title: The NIN Transcription Factor Coordinates Diverse Nodulation Programs in Different Tissues of the Medicago truncatula Root.
abstract: Biological nitrogen fixation in legumes occurs in nodules that are initiated in the root cortex following Nod factor recognition at the root surface, and this requires coordination of diverse developmental programs in these different tissues. We show that while early Nod factor signaling associated with calcium oscillations is limited to the root surface, the resultant activation of Nodule Inception (NIN) in the root epidermis is sufficient to promote cytokinin signaling and nodule organogenesis in the inner root cortex. NIN or a product of its action must be associated with the transmission of a signal between the root surface and the cortical cells where nodule organogenesis is initiated. NIN appears to have distinct functions in the root epidermis and the root cortex. In the epidermis, NIN restricts the extent of Early Nodulin 11 (ENOD11) expression and does so through competitive inhibition of ERF Required for Nodulation (ERN1). In contrast, NIN is sufficient to promote the expression of the cytokinin receptor Cytokinin Response 1 (CRE1), which is restricted to the root cortex. Our work in Medicago truncatula highlights the complexity of NIN action and places NIN as a central player in the coordination of the symbiotic developmental programs occurring in differing tissues of the root that combined are necessary for a nitrogen-fixing symbiosis.
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: Tatiana
authors.identifier: http://orcid.org/0000-0003-1387-6370
authors.initials: T
authors.lastname: Vernié
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: Jiyoung
authors.initials: J
authors.lastname: Kim
authors.affiliation: Laboratoire des Interactions Plantes Microorganismes, CNRS-INRA 2594/441, F-31320 Castanet Tolosan, France.
authors.forename: Lisa
authors.initials: L
authors.lastname: Frances
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: Yiliang
authors.initials: Y
authors.lastname: Ding
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: Jongho
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom.
authors.forename: Dian
authors.initials: D
authors.lastname: Guan
authors.affiliation: Laboratoire des Interactions Plantes Microorganismes, CNRS-INRA 2594/441, F-31320 Castanet Tolosan, France.
authors.forename: Andreas
authors.identifier: http://orcid.org/0000-0002-3402-8381
authors.initials: A
authors.lastname: Niebel
authors.affiliation: School of Life Sciences, University of Warwick, Coventry CV4 7AL, United Kingdom.
authors.forename: Miriam L
authors.identifier: http://orcid.org/0000-0002-4005-2513
authors.initials: ML
authors.lastname: Gifford
authors.affiliation: Laboratoire des Interactions Plantes Microorganismes, CNRS-INRA 2594/441, F-31320 Castanet Tolosan, France.
authors.forename: Fernanda
authors.initials: F
authors.lastname: de Carvalho-Niebel
authors.affiliation: Department of Cell and Developmental Biology, John Innes Centre, Norwich NR4 7UH, United Kingdom giles.oldroyd@jic.ac.uk.
authors.forename: Giles E D
authors.initials: GE
authors.lastname: Oldroyd
mesh_terms: D002118:Calcium / Q000378:metabolism; D003583:Cytokinins / Q000378:metabolism; D018506:Gene Expression Regulation, Plant; D017930:Genes, Reporter; D046913:Medicago truncatula / Q000166:cytology / Q000235:genetics* / Q000502:physiology; D009586:Nitrogen Fixation; D010937:Plant Growth Regulators / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D055170:Plant Root Nodulation; D018517:Plant Roots / Q000166:cytology / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D030821:Plants, Genetically Modified; D053204:Root Nodules, Plant / Q000166:cytology / Q000235:genetics / Q000502:physiology; D015398:Signal Transduction; D016962:Sinorhizobium meliloti / Q000502:physiology*; D013559:Symbiosis; D014026:Nicotiana / Q000166:cytology / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D003583:Cytokinins; C438018:ENOD11 protein, Medicago truncatula; C403406:NIN protein, Lotus japonicus; D010937:Plant Growth Regulators; D010940:Plant Proteins; D014157:Transcription Factors; D002118:Calcium