Cloning of a vacuolar invertase from Belgian endive leaves (Cichorium intybus).

Although a lot of vacuolar invertase (EC 3.2.1.26) cDNAs are available from a diversity of plant species, up to now no sequence information is available on invertases from any dicot fructan-containing species. Therefore, we describe the cloning of vacuolar acid invertase cDNA from etiolated Belgian endive leaves (Cichorium intybus L. var. foliosum cv. Flash), formed throughout the forcing process of the witloof chicory roots. Full-length cDNA was obtained by a combination of RT-PCR, PCR and 5'- and 3' RACE RT-PCR, starting with primers based on conserved amino acid sequences. The cloned chicory acid invertase groups together with vacuolar type invertases and fructan biosynthetic enzymes. A putative role for vacuolar type invertases in fructan synthesizing plants is discussed.