• Phytochrome affects transcription (lag time of less than 5 min)
Transcriptional regulation
• Phytochrome interacting factors (PIFs) act as negative regulators of phytochrome response: PIF mutants exhibit a constituative photomorphogenic response even when plants are grown in the dark.
• Phytochrome initiates degradation of PIFs in the nucleus
Shade avoidance
Figure 25.23 Phytochrome control of flowering by red (R) and far-red (FR) light