Altered dark- and photoconversion of phytochrome B mediate extreme light sensitivity and loss of photoreversibility of the phyB-401 mutant

E. Ádám, Andrea Hussong, János Bindics, Florian Wüst, András Viczián, Marcus Essing, Mátyás Medzihradszky, Stefan Kircher, Eberhard Schäfer, Ferenc Nagy

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

The phyB-401 mutant is 10 3 fold more sensitive to red light than its wild-type analogue and shows loss of photoreversibility of hypocotyl growth inhibition. The phyB-401 photoreceptor displays normal spectral properties and shows almost no dark reversion when expressed in yeast cells. To gain insight into the molecular mechanism underlying this complex phenotype, we generated transgenic lines expressing the mutant and wild-type phyB in phyB-9 background. Analysis of these transgenic lines demonstrated that the mutant photoreceptor displays a reduced rate of dark-reversion but normal P fr to P r photoconversion in vivo and shows an altered pattern of association/dissociation with nuclear bodies compared to wild-type phyB. In addition we show (i) an enhanced responsiveness to far-red light for hypocotyl growth inhibition and CAB2 expression and (ii) that far-red light mediated photoreversibility of red light induced responses, including inhibition of hypocotyl growth, formation of nuclear bodies and induction of CAB2 expression is reduced in these transgenic lines. We hypothesize that the incomplete photoreversibility of signalling is due to the fact that far-red light induced photoconversion of the chromophore is at least partially uncoupled from the P fr to P r conformation change of the protein. It follows that the phyB-401 photoreceptor retains a P fr-like structure (P r*) for a few hours after the far-red light treatment. The greatly reduced rate of dark reversion and the formation of a biologically active P r* conformer satisfactorily explain the complex phenotype of the phyB-401 mutant and suggest that amino acid residues surrounding the position 564 G play an important role in fine-tuning phyB signalling.

Original languageEnglish
Article numbere27250
JournalPLoS One
Volume6
Issue number11
DOIs
Publication statusPublished - Nov 3 2011

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Phytochrome B
Photophobia
Photosensitivity
far-red light
phytochrome
photoreceptors
hypocotyls
Light
Hypocotyl
mutants
genetically modified organisms
red light
growth retardation
phenotype
Growth
Phenotype
Protein Conformation
Chromophores
yeasts
Yeast

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Altered dark- and photoconversion of phytochrome B mediate extreme light sensitivity and loss of photoreversibility of the phyB-401 mutant. / Ádám, E.; Hussong, Andrea; Bindics, János; Wüst, Florian; Viczián, András; Essing, Marcus; Medzihradszky, Mátyás; Kircher, Stefan; Schäfer, Eberhard; Nagy, Ferenc.

In: PLoS One, Vol. 6, No. 11, e27250, 03.11.2011.

Research output: Contribution to journalArticle

Ádám, E, Hussong, A, Bindics, J, Wüst, F, Viczián, A, Essing, M, Medzihradszky, M, Kircher, S, Schäfer, E & Nagy, F 2011, 'Altered dark- and photoconversion of phytochrome B mediate extreme light sensitivity and loss of photoreversibility of the phyB-401 mutant', PLoS One, vol. 6, no. 11, e27250. https://doi.org/10.1371/journal.pone.0027250
Ádám, E. ; Hussong, Andrea ; Bindics, János ; Wüst, Florian ; Viczián, András ; Essing, Marcus ; Medzihradszky, Mátyás ; Kircher, Stefan ; Schäfer, Eberhard ; Nagy, Ferenc. / Altered dark- and photoconversion of phytochrome B mediate extreme light sensitivity and loss of photoreversibility of the phyB-401 mutant. In: PLoS One. 2011 ; Vol. 6, No. 11.
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AU - Viczián, András

AU - Essing, Marcus

AU - Medzihradszky, Mátyás

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