Brassinosteroid signaling and auxin transport are required to establish the periodic pattern of Arabidopsis shoot vascular bundles

Proc Natl Acad Sci U S A. 2009 Aug 11;106(32):13630-5. doi: 10.1073/pnas.0906416106. Epub 2009 Jul 28.


The plant vascular system provides transport and support capabilities that are essential for plant growth and development, yet the mechanisms directing the arrangement of vascular bundles within the shoot inflorescence stem remain unknown. We used computational and experimental biology to evaluate the role of auxin and brassinosteroid hormones in vascular patterning in Arabidopsis. We show that periodic auxin maxima controlled by polar transport and not overall auxin levels underlie vascular bundle spacing, whereas brassinosteroids modulate bundle number by promoting early procambial divisions. Overall, this study demonstrates that auxin polar transport coupled to brassinosteroid signaling is required to determine the radial pattern of vascular bundles in shoots.

Publication types

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

MeSH terms

  • Arabidopsis / cytology
  • Arabidopsis / growth & development*
  • Arabidopsis / metabolism*
  • Biological Transport
  • Brassinosteroids
  • Cell Count
  • Cholestanols / metabolism*
  • Indoleacetic Acids / metabolism*
  • Models, Biological
  • Mutation / genetics
  • Plant Shoots / cytology
  • Plant Shoots / growth & development*
  • Plant Shoots / metabolism
  • Signal Transduction*
  • Steroids, Heterocyclic / metabolism*


  • Brassinosteroids
  • Cholestanols
  • Indoleacetic Acids
  • Steroids, Heterocyclic
  • brassinolide