Functional analysis of yeast-derived phytochrome A and B phycocyanobilin adducts

Plant J. 1996 Oct;10(4):625-36. doi: 10.1046/j.1365-313x.1996.10040625.x.


Investigations of phytochrome mutants of Arabidopsis suggested that the expression of chalcone synthase (chs) and anthocyanin accumulation is predominantly controlled by phytochrome A. To test the functionality of phytochrome A and B at the molecular level recombinant, yeast-derived phytochrome-phycocyanobilin adducts (phyA, phyB) and oat phytochrome A (phyA) were microinjected into etiolated aurea tomato seedlings. Subsequent to microinjection anthocyanin and chlorophyll accumulation was monitored as well as beta-glucuronidase (GUS) expression mediated by light-regulated promoters (chs, chlorophyll a/b binding protein (lhcb1) and ferredoxin NADP+ oxidoreductase (fnn). Microinjection of phyA under white light conditions caused anthocyanin and chlorophyll accumulation and mediated chs-GUS, lhcb 1-GUS and fnr-GUS expression. Microinjection of phyB under identical conditions induced chlorophyll accumulation and mediated lhcb 1-GUS and fnr-GUS expression but neither anthocyanin accumulation nor chs-GUS expression were observed. The characterization of Arabidopsis phytochrome mutants and the microinjection experiments suggested that phyB cannot induce the accumulation of juvenile anthocyanin. Microinjections under far-red light conditions demonstrated that phyA can act independently of other photoreceptors. By contrast, phyB injections under red light conditions indicated that phyB needs interactions with other photoreceptors to mediate a rapid and efficient de-etiolation signal.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acyltransferases / biosynthesis
  • Anthocyanins / biosynthesis*
  • Apoproteins / genetics
  • Apoproteins / metabolism
  • Arabidopsis / metabolism
  • Arabidopsis / radiation effects
  • Arabidopsis Proteins
  • Avena
  • Light-Harvesting Protein Complexes
  • Lycopersicon esculentum / genetics
  • Lycopersicon esculentum / metabolism
  • Microinjections
  • Oryza
  • Photoreceptor Cells*
  • Photosynthetic Reaction Center Complex Proteins / biosynthesis
  • Phycobilins
  • Phycocyanin / metabolism
  • Phytochrome / genetics
  • Phytochrome / metabolism*
  • Phytochrome A
  • Phytochrome B
  • Plant Proteins / biosynthesis*
  • Plants / metabolism
  • Plants / radiation effects*
  • Pyrroles / metabolism
  • Recombinant Proteins / metabolism
  • Tetrapyrroles
  • Transcription Factors*
  • Yeasts / genetics


  • Anthocyanins
  • Apoproteins
  • Arabidopsis Proteins
  • Light-Harvesting Protein Complexes
  • PHYA protein, Arabidopsis
  • PHYB protein, Arabidopsis
  • Photosynthetic Reaction Center Complex Proteins
  • Phycobilins
  • Phytochrome A
  • Plant Proteins
  • Pyrroles
  • Recombinant Proteins
  • Tetrapyrroles
  • Transcription Factors
  • Phycocyanin
  • Phytochrome
  • Phytochrome B
  • phycocyanobilin
  • Acyltransferases
  • flavanone synthetase