Positive and negative control of nod gene expression in Rhizobium meliloti is required for optimal nodulation

E. Kondorosi, J. Gyuris, J. Schmidt, M. John, E. Duda, B. Hoffmann, J. Schell, A. Kondorosi

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Abstract

We show that expression of common nodulation genes in Rhizobium meliloti is under positive as well as negative control. A repressor protein was found to be involved in the negative control of nod gene expression. Whereas the activator NodD protein binds to the conserved cis-regulatory element (nod-box) required for coordinated regulation of nod genes, the repressor binds to the overlapping nodD1 and nodA promoters, at the RNA polymerase binding site. A model depicting the possible interaction of the plant-derived nod gene inducer (luteolin), the NodD and the repressor with the nod promoter elements is presented. Mutants lacking the repressor exhibited delayed nodulation phenotype, indicating that fine tuning of nod gene expression is required for optimal nodulation of the plant host.

Original languageEnglish
Pages (from-to)1331-1340
Number of pages10
JournalEMBO Journal
Volume8
Issue number5
Publication statusPublished - Jan 1 1989

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ASJC Scopus subject areas

  • Neuroscience(all)
  • Molecular Biology
  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)

Cite this

Kondorosi, E., Gyuris, J., Schmidt, J., John, M., Duda, E., Hoffmann, B., Schell, J., & Kondorosi, A. (1989). Positive and negative control of nod gene expression in Rhizobium meliloti is required for optimal nodulation. EMBO Journal, 8(5), 1331-1340.