title: Nod factors potentiate auxin signaling for transcriptional regulation and lateral root formation in Medicago truncatula.
abstract: Nodulation (Nod) factors (NFs) are symbiotic molecules produced by rhizobia that are essential for establishment of the rhizobium-legume endosymbiosis. Purified NFs can stimulate lateral root formation (LRF) in Medicago truncatula, but little is known about the molecular mechanisms involved. Using a combination of reporter constructs, pharmacological and genetic approaches, we show that NFs act on early steps of LRF in M. truncatula, independently of the ethylene signaling pathway and of the cytokinin receptor MtCRE1, but in interaction with auxin. We conducted a whole-genome transcriptomic study upon NF and/or auxin treatments, using a lateral root inducible system adapted for M. truncatula. This revealed a large overlap between NF and auxin signaling and, more interestingly, synergistic interactions between these molecules. Three groups showing interaction effects were defined: group 1 contained more than 1500 genes responding specifically to the combinatorial treatment of NFs and auxin; group 2 comprised auxin-regulated genes whose expression was enhanced or antagonized by NFs; and in group 3 the expression of NF regulated genes was antagonized by auxin. Groups 1 and 2 were enriched in signaling and metabolic functions, which highlights important crosstalk between NF and auxin signaling for both developmental and symbiotic processes.
authors.affiliation: LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France.
authors.forename: Violaine
authors.initials: V
authors.lastname: Herrbach
authors.affiliation: LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France.
authors.forename: Ximena
authors.initials: X
authors.lastname: Chirinos
authors.affiliation: LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France.
authors.forename: David
authors.initials: D
authors.lastname: Rengel
authors.affiliation: LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France.
authors.forename: Kokoévi
authors.initials: K
authors.lastname: Agbevenou
authors.affiliation: LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France.
authors.forename: Rémy
authors.initials: R
authors.lastname: Vincent
authors.affiliation: POPS (transcriptOmic Platform of IPS2) Platform, Institute of Plant Sciences Paris Saclay (IPS2), CNRS, INRA, Université Paris-Sud, Université Evry, Université Paris-Saclay, Orsay, France.|Institute of Plant Sciences Paris-Saclay IPS2, Paris Diderot, Sorbonne Paris-Cité, Orsay, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Pateyron
authors.affiliation: POPS (transcriptOmic Platform of IPS2) Platform, Institute of Plant Sciences Paris Saclay (IPS2), CNRS, INRA, Université Paris-Sud, Université Evry, Université Paris-Saclay, Orsay, France.|Institute of Plant Sciences Paris-Saclay IPS2, Paris Diderot, Sorbonne Paris-Cité, Orsay, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Huguet
authors.affiliation: POPS (transcriptOmic Platform of IPS2) Platform, Institute of Plant Sciences Paris Saclay (IPS2), CNRS, INRA, Université Paris-Sud, Université Evry, Université Paris-Saclay, Orsay, France.|Institute of Plant Sciences Paris-Saclay IPS2, Paris Diderot, Sorbonne Paris-Cité, Orsay, France.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Balzergue
authors.affiliation: Department of Cell & Systems Biology/ Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Canada.
authors.forename: Asher
authors.initials: A
authors.lastname: Pasha
authors.affiliation: Department of Cell & Systems Biology/ Centre for the Analysis of Genome Evolution and Function, University of Toronto, Toronto, Canada.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Provart
authors.affiliation: LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France.
authors.forename: Clare
authors.initials: C
authors.lastname: Gough
authors.affiliation: LIPM, Université de Toulouse, INRA, CNRS, Castanet-Tolosan, France.
authors.forename: Sandra
authors.initials: S
authors.lastname: Bensmihen
mesh_terms: D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000502:physiology*; D046913:Medicago truncatula / Q000235:genetics / Q000254:growth & development / Q000382:microbiology / Q000502:physiology*; D010937:Plant Growth Regulators / Q000378:metabolism*; D018517:Plant Roots / Q000235:genetics / Q000254:growth & development / Q000382:microbiology; D016962:Sinorhizobium meliloti / Q000502:physiology*
chemical_list: D007210:Indoleacetic Acids; D008070:Lipopolysaccharides; D010937:Plant Growth Regulators
keywords: Auxin; NimbleGen arrays; Nod factors; ethylene; lateral root; lateral root inducible system (LRIS); lipo-chitooligosaccharides (LCOs); symbiosis; transcriptome