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Poster

Session: Session 2 Presenting Authors at Posters (Odds)

P-151 - Silent Sabotage: How the phytoplasma effector PME2 manipulates cell fate and plant immunity

Wednesday, July 16, 2025
13:30 - 15:15  
Location: Confex Hall 3
Effector Interference Mechanisms

    Presenting Author(s)

  • CM

    Christa Malfertheiner

    Laimburg Research Centre
    Vadena, Trentino-Alto Adige, Italy

    • Author(s)

  • MR

    Margot Raffeiner

    Ruhr University Bochum
    Bochum, Nordrhein-Westfalen, Germany

  • CM

    Cecilia Mittelberger

    Laimburg Research Centre
    Vadena, Trentino-Alto Adige, Italy

  • BH

    Bettina Hause

    Prof.
    Leibiniz Institute of Plant Biochemistry
    Halle, Sachsen-Anhalt, Germany

  • SÃ

    Suayib Üstün

    Faculty of Biology and Biotechnology, Ruhr-University of Bochum
    Bochum, Nordrhein-Westfalen, Germany

  • KJ

    Katrin Janik

    Laimburg Research Centre
    Vadena, Trentino-Alto Adige, Italy


Effector proteins are key modulators of plant-pathogen interactions, manipulating host processes to promote infection and disease development. 'Candidatus Phytoplasma mali' (P. mali), the causal agent of apple proliferation disease, employs a repertoire of effector proteins to manipulate its host's physiology and disrupt key regulatory pathways. 



PME2, a P. mali effector, is expressed in Malus domestica during phytoplasma infection and has been observed to disrupt cell integrity. To study the effect of PME2 on plant gene expression and its role in infection, transgenic Arabidopsis thaliana lines expressing PME2 were used. 



Surprisingly, PME2-expressing plants exhibited enhanced resilience to endoplasmic reticulum (ER) stress and proteotoxic stress, potentially maintaining host viability for pathogen spread. RNA-Seq analysis revealed PME2-induced transcriptional changes related to stress regulation, hormone signaling, and immune suppression. These findings suggest that PME2 manipulates the host's proteostasis and dampens immune responses to enable or facilitate infection. 



Pseudomonas syringae infection assays in PME2-expressing plants displayed altered phenotypes, further supporting PME2's role in modulating host-pathogen interactions. Our research provides insights into P. mali's infection strategies and contributes to developing targeted approaches for controlling phytoplasmal diseases.Â