Journal Article

Tuber-specific Cytosolic Expression of a Bacterial Phosphoglucomutase in Potato (<i>Solanum tuberosum</i> L.) Dramatically Alters Carbon Partitioning

Anna Lytovchenko, Nicolas Schauer, Lothar Willmitzer and Alisdair R. Fernie

in Plant and Cell Physiology

Published on behalf of Japanese Society of Plant Physiologists

Volume 46, issue 4, pages 588-597
Published in print April 2005 | ISSN: 0032-0781
Published online April 2005 | e-ISSN: 1471-9053 | DOI: http://dx.doi.org/10.1093/pcp/pci058
Tuber-specific Cytosolic Expression of a Bacterial Phosphoglucomutase in Potato (Solanum tuberosum L.) Dramatically Alters Carbon Partitioning

More Like This

Show all results sharing these subjects:

  • Biochemistry
  • Molecular and Cell Biology
  • Plant Sciences and Forestry

GO

Show Summary Details

Preview

Constitutive antisense inhibition of the cytosolic isoform of phosphoglucomutase in the potato (Solanum tuberosum L.) results in restriction of photosynthesis, growth inhibition and modified tuber morphology, and a severe restriction of tuber starch synthesis. Here we describe the consequences of the tuber-specific expression of an Escherichia coli phosphoglucomutase in the cytosol. Analysis of [14C]glucose metabolism by tuber discs isolated from wild type and transformants revealed that the rates of sucrose and starch synthesis were unaltered but that the rate of glycolysis was depressed in the transgenics. The transformant tubers also contained dramatically reduced amino acid content and significantly higher levels of ADP, but were characterized by elevated levels of Krebs cycle intermediates and an unaltered rate of respiration. In addition to these metabolic consequences of the overexpression of the E. coli enzyme, we observed morphological changes in tubers, with the transformants having a smaller number of larger tubers which exhibited delayed rates of sprouting with respect to the wild type. These results are discussed with respect to current models of the regulation of central plant metabolism and tuber dormancy.

Keywords: Amino acids; Carbohydrate metabolism; Glycolysis; Phosphoglucomutase; Solanum tuberosum L.; Starch synthesis; CaMV, cauliflower mosaic virus; EcPGM, Escherichia coli phosphoglucomutase; Fru6P, fructose 6-phosphate; GC–MS, gas chromatography–mass spectrometry; Glc1P, glucose 1-phosphate; Glc6P, glucose 6-phosphate; 3PGA, 3-phosphoglycerate; PGM, phosphoglucomutase; UGPase, UDPglucose pyrophosphorylase

Journal Article.  8343 words.  Illustrated.

Subjects: Biochemistry ; Molecular and Cell Biology ; Plant Sciences and Forestry

Full text: subscription required

How to subscribe Recommend to my Librarian

Users without a subscription are not able to see the full content. Please, subscribe or login to access all content.