Abstract |
The ascorbic acid (AA)-deficient Arabidopsis thaliana mutant vtc1-1, which is defective in GDP-mannose pyrophosphorylase (GMPase), exhibits conditional hypersensitivity to ammonium (NH(4) (+) ), a phenomenon that is independent of AA deficiency. As GMPase is important for GDP-mannose biosynthesis, a nucleotide sugar necessary for protein N-glycosylation, it has been thought that GDP-mannose deficiency is responsible for the growth defect in vtc1-1 in the presence of NH(4) (+) . Therefore, the motivation for this work was to elucidate the growth and developmental processes that are affected in vtc1-1 in the presence of NH(4) (+) and to determine whether GDP-mannose deficiency generally causes NH(4) (+) sensitivity. Furthermore, as NH(4) (+) may alter cytosolic pH, we investigated the responses of vtc1-1 to pH changes in the presence and absence of NH(4) (+) . Using qRT-PCR and staining procedures, we demonstrate that defective N-glycosylation in vtc1-1 contributes to cell wall, membrane and cell cycle defects, resulting in root growth inhibition in the presence of NH(4) (+) . However, by using mutants acting upstream of vtc1-1 and contributing to GDP-mannose biosynthesis, we show that GDP-mannose deficiency does not generally lead to and is not the primary cause of NH(4) (+) sensitivity. Instead, our data suggest that GMPase responds to pH alterations in the presence of NH(4) (+) .
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Authors | Chase F Kempinski, Rawaa Haffar, Carina Barth |
Journal | Plant, cell & environment
(Plant Cell Environ)
Vol. 34
Issue 5
Pg. 847-58
(May 2011)
ISSN: 1365-3040 [Electronic] United States |
PMID | 21332510
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | © 2011 Blackwell Publishing Ltd. |
Chemical References |
- Arabidopsis Proteins
- Quaternary Ammonium Compounds
- Guanosine Diphosphate Mannose
- Nucleotidyltransferases
- mannose 1-phosphate guanylyltransferase
- Ascorbic Acid
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Topics |
- Arabidopsis
(enzymology, genetics, growth & development)
- Arabidopsis Proteins
(metabolism)
- Ascorbic Acid
(analysis)
- Cell Cycle
- Cell Membrane
(metabolism)
- Cell Wall
(metabolism)
- Endoplasmic Reticulum
(metabolism)
- Glycosylation
- Guanosine Diphosphate Mannose
(biosynthesis)
- Hydrogen-Ion Concentration
- Mutation
- Nucleotidyltransferases
(metabolism)
- Plant Roots
(growth & development)
- Quaternary Ammonium Compounds
(metabolism)
- Stress, Physiological
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