Intramolecular co-action of two independent photosensory modules in the fern phytochrome 3.
Fern phytochrome3/neochrome1 (phy3/neo1) is a chimeric photoreceptor composed of a phytochrome-chromophore binding domain and an almost full-length phototropin. phy3 thus contains two different light-sensing modules; a red/far-red light receptor phytochrome and a blue light receptor phototropin. phy3 induces both red light- and blue light-dependent phototropism in phototropin-deficient Arabidopsis thaliana (phot1 phot2) seedlings. The red-light response is dependent on the phytochrome module of phy3, and the blue-light response is dependent on the phototropin module. We recently showed that both the phototropin-sensing module and the phytochrome-sensing module mediate the blue light-dependent phototropic response. Particularly under low-light conditions, these two light-sensing modules cooperate to induce the blue light-dependent phototropic response. This intramolecular co-action of two independent light-sensing modules in phy3 enhances light sensitivity, and perhaps allowed ferns to adapt to the low-light canopy conditions present in angiosperm forests.
a Department of Biological Sciences ; Graduate School of Science and Technology; Tokyo Metropolitan University ; Tokyo , Japan.
Takeshi
T
Kanegae
D017360:Arabidopsis / Q000235:genetics / Q000528:radiation effects; D029624:Ferns / Q000378:metabolism* / Q000528:radiation effects; D008027:Light; D009154:Mutation / Q000235:genetics; D018524:Phototropism / Q000528:radiation effects; D010834:Phytochrome / Q000378:metabolism*; D030821:Plants, Genetically Modified
D010834:Phytochrome
Adiantum; fern; neochrome; phototropin; phototropism; phytochrome; phytochrome 3