title: Endosperm and Nucellus Develop Antagonistically in Arabidopsis Seeds.
abstract: In angiosperms, seed architecture is shaped by the coordinated development of three genetically different components: embryo, endosperm, and maternal tissues. The relative contribution of these tissues to seed mass and nutrient storage varies considerably among species. The development of embryo, endosperm, or nucellus maternal tissue as primary storage compartments defines three main typologies of seed architecture. It is still debated whether the ancestral angiosperm seed accumulated nutrients in the endosperm or the nucellus. During evolution, plants shifted repeatedly between these two storage strategies through molecular mechanisms that are largely unknown. Here, we characterize the regulatory pathway underlying nucellus and endosperm tissue partitioning in Arabidopsis thaliana We show that Polycomb-group proteins repress nucellus degeneration before fertilization. A signal initiated in the endosperm by the AGAMOUS-LIKE62 MADS box transcription factor relieves this Polycomb-mediated repression and therefore allows nucellus degeneration. Further downstream in the pathway, the TRANSPARENT TESTA16 (TT16) and GORDITA MADS box transcription factors promote nucellus degeneration. Moreover, we demonstrate that TT16 mediates the crosstalk between nucellus and seed coat maternal tissues. Finally, we characterize the nucellus cell death program and its feedback role in timing endosperm development. Altogether, our data reveal the antagonistic development of nucellus and endosperm, in coordination with seed coat differentiation.
authors.affiliation: Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, University of Paris-Saclay, 78026 Versailles Cedex, France.
authors.forename: Wenjia
authors.initials: W
authors.lastname: Xu
authors.affiliation: Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, University of Paris-Saclay, 78026 Versailles Cedex, France.
authors.forename: Elisa
authors.identifier: 0000-0001-6788-0231
authors.initials: E
authors.lastname: Fiume
authors.affiliation: Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, University of Paris-Saclay, 78026 Versailles Cedex, France Ecole Doctorale 145 Sciences du Végétal, University Paris-Sud, University of Paris-Saclay, 91405 Orsay Cedex, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Coen
authors.affiliation: INRA, Génétique Animale et Biologie Intégrative, Domaine de Vilvert, 78352 Jouy-en-Josas Cedex, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Pechoux
authors.affiliation: Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, University of Paris-Saclay, 78026 Versailles Cedex, France.
authors.forename: Loïc
authors.identifier: 0000-0002-5845-3323
authors.initials: L
authors.lastname: Lepiniec
authors.affiliation: Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, University of Paris-Saclay, 78026 Versailles Cedex, France enrico.magnani@versailles.inra.fr.
authors.forename: Enrico
authors.initials: E
authors.lastname: Magnani
mesh_terms: D017360:Arabidopsis / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D056625:Endosperm / Q000196:embryology / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism; D063146:Polycomb-Group Proteins / Q000235:genetics / Q000378:metabolism; D012639:Seeds / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; D026161:MADS Domain Proteins; D063146:Polycomb-Group Proteins; C470417:TT16 protein, Arabidopsis; D014157:Transcription Factors