Pfr, in turn, can be converted back to Pr by far-red light known as photoreversibility

TLS Online TPP Program

#Id: 9808

#XL - R Botany

Phytochromobilin is exported from the plastid to the cytosol where it autocatalytically attaches to the PHY apoprotein through a thioether linkage to a cysteine residue.

TLS Online TPP Program

#Id: 9809

#XL - R Botany

hy1 and hy2 mutant are chromophore biosynthesis mutant: which fail to supress hypocotyl elongation

TLS Online TPP Program

#Id: 9810

#XL - R Botany

Pfr is the physiologically active forms of Phytochrome

Wild type: short hypocotyl by white light

hy mutant (phytochrome mutant): long hypocotyl by white light

TLS Online TPP Program

#Id: 9811

#XL - R Botany

A toggle model is for phytochrome interconversion

The structure of the b-hairpin region of Pr is changed to an a helix during the conversion of Pr to Pfr, which initiates other conformational changes in the protein.

TLS Online TPP Program

#Id: 9812

#XL - R Botany

There are five phytochrome isoforms in angiosperms

TLS Online TPP Program

#Id: 9813

#XL - R Botany

PHYA is the only gene that encodes a Type I phytochrome and predominantly perceives far-red light.

Phytochrome B predominantly perceives red light