Phytochrome interacting factors 4 and 5 control seedling growth in changing light conditions by directly controlling auxin signaling

Authors

  • Patricia Hornitschek,

    1. Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
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    • Authors with equal contribution listed alphabetically.

  • Markus V. Kohnen,

    1. Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
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    • Authors with equal contribution listed alphabetically.

  • Séverine Lorrain,

    1. Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
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    • Authors with equal contribution listed alphabetically.

  • Jacques Rougemont,

    1. Bioinformatics and Biostatistics Core Facility, School of Life Sciences, and Swiss Institute of Bioinformatics, EPFL, CH-1015 Lausanne, Switzerland
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  • Karin Ljung,

    1. Umeå Plant Science Centre, Department of Forest Genetics and Plant Physiology, Swedish University of Agricultural Sciences, SE-901 83 Umeå, Sweden
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  • Irene López-Vidriero,

    1. Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas, Campus Universidad Autónoma, 28049 Madrid, Spain
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  • José M. Franco-Zorrilla,

    1. Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas, Campus Universidad Autónoma, 28049 Madrid, Spain
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  • Roberto Solano,

    1. Departamento de Genética Molecular de Plantas, Centro Nacional de Biotecnología-Consejo Superior de Investigaciones Científicas, Campus Universidad Autónoma, 28049 Madrid, Spain
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  • Martine Trevisan,

    1. Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
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  • Sylvain Pradervand,

    1. Vital-IT, Swiss Institute of Bioinformatics, Bâtiment Génopode, 1015 Lausanne, Switzerland
    2. Genomic Technologies Facility, Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
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  • Ioannis Xenarios,

    1. Vital-IT, Swiss Institute of Bioinformatics, Bâtiment Génopode, 1015 Lausanne, Switzerland
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  • Christian Fankhauser

    Corresponding author
    1. Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland
      (e-mail christian.fankhauser@unil.ch).
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(e-mail christian.fankhauser@unil.ch).

Summary

Plant growth is strongly influenced by the presence of neighbors that compete for light resources. In response to vegetational shading shade-intolerant plants such as Arabidopsis display a suite of developmental responses known as the shade-avoidance syndrome (SAS). The phytochrome B (phyB) photoreceptor is the major light sensor to mediate this adaptive response. Control of the SAS occurs in part with phyB, which controls protein abundance of phytochrome-interacting factors 4 and 5 (PIF4 and PIF5) directly. The shade-avoidance response also requires rapid biosynthesis of auxin and its transport to promote elongation growth. The identification of genome-wide PIF5-binding sites during shade avoidance revealed that this bHLH transcription factor regulates the expression of a subset of previously identified SAS genes. Moreover our study suggests that PIF4 and PIF5 regulate elongation growth by controlling directly the expression of genes that code for auxin biosynthesis and auxin signaling components.

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