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Poster

Session: Session 2 Presenting Authors at Posters (Evens)

P-162 - The MAX effector AvrRvi6 from Venturia inaequalis triggers Rvi6 resistance in apple trees.

Thursday, July 17, 2025
13:30 - 15:15  
Location: Confex Hall 3
Effector Interference Mechanisms

    Author(s)

  • MS

    Mélanie Sannier

    IRHS-UMR1345, Université d’Angers, INRAE, Institut Agro
    Beaucouze, Pays de la Loire, France

  • JC

    Jérôme Collemare

    Westerdijk Institute
    Utrecht, Utrecht, Netherlands

  • SB

    Sirine Benmamar

    IRHS-UMR1345, Université d’Angers, INRAE, Institut Agro
    beacouze, Pays de la Loire, France

  • CL

    Christophe Lemaire

    Paris Jussieu
    Paris, Ile-de-France, France

  • AP

    Antoine Porquier

    IRHS-UMR1345, Université d’Angers, INRAE, Institut Agro
    Beaucouze, Pays de la Loire, France

  • JS

    Jason Shiller

    La Trobe University
    Tauranga, Auckland, New Zealand

  • VC

    Valerie Caffier

    IRHS-UMR1345, Université d’Angers, INRAE, Institut Agro
    Beaucouze, Pays de la Loire, France

  • AV

    Alice Vayssières

    IJPB
    Versailles, Ile-de-France, France

  • HS

    Henk Schouten

    Wageningen University - WUR
    Wageningen, Gelderland, Netherlands

  • BL

    Bruno Le Cam

    IRHS-UMR1345, Université d’Angers, INRAE, Institut Agro
    Beaucouze, Pays de la Loire, France

    • Presenting Author(s)

  • MB

    Mael Baudin

    Assistant professor
    Angers University
    Beaucouze, Pays de la Loire, France

Venturia inaequalis is an ascomycete fungus responsible for apple scab, the main disease in apple orchards. During infection, the pathogen colonizes the subcuticular space and secretes hundreds of effectors to promote virulence. To mitigate disease impact, resistance genes such as the membrane-localized receptor-like protein Rvi6 have been introduced into apple cultivars, reducing the reliance on fungicides. However, over the past three decades, Rvi6-mediated resistance have been broken down in orchards, with the emergence of virulent V. inaequalis strains overcoming this defense. Through comparative genomic analyses, we identified AvrRvi6 as the avirulence factor that activates Rvi6-mediated immunity. Screening 120 V. inaequalis strains worldwide revealed 18 distinct AvrRvi6 alleles, of which 10 are recognized by Rvi6 in the apoplast, triggering an immune response in Nicotiana benthamiana. Using AlphaFold structural modeling, we showed that AvrRvi6 belongs to the MAX effector family, previously characterized as cytoplasmic effectors in the blast fungus Magnaporthe oryzae. We identified key residues required for recognition and showed the association between AvrRvi6 and Rvi6 in yeast. AvrRvi6 is the first MAX effector with an apoplastic function described to date. By investigating the structure, localization and function of AvrRvi6, this study provides new insights into the plasticity of MAX effectors and the molecular strategies employed by V. inaequalis during infection.