Tailor-made fructan synthesis in plants: A review

► Modification of fructan biosynthesis in chicory showed to have little effect. ► The fructan biosynthesis pathway can be transferred to non-fructan-accumulating plants. ► Tailor-made fructan can be synthesized in originally non-fructan-producing plants. ► The fructan chain length distribution of tailor-made fructan is dependent on FFT. ► High potential crops for tailor-made fructan production are sugar beet, sugarcane and rice. Fructan, a fructose polymer, is produced by many bacteria and plants. Fructan is used as carbohydrate reserve, and in bacteria also as protective outside layer. Chicory is a commercial fructan producing crop. The disadvantage of this crop is its fructan breakdown before harvest. Studies using genetically modification showed that fructan biosynthesis is difficult to steer in chicory. Alternatives for production of tailor-made fructan, fructan with a desired polymer length and linkage type, are originally non-fructan-accumulating plants expressing introduced fructosyltransferase genes. The usage of bacterial fructosyltransferases hindered plant performance, whereas plant-derived fructan genes can successfully be used for this purpose. The polymer length distribution and the yield are dependent on the origin of the fructan genes and the availability of sucrose in the host. Limitations seen in chicory for the production of tailor-made fructan are lacking in putative new platform crops like sugar beet and sugarcane and rice.