Identifying and dissecting novel QTL regulating seed fatty acid composition in Arabidopsis thaliana for the improvement of rapeseed oil

Hattori, Chie (2012) Identifying and dissecting novel QTL regulating seed fatty acid composition in Arabidopsis thaliana for the improvement of rapeseed oil. Doctoral thesis, University of East Anglia.

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Abstract

Genes encoding desaturases in the polyunsaturated fatty acid (PUFA) biochemical
pathway have been identified by mutation analyses and utilized in oilseed rape
(Brassica napus) breeding programs. However the regulation mechanisms of these
genes are as yet unknown and pursued by the oil industry for further manipulation of
seed oil quality.
In order to identify loci involved in such regulatory mechanisms, Arabidopsis
thaliana, a close relative of B. napus, was used as a model plant. Seed oil
characteristics such as PUFA composition and oil content are regarded as
adaptative traits (Linder, 2000) which are typically the result of complex genetic
components controlled by multiple loci. Therefore QTL analysis was performed
using six recombinant inbred populations derived from wild accessions rich in
natural variations.
QTL analysis identified loci involved in PUFA composition and oil content and 13
QTL were selected for the development of Near Isogenic lines (NIL). NILs were
used to test the robustness of QTL by ANOVA and 11 QTL were successfully
validated for their effect on phenotype in this work. Finally a QTL detected in the NG
population for 18:2/18:1 was chosen for fine mapping and the region containing the
causative locus for the QTL was narrowed down to 2Mb. Seven candidate genes
within that region were identified which could be targeted in further fine mapping in
the future.
In addition, a comparative mapping of QTL between A. thaliana and B. napus was
performed through a unigene based B. napus map developed in the Bancroft group.
This map facilitated the integration of results found in A. thaliana with B. napus and
allowed the detection of coincident QTL regions between these two species and
candidate gene analysis within these regions. The genes MTACP2, PKP-BETA1,
DGAT1 and LTP4 were identified repeatedly during the analysis and are likely
candidate genes affecting seed oil and could be target genes for future breeding.

Item Type: Thesis (Doctoral)
Faculty \ School: Faculty of Science > School of Biological Sciences
Depositing User: Mia Reeves
Date Deposited: 13 Mar 2014 10:19
Last Modified: 13 Mar 2014 10:19
URI: https://ueaeprints.uea.ac.uk/id/eprint/48146
DOI:

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