title: Redox regulation of differentiation in symbiotic nitrogen fixation.
abstract: BACKGROUND
  Nitrogen-fixing symbiosis between Rhizobium bacteria and legumes leads to the formation of a new organ, the root nodule. The development of the nodule requires the differentiation of plant root cells to welcome the endosymbiotic bacterial partner. This development includes the formation of an efficient vascular tissue which allows metabolic exchanges between the root and the nodule, the formation of a barrier to oxygen diffusion necessary for the bacterial nitrogenase activity and the enlargement of cells in the infection zone to support the large bacterial population. Inside the plant cell, the bacteria differentiate into bacteroids which are able to reduce atmospheric nitrogen to ammonia needed for plant growth in exchange for carbon sources. Nodule functioning requires a tight regulation of the development of plant cells and bacteria.
  
  
  OBJECTIVE
  Nodule functioning requires a tight regulation of the development of plant cells and bacteria. The importance of redox control in nodule development and N-fixation is discussed in this review. The involvement of reactive oxygen and nitrogen species and the importance of the antioxidant defense are analyzed.
  
  
  CONCLUSIONS
  Plant differentiation and bacterial differentiation are controlled by reactive oxygen and nitrogen species, enzymes involved in the antioxidant defense and antioxidant compounds.
  
  
  CONCLUSIONS
  The establishment and functioning of nitrogen-fixing symbiosis involve a redox control important for both the plant-bacteria crosstalk and the consideration of environmental parameters. This article is part of a Special Issue entitled Redox regulation of differentiation and de-differentiation.
authors.affiliation: Institut Sophia Agrobiotech, Université de Nice-Sophia Antipolis, 400 Route des Chappes, BP167, F-06903 Sophia Antipolis Cedex, France; Institut Sophia Agrobiotech, INRA UMR 1355, 400 Route des Chappes, BP167, F-06903 Sophia Antipolis Cedex, France; Institut Sophia Agrobiotech, CNRS UMR 7254, 400 Route des Chappes, BP167, F-06903 Sophia Antipolis Cedex, France.
authors.forename: Carolina Werner
authors.initials: CW
authors.lastname: Ribeiro
authors.affiliation: Institut Sophia Agrobiotech, Université de Nice-Sophia Antipolis, 400 Route des Chappes, BP167, F-06903 Sophia Antipolis Cedex, France; Institut Sophia Agrobiotech, INRA UMR 1355, 400 Route des Chappes, BP167, F-06903 Sophia Antipolis Cedex, France; Institut Sophia Agrobiotech, CNRS UMR 7254, 400 Route des Chappes, BP167, F-06903 Sophia Antipolis Cedex, France.
authors.forename: Geneviève
authors.initials: G
authors.lastname: Alloing
authors.affiliation: Institut Sophia Agrobiotech, Université de Nice-Sophia Antipolis, 400 Route des Chappes, BP167, F-06903 Sophia Antipolis Cedex, France; Institut Sophia Agrobiotech, INRA UMR 1355, 400 Route des Chappes, BP167, F-06903 Sophia Antipolis Cedex, France; Institut Sophia Agrobiotech, CNRS UMR 7254, 400 Route des Chappes, BP167, F-06903 Sophia Antipolis Cedex, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Mandon
authors.affiliation: Institut Sophia Agrobiotech, Université de Nice-Sophia Antipolis, 400 Route des Chappes, BP167, F-06903 Sophia Antipolis Cedex, France; Institut Sophia Agrobiotech, INRA UMR 1355, 400 Route des Chappes, BP167, F-06903 Sophia Antipolis Cedex, France; Institut Sophia Agrobiotech, CNRS UMR 7254, 400 Route des Chappes, BP167, F-06903 Sophia Antipolis Cedex, France. Electronic address: frendo@unice.fr.
authors.forename: Pierre
authors.initials: P
authors.lastname: Frendo
mesh_terms: D002454:Cell Differentiation / Q000502:physiology*; D007887:Fabaceae / Q000166:cytology / Q000378:metabolism / Q000382:microbiology; D054884:Host-Pathogen Interactions; D009586:Nitrogen Fixation / Q000502:physiology*; D010084:Oxidation-Reduction; D026361:Reactive Nitrogen Species / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D053204:Root Nodules, Plant / Q000166:cytology / Q000382:microbiology / Q000502:physiology*; D016962:Sinorhizobium meliloti / Q000378:metabolism / Q000502:physiology; D013559:Symbiosis / Q000502:physiology*
chemical_list: D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species
keywords: (Homo)glutathione; Nitrogen-fixing symbiosis; Reactive nitrogen species; Reactive oxygen species; Redox regulation; Root nodule