Phytochrome-interacting factor 1 is a critical bHLH: Regulator of chlorophyll biosynthesis

Enamul Huq, Bassem Al-Sady, Matthew Hudson, Chanhong Kim, Klaus Apel, Peter H. Quail

Research output: Contribution to journalArticlepeer-review


Photosynthetic organisms must achieve a delicate balance between the light energy absorbed by chlorophyll and their capacity to channel that energy into productive photochemical reactions. Release of excess absorbed energy in the cell can cause lethal photooxidative damage. We identified a basic helix-loop-helix (bHLH) transcription factor, designated PHYTOCHROME-INTERACTING FACTOR 1 (PIF1), that negatively regulates chlorophyll biosynthesis. pif1 mutant seedlings accumulate excess free protochlorophyllide when grown in the dark, with consequent lethal bleaching upon exposure to light. PIF1 interacts specifically with the photoactivated conformer of phytochromes A and B, suggesting a signaling pathway by which chlorophyll biosynthetic rates are tightly controlled during the critical initial emergence of seedlings from subterranean darkness into sunlight.

Original languageEnglish (US)
Pages (from-to)1937-1941
Number of pages5
Issue number5692
StatePublished - Sep 24 2004
Externally publishedYes

ASJC Scopus subject areas

  • General


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