title: The auxin response factor MONOPTEROS controls meristem function and organogenesis in both the shoot and root through the direct regulation of PIN genes.
abstract: The regulatory effect auxin has on its own transport is critical in numerous self-organizing plant patterning processes. However, our understanding of the molecular mechanisms linking auxin signal transduction and auxin transport is still fragmentary, and important regulatory genes remain to be identified. To track a key link between auxin signaling and auxin transport in development, we established an Arabidopsis thaliana genetic background in which fundamental patterning processes in both shoot and root were essentially abolished and the expression of PIN FORMED (PIN) auxin efflux facilitators was dramatically reduced. In this background, we demonstrate that activating a steroid-inducible variant of the auxin response factor (ARF) MONOPTEROS (MP) is sufficient to restore patterning and PIN gene expression. Further, we show that MP binds to distinct promoter elements of multiple genetically defined PIN genes. Our work identifies a direct regulatory link between central, well-characterized genes involved in auxin signal transduction and auxin transport. The steroid-inducible MP system directly demonstrates the importance of this molecular link in multiple patterning events in embryos, shoots and roots, and provides novel options for interrogating the properties of self-regulated auxin-based patterning in planta.
authors.affiliation: Department of Biology, American University, 4400 Massachusetts Avenue NW, Washington, DC, 20016, USA.
authors.forename: Naden T
authors.initials: NT
authors.lastname: Krogan
authors.affiliation: Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, M5S 3B2, Canada.
authors.forename: Danielle
authors.initials: D
authors.lastname: Marcos
authors.affiliation: Department of Biology, American University, 4400 Massachusetts Avenue NW, Washington, DC, 20016, USA.
authors.forename: Aaron I
authors.initials: AI
authors.lastname: Weiner
authors.affiliation: Department of Cell and Systems Biology, University of Toronto, 25 Willcocks Street, Toronto, Ontario, M5S 3B2, Canada.
authors.forename: Thomas
authors.initials: T
authors.lastname: Berleth
mesh_terms: D017360:Arabidopsis / Q000235:genetics* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D001692:Biological Transport; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D007210:Indoleacetic Acids / Q000378:metabolism; D018519:Meristem / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D038081:Organogenesis / Q000235:genetics*; D018517:Plant Roots / Q000254:growth & development / Q000378:metabolism*; D018520:Plant Shoots / Q000254:growth & development / Q000378:metabolism*; D011485:Protein Binding / Q000235:genetics; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D004268:DNA-Binding Proteins; D007210:Indoleacetic Acids; C111371:MONOPTEROS protein, Arabidopsis; D014157:Transcription Factors
keywords: Arabidopsis development; PIN FORMED genes; auxin response factor (ARF); embryogenesis; organogenesis; root apical meristem; self-organized patterning; shoot apical meristem