Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.502370
Title: Natural Variation in the Vernalization Response of Arabidopsis thaliana
Author: Strange, Amy
Awarding Body: University of East Anglia
Current Institution: University of East Anglia
Date of Award: 2008
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Abstract:
Within Arabidopsis thaliana there is extensive natural variation in the timing of flowering. This thesis focuses on the variation in vernalization response, manifested as a requirement for different lengths of cold in order to fully accelerate flowering. During vernalization, the gene encoding the floral repressor FLC is silenced and this is maintained during subsequent development by a Polycomb-mediated chromatin silencing mechanism. Three accessions from Sweden (Lov-I, Ull-2-5 and Var-2-6) require extended vernalization due to a slower accumulation ofthe chromatin silencing during the cold. In this study a QTL analysis mapped the variation in vernalization response to chromosomes 1,4 and 5. Further fine mapping identified FLC as one ofthe loci underlying the QTL and polymorphisms in FLC were located in putative regulatory rather than protein-coding regions. Allelic variation in FLC was found to be directly responsible for variation in the stability ofFLC repression after short lengths of vernalization. Work is ongoing to map the nucleotide polymorphisms which are directly responsible for the phenotypic variation. The vernalization response of two accessions from America (Kno-I8 and RRS-IO) was also investigated. They express FLC at extremely low levels, but are late flowering. Vernalization response QTL in these accessions again mapped to chromosomes 1,4 and 5. Low FLC expression was associated with a transposable element insertion in intron 1 ofFLC. Cloning of this transposon into a wild-type FLC allele showed it inactivates function and demonstrated modifiers in the American accessions that result in their late flowering. Initial results are described from a European common garden experiment, addressing whether flowering time is an adaptive trait. It was found that the Swedish accessions described above have low fitness in non-vernalizing conditions.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.502370  DOI: Not available
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