Fate map of Medicago truncatula root nodules

Ting Ting Xiao, Stefan Schilderink, Sjef Moling, Eva E. Deinum, Eva Kondorosi, Henk Franssen, Olga Kulikova, Andreas Niebel, Ton Bisseling

Research output: Contribution to journalArticle

110 Citations (Scopus)

Abstract

Legume root nodules are induced by N-fixing rhizobium bacteria that are hosted in an intracellular manner. These nodules are formed by reprogramming differentiated root cells. The model legume Medicago truncatula forms indeterminate nodules with a meristem at their apex. This organ grows by the activity of the meristem that adds cells to the different nodule tissues. In Medicago sativa it has been shown that the nodule meristem is derived from the root middle cortex. During nodule initiation, inner cortical cells and pericycle cells are also mitotically activated. However, whether and how these cells contribute to the mature nodule has not been studied. Here, we produce a nodule fate map that precisely describes the origin of the different nodule tissues based on sequential longitudinal sections and on the use of marker genes that allow the distinction of cells originating from different root tissues. We show that nodule meristem originates from the third cortical layer, while several cell layers of the base of the nodule are directly formed from cells of the inner cortical layers, root endodermis and pericycle. The latter two differentiate into the uninfected tissues that are located at the base of the mature nodule, whereas the cells derived from the inner cortical cell layers form about eight cell layers of infected cells. This nodule fate map has then been used to re-analyse several mutant nodule phenotypes. This showed, among other things, that intracellular release of rhizobia in primordium cells and meristem daughter cells are regulated in a different manner.

Original languageEnglish
Pages (from-to)3517-3528
Number of pages12
JournalDevelopment (Cambridge)
Volume141
Issue number18
DOIs
Publication statusPublished - Sep 2014

Keywords

  • Endodermis
  • Indeterminate root nodule
  • Inner cortex
  • Medicago
  • Nodule meristem
  • Nodule primordium

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology

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  • Cite this

    Xiao, T. T., Schilderink, S., Moling, S., Deinum, E. E., Kondorosi, E., Franssen, H., Kulikova, O., Niebel, A., & Bisseling, T. (2014). Fate map of Medicago truncatula root nodules. Development (Cambridge), 141(18), 3517-3528. https://doi.org/10.1242/dev.110775