Hormonal regulation of temperature-induced growth in Arabidopsis

Authors

  • Jon A. Stavang,

    1. Department of Plant and Environmental Sciences, Norwegian University of Life Sciences, N1432 Ås, Norway,
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    • Present address: Bioforsk Vest Ullensvang, 5781 Lofthus, Norway.

    • These authors contributed equally to this work.

  • Javier Gallego-Bartolomé,

    1. Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Edificio E8, Campus Universitat Politecnica de Valencia, Av de los Naranjos s/n, 46022-Valencia, Spain,
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    • These authors contributed equally to this work.

  • María D. Gómez,

    1. Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Edificio E8, Campus Universitat Politecnica de Valencia, Av de los Naranjos s/n, 46022-Valencia, Spain,
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  • Shigeo Yoshida,

    1. RIKEN Plant Science Center, Yokohama City, Kanagawa 230-0045, Japan
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  • Tadao Asami,

    1. Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
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  • Jorunn E. Olsen,

    1. Department of Plant and Environmental Sciences, Norwegian University of Life Sciences, N1432 Ås, Norway,
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  • José L. García-Martínez,

    1. Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Edificio E8, Campus Universitat Politecnica de Valencia, Av de los Naranjos s/n, 46022-Valencia, Spain,
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  • David Alabadí,

    Corresponding author
    1. Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Edificio E8, Campus Universitat Politecnica de Valencia, Av de los Naranjos s/n, 46022-Valencia, Spain,
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  • Miguel A. Blázquez

    1. Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Edificio E8, Campus Universitat Politecnica de Valencia, Av de los Naranjos s/n, 46022-Valencia, Spain,
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*For correspondence (fax +34 963 87 7859; e-mail dalabadi@ibmcp.upv.es).

Summary

Successful plant survival depends upon the proper integration of information from the environment with endogenous cues to regulate growth and development. We have investigated the interplay between ambient temperature and hormone action during the regulation of hypocotyl elongation, and we have found that gibberellins (GAs) and auxin are quickly and independently recruited by temperature to modulate growth rate, whereas activity of brassinosteroids (BRs) seems to be required later on. Impairment of GA biosynthesis blocked the increased elongation caused at higher temperatures, but hypocotyls of pentuple DELLA knockout mutants still reduced their response to higher temperatures when BR synthesis or auxin polar transport were blocked. The expression of several key genes involved in the biosynthesis of GAs and auxin was regulated by temperature, which indirectly resulted in coherent variations in the levels of accumulation of nuclear GFP–RGA (repressor of GA1) and in the activity of the DR5 reporter. DNA microarray and genetic analyses allowed the identification of the transcription factor PIF4 (phytochrome-interacting factor 4) as a major target in the promotion of growth at higher temperature. These results suggest that temperature regulates hypocotyl growth by individually impinging on several elements of a pre-existing network of signaling pathways involving auxin, BRs, GAs, and PIF4.

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