EFS12- Book of abstracts - Contact

SESSION 1: FUSARIUM – GENETICS, GENOMICS AND SYSTEMS BIOLOGY
Eukaryotic translation initiation factor 5A regulates
reactive oxygen species, DON, and virulence of
Fusarium graminearum and its activation is essential
for cell viability.
A. L. Martinez-Rocha 1 , M. Woriedh 2 , W. Schäfer 1 .
1 Biocenter Klein Flottbek, Molecular Phytopathology and Genetics, University of Hamburg, 2 Cell
Biology and Plant Biochemistry, University of Regensburg
E-mail: wilhelm.schaefer@uni-hamburg.de
The eukaryotic translation initiation factor 5A (EIF5A) is a highly conserved
protein from archeabacteria to higher eukaryotes with the exception of the
bacteria. EIF5A acts as a nucleo-cytoplasmatic shuttle protein of mRNAs to the
ribosomes and is the only known protein containing the unique aminoacid
hypusine. Hypusin is formed by a posttranslational modification of lysine in two
enzymatic steps, catalysed by deoxyhypusine synthase (DHS) and
deoxyhypusine hydroxylase (DOHH). EIF5A has a role in diseases as diverse as
HIV infection, malaria, cancer, and diabetes. The involvement of EIF5A in fungal
phyto-pathogenesis is unknown.
Until now, only inhibition or silencing has been tested to control hypusination of
eIF5A and its consequent results. We over-expressed the enzymes that control
hypusination of eIF5A in the fungal pathogen Fusarium graminearum. Overexpression
of DHS leads to an increase in virulence and a decrease of reactive
oxygen species (ROS). DON levels during wheat infection are slightly increased.
However, over-expression of DOHH abolishes infection of F. graminearum in
wheat and leads to an over-production of ROS and a strong decrease in DON.
Over-expression of both genes together produces similar levels of infection, ROS
and DON as the wild type strain. These results suggest that hypusinated
eukaryotic translation initiation factor 5A regulates reactive oxygen species, DON,
and virulence of Fusarium graminearum. We showed previously, that CNI-1493
inhibits F. graminearum DHS and thereby virulence to wheat and maize. Now, we
fused mCherry with EIF5A and labeled the nucleus with a histone H1-GFP fusion.
During germination EIF5A is evenly distributed in the cytoplasm and the nucleus.
After addition of 10 µM of the DHS inhibitor CNI-1493, EIF5A vanished from the
cytoplasm into the nucleus. Now the cells died and lysed, visualizing why gene
disruption of the DHS gene is lethal.
Keywords: Fusarium, EIF5A, DON, ROS
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