Nod factor/nitrate-induced CLE genes that drive HAR1-mediated systemic regulation of nodulation

Satoru Okamoto, Erika Ohnishi, Shusei Sato, Hirokazu Takahashi, Mikio Nakazono, Satoshi Tabata, Masayoshi Kawaguchi

Research output: Contribution to journalArticlepeer-review

287 Citations (Scopus)


Host legumes control root nodule numbers by sensing external and internal cues. A major external cue is soil nitrate, whereas a feedback regulatory system in which earlier formed nodules suppress further nodulation through shoot-root communication is an important internal cue. The latter is known as autoregulation of nodulation (AUT), and is believed to consist of two long-distance signals: a root-derived signal that is generated in infected roots and transmitted to the shoot; and a shoot-derived signal that systemically inhibits nodulation. In Lotus japonicus, the leucine-rich repeat receptor-like kinase, HYPERNODULATION ABERRANT ROOT FORMATION 1 (HAR1), mediates AUT and nitrate inhibition of nodulation, and is hypothesized to recognize the root-derived signal. Here we identify L. japonicus CLE-Root Signal 1 (LjCLE-RS1) and LjCLE-RS2 as strong candidates for the root-derived signal. A hairy root transformation study shows that overexpressing LjCLE-RS1 and -RS2 inhibits nodulation systemically and, furthermore, that the systemic suppression depends on HAR1. Moreover, LjCLE-RS2 expression is strongly up-regulated in roots by nitrate addition. Based on these findings, we propose a simple model for AUT and nitrate inhibition of nodulation mediated by LjCLE-RS1, -RS2 peptides and the HAR1 receptor-like kinase.

Original languageEnglish
Pages (from-to)67-77
Number of pages11
JournalPlant and Cell Physiology
Issue number1
Publication statusPublished - 2009 Jan
Externally publishedYes


  • CLE genes
  • Lotus japonicus
  • Nitrate
  • Nod factor signaling
  • Nodulation
  • Systemic regulation

ASJC Scopus subject areas

  • Physiology
  • Plant Science
  • Cell Biology


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