title: A regulatory framework for shoot stem cell control integrating metabolic, transcriptional, and phytohormone signals.
abstract: Plants continuously maintain pluripotent stem cells embedded in specialized tissues called meristems, which drive long-term growth and organogenesis. Stem cell fate in the shoot apical meristem (SAM) is controlled by the homeodomain transcription factor WUSCHEL (WUS) expressed in the niche adjacent to the stem cells. Here, we demonstrate that the bHLH transcription factor HECATE1 (HEC1) is a target of WUS and that it contributes to SAM function by promoting stem cell proliferation, while antagonizing niche cell activity. HEC1 represses the stem cell regulators WUS and CLAVATA3 (CLV3) and, like WUS, controls genes with functions in metabolism and hormone signaling. Among the targets shared by HEC1 and WUS are phytohormone response regulators, which we show to act as mobile signals in a universal feedback system. Thus, our work sheds light on the mechanisms guiding meristem function and suggests that the underlying regulatory system is far more complex than previously anticipated.
authors.affiliation: Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schuster
authors.affiliation: Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany.
authors.forename: Christophe
authors.initials: C
authors.lastname: Gaillochet
authors.affiliation: Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Medzihradszky
authors.affiliation: Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Busch
authors.affiliation: Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany.
authors.forename: Gabor
authors.initials: G
authors.lastname: Daum
authors.affiliation: Department of Plant Developmental Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany.
authors.forename: Melanie
authors.initials: M
authors.lastname: Krebs
authors.affiliation: Max Planck Institute for Developmental Biology, 72076 Tübingen, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: Kehle
authors.affiliation: Department of Stem Cell Biology, Centre for Organismal Studies, Heidelberg University, 69120 Heidelberg, Germany. Electronic address: jlohmann@meristemania.org.
authors.forename: Jan U
authors.initials: JU
authors.lastname: Lohmann
mesh_terms: D017360:Arabidopsis / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D003583:Cytokinins / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000235:genetics; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D018519:Meristem / Q000235:genetics / Q000378:metabolism; D010937:Plant Growth Regulators / Q000235:genetics / Q000378:metabolism*; D018520:Plant Shoots / Q000235:genetics / Q000378:metabolism; D018547:Plant Stems / Q000235:genetics* / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics*; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: C118167:AT2G27250 protein, Arabidopsis; D029681:Arabidopsis Proteins; D003583:Cytokinins; C587998:HECATE1 protein, Arabidopsis; D018398:Homeodomain Proteins; D010937:Plant Growth Regulators; D014157:Transcription Factors; C116421:WUSCHEL protein, Arabidopsis