish University of Agricultural Sciences, S901-83 Umea, Sweden
2. Center for Novel Agricultural Products, Department of Biology, University of York, York YO10 5DD, United Kingdom
3. Department of Chemistry, Umeå University, SE-90187 Umea, Sweden
4. Department of Bioscience, Rice University, Houston, Texas 77005-1827