SHA1, a novel RING finger protein, functions in shoot apical meristem maintenance in Arabidopsis

Authors

  • Yutaka Sonoda,

    1. Faculty of Advanced Life Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan,
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    • These authors contributed equally to this work.

  • Shan-Guo Yao,

    1. Faculty of Advanced Life Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan,
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    • These authors contributed equally to this work.

  • Kaori Sako,

    1. Faculty of Advanced Life Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan,
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  • Takeo Sato,

    1. Faculty of Advanced Life Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan,
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  • Wataru Kato,

    1. Faculty of Advanced Life Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan,
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  • Masa-aki Ohto,

    1. Department of Plant Science, University of California, One Shields Avenue, Davis, CA 95616, USA, and
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  • Takanari Ichikawa,

    1. Plant Functional Genomics Research Team, Plant Science Center, RIKEN Yokohama Institute, Yokohama, Kanagawa 230-0045, Japan
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  • Minami Matsui,

    1. Plant Functional Genomics Research Team, Plant Science Center, RIKEN Yokohama Institute, Yokohama, Kanagawa 230-0045, Japan
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  • Junji Yamaguchi,

    Corresponding author
    1. Faculty of Advanced Life Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan,
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  • Akira Ikeda

    1. Faculty of Advanced Life Science and Graduate School of Life Science, Hokkaido University, Kita-ku N10-W8, Sapporo 060-0810, Japan,
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    • These authors contributed equally to this work.


(fax +81 11 706 2737; e-mail jjyama@sci.hokudai.ac.jp).

Summary

Post-embryonic plant growth is dependent on a functional shoot apical meristem (SAM) that provides cells for continuous development of new aerial organs. However, how the SAM is dynamically maintained during vegetative development remains largely unclear. We report here the characterization of a new SAM maintenance mutant, sha1-1 (shoot apical meristem arrest 1-1), that shows a primary SAM-deficient phenotype at the adult stage. The SHA1 gene encodes a novel RING finger protein, and is expressed most intensely in the shoot apex. We show that, in the sha1-1 mutant, the primary SAM develops normally during the juvenile vegetative stage, but cell layer structure becomes disorganized after entering the adult vegetative stage, resulting in a dysfunctional SAM that cannot initiate floral primordia. The sha1-1 SAM terminates completely at the stage when the wild-type begins to bolt, producing adult plants with a primary inflorescence-deficient phenotype. These observations indicate that SHA1, a putative E3 ligase, is required for post-embryonic SAM maintenance by controlling proper cellular organization.

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