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SESSION 4: GENETICS OF HOSTS – PLANT RESISTANCE TO FUSARIUM,
VARIETY DEVELOPMENT
Wheat gene network dynamics in response to
Fusarium graminearum and functional validation of
candidate resistance genes
G. Siegwart 1 , C. Ametz 1 , B. Steiner 1 , K. Kugler 2 , T. Nussbaumer 2 , W.
Schweiger 2 , K. Mayer 2 , H. Buerstmayr 1
1 BOKU - University of Natural Resources and Life Sciences, A-1180 ViennaDepartment for
Biotechnology in Plant production, A-3430 Tulln; 2 Helmholtz Zentrum München, Institute for
Bioinformatics and Systems Biology, D-85764 Neuherberg
E-mail: gerald.siegwart@boku.ac.at
Fusarium head blight is a prominent disease on small grain cereals. Resistance to
the causative fungus Fusarium graminearum is quantitative. Two of the most
effective QTL are located on chromosome 3B and 5A and designated Fhb1 and
Qfhs.ifa-5A, respectively (Buerstmayr 2002, Buerstmayr 2003). Recently we
developed near-isogenic lines (NIL) using the susceptible Austrian spring wheat
cultivar Remus as recurrent parent and CM-82036 (a descendant of Sumai 3) as
donor for the resistance QTL (Schweiger et al. submitted). NILs possessing both
QTL, only one of them or none of both were produced and served as ideal
resource for investigating the effects of these QTL in a near-isogenic, susceptible
background.A greenhouse experiment was conducted in three replications,
generating in total 60 samples of mock and F. graminearum challenged tissue
derived from five genotypes and two timepoints - the resulting RNA was used for
RNA-seq on the Illumina platform.The reads were mapped against the recently
published wheat ortholome (Brenchley et al. 2012); the retrieved transcripts were
then compared to the barley high confidence genes and these were used for
further analysis because of the much more comprehensive annotation and better
gene models. We observed differentially expressed genes specific for either
condition or genotype and also genes constitutively more abundant for either
QTL. We further identified network modules showing expression patterns linked to
genotype-specific response at different time points. Particular domains and
transcription factors were found to play a central role as hubs within the Fusarium
associated gene co-expression network. Selected candidate genes have been
cloned and functionally analyzed using virus-induced gene silencing. Results will
be presented.
Keywords: RNA-seq, gene network, Fusarium resistance, wheat
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