Description
Light initiates the seedling deetiolation transition by promoting major changes in gene expression mainly regulated by phytochrome (phy) photoreceptors. During the initial dark-to-light transition, phy photoactivation induces rapid changes in gene expression that eventually lead to the photomorphogenic development. Recent reports indicate that this process is achieved by phy-induced degradation of Phy-Interacting bHLH transcription Factors (PIFs) PIF1, PIF3 PIF4 and PIF5, which are partly redundant constitutive repressors of photomorphogenesis that accumulate in darkness. In order to test whether light/phy-regulated gene expression occurs through these PIFs, we have performed whole-genome expression analysis in the pif1pif3pif4pif5 quadruple mutant (pifq).