GTL1 and DF1 regulate root hair growth through transcriptional repression of ROOT HAIR DEFECTIVE 6-LIKE 4 in Arabidopsis

Development. 2018 Feb 8;145(3):dev159707. doi: 10.1242/dev.159707.


How plants determine the final size of growing cells is an important, yet unresolved, issue. Root hairs provide an excellent model system with which to study this as their final cell size is remarkably constant under constant environmental conditions. Previous studies have demonstrated that a basic helix-loop helix transcription factor ROOT HAIR DEFECTIVE 6-LIKE 4 (RSL4) promotes root hair growth, but how hair growth is terminated is not known. In this study, we demonstrate that a trihelix transcription factor GT-2-LIKE1 (GTL1) and its homolog DF1 repress root hair growth in Arabidopsis Our transcriptional data, combined with genome-wide chromatin-binding data, show that GTL1 and DF1 directly bind the RSL4 promoter and regulate its expression to repress root hair growth. Our data further show that GTL1 and RSL4 regulate each other, as well as a set of common downstream genes, many of which have previously been implicated in root hair growth. This study therefore uncovers a core regulatory module that fine-tunes the extent of root hair growth by the orchestrated actions of opposing transcription factors.

Keywords: Cell growth; Gene regulatory network; Root hair; Trihelix transcription factor.

Publication types

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

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / growth & development*
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Basic Helix-Loop-Helix Transcription Factors / genetics
  • Basic Helix-Loop-Helix Transcription Factors / metabolism*
  • Gene Expression Regulation, Developmental
  • Gene Expression Regulation, Plant
  • Gene Regulatory Networks
  • Genes, Plant
  • Indoleacetic Acids / metabolism
  • Models, Biological
  • Mutation
  • Plant Growth Regulators / metabolism
  • Plant Roots / growth & development
  • Plant Roots / metabolism
  • Plants, Genetically Modified
  • Promoter Regions, Genetic
  • Signal Transduction
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transcription, Genetic


  • Arabidopsis Proteins
  • Basic Helix-Loop-Helix Transcription Factors
  • GT2L protein, Arabidopsis
  • Indoleacetic Acids
  • Plant Growth Regulators
  • RSL4 protein, Arabidopsis
  • Transcription Factors