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Research article - Peer-reviewed, 2019

A Molecular Framework for the Control of Adventitious Rooting by TIR1/AFB2-Aux/IAA-Dependent Auxin Signaling in Arabidopsis

Lakehal, Abdellah; Chaabouni, Salma; Cavel, Emilie; Le Hir, Rozenn; Ranjan, Alok; Raneshan, Zahra; Novak, Ondrej; Pacurar, Daniel, I; Perrone, Irene; Jobert, Francois; Gutierrez, Laurent; Bako, Laszlo; Bellini, Catherine


In Arabidopsis thaliana, canonical auxin-dependent gene regulation is mediated by 23 transcription factors from the AUXIN RESPONSE FACTOR (ARF) family that interact with auxin/indole acetic acid repressors (Aux/IAAs), which themselves form co-receptor complexes with one of six TRANSPORT INHIBITOR1/AUXIN-SIGNALLING F-BOX (TIR1/AFB) proteins. Different combinations of co-receptors drive specific sensing outputs, allowing auxin to control a myriad of processes. ARF6 and ARF8 are positive regulators of adventitious root initiation upstream of jasmonate, but the exact auxin co-receptor complexes controlling the transcriptional activity of these proteins has remained unknown. Here, using loss-of-function mutants we show that three Aux/IAA genes, IAA6, IAA9, and IAA17, act additively in the control of adventitious root (AR) initiation. These three IAA proteins interact with ARF6 and/or ARF8 and likely repress their activity in AR development. We show that TIR1 and AFB2 are positive regulators of AR formation and TIR1 plays a dual role in the control of jasmonic acid (JA) biosynthesis and conjugation, as several JA biosynthesis genes are up-regulated in the tir1-1 mutant. These results lead us to propose that in the presence of auxin, TIR1 and AFB2 form specific sensing complexes with IAA6, IAA9, and/or IAA17 to modulate JA homeostasis and control AR initiation.


TIR1/AFB; AuxIAA; jasmonate; adventitious roots; Arabidopsis

Published in

Molecular Plant
2019, Volume: 12, number: 11, pages: 1499-1514
Publisher: CELL PRESS

    SLU Authors

      • Jobert, Francois

        • University of Picardie Jules Verne

      UKÄ Subject classification

      Cell and Molecular Biology

      Publication Identifiers


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