SCARECROW and SHORTROOT control the auxin/cytokinin balance necessary for embryonic stem cell niche specification

Plant Signal Behav. 2018;13(8):e1507402. doi: 10.1080/15592324.2018.1507402. Epub 2018 Aug 20.

Abstract

The root apical meristem is established during embryogenesis, when its organizer, the quiescent center, is specified and the stem cell niche is positioned. The SCARECROW-SHORTROOT heterodimer is essential for quiescent center specification and maintenance. As continuous post-embryonic root growth relies upon the SCARECROW-mediated control of the cytokinin/auxin balance, we investigated the role of SCARECROW and SHORTROOT in controlling cytokinin signaling during embryonic quiescent center specification. We found that from embryogenesis onward both SCARECROW and SHORTROOT antagonize cytokinin signaling, thus repressing the expression of the auxin biosynthetic enzyme ANTRANILATHE SYNTHASE BETA 1. This mechanism prevents detrimental and premature high auxin levels in the QC allowing the establishment of a functional embryonic root pole.

Keywords: QC specification; SCARECROW; SHORTROOT; auxin; cytokinin; embryogenesis; stem cell niche.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Arabidopsis / genetics
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics
  • Arabidopsis Proteins / metabolism*
  • Cytokinins / metabolism*
  • Gene Expression Regulation, Plant
  • Indoleacetic Acids / metabolism*
  • Stem Cell Niche / physiology*
  • Transcription Factors / genetics
  • Transcription Factors / metabolism*

Substances

  • Arabidopsis Proteins
  • Cytokinins
  • Indoleacetic Acids
  • SCR protein, Arabidopsis
  • Transcription Factors

Grants and funding

This work was supported by the European Research Council [Grant 260368];Ministero dell’Istruzione, dell’Università e della Ricerca;