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-217 - Beneficial Pseudomonas reprograms plant-wide transcription to induce coumarin-dependent systemic resistance

Wednesday, July 16, 2025
13:30 - 15:15  
Location: Confex Hall 3
Local and inter-organ signaling in immunity and mutualistic interactions

    Presenting Author(s)

  • SH

    Shu-Hua Hsu

    Postdoctoral Researcher
    Utrecht University
    Utrecht, Utrecht, Netherlands

    • Author(s)

  • MS

    Max J.J Stassen

    Utrecht University
    Utrecht, Utrecht, Netherlands

  • KR

    Kevin Robe

    IPSiM, University of Montpellier, CNRS, INRAE, Institut Agro
    Montpellier, Languedoc-Roussillon, France

  • EI

    Esther Izquierdo

    IPSiM, University of Montpellier, CNRS, INRAE, Institut Agro
    Montpellier, Languedoc-Roussillon, France

  • CD

    Christian Dubos

    IPSiM, University of Montpellier, CNRS, INRAE, Institut Agro
    Montpellier, Languedoc-Roussillon, France

  • CP

    Corné M.J. Pieterse, PhD (he/him/his)

    Professor Plant-Microbe Interactions
    Utrecht University
    Utrecht, Utrecht, Netherlands

  • IS

    Ioannis A. Stringlis

    Agricultural University of Athens
    Athens, Attiki, Greece

Induced systemic resistance (ISR) is a defense mechanism expressed in leaves upon root colonization by beneficial microbes. In the Arabidopsis-Pseudomonas simiae WCS417 (WCS417) model system, the root-specific transcription factor MYB72 is crucial in ISR onset. MYB72 together with downstream components F6’H1 and BGLU42 contribute to in the iron (Fe) deficiency response through the production of Fe-mobilizing coumarins. While coumarin-related genes are essential for ISR activation, the precise mechanisms remains unclear. To study this, we investigated the temporospatial transcriptomic and metabolic response related to coumarins in ISR-expressing Arabidopsis. RNA-seq analysis (1 to 7 days) showed that WCS417 activated a broad set of Fe deficiency- and coumarin biosynthesis-related genes, first in the roots and later in the shoots. Multispectral imaging showed differential coumarin distribution in roots of Fe-starved and WCS417-treated plants. Using liquid chromatography, we found that WCS417 treatment led to altered coumarin levels, with a transient peak observed in both roots and shoots. This suggests that systemic coumarin accumulation may play a role in ISR. ISR bioassays using the f6’h1 mutant and an F6’H1 overexpressing line further displyed that functional coumarin biosynthesis is essential for ISR establisment. Together, our findings reveal how the beneficial bacterium WCS417 reprograms plant-wide transcriptional activity to induce coumarin-dependent systemic resistance.