LAUSR

Fructans are polymers of fructose that are present as storage carbohydrates in various plants. Jerusalem artichoke (Helianthus tuberosus L.) contains a high amount of inulin. Two enzymes are involved in inulin biosynthesis. The sucrose:sucrose 1-fructosyltransferase (1-SST) enzyme mainly catalyzes the synthesis of 1-kestose from sucrose. In the next step, fructan:fructan 1-fructosyltransferase (1-FFT) catalyzes the synthesis of inulin from 1-kestose. In this study, the Ht1-SST and Ht1-FFT genes were isolated from Jerusalem artichoke and expressed in potato (Solanum tuberosum L.), either separately or together, via Agrobacterium-mediated transformation. Transgenic potato tubers overexpressing Ht1-SST accumulated 1-kestose to a high level (up to 3.36 mg/g), while tubers overexpressing both Ht1-SST and Ht1-FFT accumulated up to 3.14 mg/g short-chain inulin-type fructans, with the degree of polymerization (DP) ranging from 3 to 5, excluding high DP inulins. Transgenic potato plants accumulated fructo-oligosaccharides to a high level, following the fructan biosynthetic pathway of Jerusalem artichoke, and therefore present a high potential for the mass production of inulin through established potato breeding and cultivation methods.