Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.640367
Title: Regulation of the synthesis and activity of the STP1 monosaccharide transporter in Arabidopsis thaliana
Author: Alford, Heather Lynne
Awarding Body: University of Edinburgh
Current Institution: University of Edinburgh
Date of Award: 2002
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Abstract:
In plants the effective partitioning of carbon and nitrogen assimilates between source and sink tissues is essential for growth and development. The regulation of sugar transporters is pivotal not only to the allocation of carbohydrates throughout the plant but in providing sugars, which may act as signals in the modulation of gene expression. Many of the genes associated with the production, distribution, utilisation and storage of assimilates are regulated by sugars. The Arabidopsis thaliana Sugar Transport Protein 1 (AtSTP1) is the principal monosaccharide transporter in Arabidopsis seedlings, accounting for approximately 60% of 3-O-methyl glucose uptake activity. Characterisation of AtSTP1 gene expression and transport activity in vitro in plantlets growth in continuous light and in a diurnal growth regime reveal regulation in light, glucose and mechanical stimulation. A rapid accumulation of AtSTP1 transcripts upon transfer to the dark was observed in all growth regimes tested. This appears to be a novel feature in sugar transporter regulation. In light grown plantlets, dark-induced AtSTP1 transcripts diminished within 1 h of subsequent treatment with exogenous 3 mM D-glucose or white light. Furthermore, a 5 min pulse of white light resulted in a marked repression of dark-induced AtSTP1 transcripts, which is indicative of sugar-independent regulation. The diurnal regulation of the AtSTP1 gene in plantlets entrained a L12 h:D12 h regime is complex, as is the subsequent AtSTP1 response to sugars. The expression pattern of the AtSTP1 gene was different in the shoot and roots; furthermore in the shoots AtSTP1 transcripts displayed circadian rhythm upon transfer to continuous light. It appears that at least three signalling pathways interact in the regulation of STP1 synthesis and activity in Arabidopsis thaliana. These results are discussed in terms of the possible physiological functions of AtSTP1, including retrieval of sugars derived from the cell wall.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.640367  DOI: Not available
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