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SESSION 4: GENETICS OF HOSTS – PLANT RESISTANCE TO FUSARIUM,
VARIETY DEVELOPMENT
Expression QTL mapping for Fusarium Head Blight
resistance in Wheat
M. Samad Zamini, C. Ametz, E. Sam, G. Siegwart, B. Steiner, M. Lemmens,
W. Schweiger, H. Buerstmayr
BOKU-University of Natural Resources and Life Sciences Vienna, Department IFA-Tulln, Institute for
Biotechnology in Plant Production, Konrad Lorenz Str. 20, A-3430 Tulln, Austria
E-mail: mina.zamini@boku.ac.at
Breeding for Fusarium head blight (FHB) resistance is a challenging task for
breeders worldwide, also due to the quantitative nature of resistance in wheat. To
date more than 200 QTL on almost all chromosomes have been reported to
contribute to resistance, with most of them encoding for minor effect genes. The
application of genome-wide approaches to analyse quantitative traits has yielded
relevant genes, involved in the expression of related traits (Druka et.al. Plant
Biotec J. 2010). The analysis of expression Quantitative Trait Loci (eQTL) is a
method to identify novel QTL by employing transcriptome variation. In this study
we exploited eQTL mapping that correlate microarray gene expression data and
genetic markers data to identify genes involved in the specific response of wheat
to Fusarium graminearum in a population of 200 doubled haploid lines
segregating for FHB resistance. This population derives from the resistant line
CM-82036 (progeny of Sumai 3) and the susceptible European spring wheat
cultivar Remus (Buerstmayr et.al. TAG, 2002, TAG 2003). Six central spikelets
were inoculated with a Fusarium spore suspension at anthesis and samples were
harvested at two time points (30 and 50 hours) after inoculation. RNA was
hybridized onto a custom-build microarray (Agilent 8x60k), comprising 44.000
wheat unigenes, several hundred wheat candidate genes, that have been
reported responsive to Fusarium in literature and the entire transcriptome of
Fusarium graminearum (ca. 14.000 genes). In total, we hybridized about 500
microarrays. eQTL mapping was carried out by interval mapping analysis. We
discovered 20,420 significant eQTL (based on high LOD score), distributed
throughout all chromosomes. In a next step we detected “eQTL hotspots”, which
describe gene-rich regions potentially co-regulated by eQTL. We further identified
cis and trans-eQTL, based on the distance of the eQTL map position to the
location of the actual genes controlled by the respective eQTL.
Keyword: Expression QTL, transcriptome analysis, eQTL hotspots, Fusarium
head blight
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