Mutant Name: mur1

Gene Name MUR1
Protein Name GDP-D-mannose 4,6-dehydratase
Mutagen EMS
Category forward genetics
Organism Arabidopsis thaliana
Ecotype Col
Donor
General Description Mutant plants are slightly dwarf; elongating stem segments are more fragile than normal.
Organ Specificity

In contrast to wild type plants, immunolocalizations with the monoclonal antibodies recognize fucosylated epitope showed:
1. The walls of the body of the root hair-forming cell are weakly labeled, whereas those of the non-root hair-forming epidermal cells do not label.
2. No labeling of any cell walls in the seedling.
3. Lateral root primordia of mur1 seedlings do not label.
4. Except stipules, the aboveground vegetative tissues of mur1 plants do not label.

GMD2::GUS expression showed:
1. In the underground part, GUS expression was found in all other regions except for the root meristem and the proximal part of the elongation zone.
2. In the aboveground part, GUS expression was observed in portions of the inflorescence stem, the vasculature of flowers, the style.
Impact on Wall
Impact on Sugar Composition All eight mutant alleles exhibit 50- to 200-fold reductions in L-fucose in the cell walls of shoot organs, while the L-fucose content in roots is only reduced by 40%.
Reference 1.Bonin CP, Potter I, Vanzin GF, Reiter WD. (1997)The MUR1 gene of Arabidopsis thaliana encodes an isoform of GDP-D-mannose-4,6-dehydratase, catalyzing the first step in the de novo synthesis of GDP-L-fucose. Proc Natl Acad Sci U S A. Mar 4;94(5):2085-90.

2. Glenn Freshour, Christopher P. Bonin, Wolf-Dieter Reiter, Peter Albersheim, Alan G. Darvill, and Michael G. Hahn. (2003) Distribution of Fucose-Containing Xyloglucans in Cell Walls of the mur1 Mutant of Arabidopsis. Plant Physiol. 131: 1602-1612.

3. Christopher P. Bonin, Glenn Freshour, Michael G. Hahn, Gary F. Vanzin, and Wolf-Dieter Reiter. (2003) The GMD1 and GMD2 Genes of Arabidopsis Encode Isoforms of GDP-D-Mannose 4,6-Dehydratase with Cell Type-Specific Expression Patterns. Plant Physiol. 132: 883-892.

4. van Hengel AJ, Roberts K. Fucosylated arabinogalactan-proteins are required for full root cell elongation in arabidopsis. Plant J. 2002 Oct;32(1):105-13.