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Poster

Session: Session 2 Presenting Authors at Posters (Evens)

P-174 - Unmasking a Pathogen Shield: Characterization of an Effector-mediated Strategy for Intracellular Survival in Phytoplasmas

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

    Presenting Author(s)

  • MC

    Mariama D. Carter

    Postdoctoral Scientist
    Crop Genetics Dept., John Innes Centre
    NORWICH, England, United Kingdom

    • Author(s)

  • VB

    Vanessa Boll

    Institute for Genetics, University of Cologne
    Cologne, Nordrhein-Westfalen, Germany

  • KH

    Kay Hofmann

    Institute for Genetics, University of Cologne
    Cologne, Nordrhein-Westfalen, Germany

  • SH

    Saskia A. Hogenhout

    Group Leader
    Crop Genetics Dept., John Innes Centre
    Norwich, England, United Kingdom

Phytoplasmas are among the few bacteria capable of colonizing both plants and insects, thriving inside plant phloem cells and systemically spreading throughout the insect body. These pathogens deploy a diverse array of effectors that destabilize transcription factor families responsible for regulating plant development. This disruption causes dramatic phenotypic aberrations, including stem and leaf proliferations, the emergence of leaf-like flowers, and prolonged juvenile stages. Notably, these effectors induce direct proteasomal degradation of target proteins in a ubiquitin-independent manner. Despite this, the mechanisms underpinning robust cytoplasmic colonization of plant and insect cells without triggering autophagic clearance remains enigmatic. In this study, we identified and isolated a phytoplasma protein, likely functioning as an effector, and hypothesize that it shields the pathogen from host ubiquitylation machinery. Analysis of its enzymatic activity suggests that this protein enables phytoplasmas to rapidly evade ubiquitin-mediated defenses in the plant and insect cells. Collectively, our findings reveal that phytoplasmas not only deploy effectors to circumvent the ubiquitin-proteasome pathway but likely also do so to directly counteract host innate immune responses, thereby ensuring persistence in diverse intracellular environments.