Phytochrome control of flowering is temperature sensitive and correlates with expression of the floral integrator FT

Plant J. 2003 Mar;33(5):875-85. doi: 10.1046/j.1365-313x.2003.01674.x.


In Arabidopsis flowering is accelerated by reduced red:far-red (R:FR) ratio which signals the presence of neighbouring vegetation. Hastened flowering is one component of the shade-avoidance syndrome of responses, which alter many aspects of development in response to the threat of potential competition. Of the red/far-red-absorbing photoreceptors it is phyB that plays the most prominent role in shade-avoidance, although other related phytochromes act redundantly with phyB. It is well established that the phyB mutant has a constitutively early flowering phenotype. However, we have shown that the early flowering phenotype of phyB is temperature-dependent. We have established that this temperature-sensitive flowering response defines a pathway that appears to be independent of the autonomous-FLC pathway. Furthermore, we have demonstrated that the phytochromes control the expression of the floral promoter FT. We have also shown that other phyB-controlled responses, including petiole elongation, are not sensitive to the same temperature change. This suggests that discrete pathways control flowering and petiole elongation, components of the shade-avoidance response. This work provides an insight into the phytochrome and temperature interactions that maintain flowering control.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoproteins / genetics
  • Apoproteins / metabolism
  • Arabidopsis / genetics*
  • Arabidopsis / metabolism*
  • Arabidopsis Proteins / genetics*
  • Arabidopsis Proteins / metabolism*
  • Flowers / genetics
  • Flowers / metabolism*
  • Gene Expression Regulation, Plant*
  • Light
  • Mutation
  • Phenotype
  • Photoreceptor Cells*
  • Phytochrome / genetics
  • Phytochrome / metabolism*
  • Phytochrome B
  • Signal Transduction
  • Temperature*
  • Time Factors
  • Transcription Factors*


  • Apoproteins
  • Arabidopsis Proteins
  • FT protein, Arabidopsis
  • PHYB protein, Arabidopsis
  • Transcription Factors
  • Phytochrome
  • Phytochrome B
  • PHYD protein, Arabidopsis