A positive regulatory role for LjERF1 in the nodulation process is revealed by systematic analysis of nodule-associated transcription factors of Lotus japonicus

Erika Asamizu, Yoshikazu Shimoda, Hiroshi Kouchi, Satoshi Tabata, Shusei Sato

Research output: Contribution to journalArticlepeer-review

48 Citations (Scopus)

Abstract

We have used reverse genetics to identify genes involved in legume-rhizobium symbiosis in Lotus japonicus. We obtained the sequences of 20 putative transcription factors from previously reported large-scale transcriptome data. The transcription factors were classified according to their DNA binding domains and patterns of expression during the nodulation process. We identified two homologues of Medicago truncatula MtHAP2-1, which encodes a CCAAT-binding protein and has been shown to play a role in nodulation. The functions of the remaining genes in the nodulation process have not been reported. Seven genes were found to encode proteins with AP2-EREBP domains, six of which were similar to proteins that have been implicated in ethylene and/or jasmonic acid signal transduction and defense gene regulation in Arabidopsis (Arabidopsis thaliana). We identified a gene, LjERF1, that is most similar to Arabidopsis ERF1, which is up-regulated by ethylene and jasmonic acid and activates downstream defense genes. LjERF1 showed the same pattern of up-regulation in roots as Arabidopsis ERF1. The nodulation phenotype of roots that overexpressed LjERF1 or inhibited LjERF1 expression using an RNA interference construct indicated that this gene functions as a positive regulator of nodulation. We propose that LjERF1 functions as a key regulator of successful infection of L. japonicus by Mesorhizobium loti.

Original languageEnglish
Pages (from-to)2030-2040
Number of pages11
JournalPlant physiology
Volume147
Issue number4
DOIs
Publication statusPublished - 2008 Aug
Externally publishedYes

ASJC Scopus subject areas

  • Physiology
  • Genetics
  • Plant Science

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