title: To be or noot to be: evolutionary tinkering for symbiotic organ identity.
abstract: Legume plants develop symbiosis specific organs on their roots as a result of their interaction with rhizobia. These organs, called nodules, house the nitrogen fixing bacteria. The molecular mechanisms governing the identity and maintenance of this organ are still poorly understood, but it is supposed that root and nodule development share common features. We have identified the Medicago truncatula nodule root (NOOT) and Pisum sativum cochleata (COCH) orthologous genes as necessary for the robust maintenance of nodule identity throughout the nodule developmental program. NOOT and COCH are Arabidopsis blade-on-petiole (BOP) orthologs and NOOT and COCH show functions in leaf and flower development in M. truncatula and P. sativum respectively that are conserved with the functions of BOP in Arabidopsis. The characterization of the noot and coch mutants highlights the root evolutionary origin of nodule vascular strands and suggests that the NOOT and COCH genes were recruited to repress root identity in the legume symbiotic organ.
authors.affiliation: Institut des Sciences du Végétal; CNRS; Gif sur Yvette Cedex, France; Laboratoire de Recherche en Sciences Végétales; Université Paul Sabatier CNRS; Castanet Tolosan, France.
authors.forename: Jean-Malo
authors.initials: JM
authors.lastname: Couzigou
authors.forename: Samuel
authors.initials: S
authors.lastname: Mondy
authors.forename: Lucien
authors.initials: L
authors.lastname: Sahl
authors.forename: Benjamin
authors.initials: B
authors.lastname: Gourion
authors.forename: Pascal
authors.initials: P
authors.lastname: Ratet
mesh_terms: D017360:Arabidopsis / Q000235:genetics; D005075:Biological Evolution; D017343:Genes, Plant; D007210:Indoleacetic Acids / Q000378:metabolism; D046913:Medicago truncatula / Q000235:genetics; D009928:Organ Specificity / Q000235:genetics; D018532:Pisum sativum / Q000235:genetics; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D053204:Root Nodules, Plant / Q000235:genetics / Q000378:metabolism*; D013559:Symbiosis
chemical_list: D007210:Indoleacetic Acids; D010940:Plant Proteins
keywords: auxin; evolution; homeosis; meristem; organogenesis; root nodule symbiosis