title: Intramolecular uncoupling of chromophore photoconversion from structural signaling determinants drive mutant phytochrome B photoreceptor to far-red light perception.
abstract: The phytochrome (phy) photoreceptor family regulates almost all aspects of plant development in a broad range of light environments including seed germination, onset of the photomorphogenic program in seedling stage, the shade avoidance syndrome in competing plant communities, flowering induction and senescence of adult plants. During evolution two clearly distinct classes of phy-s emerged covering these very different physiological tasks. ( 1)  PhyA is rapidly degraded in its activated state. PhyA functions in controlling seed germination at very low light intensities (very low fluence response, VLFR) and seedling establishment under photosynthetic shade conditions (high irradiance response, HIR) where the far-red portion of the transmitted light to understorey habitats is substantially enhanced. Arabidopsis phyB together with phyC, D and E belongs to the relatively stable sensor class in comparison to the light labile phyA. PhyB functions at all stages of development including seed germination and seedling establishment, mediates classical red/far-red reversible low fluence responses (LFR) as well as red light high irradiance responses, and it is considered to be the dominating phytochrome sensor of its class.
authors: Institute of Biology II; Faculty of Biology, University of Freiburg, Germany. Stefan.kircher@biologie.uni-freiburg.de
authors: Stefan
authors: S
authors: Kircher
authors: Diana
authors: D
authors: Bauer
authors: Eberhard
authors: E
authors: Schäfer
authors: Ferenc
authors: F
authors: Nagy
mesh_terms: D000483:Alleles; D017360:Arabidopsis / Q000235:genetics / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000235:genetics* / Q000378:metabolism; D008027:Light; D055537:Light Signal Transduction / Q000528:radiation effects*; D009154:Mutation / Q000235:genetics*; D051939:Phytochrome B / Q000235:genetics* / Q000378:metabolism; D030821:Plants, Genetically Modified; D021381:Protein Transport / Q000528:radiation effects; D019076:Transgenes
chemical_list: D029681:Arabidopsis Proteins; C497952:PHYB protein, Arabidopsis; D051939:Phytochrome B