Fungal genetics

F3702: Genetic dissection of Fusarium secondary metabolite production and virulence

Based on results of the first period the following topics will be pursued: 

1) Glutathione mediated-detoxification of type B trichothecenes: we will investigate the role of plant glutathione-S-transferases (GSTs) in detoxification and other enzymes involved in processing of conjugates to the terminal product S-methyl DON. 
2) We will address the question about the biosynthetic origin of the new trichothecene, NX2, produced by the Northland population by functional testing of its TRI1 alleles. We will furthermore investigate, whether due to lack of a conjugated keto group this trichothecene can escape glutathione mediated detoxification. 
3) We will follow up the finding that Fusarium can produce the plant hormones auxin and ethylene. The relevance will be tested by multiple gene disruptions in Fusarium. This part requires strong analytical support from F3706.  

F3708: Detoxification by plant UDP-glucosyltransferases

UDP-glucosyltransferases from barley, Brachypodium distachyon and wheat, will be characterized for their ability to inactivate nivalenol (most likely into NIV-3-O-glucoside). The crystal structure of a rice UGT detoxifying DON and NIV (available as result of a collaboration with the group of Ivan Rayment, Univ. Wisconsin) will be used to pinpoint sequence differences responsible for the striking differences in substrate specificity of highly similar cluster members. Furthermore, UGTs inactivating zearalenone (into the novel metabolite zearalenone-2-O-glucoside), and auxin into auxin-glucoside will be characterized. Candidate genes for conversion of auxin-glucosides into the predominant storage form of auxin-myo-inositol conjugates will be characterized. 

We furthermore plan to test a novel hypothesis about the nature of the Fhb1 Fusarium resistance gene of wheat. At the expected genomic location a pseudogene for a UDP-glucose dehydrogenase (UGDH) was identified. We plan to experimentally test the hypothesis that this pseudogene in the resistant cultivar produces a trans-acting antisense RNA, which down-regulates other functional UGDH genes, leading to higher availability of UDP-glucose and consequently DON detoxification ability. To perform these experiments strong support of partner F3706 is needed, as well as bioinformatics support from F3705 for analysis of the UGDH gene family and expression differences in near isogenic lines differing in Fhb1 from F3711.

Gerhard  Adam Ao.Univ.Prof Dr. Dipl.Ing. 
Department of Applied Genetics and Cell Biology
University of Natural Resources and Life Sciences, Vienna (BOKU)
Konrad Lorenz Str. 24, A-3430 Tulln

Research Interests:

  • Plant-pathogen interactions, role of microbial secondary metabolites in plant disease.
  • Plant detoxification reactions and other plant resistance mechanisms.
  • Microbial inactivation of Fusarium mycotoxins.
  • Stress physiology and molecular biology of plants, filamentous fungi and yeasts.