Recent Progress in Studies on Fructans in Higher Plants

About 15% of the flowering plant species store fructans, frucose_based carbohydrates. With different DP (degree of polymerization), five major classes of fructans -- linear inulin, inulin neoseries, linear levans, levans neoseries and mixed levans -- have been distinguished in higher plants. So far three models of fructan biosynthesis have been elucidated and structurally different fructan molecules can be produced by the concerted action of different fructosyltransferase. Recently the genes encoding these fructosyl_transferases have been cloned, opening new biotechnological opportunities for the use of fructans.