title: Actinorhizal root nodule symbioses: what is signalling telling on the origins of nodulation?
abstract: Two groups of bacteria are able to induce the formation of nitrogen-fixing nodules: proteobacteria called rhizobia, which associate with Legumes or Parasponia and actinobateria from the genus Frankia which are able to interact with ∼220 species belonging to eight families called actinorhizal plants. Legumes and different lineages of actinorhizal plants differ in bacterial partners, nodule organogenesis and infection patterns and have independent evolutionary origins. However, recent technical achievements are revealing a variety of conserved signalling molecules and gene networks. Actinorhizal interactions display several primitive features and thus provide the ideal opportunity to determine the minimal molecular toolkit needed to build a nodule and to understand the evolution of root nodule symbioses.
authors.affiliation: Institut de Recherche pour le Développement (IRD), Unité mixte de recherche DIADE, 911 Avenue Agropolis, BP 64501, 34394 Montpellier Cedex 5, France. Electronic address: sergio.svistoonoff@ird.fr.
authors.forename: Sergio
authors.initials: S
authors.lastname: Svistoonoff
authors.affiliation: Institut de Recherche pour le Développement (IRD), Unité mixte de recherche DIADE, 911 Avenue Agropolis, BP 64501, 34394 Montpellier Cedex 5, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Hocher
authors.affiliation: Institut de Recherche pour le Développement (IRD), Unité mixte de recherche DIADE, 911 Avenue Agropolis, BP 64501, 34394 Montpellier Cedex 5, France.
authors.forename: Hassen
authors.initials: H
authors.lastname: Gherbi
mesh_terms: D005075:Biological Evolution; D007887:Fabaceae / Q000382:microbiology / Q000502:physiology; D040161:Frankia / Q000502:physiology*; D009586:Nitrogen Fixation; D055170:Plant Root Nodulation; D018517:Plant Roots / Q000382:microbiology*; D010944:Plants / Q000382:microbiology*; D015398:Signal Transduction; D013559:Symbiosis