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Poster

Session: Session 2 Presenting Authors at Posters (Odds)

P-043 - Functional Characterization of the Wheat Fusion Protein Kinase Pm4 in Immunity

Wednesday, July 16, 2025
13:30 - 15:15  
Location: Confex Hall 3
Crop resistance genetics and genomics

    Presenting Author(s)

  • MC

    Maria Del Pilar Caro

    Postdoc/Dr.
    Institute of Plant and Microbial Biology, Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
    Zurich, Zurich, Switzerland

    • Author(s)

  • LY

    Lili Yue

    Postdoc/Dr.
    Institute of Plant and Microbial Biology, Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland.
    Zurich, Zurich, Switzerland

  • KB

    Kyle W. Bender

    Institute of Plant and Microbial Biology, University of Zurich
    Zurich, Zurich, Switzerland

  • GG

    Gerhard Gerren

    Institute of Plant and Microbial Biology, Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland.
    Zurich, Zurich, Switzerland

  • JS

    Javier Sánchez-Martín

    Department of Microbiology and Genetics, Spanish-Portuguese Agricultural Research Centre (CIALE), University of Salamanca, Salamanca, Spain
    Salamanca, Castilla y Leon, Spain

  • CZ

    Cyril Zipfel

    Institute of Plant and Microbial Biology, University of Zurich / The Sainsbury Laboratory
    Zurich, Zurich, Switzerland

  • BK

    Beat Keller

    Professor
    Univ of Zurich
    Zurich, Zurich, Switzerland

Most race-specific resistance genes in plants encode intracellular nucleotide-binding leucine-rich repeat (NLR) immune receptors that recognize pathogenic effectors. In wheat and barley, however, tandem kinases and fusion-protein kinases lacking an NLR structure represent a novel and distinct class of resistance determinants. Wheat Pm4 encodes a chimeric protein with a serine/threonine kinase domain and a C-terminal region belonging to the multiple C2 domain and transmembrane proteins (MCTPs) family. Alternative splicing of Pm4 generates two mutually exclusive isoforms, Pm4_V1 and Pm4_V2, both of which are required for resistance against powdery mildew (caused by Blumeria graminis f. sp. tritici) and wheat blast (caused by Magnaporthe oryzae pathotype triticum). Additionally, the Pm4 gene occurs in functionally different alleles and in this study, we focus on the Pm4b allele. Combining confocal microscopy, genetic and biochemistry approaches, we show that Pm4b isoforms individually localize to the cytosol and endoplasmic reticulum (ER) in wheat protoplasts but co-localize at ER-plasma membrane contact sites when co-expressed. Additionally, we are investigating the role of calcium and phospholipid binding in the C2 domains as  key components required for resistance. Our findings uncover a unique molecular basis for race-specific resistance in a major crop.