Skip to main content
ISMPMI Congress 2025 Main banner
Icon Legend
This session is not in your schedule.
This session is in your schedule. Click again to remove it.

Poster

Session: Session 2 Presenting Authors at Posters (Odds)

P-305 - Arabidopsis root-secreted coumarins exert antimicrobial activity against taxonomically diverse rhizobacteria

Wednesday, July 16, 2025
13:30 - 15:15  
Location: Confex Hall 3
Plant microbiota functions and intermicrobial interactions

    Author(s)

  • SH

    Sho Hirashima

    Master's student
    Shizuoka University
    Shizuoka, Shizuoka, Japan

  • MM

    Milena Malisic

    PhD student
    Max Planck Institute for Plant Breeding Research, Cologne, Germany
    Köln, Nordrhein-Westfalen, Germany

  • JC

    Jae-Hoon Choi

    Professor
    Shizuoka University
    Shizuoka, Shizuoka, Japan

  • HK

    Hirokazu Kawagishi

    Distinguished Professor
    Shizuoka University
    Shizuoka, Shizuoka, Japan

  • PS

    Paul Schulze-Lefert

    Professor
    Max Planck Institute for Plant Breeding Research
    Köln, Nordrhein-Westfalen, Germany

    • Presenting Author(s)

  • MH

    Masayoshi Hashimoto

    Associate Professor
    Shizuoka University
    Shizuoka, Shizuoka, Japan


The root-associated microbiota has several beneficial functions for plants, including enhanced pathogen protection. Coumarins secreted from the roots of Arabidopsis thaliana influence the community establishment of bacterial root microbiota in iron-limiting soils. Here we aim to investigate whether and how coumarins affect the growth of taxonomically diverse rhizobacteria. Here, we employed a part of the rhizobacterial culture collection At-RSPEHRE isolated from Arabidopsis roots. First, the major secreted coumarins, scopoletin and fraxetin, were added to the liquid culture of 12 rhizobacterial strains belonging to six taxonomic groups. The results demonstrated that fraxetin significantly inhibited the growth of most tested strains, with strongest antibacterial activity against rhizobacteria belonging to the phylum Firmicutes and Actinobacteria. Furthermore, the structure-activity relationship of coumarins was examined based on the antibacterial activity. Esculetin, another major coumarin having a catechol group in common with fraxetin, showed similar antibacterial activity. On the other hand, derivatives lacking the catechol group showed weaker antibacterial activity than fraxetin or esculetin. Based on these results, the mechanism of antibacterial activity of catechol coumarins against rhizobacteria will be discussed.