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Poster

Session: Session 1 Presenting Authors at Posters (Evens)

P-018 - Comparative analysis of conserved TIR-only proteins in dicot and monocot plant immunity

Tuesday, July 15, 2025
09:55 - 11:30  
Location: Confex Hall 3
Extracellular & Intracellular non-self recognition & signaling

    Presenting Author(s)

  • HL

    Henriette Lässle

    Department of Plant-Microbe Interactions, Max-Planck Institute for Plant Breeding Research
    Koln, Nordrhein-Westfalen, Germany

    • Author(s)

  • OJ

    Oliver Johanndrees

    Molecular and Cellular Plant Physiology University of Zurich
    Zurich, Zurich, Switzerland

  • WS

    WEN SONG (he/him/his)

    China Agricultural University
    Beijing, Beijing, China

  • LL

    Li Liu

    Beijing Normal University
    Beijing, Beijing, China (People's Republic)

  • JJ

    Jan Jirschitzka

    Institute of Biochemistry, University of Cologne, Cologne, Germany.
    C, Nordrhein-Westfalen, Germany

  • SH

    Shijia Huang

    Westlake Institute for Advanced Study
    Hangzhou, Zhejiang, China (People's Republic)

  • JB

    Jaqueline Bautor

    Max Planck Institute for Plant Breeding Research
    Koln, Nordrhein-Westfalen, Germany

  • JP

    Jane Parker

    Senior Group Leader
    Department of Plant-Microbe Interactions, Max-Planck Institute for Plant Breeding Research
    Cologne, GERMANY

Toll/interleukin-1/resistance (TIR) domain-containing proteins are key components of induced plant defence against pathogens. While TIR-domain enzymatic (NADase) functions are well-studied in dicots, they remain less understood in monocots, despite their agricultural importance. Our study addresses this gap by comparing TIR-only protein functions between dicot and monocot species. Phylogenetic analysis identified a conserved group of TIR-only proteins in dicots and monocots, that are upregulated early in pathogen-triggered tissues. TIR signalling requires the EDS1 family dimers cooperating with RNL-type helper NLRs. We generated tir knock-out mutants in Arabidopsis thaliana and Hordeum vulgare (barley) to assess their roles in immunity. Our results show that TIR-only proteins induce NADase-dependent cell death, with HvTIR, being a potent NADase generating immunogenic molecules in barley protoplasts. The tir-only mutants displayed impaired immunity to virulent pathogens and reduced induction of defence genes after treatment with a PAMP in both species. Transcriptome analysis in barley after PAMP triggering identified a number of ATP binding- and calcium ion binding-associated genes to be down-regulated by HvTIR and HvEDS1-PAD4. Our findings highlight the critical role of conserved TIR-only proteins early in pattern-triggered immunity and their importance in immune signal propagation across different lineages.