Projects
Projects: Summary of Projects by RegionProjects in Region Scotland involving University of Edinburgh : BB/D00134X/1 |
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| Reference Number | BB/D00134X/1 | |
| Title | Xyloglucans xyloglucan endotransglucosylase (XET) activity and arabinogalactan-protein (AGP)-like molecules: a new inter-relationship | |
| Status | Completed | |
| Energy Categories | Not Energy Related 75%; Renewable Energy Sources(Bio-Energy, Production of transport biofuels (incl. Production from wastes)) 25%; |
|
| Research Types | Basic and strategic applied research 100% | |
| Science and Technology Fields | BIOLOGICAL AND AGRICULTURAL SCIENCES (Biological Sciences) 100% | |
| UKERC Cross Cutting Characterisation | Not Cross-cutting 100% | |
| Principal Investigator |
Prof S (Stephen ) Fry No email address given Institute for Molecular Plant Science University of Edinburgh |
|
| Award Type | Research Grant | |
| Funding Source | BBSRC | |
| Start Date | 01 February 2006 | |
| End Date | 31 January 2009 | |
| Duration | 36 months | |
| Total Grant Value | £262,561 | |
| Industrial Sectors | Transport Systems and Vehicles | |
| Region | Scotland | |
| Programme | ||
| Investigators | Principal Investigator | Prof S (Stephen ) Fry , Institute for Molecular Plant Science, University of Edinburgh (100.000%) |
| Web Site | ||
| Objectives | Objectives not supplied | |
| Abstract | We aim to provide basic new information on the mechanisms by which plant cells regulate the assembly and loosening of their primary walls. Xyloglucan is a major hemicellulose of primary cell walls that hydrogen-bonds to, and probably tethers, cellulosic microfibrils. XTHs (xyloglucan endotransglucosylase/endohydrolases) are wall-localised proteins with two distinct enzymic activities: XET and XEH, catalysing the inter-polymeric endotransglycosylation of xyloglucan and the endo-hydrolysis of xyloglucan respectively. XET activity is thought to contribute to the integration of newly-synthesised xyloglucan chains into the inner face of the wall and also to the re-structuring of existing wall-bound xyloglucan chains. The latter process in particular may contribute to wall loosening and hence to cell expansion and tissue softening. Arabinogalactan-proteins (AGPs) are high-carbohydrate glycoproteins (i.e., proteoglycans; often 85-95 per cent sugar residues, usually rich in Gal, Ara and GlcA) with a short polypeptide backbone usually rich in Hyp, Ala, Gly, Ser and Thr, and often associated with a phosphorylated GPI anchor. AGPs occur mainly at the plasma membrane/wall interface, in the wall itself and in extracellular secretions. AGPs have been strongly implicated as promoters of wall loosening and hence cell expansion. The inner face of the wall, adjacent to the plasma membrane, is a particularly significant location because it is probably the load-bearing stratum of the wall. However, no widely accepted mechanism has yet been proposed to explain biochemically how AGPs influence irreversible wall extensibility. We now wish to study the interactions between XTHs and AGPs. Takeda & Fry (2004 and unpublished data) showed that AGPs and partially characterised AGP-like molecules from cauliflower florets can promote the XET activity of de-salted XTHs. Our central HYPOTHESIS is therefore that AGPs interact with XTHs and promote their XET activity, thereby regulating, spatially and temporally, wall-loosening and/or assembly. We will purify and further characterise several specific XTHs and AGP-like molecules from various crucifer tissues (Arabidopsis cell cultures, cauliflower florets and etiolated Brassica hypocotyls), and quantitatively assay the effect of various AGPs on various XTHs. We will further explore the central hypothesis by testing the effect of beta-Glc3-Yariv reagent (which binds to and inactivates many AGPs), in comparison with that of alpha-Gal3-Yariv reagent (which does not), on the in-vivo action of XTHs in living plant tissues. Further, we will test whether, and how, AGPs bind non-covalently to XTHs and/or to xyloglucans and oligosaccharide fragments thereof. The specific sub-hypotheses to be tested are listed in Section J. Although the project is targeted at crucifers because of their experimental convenience and because of initial successes with these plants, the potential outcome of the work is an ability to regulate more closely the growth and development of essentially any food, fodder or industrial crop by modification of the structure and expression of cell wall components. | |
| Data | No related datasets |
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| Projects | No related projects |
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| Publications | No related publications |
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| Added to Database | 22/11/13 | |
