A new type of mutation in the plant photoreceptor phytochrome B causes loss of photoreversibility and an extremely enhanced light sensitivity.
Photoreversibility, reversion of the inductive effect of a brief red light pulse by a subsequent far-red light pulse, is a property of photoresponses regulated by the plant photoreceptor phytochrome B (phyB). We screened for mutants with impaired photoreversibility to gain better insight into the phyB-specific signalling cascade. The phenotype of the mutant described is caused by a single amino acid exchange in a phyB subdomain that is highly conserved in all phytochromes but whose functional significance was unknown. The mutated phyB showed a slower dark reversion but no major alterations in its spectral properties. In addition to its loss of photoreversibility, the mutant also exhibited a hypersensitivity towards continuous red-light irradiation and an altered phenotype of adult plants under short-day conditions.
Kretsch
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Universität Freiburg, Institut für Biologie 2/Botanik, Schänzlestrasse 1, D-79104 Freiburg, Germany. kretsch@ruf.uni-freiburg.de
Poppe
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Schäfer
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D000483:Alleles; D000595:Amino Acid Sequence; D001483:Base Sequence; D017931:DNA Primers; D008027:Light; D008969:Molecular Sequence Data; D009154:Mutation; D010641:Phenotype; D010786:Photoreceptor Cells; D010834:Phytochrome / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D051939:Phytochrome B; D011836:Radiation Tolerance; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors
D017931:DNA Primers; D014157:Transcription Factors; D010834:Phytochrome; D051939:Phytochrome B