Genetic interactions between phytochrome A, phytochrome B, and cryptochrome 1 during Arabidopsis development

Plant Physiol. 1998 Sep;118(1):27-35. doi: 10.1104/pp.118.1.27.


Single, double, and triple null combinations of Arabidopsis mutants lacking the photoreceptors phytochrome (phy) A (phyA-201), phyB (phyB-5), and cryptochrome (cry) 1 (hy4-2.23n) were examined for de-etiolation responses in high-fluence red, far-red, blue, and broad-spectrum white light. Cotyledon unhooking, unfolding, and expansion, hypocotyl growth, and the accumulation of chlorophylls and anthocyanin in 5-d-old seedlings were measured under each light condition and in the dark. phyA was the major photoreceptor/effector for most far-red-light responses, although phyB and cry1 modulated anthocyanin accumulation in a phyA-dependent manner. phyB was the major photoreceptor in red light, although cry1 acted as a phyA/phyB-dependent modulator of chlorophyll accumulation under these conditions. All three photoreceptors contributed to most blue light deetiolation responses, either redundantly or additively; however, phyB acted as a modulator of cotyledon expansion dependent on the presence of cry1. As reported previously, flowering time in long days was promoted by phyA and inhibited by phyB, with each suppressing the other's effect. In addition to the effector/modulator relationships described above, measurements of hypocotyls from blue-light-grown seedlings demonstrated phytochrome activity in blue light and cry1 activity in a phyAphyB mutant background.

Publication types

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

MeSH terms

  • Arabidopsis / genetics*
  • Arabidopsis / growth & development
  • Arabidopsis / radiation effects
  • Arabidopsis Proteins
  • Base Sequence
  • Cryptochromes
  • DNA Primers / genetics
  • Drosophila Proteins*
  • Eye Proteins*
  • Flavoproteins / genetics*
  • Flavoproteins / physiology
  • Flavoproteins / radiation effects
  • Genes, Plant*
  • Light
  • Light-Harvesting Protein Complexes
  • Mutation
  • Phenotype
  • Photobiology
  • Photoreceptor Cells*
  • Photoreceptor Cells, Invertebrate*
  • Photosynthetic Reaction Center Complex Proteins / genetics
  • Photosynthetic Reaction Center Complex Proteins / metabolism
  • Photosynthetic Reaction Center Complex Proteins / radiation effects
  • Phytochrome / genetics*
  • Phytochrome / physiology
  • Phytochrome / radiation effects
  • Phytochrome A
  • Phytochrome B
  • Plant Proteins / genetics*
  • Plant Proteins / physiology
  • Plant Proteins / radiation effects
  • Polymerase Chain Reaction
  • Receptors, G-Protein-Coupled
  • Transcription Factors*


  • Arabidopsis Proteins
  • CRY1 protein, Arabidopsis
  • Cryptochromes
  • DNA Primers
  • Drosophila Proteins
  • Eye Proteins
  • Flavoproteins
  • Light-Harvesting Protein Complexes
  • PHYA protein, Arabidopsis
  • PHYB protein, Arabidopsis
  • Photosynthetic Reaction Center Complex Proteins
  • Phytochrome A
  • Plant Proteins
  • Receptors, G-Protein-Coupled
  • Transcription Factors
  • cry protein, Drosophila
  • Phytochrome
  • Phytochrome B