Arabidopsiscytosolic alpha-glycan phosphorylase, PHS2, is important during carbohydrate imbalanced conditions
| Autor: | Linda Hellborg, Carolin Sörensson, Simone Schopper, E Andreasson, Joerg Fettke, Susanne Widell, P Mühlenbock, Marit Lenman |
|---|---|
| Rok vydání: | 2014 |
| Předmět: |
Glycan
Light Phosphorylases Mutant Arabidopsis Plant Science Hypocotyl Gene Knockout Techniques Glycogen phosphorylase Cytosol Gene Expression Regulation Plant Polysaccharides Stress Physiological Arabidopsis thaliana Plastid Cellular Senescence Ecology Evolution Behavior and Systematics biology Arabidopsis Proteins food and beverages General Medicine Darkness Carbohydrate Plants Genetically Modified biology.organism_classification Plant Leaves Phenotype Biochemistry Seedlings Mutation biology.protein Carbohydrate Metabolism |
| Zdroj: | Plant Biology. 17:74-80 |
| ISSN: | 1435-8603 |
| Popis: | Arabidopsis thaliana has two isoforms of alpha-glycan phosphorylase (EC 2.4.1.1), one residing in the plastid and the other in the cytosol. The cytosolic phosphorylase, PHS2, acts on soluble heteroglycans that constitute a part of the carbohydrate pool in a plant. This study aimed to define a physiological role for PHS2. Under standard growth conditions phs2 knock-out mutants do not show any clear growth phenotype, and we hypothesised that during low-light conditions where carbohydrate imbalance is perturbed, this enzyme is important. Soil-grown phs2 mutant plants developed leaf lesions when placed in very low light. Analysis of soluble heteroglycan (SHG) levels showed that the amount of glucose residues in SHG was higher in the phs2 mutant compared to wild-type plants. Furthermore, a standard senescence assay from soil-grown phs2 mutant plants showed that leaves senesced significantly faster in darkness than the wild-type leaves. We also found decreased hypocotyl extension in in vitro-grown phs2 mutant seedlings when grown for long time in darkness at 6 °C. We conclude that PHS2 activity is important in the adult stage during low-light conditions and senescence, as well as during prolonged seedling development when carbohydrate levels are unbalanced. |
| Databáze: | OpenAIRE |
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