Multiple Phytochrome-Interacting bHLH Transcription Factors Repress Premature Seedling Photomorphogenesis in Darkness

Pablo Leivar, Elena Monte, Yoshito Oka, Tiffany Liu, Christine Carle, Alicia Castillon, Enamul Huq, Peter H. Quail

Research output: Indexed journal article Articlepeer-review

457 Citations (Scopus)

Abstract

Background: An important contributing factor to the success of terrestrial flowering plants in colonizing the land was the evolution of a developmental strategy, termed skotomorphogenesis, whereby postgerminative seedlings emerging from buried seed grow vigorously upward in the subterranean darkness toward the soil surface. Results: Here we provide genetic evidence that a central component of the mechanism underlying this strategy is the collective repression of premature photomorphogenic development in dark-grown seedlings by several members of the phytochrome (phy)-interacting factor (PIF) subfamily of bHLH transcription factors (PIF1, PIF3, PIF4, and PIF5). Conversely, evidence presented here and elsewhere collectively indicates that a significant component of the mechanism by which light initiates photomorphogenesis upon first exposure of dark-grown seedlings to irradiation involves reversal of this repression by rapid reduction in the abundance of these PIF proteins, through degradation induced by direct interaction of the photoactivated phy molecule with the transcription factors. Conclusions: We conclude that bHLH transcription factors PIF1, PIF3, PIF4, and PIF5 act as constitutive repressors of photomorphogenesis in the dark, action that is rapidly abrogated upon light exposure by phy-induced proteolytic degradation of these PIFs, allowing the initiation of photomorphogenesis to occur.

Original languageEnglish
Pages (from-to)1815-1823
Number of pages9
JournalCurrent Biology
Volume18
Issue number23
DOIs
Publication statusPublished - 9 Dec 2008
Externally publishedYes

Keywords

  • DEVBIO
  • DNA
  • SIGNALING

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