To modify DNA at a new position requires the action of a de novo methyltransferase, which recognizes DNA by virtue of a specific sequence. It acts only on unmethylated DNA to add a methyl group to one strand.

TLS Online TPP Program

#Id: 9829

#Unit 6. System Physiology – Plant

The phyB mutants are deficient in chlorophyll

phyB also appears to regulate LFRs, such as photoreversible seed germination

Mutants that lack phyA respond normally to red light, whereas mutants deficient in phyB are unable to respond to low-fluence red light

TLS Online TPP Program

#Id: 9830

#Unit 6. System Physiology – Plant

Plants that are deficient in phyB often look like wild-type plants that are grown under dense vegetative canopies.

TLS Online TPP Program

#Id: 9831

#Unit 6. System Physiology – Plant

TLS Online TPP Program

#Id: 9832

#Unit 6. System Physiology – Plant

Phytochrome interacting factors (PIFs) are a family of proteins that act primarily as negative regulators of photomorphogenic responses.

TLS Online TPP Program

#Id: 9833

#Unit 6. System Physiology – Plant

PIFs promote etiolated development in the dark (skotomorphogenesis) primarily by serving as transcriptional activators of dark induced genes

TLS Online TPP Program

#Id: 9834

#Unit 6. System Physiology – Plant

Red light-induced Pfr formation initiates the degradation of PIF proteins through phosphorylation, followed by degradation via the proteasome complex