Regulation of plant stem cell quiescence by a brassinosteroid signaling module

Dev Cell. 2014 Jul 14;30(1):36-47. doi: 10.1016/j.devcel.2014.05.020. Epub 2014 Jun 26.

Abstract

The quiescent center (QC) maintains the activity of the surrounding stem cells within the root stem cell niche, yet specific molecular players sustaining the low rate of QC cell division remain poorly understood. Here, we identified a R2R3-MYB transcription factor, BRAVO (BRASSINOSTEROIDS AT VASCULAR AND ORGANIZING CENTER), acting as a cell-specific repressor of QC divisions in the primary root of Arabidopsis. Ectopic BRAVO expression restricts overall root growth and ceases root regeneration upon damage of the stem cells, demonstrating the role of BRAVO in counteracting Brassinosteroid (BR)-mediated cell division in the QC cells. Interestingly, BR-regulated transcription factor BES1 (BRI1-EMS SUPRESSOR 1) directly represses and physically interacts with BRAVO in vivo, creating a switch that modulates QC divisions at the root stem cell niche. Together, our results define a mechanism for BR-mediated regulation of stem cell quiescence in plants.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Arabidopsis / drug effects
  • Arabidopsis / growth & development*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Biomarkers / metabolism
  • Blotting, Western
  • Brassinosteroids / pharmacology*
  • Cell Division
  • Cell Proliferation
  • Chromatin Immunoprecipitation
  • Enzyme-Linked Immunosorbent Assay
  • Gene Expression Profiling
  • Gene Expression Regulation, Plant
  • Immunoprecipitation
  • Models, Theoretical
  • Mutation / genetics
  • Oligonucleotide Array Sequence Analysis
  • Plant Growth Regulators / pharmacology
  • Plant Roots / cytology
  • Plant Roots / drug effects
  • Plant Roots / metabolism
  • Plants, Genetically Modified / drug effects
  • Plants, Genetically Modified / growth & development
  • Plants, Genetically Modified / metabolism
  • RNA, Messenger / genetics
  • Real-Time Polymerase Chain Reaction
  • Reverse Transcriptase Polymerase Chain Reaction
  • Signal Transduction / drug effects*
  • Stem Cell Niche / drug effects*
  • Stem Cells / cytology*
  • Stem Cells / drug effects
  • Stem Cells / metabolism

Substances

  • Arabidopsis Proteins
  • Biomarkers
  • Brassinosteroids
  • Plant Growth Regulators
  • RNA, Messenger