title: Differential regulation of meristem size, morphology and organization by the ERECTA, CLAVATA and class III HD-ZIP pathways.
abstract: The shoot apical meristem (SAM) of angiosperm plants is a small, highly organized structure that gives rise to all above-ground organs. The SAM is divided into three functional domains: the central zone (CZ) at the SAM tip harbors the self-renewing pluripotent stem cells and the organizing center, providing daughter cells that are continuously displaced into the interior rib zone (RZ) or the surrounding peripheral zone (PZ), from which organ primordia are initiated. Despite the constant flow of cells from the CZ into the RZ or PZ, and cell recruitment for primordium formation, a stable balance is maintained between the distinct cell populations in the SAM. Here we combined an in-depth phenotypic analysis with a comparative RNA-Seq approach to characterize meristems from selected combinations of clavata3 (clv3), jabba-1D (jba-1D) and erecta (er) mutants of Arabidopsis thaliana We demonstrate that CLV3 restricts meristem expansion along the apical-basal axis, whereas class III HD-ZIP and ER pathways restrict meristem expansion laterally, but in distinct and possibly perpendicular orientations. Our k-means analysis reveals that clv3, jba-1D/+ and er lead to meristem enlargement by affecting different aspects of meristem function; for example, clv3 displays an increase in the stem cell population, whereas jba-1D/+ er exhibits an increase in mitotic activity and in the meristematic cell population. Our analyses demonstrate that a combined genetic and mRNA-Seq comparative approach provides a precise and sensitive method to identify cell type-specific transcriptomes in a small structure, such as the SAM.
authors.affiliation: The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 76100, Israel.
authors.forename: Tali
authors.initials: T
authors.lastname: Mandel
authors.affiliation: Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, Elche 03202, Spain.
authors.forename: Héctor
authors.initials: H
authors.lastname: Candela
authors.affiliation: The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 76100, Israel.
authors.forename: Udi
authors.initials: U
authors.lastname: Landau
authors.affiliation: The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 76100, Israel.
authors.forename: Lior
authors.initials: L
authors.lastname: Asis
authors.affiliation: The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 76100, Israel.
authors.forename: Einat
authors.initials: E
authors.lastname: Zelinger
authors.affiliation: Université Grenoble Alpes, Laboratoire de Physiologie Cellulaire et Végétale (LPCV), Grenoble F-38054, France CNRS, LPCV, UMR 5168, Grenoble F-38054, France CEA, Direction des Sciences du Vivant, BIG, LPCV, Grenoble F-38054, France INRA, LPCV, Grenoble F-38054, France.
authors.forename: Cristel C
authors.initials: CC
authors.lastname: Carles
authors.affiliation: The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, POB 12, Rehovot 76100, Israel leor.williams@mail.huji.ac.il.
authors.forename: Leor Eshed
authors.initials: LE
authors.lastname: Williams
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins / Q000235:genetics*; D002454:Cell Differentiation; D049109:Cell Proliferation; D018506:Gene Expression Regulation, Plant; D018398:Homeodomain Proteins / Q000235:genetics*; D018519:Meristem / Q000166:cytology / Q000254:growth & development*; D035683:MicroRNAs / Q000235:genetics; D030821:Plants, Genetically Modified; D017346:Protein Serine-Threonine Kinases / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D011956:Receptors, Cell Surface / Q000235:genetics*; D015398:Signal Transduction / Q000502:physiology
chemical_list: C118167:AT2G27250 protein, Arabidopsis; D029681:Arabidopsis Proteins; C493946:HD-Zip protein, Arabidopsis; D018398:Homeodomain Proteins; C580969:MIRN166 microRNA, Arabidopsis; D035683:MicroRNAs; D012333:RNA, Messenger; D011956:Receptors, Cell Surface; C457763:ER protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases
keywords: MIR166; Organizing center; Phyllotaxis; Stem cells; WUSCHEL