Cell-by-cell dissection of phloem development links a maturation gradient to cell specialization

Science. 2021 Dec 24;374(6575):eaba5531. doi: 10.1126/science.aba5531. Epub 2021 Dec 24.


In the plant meristem, tissue-wide maturation gradients are coordinated with specialized cell networks to establish various developmental phases required for indeterminate growth. Here, we used single-cell transcriptomics to reconstruct the protophloem developmental trajectory from the birth of cell progenitors to terminal differentiation in the Arabidopsis thaliana root. PHLOEM EARLY DNA-BINDING-WITH-ONE-FINGER (PEAR) transcription factors mediate lineage bifurcation by activating guanosine triphosphatase signaling and prime a transcriptional differentiation program. This program is initially repressed by a meristem-wide gradient of PLETHORA transcription factors. Only the dissipation of PLETHORA gradient permits activation of the differentiation program that involves mutual inhibition of early versus late meristem regulators. Thus, for phloem development, broad maturation gradients interface with cell-type-specific transcriptional regulators to stage cellular differentiation.

Publication types

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

MeSH terms

  • Arabidopsis / cytology*
  • Arabidopsis / genetics
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Cell Differentiation
  • GTP-Binding Proteins / genetics
  • GTP-Binding Proteins / metabolism
  • Meristem / cytology
  • Phloem / cytology*
  • Phloem / genetics
  • Phloem / growth & development*
  • Phloem / metabolism
  • Plant Roots / cytology*
  • Plant Roots / genetics
  • Plant Roots / growth & development
  • Plant Roots / metabolism
  • RNA-Seq
  • Signal Transduction
  • Single-Cell Analysis
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*
  • Transcriptome


  • APL protein, Arabidopsis
  • AT2G37590 protein, Arabidopsis
  • Arabidopsis Proteins
  • Transcription Factors
  • GTP-Binding Proteins