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Poster

Session: Session 2 Presenting Authors at Posters (Evens)

P-212 - Structural studies of MAX effectors and their host targets to guide targeted engineering of plant proteins for disease resistance

Thursday, July 17, 2025
13:30 - 15:15  
Location: Confex Hall 3
Engineering plant-microbe traits

    Presenting Author(s)

  • JM

    Josephine Maidment

    Postdoctoral Scientist
    Plant Health Institute of Montpellier / Centre de Biologie Structurale
    Montpellier, Languedoc-Roussillon, France

    • Author(s)

  • SS

    Svenja C. Saile

    Plant Health Institute of Montpellier
    Montpellier, Languedoc-Roussillon, France

  • AB

    Aurélien Bocquet

    Plant Health Institute of Montpellier / Centre de Biologie Structurale
    Montpellier, Languedoc-Roussillon, France

  • SR

    Sébastien Ribeiro

    Plant Health Institute of Montpellier
    Montpellier, Languedoc-Roussillon, France

  • LB

    Léo Bourcet

    Centre de Biologie Structurale
    Montpellier, Languedoc-Roussillon, France

  • CT

    Céline Thivolle

    Plant Health Institute of Montpellier
    Montpellier, Languedoc-Roussillon, France

  • LP

    Lisa-Fatimatou Planel

    Plant Health Institute of Montpellier
    Montpellier, Languedoc-Roussillon, France

  • ML

    Mounia Lahfa

    Centre de Biologie Structurale
    Montpellier, Languedoc-Roussillon, France

  • ML

    Marie Le Naour--Vernet, PhD (she/her/hers)

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

  • AP

    André Padilla

    Centre de Biologie Structurale
    Montpellier, Languedoc-Roussillon, France

  • TK

    Thomas Kroj

    Plant Health Institute of Montpellier
    Montpellier, Languedoc-Roussillon, France

  • Kd

    Karine de Guillen

    Centre de Biologie Structurale
    Montpellier, Languedoc-Roussillon, France

  • SC

    Stella Cesari (she/her/hers)

    PHIM Plant Health Institute, Univ Montpellier, INRAE, CIRAD, Institut Agro, IRD
    Montpellier, FRANCE

During infection, phytopathogenic fungi secrete arsenals of effector proteins to promote virulence. Previous work identified a large family of sequence-diverse effectors that share a six-stranded β-sandwich structure, termed the MAX (Magnaporthe Avrs and ToxB-like) fold. While the core fold is conserved, MAX effectors differ in surface properties and the presence of extensions at the N- and C-termini. We hypothesised that these differences underpin interaction with diverse host targets; however, the virulence targets of most MAX effectors are unknown. Large-scale screens in homologous and heterologous systems identified candidate targets of the MAX effectors AVR-Pia and AvrPib. AVR-Pia interacts with a novel clade of heavy metal-associated (HMA) domain-containing proteins, distinct from those reported to be targeted by the MAX effectors AVR-Pik and PWL2. The crystal structure of AVR-Pia bound to the HMA domain of HPP2070 revealed the molecular detail of the binding interface, enabling identification of mutations in HPP2070 which prevent AVR-Pia binding without compromising the HMA fold. AvrPib interacts with the kinase domain of a MAPKKK, and preliminary results from NMR experiments indicate residues in AvrPib involved in binding. By combining structural data with functional studies, we aim to engineer host proteins to evade manipulation by effectors without compromising their regular activity. This represents a promising approach for engineering disease resistance.