Auxin‐mediated Aux/ IAA‐ARF‐HB signaling cascade regulates secondary xylem development in Populus - Université Toulouse III - Paul Sabatier - Toulouse INP Accéder directement au contenu
Article Dans Une Revue New Phytologist Année : 2019

Auxin‐mediated Aux/ IAA‐ARF‐HB signaling cascade regulates secondary xylem development in Populus

Résumé

Wood development is strictly regulated by various phytohormones and auxin plays a central regulatory role in this process. However, how the auxin signaling is transducted in developing secondary xylem during wood formation in tree species remains unclear. Here, we identified an Aux/INDOLE-3-ACETIC ACID 9 (IAA9)-AUXIN RESPONSE FACTOR 5 (ARF5) module in Populus tomentosa as a key mediator of auxin signaling to control early developing xylem development. PtoIAA9, a canonical Aux/IAA gene, is predominantly expressed in vascular cambium and developing secondary xylem and induced by exogenous auxin. Overexpression of PtoIAA9m encoding a stabilized IAA9 protein significantly represses secondary xylem development in transgenic poplar. We further showed that PtoIAA9 interacts with PtoARF5 homologs via the C-terminal III/IV domains. The truncated PtoARF5.1 protein without the III/IV domains rescued defective phenotypes caused by PtoIAA9m. Expression analysis showed that the PtoIAA9-PtoARF5 module regulated the expression of genes associated with secondary vascular development in PtoIAA9m- and PtoARF5.1-overexpressing plants. Furthermore, PtoARF5.1 could bind to the promoters of two Class III homeodomain-leucine zipper (HD-ZIP III) genes, PtoHB7 and PtoHB8, to modulate secondary xylem formation. Taken together, our results suggest that the Aux/IAA9-ARF5 module is required for auxin signaling to regulate wood formation via orchestrating the expression of HD-ZIP III transcription factors in poplar.
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Dates et versions

hal-03602125 , version 1 (04-05-2023)

Identifiants

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Changzheng Xu, Yun Shen, Fu He, Xiaokang Fu, Hong Yu, et al.. Auxin‐mediated Aux/ IAA‐ARF‐HB signaling cascade regulates secondary xylem development in Populus. New Phytologist, 2019, 222 (2), pp.752-767. ⟨10.1111/nph.15658⟩. ⟨hal-03602125⟩
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