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Poster

Session: Session 1 Presenting Authors at Posters (Evens)

P-410 - Exploring the Peltigera lichen symbiosis: From community composition to molecular insights

Tuesday, July 15, 2025
09:55 - 11:30  
Location: Confex Hall 3
Symbiosis and Mutualism (mycorrhiza and N-fixing Rhizobia)

    Author(s)

  • MH

    Max Heinen

    Heinrich-Heine University
    Duesseldorf, Nordrhein-Westfalen, Germany

  • VR

    Vivien Rosenthal

    Heinrich-Heine University Düsseldorf
    Düsseldorf, Nordrhein-Westfalen, Germany

  • CK

    Ciaran Kelly

    University of Cologne
    Cologne, Nordrhein-Westfalen, Germany

  • LH

    Lukas Hüttebräucker

    Heinrich-Heine University
    Duesseldorf, Nordrhein-Westfalen, Germany

  • BT

    Bart Thomma (he/him/his)

    CEPLAS/University of Cologne
    Cologne, GERMANY

  • BU

    Björn Usadel

    Principal Investigator
    Institute for Biological Data Science, Heinrich Heine University, Dusseldorf
    Duesseldorf, Nordrhein-Westfalen, Germany

  • MP

    Markus Pauly

    Professor
    Heinrich-Heine University
    Duesseldorf, Nordrhein-Westfalen, Germany

    • Presenting Author(s)

  • FA

    Florian Altegoer

    Research Group Leader
    CEPLAS/Heinrich-Heine University
    Duesseldorf, Nordrhein-Westfalen, Germany


Lichens are among the most ancient and fascinating examples of complex microbial communities, known as pioneers in extreme environments. In lichens, a fungal mycobiont tightly associates with an algal and/or cyanobacterial photobiont to form complex morphological structures. Despite intensive research on lichen biology, molecular mechanisms that govern the establishment and maintenance of these symbioses remain poorly understood. The genus Peltigera is widespread across multiple continents and serves as a representative of cyanolichens, with Nostoc cyanobacteria as the core photobiont. By combining metagenomics of different Peltigera isolates with transcriptomics and protein structure prediction, we dissected both community composition and molecular interactions. Our analysis revealed expanded structural classes of secreted effectors, including candidates with antimicrobial activity that may modulate microbiome composition. We also identified lectins that selectively bind cyanobacterial carbohydrates and are enriched in the photobiont layer, suggesting a role in partner recognition or stabilization. In addition, we uncovered an array of fungal G-protein coupled receptors that show similarity to GPCRs from phytopathogenic fungi. Collectively, our in-depth analysis allows to gain insights into the molecular mechanisms underlying the initiation and maintenance of these complex microbial interactions.