The REL3-mediated TAS3 ta-siRNA pathway integrates auxin and ethylene signaling to regulate nodulation in Lotus japonicus

Authors

  • Xiaolin Li,

    1. National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
    Search for more papers by this author
  • Mingjuan Lei,

    1. National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
    Search for more papers by this author
  • Zhongyuan Yan,

    1. National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
    Search for more papers by this author
  • Qi Wang,

    1. National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
    Search for more papers by this author
  • Aimin Chen,

    1. National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
    Search for more papers by this author
  • Jie Sun,

    1. The key Laboratory of Oasis Eco-agriculture, Agriculture College of Shihezi University, Shihezi, China
    Search for more papers by this author
  • Da Luo,

    1. School of Life Sciences, Sun Yat-Sen University, Guangzhou, China
    Search for more papers by this author
  • Yanzhang Wang

    Corresponding author
    1. National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology & Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
    • Author for correspondence:

      Yanzhang Wang

      Tel: +86 21 5492 4167

      Email: yzwang@sippe.ac.cn

    Search for more papers by this author

Summary

  • The ta-siRNA pathway is required for lateral organ development, including leaf patterning, flower differentiation and lateral root growth. Legumes can develop novel lateral root organs – nodules – resulting from symbiotic interactions with rhizobia. However, ta-siRNA regulation in nodule formation remains unknown. To explore ta-siRNA regulation in nodule formation, we investigated the roles of REL3, a key component of TAS3 ta-siRNA biogenesis, during nodulation in Lotus japonicus.
  • We characterized the symbiotic phenotypes of the TAS3 ta-siRNA defective rel3 mutant, and analyzed the responses of the rel3 mutant to auxin and ethylene in order to gain insight into TAS3 ta-siRNA regulation of nodulation.
  • The rel3 mutant produced fewer pink nitrogen-fixing nodules, with substantially decreased infection frequency and nodule initiation. Moreover, the rel3 mutant was more resistant than wild-type to 1-naphthaleneacetic acid (NAA) and N-1-naphthylphthalamic acid (NPA) in root growth, and exhibited insensitivity to auxins but greater sensitivity to auxin transport inhibitors during nodulation. Furthermore, the rel3 mutant has enhanced root-specific ethylene sensitivity and altered responses to ethylene during nodulation; the low-nodulating phenotype of the rel3 mutant can be restored by ethylene synthesis inhibitor L-α-(2-aminoethoxyvinyl)-glycine (AVG) or action inhibitor Ag+.
  • The REL3-mediated TAS3 ta-siRNA pathway regulates nodulation by integrating ethylene and auxin signaling.

Ancillary