1. Département des Sciences biologiques, Université du Québec à Montréal, C.P. 8888 Succursale Centre-ville, Montréal, Québec, Canada H3C 3P8 (C.N., J.D., F.S.);
2. Department of Molecular Biology, University of Geneva, 30 Quai Ernest-Ansermet, CH–1211 Geneva 4, Switzerland (K.E.W.); and
3. Department of Plant Sciences, University of Western Ontario, London, Ontario, Canada N6A 5B7 (T.P., N.P.A.H.)