Use this URL to cite or link to this record in EThOS: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.614597
Title: Natural variation in Arabidopsis thaliana growth in response to ambient temperatures
Author: Khattak, Asif
ISNI:       0000 0004 5367 0534
Awarding Body: University of East Anglia
Current Institution: University of East Anglia
Date of Award: 2014
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Abstract:
Temperature is one of the most important abiotic environmental regulators of plant growth and development. The temperature-dependent elongation of the Arabidopsis thaliana hypocotyls (seedling stems) is a well-characterised environmental response. The aim of this study was to identify allelic variants underlying Quantitative Trait Loci (QTL) responsible for the natural genetic variation of hypocotyl length in response to ambient temperatures. The Arabidopsis thaliana accessions were phenotyped for hypocotyl length at 12°C, 17°C, 22°C and 27°C ambient temperature environments and substantial genetic variation was established. This facilitated a forward genetic approach by performing a QTL analysis to identify the genetic basis of thermal sensitivity. Firstly, fine-mapped QTL were identified for hypocotyl length in response to different temperatures. SMALL AUXIN UPREGULATED RNA 38 (SAUR38) is a novel candidate gene for a QTL. Another major-effect QTL ‘Temp22.2’ was also identified which harbours the candidate gene PHYTOCHROME B (PHYB). Secondly, fine-mapped ‘Environmental QTL’ were also discovered for the genotype by environment (G x E) interaction. PHYTOCHROME D (PHYD) is a candidate for a temperature-responsiveness QTL. For QTL cloning, functional characterisation of SAUR38 and PHYB was carried out by knockout analysis and transgenic allelic complementation. The results showed that SAUR38 controlled natural variation in the Tsu-0 accession by increasing elongation. The PHYB alleles of Ct-1, Sf-2 and Col-0 accessions explain the Temp22.2 QTL. Ct-1 and Sf-2 alleles are positive regulators increasing elongation, whereas Col-0 allele is a negative regulator. Temp22.2 QTL was cloned and novel alleles were discovered revealing the molecular basis of quantitative variation in hypocotyl length in response to temperature.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.614597  DOI: Not available
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