Ruprecht-Karls-Universität Heidelberg
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Plant Molecular Physiology

Dr. Anja Bausewein

Dr. Anja Bausewein
Dr. Anja Bausewein
ed.grebledieh-inu.inmula TEA niewesuab.ajna

Fig. 1: Inulin metabolism in chicory taproot and CiHRC. Inulin is synthesized from sucrose by transfer of fructose units. During inulin degradation terminal fructose units are cleaved off from the end of the fructan chain. Final breakdown to hexoses is catalyzed by acid invertase.

 Inulin metabolism in Chicory

Inulin is used as carbohydrate storage compound in plants but may also be involved in several stress responses. The economically most important source is chicory, which accumulates inulin in its taproots. Biotechnological goals are to increase inulin yield and its degree of polymerization (DP). Enzymes responsible for inulin biosynthesis in chicory are sucrose:sucrose 1-fructosyltransferase (1-SST) and fructan:fructan 1-fructosyltransferase (1-FFT), inulin degradation is catalyzed by fructan 1-exohydrolases (1-FEHs). We are investigating the possibility of post-translational control of FAZYs via proteinaceous inhibitors, as found for acid invertases, enzymes evolutionarily and structurally related to FAZYs. We are pursuing 3 different strategies in order to isolate FAZY specific inhibitors: a) affinity chromatography with recombinant FAZY proteins as bait; b) Deep Sequencing of chicory cDNAs; c) Invertase inhibitor engineering.

Additionally, we have established the chicory hairy root culture (CiHRC) as a model system to explore regulatory mechanisms impacting on inulin metabolism in planta. We are currently studying aspects of hormonal regulation of FAZYs in CiHRC.

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