1. SwissProt Group, Swiss Institute of Bioinformatics, 1 rue Michel Servet, CH–1211 Geneva 4, Switzerland (K.B.A.); and
2. Plant Physiology and Anatomy Laboratory, Department of Plant Biology, The Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK–1871 Frederiksberg C, Copenhagen, Denmark (M.G.P.)