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Poster

Session: Session 1 Presenting Authors at Posters (Odds)

P-393 - A barley GH81 beta-glucanase shapes fungal symbiosis and microbiome composition

Monday, July 14, 2025
13:30 - 15:15  
Location: Confex Hall 3
Symbiosis and Mutualism (mycorrhiza and N-fixing Rhizobia)

    Presenting Author(s)

  • Sv

    Sarah van Boerdonk

    Doctoral candidate
    Institute for Plant Sciences, University of Cologne, Max Planck Institute for Plant Breeding Research
    Cologne, Nordrhein-Westfalen, Germany

    • Author(s)

  • AW

    Alan Wanke

    Research Associate
    Sainsbury Laboratory Cambridge University
    Cambridge, England, United Kingdom

  • LM

    Lisa Mahdi

    Postdoc
    Institute for Plant Sciences, University of cologne
    Cologne, Nordrhein-Westfalen, Germany

  • SA

    Sinaeda Anderssen

    Institute for Plant Sciences, University of Cologne
    Cologne, Nordrhein-Westfalen, Germany

  • MB

    Mathias Brands

    Postdoc
    Institute for Plant Sciences, University of Cologne
    Cologne, Nordrhein-Westfalen, Germany

  • AZ

    Alga Zuccaro (she/her/hers)

    Institute for Plant Sciences, University of Cologne, The Cluster of Excellence on Plant Sciences (CEPLAS)
    Köln, Nordrhein-Westfalen, Germany

Beta-glucans are structurally diverse polysaccharides present in fungal cell walls, extracellular polysaccharide matrices of bacteria and fungi, and callose deposits in plant cell walls during immune responses. Despite their ubiquitous presence, the role of beta-glucans in shaping plant-microbe interactions remains poorly understood. Using a pull-down approach, beta-glucan-binding protein (GBP) was identified as a novel β-glucan interactor in barley (Hordeum vulgare). Colonization by beneficial fungi Serendipita indica, S. vermifera, and Rhizophagus irregularis was significantly reduced in gbp mutant lines compared to wild-type, suggesting that GBP promotes symbiotic fungal establishment. Confocal microscopy showed enhanced callose deposition and cell wall appositions upon fungal colonization in gbp mutants. Functional assays confirmed that GBP exhibits β-1,3-endoglucanase activity, indicating a possible role in callose remodeling. Pathogenesis-Related Protein 10 was strongly induced in gbp mutant plants, further supporting the role of GBP in modulating plant immune responses (Wanke et al., 2023). Beyond individual fungal associations, amplicon sequencing revealed that GBP also influences both root and rhizosphere microbiome composition, suggesting a broader role in shaping microbial community structure. Collectively, our findings demonstrate that GBP modulates barley immune responses, likely facilitating the establishment of beneficial symbioses by reducing defense barriers.