enod40 induces dedifferentiation and division of root cortical cells in legumes

Celine Charon, Christina Johansson, Eva Kondorosi, Adam Kondorosi, Martin Crespi

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Under nitrogen-limiting conditions Rhizobium meliloti can establish symbiosis with Medicago plants to form nitrogen-fixing root nodules. Nodule organogenesis starts with the dedifferentiation and division of root cortical cells. In these cells the early nodulin gene enod40, which encodes an unusually small peptide (12 or 13 amino acids), is induced from the beginning of this process. Herein we show that enod40 expression evokes root nodule initiation. (i) Nitrogen-deprived transgenic Medicago truncatula plants overexpressing enod40 exhibit extensive cortical cell division in their roots in the absence of Rhizobium, (ii) Bombardment of Medicago roots with an enod40-expressing DNA cassette induces dedifferentiation and division of cortical cells and the expression of another early nodulin gene, Msenod12A. Moreover, transient expression of either the enod40 region spanning the oligopeptide sequence or only the downstream region without this sequence induces these responses. Our results suggest that the cell-specific growth response elicited by enod40 is involved in the initiation of root nodule organogenesis.

Original languageEnglish
Pages (from-to)8901-8906
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number16
Publication statusPublished - Aug 5 1997



  • Early nodulin
  • Nitrogen control
  • Nodule initiation
  • Plant growth regulator

ASJC Scopus subject areas

  • General

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