[1] Univ Rome La Sapienza, Ist Pasteur, Fdn Cenci Bolognetti, Dipartimento Biotecnol Cellulari,Sez Genet Mol, I-00161 Rome, Italy
[2] Univ Rome La Sapienza, Dipartimento Genet & Biol Mol, Ctr Studio Acidi Nucl, I-00185 Rome, Italy
[3] Univ Konstanz, Lehrstuhl Physiol & Biochem Pflanzen, D-78434 Constance, Germany