STOP1 attenuates the auxin response to maintain root stem cell niche identity

Cell Rep. 2024 Jan 23;43(1):113617. doi: 10.1016/j.celrep.2023.113617. Epub 2023 Dec 26.

Abstract

In plant roots, the identity of the stem cell niche (SCN) is maintained by an auxin gradient with its maximum in the quiescent center (QC). Optimal levels of auxin signaling are essential for root SCN identity, but the regulatory mechanisms that control this pathway in root are largely unknown. Here, we find that the zinc finger transcription factor sensitive to proton rhizotoxicity 1 (STOP1) regulates root SCN identity by negative feedback of auxin signaling in root tips. Mutation and overexpression of STOP1 both affect QC cell division and distal stem cell differentiation in the root. We find that auxin treatment stabilizes STOP1 via MPK3/6-dependent phosphorylation. Accumulating STOP1 can compete with AUX/IAAs to interact with, and enhance the repressive activity of, auxin-repressive response factor ARF2. Overall, we show that the MPK3/6-STOP1-ARF2 module prevents excessive auxin signaling in the presence of auxin to maintain root SCN identity.

Keywords: ARF2; CP: Plants; MPK3/6; STOP1; auxin; root stem cell niche.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis Proteins* / genetics
  • Arabidopsis Proteins* / metabolism
  • Arabidopsis* / metabolism
  • Gene Expression Regulation, Plant
  • Indoleacetic Acids / metabolism
  • Indoleacetic Acids / pharmacology
  • Meristem / metabolism
  • Plant Roots
  • Stem Cell Niche
  • Transcription Factors / metabolism

Substances

  • Indoleacetic Acids
  • Arabidopsis Proteins
  • STOP1 protein, Arabidopsis
  • Transcription Factors