title: Live and let die: a REM complex promotes fertilization through synergid cell death in Arabidopsis.
abstract: Fertilization in flowering plants requires a complex series of coordinated events involving interaction between the male and female gametophyte. We report here molecular data on one of the key events underpinning this process - the death of the receptive synergid cell and the coincident bursting of the pollen tube inside the ovule to release the sperm. We show that two REM transcription factors, VALKYRIE (VAL) and VERDANDI (VDD), both targets of the ovule identity MADS-box complex SEEDSTICK-SEPALLATA3, interact to control the death of the receptive synergid cell. In vdd-1/+ mutants and VAL_RNAi lines, we find that GAMETOPHYTIC FACTOR 2 (GFA2), which is required for synergid degeneration, is downregulated, whereas expression of FERONIA (FER) and MYB98, which are necessary for pollen tube attraction and perception, remain unaffected. We also demonstrate that the vdd-1/+ phenotype can be rescued by expressing VDD or GFA2 in the synergid cells. Taken together, our findings reveal that the death of the receptive synergid cell is essential for maintenance of the following generations, and that a complex comprising VDD and VAL regulates this event.
authors.affiliation: Dipartimento di BioScienze, Università degli Studi di Milano, Milan 20133, Italy Departamento de Biologia, Faculdade de Ciências, Universidade do Porto, 4169-007 Porto, Portugal.
authors.forename: Marta Adelina
authors.initials: MA
authors.lastname: Mendes
authors.affiliation: Dipartimento di BioScienze, Università degli Studi di Milano, Milan 20133, Italy.
authors.forename: Rosalinda Fiorella
authors.initials: RF
authors.lastname: Guerra
authors.affiliation: Dipartimento di BioScienze, Università degli Studi di Milano, Milan 20133, Italy.
authors.forename: Beatrice
authors.initials: B
authors.lastname: Castelnovo
authors.affiliation: Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK.
authors.forename: Yuriria
authors.initials: Y
authors.lastname: Silva-Velazquez
authors.affiliation: Dipartimento di BioScienze, Università degli Studi di Milano, Milan 20133, Italy.
authors.forename: Piero
authors.initials: P
authors.lastname: Morandini
authors.affiliation: Dipartimento di BioScienze, Università degli Studi di Milano, Milan 20133, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Manrique
authors.affiliation: Center for Plant Molecular Biology (ZMBP), University of Tübingen, 72076 Tübingen, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Baumann
authors.affiliation: Center for Plant Molecular Biology (ZMBP), University of Tübingen, 72076 Tübingen, Germany Center for Biomolecular Interactions Bremen, University of Bremen, Leobener Straße NW2, 28359 Bremen, Germany.
authors.forename: Rita
authors.initials: R
authors.lastname: Groß-Hardt
authors.affiliation: Department of Plant Sciences, University of Oxford, South Parks Road, Oxford OX1 3RB, UK.
authors.forename: Hugh
authors.initials: H
authors.lastname: Dickinson
authors.affiliation: Dipartimento di BioScienze, Università degli Studi di Milano, Milan 20133, Italy lucia.colombo@unimi.it.
authors.forename: Lucia
authors.identifier: 0000-0001-8415-1399
authors.initials: L
authors.lastname: Colombo
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D018506:Gene Expression Regulation, Plant / Q000235:genetics / Q000502:physiology; D055993:Germ Cells, Plant / Q000378:metabolism; D053205:Pollen Tube / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C510497:MYB98 protein, Arabidopsis; D014157:Transcription Factors
keywords: Cell death; Fertilization; MADS box; Pollen tube; REM; Receptive synergid cell