1. School of Agricultural Biotechnology, Seoul National University, Seoul 151-742, South Korea; Center for Agricultural Biomaterials, Seoul National University, Seoul 151-921, South Korea; Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, Hawaii 96822; and Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, California 94710