Strategies for Fructan Production in Transgenic Sugarcane (Saccharmu spp L.) and Sweet Potato (Ipomoea batata L.) Plants Expressing the Acetobacter diazotrophicus levansucrase

This chapter discusses strategies for fructan production in transgenic sugarcane (Saccharum spp. L.) and sweet potato (Ipomoea batata L.) plants expressing the Acetobacter diazotrophicus levansucrase. Fructans are polyfructose molecules produced by the action of fructosyltransferases on sucrose. Included in the diet, fructans function as fiber because of their nondigestibility. Those of low polymerization degree have a sweet taste and can be used as low-calorie edulcorants. Their ingestion promotes the growth of beneficial bacteria in the gut, improving human and animal health. Difficulties in fructan purification from natural sources or its production through biotechnological methods hamper its potential applications. This problem could be overcome by the recombinant production and accumulation of these carbohydrates in economically important crops. Enhancement of stress resistance is another application that is envisioned for fructan production in plants. These compounds may be involved in resistance to drought and low temperatures. Sugarcane is a potential target crop for fructosyltransferase expression because of its high sucrose content in both the vacuoles and apoplastic spaces.