| Alterations in cytosolic glucose-phosphate metabolism affect structural features and biochemical properties of starch-related heteroglycans. | |
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MedLine Citation:
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PMID: 18805950 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The cytosolic pools of glucose-1-phosphate (Glc-1-P) and glucose-6-phosphate are essential intermediates in several biosynthetic paths, including the formation of sucrose and cell wall constituents, and they are also linked to the cytosolic starch-related heteroglycans. In this work, structural features and biochemical properties of starch-related heteroglycans were analyzed as affected by the cytosolic glucose monophosphate metabolism using both source and sink organs from wild-type and various transgenic potato (Solanum tuberosum) plants. In leaves, increased levels of the cytosolic phosphoglucomutase (cPGM) did affect the cytosolic heteroglycans, as both the glucosyl content and the size distribution were diminished. By contrast, underexpression of cPGM resulted in an unchanged size distribution and an unaltered or even increased glucosyl content of the heteroglycans. Heteroglycans prepared from potato tubers were found to be similar to those from leaves but were not significantly affected by the level of cPGM activity. However, external glucose or Glc-1-P exerted entirely different effects on the cytosolic heteroglycans when added to tuber discs. Glucose was directed mainly toward starch and cell wall material, but incorporation into the constituents of the cytosolic heteroglycans was very low and roughly reflected the relative monomeric abundance. By contrast, Glc-1-P was selectively taken up by the tuber discs and resulted in a fast increase in the glucosyl content of the heteroglycans that quantitatively reflected the level of the cytosolic phosphorylase activity. Based on (14)C labeling experiments, we propose that in the cytosol, glucose and Glc-1-P are metabolized by largely separated paths. |
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Authors:
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Joerg Fettke; Adriano Nunes-Nesi; Jessica Alpers; Michal Szkop; Alisdair R Fernie; Martin Steup |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2008-09-19 |
Journal Detail:
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Title: Plant physiology Volume: 148 ISSN: 0032-0889 ISO Abbreviation: Plant Physiol. Publication Date: 2008 Nov |
Date Detail:
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Created Date: 2008-11-07 Completed Date: 2009-01-02 Revised Date: 2010-09-21 |
Medline Journal Info:
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Nlm Unique ID: 0401224 Medline TA: Plant Physiol Country: United States |
Other Details:
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Languages: eng Pagination: 1614-29 Citation Subset: IM |
Affiliation:
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Department of Plant Physiology, University of Potsdam, 14476 Potsdam-Golm, Germany. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Carbohydrate Conformation Cytosol / metabolism* Glucosephosphates / metabolism* Plants, Genetically Modified / metabolism Polysaccharides / metabolism* Solanum tuberosum / metabolism* Starch / metabolism* |
| Chemical | |
Reg. No./Substance:
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0/Glucosephosphates; 0/Polysaccharides; 9005-25-8/Starch |
| Comments/Corrections | |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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