The 14-3-3 Proteins mu and upsilon influence transition to flowering and early phytochrome response

Plant Physiol. 2007 Dec;145(4):1692-702. doi: 10.1104/pp.107.108654. Epub 2007 Oct 19.


14-3-3 proteins regulate a diverse set of biological responses but developmental phenotypes associated with 14-3-3 mutations have not been described in plants. Here, physiological and biochemical tests demonstrate interactions between 14-3-3s and the well-established mechanisms that govern light sensing and photoperiodic flowering control. Plants featuring homozygous disruption of 14-3-3 isoforms upsilon and mu display defects in light sensing and/or response. Mutant plants flower late and exhibit long hypocotyls under red light, with little effect under blue or far-red light. The long hypocotyl phenotype is consistent with a role for 14-3-3 upsilon and mu in phytochrome B signaling. Yeast two-hybrid and coimmunoprecipitation assays indicate that 14-3-3 upsilon and mu proteins physically interact with CONSTANS, a central regulator of the photoperiod pathway. Together, these data indicate a potential role for specific 14-3-3 isoforms in affecting photoperiodic flowering via interaction with CONSTANS, possibly as integrators of light signals sensed through the phytochrome system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 14-3-3 Proteins / metabolism
  • 14-3-3 Proteins / physiology*
  • Arabidopsis / growth & development*
  • Arabidopsis / metabolism
  • Arabidopsis Proteins / metabolism
  • Biological Clocks / physiology
  • Color
  • DNA-Binding Proteins / metabolism
  • Flowers / growth & development*
  • Hypocotyl / growth & development
  • Mutagenesis, Insertional
  • Phenotype
  • Photoperiod*
  • Phytochrome / physiology*
  • Signal Transduction / physiology
  • Transcription Factors / metabolism
  • Two-Hybrid System Techniques


  • 14-3-3 Proteins
  • Arabidopsis Proteins
  • CONSTANS protein, Arabidopsis
  • DNA-Binding Proteins
  • Transcription Factors
  • Phytochrome