A novel virus defense gene determines fitness in the cereal pathogen Fusarium graminearum
J. BORMANN (1), C. Heinze (1), M. Mentges (1), A. Brockmann (1), A. Alder (1), C. Blum (1), M. Freitag (2), W. Schäfer (1) (1) Molecular Phytopathology, University Hamburg, Germany; (2) Biochemistry and Biophysics, Oregon State University, U.S.A.

Mycovirus FgV-ch9-infection of the phytopathogenic ascomycete Fusarium graminearum causes hypovirulence and negatively affects sporulation and vegetative growth. The molecular basis of this effect is unknown. We identified a putative mRNA-binding protein, named fungal defense gene 1 (fd1), as the central facilitator of fungal response to virus infection. Fd1 transcription level is markedly reduced in the presence of virus and deletion of fd1 causes virus-like symptoms, while constitutive overexpression of fd1 overrules the cytopathic effects of a virus infection leading to a symptomless accumulation of virus particles. Hence, fd1 expression levels determine fungal fitness as measured by conidiation, pathogenicity, and vegetative growth. We propose a gene-for-gene model in which the fungus actively triggers the downregulation of fd1 in order to restrict virus spread. This novel fungal defense reaction will accelerate future strategies for resistance breeding and combat of Fusarium infections.

Abstract Number: P18-660
Session Type: Poster