Distinctive expression patterns and roles of the miRNA393/TIR1 homolog module in regulating flag leaf inclination and primary and crown root growth in rice (Oryza sativa)

Authors

  • Hongwu Bian,

    1. Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China
    Search for more papers by this author
    • These authors contributed equally to this work.

  • Yakun Xie,

    1. Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China
    Search for more papers by this author
    • These authors contributed equally to this work.

  • Fu Guo,

    1. Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China
    Search for more papers by this author
  • Ning Han,

    1. Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China
    Search for more papers by this author
  • Shengyun Ma,

    1. Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China
    Search for more papers by this author
  • Zhanghui Zeng,

    1. Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China
    Search for more papers by this author
  • Junhui Wang,

    1. Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China
    Search for more papers by this author
  • Yinong Yang,

    1. Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China
    2. Department of Plant Pathology and Huck Institute of Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
    Search for more papers by this author
  • Muyuan Zhu

    1. Key Laboratory for Cell and Gene Engineering of Zhejiang Province, Institute of Genetics, College of Life Sciences, Zhejiang University, Hangzhou 310058, Zhejiang, China
    Search for more papers by this author

Author for correspondence:
Muyuan Zhu
Tel: +86 571 88206536
Email: myzhu@zju.edu.cn

Summary

  • MicroRNA (miRNA)-mediated regulation of auxin signaling components plays a critical role in plant development. miRNA expression and functional diversity contribute to the complexity of regulatory networks of miRNA/target modules.
  • This study functionally characterizes two members of the rice (Oryza sativa) miR393 family and their target genes, OsTIR1 and OsAFB2 (AUXIN SIGNALING F-BOX), the two closest homologs of Arabidopsis TRANSPORT INHIBITOR RESPONSE 1 (TIR1).
  • We found that the miR393 family members possess distinctive expression patterns, with miR393a expressed mainly in the crown and lateral root primordia, as well as the coleoptile tip, and miR393b expressed in the shoot apical meristem. Transgenic plants overexpressing miR393a/b displayed a severe phenotype with hallmarks of altered auxin signaling, mainly including enlarged flag leaf inclination and altered primary and crown root growth. Furthermore, OsAFB2- and OsTIR1-suppressed lines exhibited increased inclination of flag leaves at the booting stage, resembling miR393-overexpressing plants. Moreover, yeast two-hybrid and bimolecular fluorescence complementation assays showed that OsTIR1 and OsAFB2 interact with OsIAA1.
  • Expression diversification of miRNA393 implies the potential role of miRNA regulation during species evolution. The conserved mechanisms of the miR393/target module indicate the fundamental importance of the miR393-mediated regulation of auxin signal transduction in rice.

Ancillary