Down-regulation of UDP-glucuronic acid biosynthesis leads to swollen plant cell walls and severe developmental defects associated with changes in pectic polysaccharides |
| |
Authors: | Reboul Rebecca Geserick Claudia Pabst Martin Frey Beat Wittmann Doris Lütz-Meindl Ursula Léonard Renaud Tenhaken Raimund |
| |
Institution: | Department of Cell Biology, Molecular Cell Physiology, University of Salzburg, 5020 Salzburg, Austria. |
| |
Abstract: | UDP-glucose dehydrogenase (UGD) plays a key role in the nucleotide sugar biosynthetic pathway, as its product UDP-glucuronic acid is the common precursor for arabinose, xylose, galacturonic acid, and apiose residues found in the cell wall. In this study we characterize an Arabidopsis thaliana double mutant ugd2,3 that lacks two of the four UGD isoforms. This mutant was obtained from a cross of ugd2 and ugd3 single mutants, which do not show phenotypical differences compared with the WT. In contrast, ugd2,3 has a strong dwarfed phenotype and often develops seedlings with severe root defects suggesting that the UGD2 and UGD3 isoforms act in concert. Differences in its cell wall composition in comparison to the WT were determined using biochemical methods indicating a significant reduction in arabinose, xylose, apiose, and galacturonic acid residues. Xyloglucan is less substituted with xylose, and pectins have a reduced amount of arabinan side chains. In particular, the amount of the apiose containing side chains A and B of rhamnogalacturonan II is strongly reduced, resulting in a swollen cell wall. The alternative pathway to UDP-glucuronic acid with the key enzyme myo-inositol oxygenase is not up-regulated in ugd2,3. The pathway also does not complement the ugd2,3 mutation, likely because the supply of myo-inositol is limited. Taken together, the presented data underline the importance of UDP GlcA for plant primary cell wall formation. |
| |
Keywords: | Carbohydrate Biosynthesis Carbohydrate Metabolism Cell Wall Development Nucleoside Nucleotide Biosynthesis Plant Rhamnogalacturonan II UDP-glucose Dehydrogenase |
本文献已被 PubMed 等数据库收录! |
|