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Oligosaccharins as plant growth regulators
1Division of Biological Sciences, University of Edinburgh, U.K.
Biochemical Society Symposium
|January 1, 1994
Summary
Xyloglucan-derived oligosaccharides (XGOs) show dual effects on plant cell growth. At low concentrations, L-fucosylated XGOs inhibit growth, while at higher concentrations, cellotetraose-based XGOs promote growth by mimicking auxin.
Area of Science:
- Plant biology
- Biochemistry
- Molecular biology
Background:
- Plant cell wall polysaccharides, like xyloglucan, are sources of bioactive oligosaccharides.
- Xyloglucan-derived oligosaccharides (XGOs) are implicated in plant growth regulation.
Purpose of the Study:
- To investigate the distinct effects of XGOs on plant cell growth.
- To elucidate the mechanisms underlying XGO-mediated growth regulation.
Main Methods:
- Partial hydrolysis of xyloglucan to obtain XGOs.
- Assaying XGO effects on pea-stem segment growth.
- In vivo labeling with L-[3H]arabinose and L-[3H]fucose in spinach cell cultures.
Main Results:
- L-fucosylated XGOs (e.g., XXFG) inhibit auxin-stimulated growth at nanomolar concentrations.
- Cellotetraose-based XGOs (e.g., XXXG) promote growth at micromolar concentrations, mimicking auxin.
- XXFG is synthesized via polysaccharide degradation, accumulates extracellularly, and is incorporated into the cell wall.
Conclusions:
- XGOs exhibit concentration-dependent dual regulatory roles in plant cell growth.
- Growth inhibition is linked to L-fucosylation and membrane binding.
- Growth promotion is mediated by cellotetraose structures acting as substrates for xyloglucan endotransglycosylase.