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Important roles of drought- and cold-inducible genes for galactinol synthase in stress tolerance in Arabidopsis thaliana.
- Source :
-
The Plant journal : for cell and molecular biology [Plant J] 2002 Feb; Vol. 29 (4), pp. 417-26. - Publication Year :
- 2002
-
Abstract
- Raffinose family oligosaccharides (RFO) accumulating during seed development are thought to play a role in the desiccation tolerance of seeds. However, the functions of RFO in desiccation tolerance have not been elucidated. Here we examine the functions of RFO in Arabidopsis thaliana plants under drought- and cold-stress conditions, based on the analyses of function and expression of genes involved in RFO biosynthesis. Sugar analysis showed that drought-, high salinity- and cold-treated Arabidopsis plants accumulate a large amount of raffinose and galactinol, but not stachyose. Raffinose and galactinol were not detected in unstressed plants. This suggests that raffinose and galactinol are involved in tolerance to drought, high salinity and cold stresses. Galactinol synthase (GolS) catalyses the first step in the biosynthesis of RFO from UDP-galactose. We identified three stress-responsive GolS genes (AtGolS1, 2 and 3) among seven Arabidopsis GolS genes. AtGolS1 and 2 were induced by drought and high-salinity stresses, but not by cold stress. By contrast, AtGolS3 was induced by cold stress but not by drought or salt stress. All the GST fusion proteins of GST-AtGolS1, 2 and 3 expressed in Escherichia coli had galactinol synthase activities. Overexpression of AtGolS2 in transgenic Arabidopsis caused an increase in endogenous galactinol and raffinose, and showed reduced transpiration from leaves to improve drought tolerance. These results show that stress-inducible galactinol synthase plays a key role in the accumulation of galactinol and raffinose under abiotic stress conditions, and that galactinol and raffinose may function as osmoprotectants in drought-stress tolerance of plants.
- Subjects :
- Acclimatization physiology
Amino Acid Sequence
Arabidopsis genetics
Arabidopsis growth & development
Carbohydrate Sequence
Cold Temperature
Disaccharides chemistry
Disaccharides metabolism
Disasters
Escherichia coli genetics
Galactosyltransferases metabolism
Gene Expression
Molecular Sequence Data
Molecular Structure
Phylogeny
Plant Transpiration genetics
Plant Transpiration physiology
Plants, Genetically Modified
Raffinose analogs & derivatives
Raffinose chemistry
Raffinose metabolism
Salts
Seeds enzymology
Seeds genetics
Seeds growth & development
Sequence Homology, Amino Acid
Soil analysis
Transcription Factors genetics
Transcription Factors metabolism
Water metabolism
Acclimatization genetics
Arabidopsis enzymology
Arabidopsis Proteins
Galactosyltransferases genetics
Subjects
Details
- Language :
- English
- ISSN :
- 0960-7412
- Volume :
- 29
- Issue :
- 4
- Database :
- MEDLINE
- Journal :
- The Plant journal : for cell and molecular biology
- Publication Type :
- Academic Journal
- Accession number :
- 11846875
- Full Text :
- https://doi.org/10.1046/j.0960-7412.2001.01227.x