1. Seção de Fisiologia e Bioquímica de Plantas, Instituto de Botânica CP 4005 CEP 01061-970, São Paulo, SP Brazil.
2. Department of Botany and Plant Pathology, Purdue University West Lafayette, IN 47907-1155.
3. Present address: UMR CNRS-UPS 5546, Pôle de Biotechnologie Végétale, BP 17, Auzeville, F-31326 Castanet Tolosan, France.
4. Present address: Department of Plant Biology, 228 Plant Science Building, Cornell University, Ithaca, NY 14853.
5. Corresponding author. Phone: +1-765-494-4653. Fax:+1-765-494-0393. E-mail: carpita@purdue.edu