Genetic Evidence for the Role of GDP-Mannose in Plant Ascorbic Acid (Vitamin C) Biosynthesis
Vitamin C (L-ascorbic acid; AsA) acts as a potent antioxidant and cellular reductant in plants and animals. AsA has long been known to have many critical physiological roles in plants, yet its biosynthesis is only currently being defined. A pathway for AsA biosynthesis that features GDP-mannose and...
Saved in:
Published in | Proceedings of the National Academy of Sciences - PNAS Vol. 96; no. 7; pp. 4198 - 4203 |
---|---|
Main Authors | , , , , , |
Format | Journal Article |
Language | English |
Published |
United States
National Academy of Sciences of the United States of America
30.03.1999
National Acad Sciences National Academy of Sciences The National Academy of Sciences |
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | Vitamin C (L-ascorbic acid; AsA) acts as a potent antioxidant and cellular reductant in plants and animals. AsA has long been known to have many critical physiological roles in plants, yet its biosynthesis is only currently being defined. A pathway for AsA biosynthesis that features GDP-mannose and L-galactose has recently been proposed for plants. We have isolated a collection of AsA-deficient mutants of Arabidopsis thaliana that are valuable tools for testing of an AsA biosynthetic pathway. The best-characterized of these mutants (vtc1) contains ≈ 25% of wild-type AsA and is defective in AsA biosynthesis. By using a combination of biochemical, molecular, and genetic techniques, we have demonstrated that the VTC1 locus encodes a GDP-mannose pyrophosphorylase (mannose-1-P guanyltransferase). This enzyme provides GDP-mannose, which is used for cell wall carbohydrate biosynthesis and protein glycosylation as well as for AsA biosynthesis. In addition to genetically defining the first locus involved in AsA biosynthesis, this work highlights the power of using traditional mutagenesis techniques coupled with the Arabidopsis Genome Initiative to rapidly clone physiologically important genes. |
---|---|
Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 Present address: Section of Genetics and Development, Cornell University, Ithaca, NY 14853-1801. To whom reprint requests should be addressed at: Boyce Thompson Institute for Plant Research, Tower Road, Ithaca, NY 14853-1801. e-mail: PLC3@cornell.edu. Present address: Cereon Genomics, LLC, 270 Albany Street, Cambridge, MA 02139. Communicated by André T. Jagendorf, Cornell University, Ithaca, NY |
ISSN: | 0027-8424 1091-6490 |
DOI: | 10.1073/pnas.96.7.4198 |