Brassinosteroid production and signaling differentially control cell division and expansion in the leaf

Authors

  • Miroslava K. Zhiponova,

    1. Department of Plant Systems Biology, VIB, Ghent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
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  • Isabelle Vanhoutte,

    1. Department of Plant Systems Biology, VIB, Ghent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
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  • Véronique Boudolf,

    1. Department of Plant Systems Biology, VIB, Ghent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
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  • Camilla Betti,

    1. Department of Plant Systems Biology, VIB, Ghent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
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  • Stijn Dhondt,

    1. Department of Plant Systems Biology, VIB, Ghent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
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  • Frederik Coppens,

    1. Department of Plant Systems Biology, VIB, Ghent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
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  • Evelien Mylle,

    1. Department of Plant Systems Biology, VIB, Ghent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
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  • Sara Maes,

    1. Department of Plant Systems Biology, VIB, Ghent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
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  • Mary-Paz González-García,

    1. Molecular Genetics Department, Centre for Research in Agricultural Genomics CSIC-IRTA-UAB, Barcelona, Spain
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  • Ana I. Caño-Delgado,

    1. Molecular Genetics Department, Centre for Research in Agricultural Genomics CSIC-IRTA-UAB, Barcelona, Spain
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  • Dirk Inzé,

    1. Department of Plant Systems Biology, VIB, Ghent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
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  • Gerrit T. S. Beemster,

    1. Department of Biology, University of Antwerp, Antwerp, Belgium
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  • Lieven De Veylder,

    1. Department of Plant Systems Biology, VIB, Ghent, Belgium
    2. Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
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  • Eugenia Russinova

    Corresponding author
    1. Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium
    • Department of Plant Systems Biology, VIB, Ghent, Belgium
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Author for correspondence:

Eugenia Russinova

Tel:+32 9 331 39 31

Email: jenny.russinova@psb.vib-ugent.be

Summary

  • Brassinosteroid (BR) hormones control plant growth through acting on both cell expansion and division. Here, we examined the role of BRs in leaf growth using the Arabidopsis BR-deficient mutant constitutive photomorphogenesis and dwarfism (cpd).
  • We show that the reduced size of cpd leaf blades is a result of a decrease in cell size and number, as well as in venation length and complexity. Kinematic growth analysis and tissue-specific marker gene expression revealed that the leaf phenotype of cpd is associated with a prolonged cell division phase and delayed differentiation.
  • cpd-leaf-rescue experiments and leaf growth analysis of BR biosynthesis and signaling gain-of-function mutants showed that BR production and BR receptor-dependent signaling differentially control the balance between cell division and expansion in the leaf.
  • Investigation of cell cycle markers in leaves of cpd revealed the accumulation of mitotic proteins independent of transcription. This correlated with an increase in cyclin-dependent kinase activity, suggesting a role for BRs in control of mitosis.

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