The Arabidopsis ARGOS-LIKE gene regulates cell expansion during organ growth

Authors

  • Yuxin Hu,

    1. Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604,
    2. Key Laboratory of Photosynthesis and Environmental Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China, and
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  • Huay Mei Poh,

    1. Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604,
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  • Nam-Hai Chua

    Corresponding author
    1. Laboratory of Plant Molecular Biology, Rockefeller University, New York, NY 10021, USA
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Errata

This article is corrected by:

  1. Errata: Corrigendum Volume 47, Issue 3, 490, Article first published online: 11 July 2006

*(fax +1 212 327 8327; e-mail chua@mail.rockefeller.edu).

Summary

Cell expansion, and its coordination with cell division, plays a critical role in the growth and development of plant organs. However, the genes controlling cell expansion during organogenesis are largely unknown. Here, we demonstrate that a novel Arabidopsis gene, ARGOS-LIKE (ARL), which has some sequence homology to the ARGOS gene, is involved in this process. Reduced expression or overexpression of ARL in Arabidopsis results in smaller or larger cotyledons and leaves as well as other lateral organs, respectively. Anatomical examination of cotyledons and leaves in ARL transgenic plants demonstrates that the alteration in size can be attributed to changes in cell size rather than cell number, indicating that ARL plays a role in cell expansion-dependent organ growth. ARL is upregulated by brassinosteroid (BR) and this induction is impaired in the BR-insensitive mutant bri1, but not in the BR-deficient mutant det2. Ectopic expression of ARL in bri1–119 partially restores cell growth in cotyledons and leaves. Our results suggest that ARL acts downstream of BRI1 and partially mediates BR-related cell expansion signals during organ growth.

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