EFS12- Book of abstracts - Contact

SESSION 3: PATHOGENESIS – EPIDEMIOLOGY AND POPULATION
GENETICS
P43 - Heterochromatin protein 1 (Hep1) deletion in F.
graminearum causes hypervirulence on wheat heads.
S. Boedi 1 , M. Imer 2 , U. Güldener 3 , T. Nussbaumer 3 , K. Kugler 3 , M. Sulyok 2 , V.
Preiser 2 , G. Siegwart 2 , E. Sam 2 , M. Lemmens 2 , H. Bürstmayr 2 , R. Krska 2 , K.
Brunner 2 , J. Strauss 1
1 Department of Applied Genetics and Cell Biology, University of Natural Resources and Life Sciences
Vienna, University and Research Center Tulln (UFT), Konrad Lorenz Strasse 24, A-3430 Tulln,
Austria; 2 Department for Agrobiotechnology (IFA-Tulln), University of Natural Resources and Life
Sciences Vienna, Konrad Lorenz Strasse 20, 3430 Tulln, Austria; 3 Helmholtz Zentrum München,
Deutsches Forschungszentrum für Gesundheit und Umwelt (GmbH), Ingolstädter Landstr. 1, 85764
Neuherberg
E-mail: stefan.boedi@boku.ac.at
Chromatin modifications and formation of facultative heterochromatin have been
shown to be involved in the regulation of secondary metabolism gene clusters in
the fungal model organism Aspergillus nidulans. Based on that work we deleted
the heterochromatin protein-1 homologue, Hep1, in F. graminearum Ph-1
background and measured its impact on histone H3K9 methylation by ChIP
analysis, confirming its functionality. We investigated the effect of Hep1 deletion
on the ability of F. graminearum to infect wheat heads of the susceptible cultivar
Remus and found the hep1 mutant to be hypervirulent with a ~2 fold increased
infection rate. These findings correlated with an increased production of the
trichothecene deoxynivalenol (DON) during pathogenic growth on living wheat
heads. Interestingly the hep1 mutant produced less DON than the Ph-1 wildtype
on axenic minimal medium and the produced DON amounts on dead wheat
heads, which served as non- response control, were much smaller than the
produced amounts on living wheat heads. This indicates that the plant response
system plays a crucial role in the activation of this secondary metabolite cluster as
well as that a crosstalk between heterochromatin status and pathogenicity exists.
Our aim in this study is to understand the molecular basis of the hypervirulence
caused by hep1 deletion as well as to investigate the effect of the plant response
on F. graminearum by determination of the transcriptome levels of the hep1
deletion versus the Ph-1 wildtype strain on alive and dead (non-responding)
wheat heads using RNA-seq methodology. Preliminary results show that the plant
response has a huge systemic impact on F. graminearum transcript levels what
will be further investigated. The RNA-seq analysis of the complex infection
samples will also mark plant genes differentially responding to the hep1 mutant.
Keywords: Fusarium graminearum infection of wheat, heterochromatin protein 1,
secondary metabolism, RNA-seq
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