title: Positive Gene Regulation by a Natural Protective miRNA Enables Arbuscular Mycorrhizal Symbiosis.
abstract: Arbuscular mycorrhizal (AM) symbiosis associates most plants with fungi of the phylum Glomeromycota. The fungus penetrates into roots and forms within cortical cell branched structures called arbuscules for nutrient exchange. We discovered that miR171b has a mismatched cleavage site and is unable to downregulate the miR171 family target gene, LOM1 (LOST MERISTEMS 1). This mismatched cleavage site is conserved among plants that establish AM symbiosis, but not in non-mycotrophic plants. Unlike other members of the miR171 family, miR171b stimulates AM symbiosis and is expressed specifically in root cells that contain arbuscules. MiR171b protects LOM1 from negative regulation by other miR171 family members. These findings uncover a unique mechanism of positive post-transcriptional regulation of gene expression by miRNAs and demonstrate its relevance for the establishment of AM symbiosis.
authors.affiliation: Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 24 chemin de Borde Rouge, Auzeville, BP42617, 31326 Castanet Tolosan, France.
authors.forename: Jean-Malo
authors.initials: JM
authors.lastname: Couzigou
authors.affiliation: Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 24 chemin de Borde Rouge, Auzeville, BP42617, 31326 Castanet Tolosan, France.
authors.forename: Dominique
authors.initials: D
authors.lastname: Lauressergues
authors.affiliation: Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 24 chemin de Borde Rouge, Auzeville, BP42617, 31326 Castanet Tolosan, France; Toulouse Tech Transfer, Maison de la Recherche et de la Valorisation, 118 route de Narbonne, 31432 Toulouse, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: André
authors.affiliation: Faculty of Biology, Genetics, Ludwig Maximilians University Munich, Großhaderner Straße 2-4, 82152 Martinsried, Germany.
authors.forename: Caroline
authors.initials: C
authors.lastname: Gutjahr
authors.affiliation: Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 24 chemin de Borde Rouge, Auzeville, BP42617, 31326 Castanet Tolosan, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Guillotin
authors.affiliation: Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 24 chemin de Borde Rouge, Auzeville, BP42617, 31326 Castanet Tolosan, France.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Bécard
authors.affiliation: Laboratoire de Recherche en Sciences Végétales, Université de Toulouse, CNRS, UPS, 24 chemin de Borde Rouge, Auzeville, BP42617, 31326 Castanet Tolosan, France. Electronic address: combier@lrsv.ups-tlse.fr.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Combier
mesh_terms: D001483:Base Sequence; D018506:Gene Expression Regulation, Plant; D055137:Glomeromycota / Q000254:growth & development*; D046913:Medicago truncatula / Q000235:genetics* / Q000382:microbiology*; D035683:MicroRNAs / Q000235:genetics*; D038821:Mycorrhizae / Q000254:growth & development*; D018517:Plant Roots / Q000382:microbiology; D013559:Symbiosis / Q000502:physiology; D014026:Nicotiana / Q000235:genetics* / Q000382:microbiology*
chemical_list: D035683:MicroRNAs
keywords: arbuscular mycorrhiza; miPEP; protective microRNA