Control of lateral organ development and flowering time by the Arabidopsis thaliana MADS-box Gene AGAMOUS-LIKE6

Authors

  • Sung C. Koo,

    1. Division of Applied Life Science (BK21 program), Plant Molecular Biology and Biotechnology Research Center and Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660–701, Korea
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    • These authors are contributed equally to this work.

  • Oliver Bracko,

    1. Department of Molecular Biology, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
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    • These authors are contributed equally to this work.

  • Mi S. Park,

    1. Division of Applied Life Science (BK21 program), Plant Molecular Biology and Biotechnology Research Center and Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660–701, Korea
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    • These authors are contributed equally to this work.

  • Rebecca Schwab,

    1. Department of Molecular Biology, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
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  • Hyun J. Chun,

    1. Division of Applied Life Science (BK21 program), Plant Molecular Biology and Biotechnology Research Center and Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660–701, Korea
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  • Kyoung M. Park,

    1. Division of Applied Life Science (BK21 program), Plant Molecular Biology and Biotechnology Research Center and Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660–701, Korea
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  • Jun S. Seo,

    1. Division of Applied Life Science (BK21 program), Plant Molecular Biology and Biotechnology Research Center and Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660–701, Korea
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  • Vojislava Grbic,

    1. Department of Molecular Biology, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
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    • Present address: Department of Biology, University of Western Ontario, London, ON, N6A 5B8, Canada.

  • Sureshkumar Balasubramanian,

    1. Department of Molecular Biology, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
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    • §

      Present address: University of Queensland, School of Biological Sciences, St. Lucia, Qld 4072, Australia.

  • Markus Schmid,

    1. Department of Molecular Biology, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
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  • François Godard,

    1. Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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    • #

      Deceased.

  • Dae-Jin Yun,

    1. Division of Applied Life Science (BK21 program), Plant Molecular Biology and Biotechnology Research Center and Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660–701, Korea
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  • Sang Y. Lee,

    1. Division of Applied Life Science (BK21 program), Plant Molecular Biology and Biotechnology Research Center and Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660–701, Korea
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  • Moo J. Cho,

    1. Division of Applied Life Science (BK21 program), Plant Molecular Biology and Biotechnology Research Center and Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660–701, Korea
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  • Detlef Weigel,

    Corresponding author
    1. Department of Molecular Biology, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
    2. Plant Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
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  • Min C. Kim

    Corresponding author
    1. Division of Applied Life Science (BK21 program), Plant Molecular Biology and Biotechnology Research Center and Environmental Biotechnology National Core Research Center, Gyeongsang National University, Jinju 660–701, Korea
    2. Department of Molecular Biology, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
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For correspondence (fax +49 7071 601 1409; e-mail weigel@weigelworld.org; fax +82 55 751 5420; e-mail mckim@gnu.ac.kr).

Summary

MADS-domain transcription factors play pivotal roles in various developmental processes. The lack of simple loss-of-function phenotypes provides impediments to understand the biological function of some of the MADS-box transcription factors. Here we have characterized the potential role of the Arabidopsis thaliana AGAMOUS-LIKE6 (AGL6) gene by fusing full-length coding sequence with transcriptional activator and repressor domains and suggest a role for AGL6 in lateral organ development and flowering. Upon photoperiodic induction of flowering, AGL6 becomes expressed in abaxial and proximal regions of cauline leaf primordia, as well as the cryptic bracts subtending flowers. In developing flowers, AGL6 is detected in the proximal regions of all floral organs and in developing ovules. Converting AGL6 into a strong activator through fusion to the VP16 domain triggers bract outgrowth, implicating AGL6 in the development of bractless flowers in Arabidopsis. In addition, ectopic reproductive structures form on both bracts and flowers in gAGL6::VP16 transgenic plants, which is dependent on B and C class homeotic genes, but independent of LEAFY. Overexpression of both AGL6 and its transcriptional repressor form, AGL6::EAR, causes precocious flowering and terminal flower formation, suggesting that AGL6 suppresses the function of a floral repressor.

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