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Poster

Session: Session 2 Presenting Authors at Posters (Odds)

P-041 - From forward to reverse Genetics: How we study transcriptional Activation by Xanthomonas and Ralstonia TAL-effectors

Wednesday, July 16, 2025
13:30 - 15:15  
Location: Confex Hall 3
Crop resistance genetics and genomics

    Presenting Author(s)

  • NG

    Niels Gallas

    PhD Student
    ZMBP, University of Tuebingen
    Reutlingen, Baden-Wurttemberg, Germany

    • Author(s)

  • TS

    Tom Schreiber

    Leibniz Institute of Plant Biochemistry
    Halle (Saale), Sachsen-Anhalt, Germany

  • RM

    Robert Morbitzer

    ZMBP, University of Tuebingen
    Tuebingen, Baden-Wurttemberg, Germany

  • KB

    Kenneth W. Berendzen

    ZMBP, University of Tuebingen
    Tuebingen, Baden-Wurttemberg, Germany

  • PT

    Paulo Teixeira (he/him/his)

    Assistant Professor
    University of Sao Paulo/
    Piracicaba, Sao Paulo, Brazil

  • AT

    Alain Tissier

    Head of Institute
    Leibniz Institute of Plant Biochemistry
    Halle, Sachsen-Anhalt, Germany

  • TL

    Thomas Lahaye

    Eberhard-Karls-University Tübingen
    Tuebingen, GERMANY

Xanthomonas manipulates host plants by injecting TALEs that bind target gene promoters and activate transcription. TALEs interact with the general transcription factor TFIIAγ to recruit the RNA pol II complex, enabling them to create a shortcut in eukaryotic transcription without the need of other transcription factors and the mediator complex. In an EMS-screen, we identified a pepper plant (C. annuum) that is insensitive to TALEs. Mapping suggested a SNP that changed a single residue (D42N) in TFIIAγ as the causal mutation. Interestingly, not only TALEs but also RipTALs from Ralstonia were affected, despite sharing little homology to TALEs. For further analysis, we used a novel, precise editing approach that enables scarless knock-ins in Arabidopsis and tomato. We used this technology to introduce TFIIAγ polymorphisms into the tomato genome. Genotyping confirmed scar-free knock-ins in endogenes and edited plants that carried the TFIIAγ polymorphisms D42N or V39E (originating from rice xa5) showed a drastically reduced response to TALEs and RipTALs, strongly suggesting that these plants might be resistant to bacteria that use TALEs for susceptibility. Overall, we showed that precise editing by knock-in is feasible in tomato and this novel technology can be used to edit plant genomes at unprecedented levels. Our work highlights the importance of TFIIAγ for TALE-based manipulation of the host while TFIIAγD42N expands the possibilities of a TFIIAγ-based resistance beyond xa5.