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Planta

, Volume 209, Issue 3, pp 330–337 | Cite as

The contribution of adenosine 5′-diphosphoglucose pyrophosphorylase to the control of starch synthesis in potato tubers

  • Lee J. Sweetlove
  • Bernd Müller-Röber
  • Lothar Willmitzer
  • Steven A. Hill
Article

Abstract.

The aim of this work was to investigate the extent to which starch synthesis in potato (Solanum tuberosum L.) tubers is controlled by the activity of ADPglucose pyrophosphorylase (EC 2.7.7.27; AGPase). In order to do this, fluxes of carbohydrate metabolism were measured in tubers that had reduced AGPase activity as a result of the expression of a cDNA encoding the B subunit in the antisense orientation. Reduction in AGPase activity led to a reduction in starch accumulation, and an increase in sucrose accumulation. The control coefficient of AGPase on starch accumulation in intact plants was estimated to be around 0.3. The fluxes of carbohydrate metabolism were measured in tuber discs from wild-type and transgenic plants by investigating the metabolism of [U-14C]glucose. In tuber discs, the control coefficient of AGPase over starch synthesis was estimated as 0.55, while the control coefficient of the enzyme over sucrose synthesis was −0.47. The values obtained suggest that AGPase activity exerts appreciable control over tuber metabolism in potato.

Key words: Adenosine 5′-diphosphoglucose pyrophos-phorylase Metabolic control analysis Solanum (starch synthesis) Starch synthesis 

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Copyright information

© Springer-Verlag Berlin Heidelberg 1999

Authors and Affiliations

  • Lee J. Sweetlove
    • 1
  • Bernd Müller-Röber
    • 2
  • Lothar Willmitzer
    • 2
  • Steven A. Hill
    • 1
  1. 1.Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UKGB
  2. 2.Max-Planck-Institut für Molekulare Pflanzenphysiologie, Karl Liebknecht Str. 25, Haus 20, D-14476 Golm, GermanyDE

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