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Poster

Session: Session 1 Presenting Authors at Posters (Odds)

P-195 - Order from Disorder: a structurally disordered domain of PnPf2 is essential for regulation of virulence factors in a phytopathogenic fungus

Monday, July 14, 2025
13:30 - 15:15  
Location: Confex Hall 3
Microbial infection strategies (pathogens & non-pathogens)

    Presenting Author(s)

  • CV

    Callum J. Verdonk

    Research Fellow
    Centre For Crop And Disease Management
    Bentley, Western Australia, Australia

    • Author(s)

  • SM

    Shota Morikawa

    Centre For Crop And Disease Management
    Bentley, Western Australia, Australia

  • EJ

    Evan John, PhD

    Postdoc
    Department of Plant Pathology, Institute of Crop Science and Resource Conservation (INRES), University of Bonn
    Bonn, Nordrhein-Westfalen, Germany

  • CM

    Carl Mousley

    Curtin Medical School and Curtin Medical Research Institute
    Bentley, Western Australia, Australia

  • BH

    Bernadette Henares

    Centre For Crop And Disease Management
    Bentley, Western Australia, Australia

  • KT

    Kar-Chun Tan

    Curtin University
    Bentley, Western Australia, Australia

Septoria nodorum blotch (SNB) is a devastating disease of wheat and is caused by the fungal pathogen Parastagonospora nodorum. The primary cause of SNB is proteinaceous effectors, which interact with wheat host sensitivity genes. These effectors are controlled by DNA-binding regulatory proteins called transcription factors (TF), of which the Zn2Cys6 zinc-finger type is one of the most abundant in fungi. These zinc-finger-containing TFs possess a DNA-binding domain (DBD) and central “middle homology domain” (MHD). In P. nodorum the TF PnPf2 is a positive regulator of major necrotrophic effector genes required for host-specific virulence on wheat. PnPf2 is a DBD-MHD protein with a disordered C-terminus tail which has low homology with its orthologs. We demonstrated that both the DBD and MHD are essential for PnPf2 function but are not the main drivers of pathogenicity. Instead, only the disordered C-terminus tail is seemingly required for both full effector activation, as well as disease symptoms on specific wheat cultivars. We also show the PnPf2 MHD interacts with genes related to transcription via a modified two-hybrid methodology. Identification of PnPf2-interacting partners has highlighted a potentially novel mechanism for gene regulation by these ubiquitous TFs. By understanding the structural and biological mechanisms of PnPf2, we can untangle the complexity surrounding effector regulation in necrotrophs and other phytopathogenic fungi.