caa a22 4500 477101798 CHVBK 20180405111544.0 cr unu---uuuuu 170330e19960801xx s 000 0 eng 10.1007/BF00195183 doi (NATIONALLICENCE)springer-10.1007/BF00195183 Synthesis of fructans in tubers of transgenic starch-deficient potato plants does not result in an increased allocation of carbohydrates [Elektronische Daten] [Manuela Röber, Klaus Geider, Bernd Müller-Röber, Lothar Willmitzer] Inhibition of starch biosynthesis in transgenic potato (Solanum tuberosum L. cv. Désirée) plants (by virtue of antisense inhibition of ADP-glucose pyrophosphorylase) has recently been reported to influence tuber formation and drastically reduce dry matter content of tubers, indicating a reduction in sink strength (Müller-Röber et al. 1992, EMBO J 11: 1229-1238). Transgenic tubers produced low levels of starch, but instead accumulated high levels of soluble sugars. We wanted to know whether these changes in tuber development/sink strength could be reversed by the production of a new high-molecular-weight polymer, i.e. fructan, that incorporates sucrose and thereby should reduce the level of osmotically active compounds. To this end the enzyme levan sucrase from the gram-negative bacterium Erwinia amylovora was expressed in tubers of transgenic potato plants inhibited for starch biosynthesis. Levan sucrase was targeted to different subcellular compartments (apoplasm, vacuole and cytosol). Only in the case of apoplastic and vacuolar targeting was significant accumulation of fructan observed, leading to fructan representing between 12% and 19% of the tuber dry weight. Gel filtration and 13C-nuclear magnetic resonance spectroscopy showed that the molecular weight and structure of the fructan produced in transgenic plants is identical to levan isolated from E. amylovora. Whereas apoplastic expression of levansucrase had deleterious effects on tuber development, tubers containing the levansucrase in the vacuole did not differ in phenotype from tubers of the starch-deficient plants used as starting material for transformation with the levansucrase. When tuber yield was analysed, no increase but rather a further decrease relative to ADP-glucose pyrophosphorylase antisense plants was observed. Springer-Verlag, 1996 Erwinia nationallicence Fructan nationallicence Levan sucrase nationallicence Transgenic potato nationallicence Sink strength nationallicence Solanum nationallicence CaMV : cauliflower mosaic virus nationallicence NMR : nuclear magnetic resonance nationallicence Röber Manuela Institut für Genbiologische Forschung Berlin GmbH, Ihnestrasse 63, D-14195, Berlin, Germany aut Geider Klaus Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, D-69028, Heidelberg, Germany aut Müller-Röber Bernd Institut für Genbiologische Forschung Berlin GmbH, Ihnestrasse 63, D-14195, Berlin, Germany aut Willmitzer Lothar Institut für Genbiologische Forschung Berlin GmbH, Ihnestrasse 63, D-14195, Berlin, Germany aut Planta Springer-Verlag 199/4(1996-08-01), 528-536 0032-0935 199:4<528 1996 199 425 https://doi.org/10.1007/BF00195183 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00195183 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Röber Manuela Institut für Genbiologische Forschung Berlin GmbH, Ihnestrasse 63, D-14195, Berlin, Germany aut NATIONALLICENCE 700 1- Geider Klaus Max-Planck-Institut für medizinische Forschung, Jahnstrasse 29, D-69028, Heidelberg, Germany aut NATIONALLICENCE 700 1- Müller-Röber Bernd Institut für Genbiologische Forschung Berlin GmbH, Ihnestrasse 63, D-14195, Berlin, Germany aut NATIONALLICENCE 700 1- Willmitzer Lothar Institut für Genbiologische Forschung Berlin GmbH, Ihnestrasse 63, D-14195, Berlin, Germany aut NATIONALLICENCE 773 0- Planta Springer-Verlag 199/4(1996-08-01), 528-536 0032-0935 199:4<528 1996 199 425 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer