Skip Navigation



Plant and Cell Physiology Advance Access published online on April 13, 2009
Plant and Cell Physiology, doi:10.1093/pcp/pcp052
This Article
Right arrow Advance Access manuscript (PDF) Freely available
Right arrow All Versions of this Article:
50/5/998    most recent
pcp052v1
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Google Scholar
Right arrow Articles by Meng, M.
Right arrow Articles by Kleczkowski, L. A.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Meng, M.
Right arrow Articles by Kleczkowski, L. A.
Agricola
Right arrow Articles by Meng, M.
Right arrow Articles by Kleczkowski, L. A.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

© The Author 2009. Published by Oxford University Press on behalf of Japanese Society of Plant Physiologists. All rights reserved. For Permissions, please e-mail: journals.permissions@oxfordjournals.org

UDP-glucose pyrophosphorylase is not rate-limiting, but is essential in Arabidopsis

Meng Meng1, Matt Geisler2, Henrik Johansson1, Jesper Harholt3, Henrik V. Scheller3,5, Ewa J. Mellerowicz4 and Leszek A. Kleczkowski1,*

1Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, 901 87 Umeå, Sweden
2Dept. Plant Biology, Southern Illinois University, Carbondale, IL, USA
3Dept. Plant Physiology, University of Copenhagen, Copenhagen, Denmark
4Dept. Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, Umeå, Sweden

*Corresponding author: Prof. Leszek A. Kleczkowski E-mail, leszek.kleczkowski{at}plantphys.umu.se; Fax, +46 90 786 6676.


  Abstract

UDP-glucose pyrophosphorylase (UGPase) produces UDP-glucose which is essential for sucrose and polysaccharide synthesis. Using Arabidopsis, we demonstrated that two UGPase genes (UGP1 and UGP2) are differentially expressed in a variety of organs, with UGP1 being predominant. Co-expression analyses of UGP genes suggest that UGP1 is closely co-regulated with carbohydrate metabolism genes, late embryogenesis and seed loading, while UGP2 co-regulates with stress response genes, fertilized flowers and photosynthetic genes. We have used Arabidopsis mutants for the UGPs to characterize the role of both genes. The UGPase activity/ protein was reduced by 70, 10 and 85% in ugp1, ugp2 and ugp1/ugp2 double mutant (DK) plants, respectively. A decrease in UGPase activity/ protein was accompanied by an increase in USP expression, a gene for UDP-sugar pyrophosphorylase, suggesting a compensatory mechanism. Generally, the mutants had no effects on soluble sugar/ starch content (except in certain cases for DK plants), and there were no differences in cell wall composition/ content between wild-type (wt) and the mutants. On the other hand, DK plants had longer hypocotyl and root lengths. When grown in the field, the mutants had as much as a 50% decrease in the number of seeds produced (consistent with a substantial decrease in field fitness), suggesting that they would be outcompeted in the field in few generations. Overall, the data suggest that UGPase is not rate-limiting for sucrose/ starch and cell wall synthesis, but that it is essential in Arabidopsis.

Keywords: Callose - cellulose - cell wall synthesis - seed fitness - sucrose synthesis

5 Present address: Feedstocks Division, Joint Bioenergy Institute, Emeryville, CA 94608, USA

(Received February 25, 2009; Accepted April 7, 2009)
Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?




Disclaimer: Please note that abstracts for content published before 1996 were created through digital scanning and may therefore not exactly replicate the text of the original print issues. All efforts have been made to ensure accuracy, but the Publisher will not be held responsible for any remaining inaccuracies. If you require any further clarification, please contact our Customer Services Department.