Defoliation induces fructan 1-exohydrolase II in witloof chicory roots. Cloning and purification of two isoforms, fructan 1-exohydrolase IIa and fructan 1-exohydrolase IIb. Mass fingerprint of the fructan 1-exohydrolase II enzymes

The cloning of two highly homologous chicory (Cichorium intybus var, folios um cv mash) fructan 1-exohydrolase cDNAs (1-FEH IIa and 1-FEH IIb) is descr ibed. Both isoenzymes could be purified from forced chicory roots as well a s from the etiolated "Belgian endive" leaves where the 1-FEH IIa isoform is present in higher concentrations. Full-length cDNAs were obtained by a com bination of reverse transcriptase-polymerase chain reaction (PCR), PCR and 5 '- and 3 ' -rapid amplification of cDNA ends using primers based on N-ter minal and conserved amino acid sequences. 1-FEH IIa and 1-FEH IIb cDNA-deri ved amino acid sequences are most homologous to a new group of plant glycos yl hydrolases harboring cell wall-type enzymes with acid isoelectric points . Unlike the observed expression profiles of chicory I-FEH I, northern anal ysis revealed that 1-FEH II is expressed when young chicory plants are defo liated, suggesting that this enzyme can be induced at any developmental sta ge when large energy supplies are necessary (regrowth after defoliation).