EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
EFS12- Book of abstracts - Contact
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SESSION 1: FUSARIUM – GENETICS, GENOMICS AND SYSTEMS BIOLOGY<br />
P3 - Significance <strong>of</strong> the hydrophobin FgHyd5p in<br />
Fusarium graminearum<br />
E. Minenko, R. F. Vogel, L. Niessen<br />
Technische Universität München, Lehrstuhl für Technische Mikrobiologie, Weihenstephaner Steig 16,<br />
85350 Freising, Germany.<br />
E-mail: Ekaterina.Minenko@wzw.tum.de<br />
Fusarium graminearum and Fusarium culmorum are causative agents <strong>of</strong> beer<br />
gushing. Class II hydrophobins have been demonstrated to induce it.<br />
Hydrophobins are a group <strong>of</strong> small secreted proteins ubiquitously found in<br />
filamentous fungi. Some hydrophobins were shown to have functions in fungal<br />
development, while others seem to lack known function. Also, cellular functions <strong>of</strong><br />
FgHyd5p are still unknown. FgHyd5p, the F. graminearum homologue to FcHyd5p<br />
(F. culmorum) is a small secreted protein typified by the presence <strong>of</strong> 8 cysteine<br />
residues at conserved positions. FgHyd5p is characterized by formation <strong>of</strong> low<br />
stability aggregates and solubility in organic solvents. We showed that FgHyd5p<br />
does not have an effect on morphology <strong>of</strong> F. graminearum since colony<br />
morphology and growth rate, hyphal length and diameter as well as biomass<br />
production were shown to stay unaffected in Fg∆hyd5 knockout strains. Knockout<br />
<strong>of</strong> the fghyd5 gene causes a reduction <strong>of</strong> spore length and an increase in spore<br />
numbers. Using an F. graminearum reporter strain expressing sGFP under the<br />
control <strong>of</strong> the Phyd5 promoter we found that FcHyd5p was not expressed in<br />
media with different carbon or nitrogen sources, respectively. Moreover we did not<br />
observe any pH dependent fghyd5 gene expression. FgHyd5p showed an effect<br />
on the hydrophobicity <strong>of</strong> hyphae resulting in an easy wettable phenotype <strong>of</strong><br />
transformants. Results <strong>of</strong> our studies also showed that FgHyd5p has an effect on<br />
the virulence <strong>of</strong> F. graminearum. Wheat and barley plants infected with spores<br />
from an Fg∆hyd5 knockout strain at EC 0-9 were significantly longer in EC 12 as<br />
compared to plants that were infected with the F. graminearum parent strain.<br />
Using the F. graminearum sGFP reporter strain and histological analysis we<br />
showed that the gene is expressed during plant infection and may thus play a role<br />
as a virulence factor during the infection <strong>of</strong> cereals.<br />
Keywords: Fusarium, hydrophobin, expression, virulence<br />
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