Expression profiling of cytokinin action in Arabidopsis

Plant Physiol. 2003 Aug;132(4):1998-2011. doi: 10.1104/pp.103.021436.


The phytohormone cytokinin is an important regulator of plant growth and development; however, relatively few genes that mediate cytokinin responses have been identified. Genome-wide analyses of Arabidopsis seedlings using the approximately 8,300-element Affymetrix Arabidopsis GeneChips (Affymetrix, Santa Clara, CA) to examine cytokinin-responsive genes were conducted, revealing at least 30 genes whose steady-state level of mRNA was elevated and at least 40 that were down-regulated at multiple time points after application of cytokinin. The cytokinin up-regulated genes include the type-A Arabidopsis response regulators (ARRs), which had been shown previously to be cytokinin primary response genes, cytokinin oxidase, which encodes an enzyme that degrades cytokinins, and several transcription factors. Cytokinin down-regulated genes include several peroxidases and kinases and an E3 ubiquitin ligase. We identified a common sequence motif enriched in the upstream regions of the most consistently cytokinin up-regulated genes. This motif is highly similar to the optimal DNA-binding sites for ARR1/ARR2, type-B ARRs that have been implicated in the transcriptional elevation of the type-A ARRs. Additionally, genome-wide analyses of cytokinin receptor mutants (wol/cre1) revealed large-scale changes in gene expression, including down-regulation of the type-A ARRs and several meristem and cell cycle genes, such as CycD3. Mutations in CRE1 reduced but did not eliminate the effect of cytokinin on gene expression for a subset of cytokinin-responsive genes and had little or no effect on others, suggesting functional redundancy among the cytokinin receptors.

Publication types

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

MeSH terms

  • Arabidopsis / genetics*
  • Arabidopsis Proteins / biosynthesis
  • Arabidopsis Proteins / genetics
  • Cytokinins / pharmacology*
  • Gene Expression Profiling*
  • Gene Expression Regulation, Plant / drug effects*
  • Genes, Plant / genetics
  • Mutation / genetics
  • Protein Kinases / genetics
  • Receptors, Cell Surface / genetics


  • Arabidopsis Proteins
  • Cytokinins
  • Receptors, Cell Surface
  • Protein Kinases
  • WOL protein, Arabidopsis