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Research article - Peer-reviewed, 2021

Jasmonic Acid-Dependent MYC Transcription Factors Bind to a Tandem G-Box Motif in the YUCCA8 and YUCCA9 Promoters to Regulate Biotic Stress Responses

Perez-Alonso, Marta-Marina; Sanchez-Parra, Beatriz; Ortiz-Garcia, Paloma; Santamaria, Maria Estrella; Diaz, Isabel; Pollmann, Stephan


The indole-3-pyruvic acid pathway is the main route for auxin biosynthesis in higher plants. Tryptophan aminotransferases (TAA1/TAR) and members of the YUCCA family of flavin-containing monooxygenases catalyze the conversion of l-tryptophan via indole-3-pyruvic acid to indole-3-acetic acid (IAA). It has been described that jasmonic acid (JA) locally produced in response to mechanical wounding triggers the de novo formation of IAA through the induction of two YUCCA genes, YUC8 and YUC9. Here, we report the direct involvement of a small number of basic helix-loop-helix transcription factors of the MYC family in this process. We show that the JA-mediated regulation of the expression of the YUC8 and YUC9 genes depends on the abundance of MYC2, MYC3, and MYC4. In support of this observation, seedlings of myc knockout mutants displayed a strongly reduced response to JA-mediated IAA formation. Furthermore, transactivation assays provided experimental evidence for the binding of MYC transcription factors to a particular tandem G-box motif abundant in the promoter regions of YUC8 and YUC9, but not in the promoters of the other YUCCA isogenes. Moreover, we demonstrate that plants that constitutively overexpress YUC8 and YUC9 show less damage after spider mite infestation, thereby underlining the role of auxin in plant responses to biotic stress signals.


Arabidopsis thaliana; indole-3-acetic acid; jasmonic acid; plant hormone crosstalk; transcriptional regulation; wound response; biotic stress; growth-defense trade-off

Published in

International Journal of Molecular Sciences
2021, volume: 22, number: 18, article number: 9768
Publisher: MDPI

Authors' information

Pérez Alonso, Marta
Technical University of Madrid (UPM)
Pérez Alonso, Marta
Swedish University of Agricultural Sciences, Department of Forest Genetics and Plant Physiology
Sanchez-Parra, Beatriz
Universidad Politecnica de Madrid
Sanchez-Parra, Beatriz
University of Graz
Ortiz-Garcia, Paloma
Universidad Politecnica de Madrid
Santamaria, Maria Estrella
Universidad Politecnica de Madrid
Diaz, Isabel
Universidad Politecnica de Madrid
Pollmann, Stephan
Universidad Politecnica de Madrid

UKÄ Subject classification

Biochemistry and Molecular Biology

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