Skip to main content
ISMPMI Congress 2025 Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.

Poster

Session: Session 1 Presenting Authors at Posters (Evens)

P-016 - Characterization of plant TIR-dependent metabolites and signalling mechanisms in effector-triggered immunity

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

    Presenting Author(s)

  • MS

    Mitchell Sorbello (he/him/his)

    The University of Queensland
    Brisbane, Queensland, Australia

    • Author(s)

  • NM

    Natsumi Maruta

    School of Chemistry and Molecular Biosciences, Australian Infectious Diseases Research Centre and the Institute for Molecular Bioscience, The University of Queensland
    Brisbane, Queensland, Australia

  • BL

    Bryan Ying Jie Lim

    School of Chemistry and Molecular Biosciences, Australian Infectious Diseases Research Centre and the Institute for Molecular Bioscience, The University of Queensland
    Brisbane, Queensland, Australia

  • BK

    Bostjan Kobe

    The University of Queensland
    Brisbane, Queensland, Australia

Plant NLRs detect effector proteins that are secreted by pathogens into plant cells, leading to localized cell death and disease resistance. NLRs consist of LRR, NB-ARC and N-terminal TIR or CC domains involved in effector recognition, NLR oligomerisation and signalling, respectively. TIR-NLRs (TNLs) possess NAD+ hydrolysis activity. NAD+-cleavage by TIR domains leads to production of various compounds that activate EDS1 family heterodimers. It is unknown if all plant TIRs produce the same set of signalling molecules. We developed enzymatic assays to evaluate signalling molecules. Our assays indicate that all surveyed, plant TIRs produced 2’cADPR, but showed variability in producing the cell-death signalling molecule, ADPr-ATP. Plant TIR domains can interact with the EDS1 family proteins. Using MST, we confirmed this direct interaction in vitro, this interaction did not affect enzyme activity. Further research is required to establish the function of this interaction. Flax TNLs can be inhibited by the rust effector, “I”. Our enzyme data showed I inhibits the NAD+ hydrolysis of flax M and L6, but not other tested plant TIR-only proteins. Our mass photometry data also showed the I effector binds M and inhibits oligomerisation. We are using XL-MS and cryo-EM to understand the structural basis of this interaction. Together, this work may contribute to informing the rational design of synthetic receptors with tuneable signalling output, that could escape inhibitory effectors.