Engineering fructan metabolism in plants.

Fructans, or polyfructosylsucroses, are storage carbohydrates present in many higher plants. They are also considered healthy food ingredients. Engineering crops into high level production of specific fructan molecules is one of the mayor strategic research goals. Understanding the properties of fructosyltransferases is important, in order to direct the synthesis of fructans. In plants at least two fructosyltransferases are needed to synthesise fructans. One enzyme synthesises the fructan trisaccharide 1-kestose, the next enzyme uses 1-kestose for elongation and/or modification, producing longer fructans. The specificity of fructosyltransferases determines the type of glycosidic bond formed and the donor and acceptor substrates used. This enables the synthesis of many structurally diverse fructans. The production of these molecules in crops such as sugar beet and potato makes the commercial use of fructans feasible.