title: The Aspergillus nidulans phytochrome FphA represses sexual development in red light.
abstract: Phytochrome photoreceptors sense red and far-red light through photointerconversion between two stable conformations, a process mediated by a linear tetrapyrrole chromophore. Originally, phytochromes were thought to be confined to photosynthetic organisms including cyanobacteria, but they have been recently discovered in heterotrophic bacteria and fungi, where little is known about their functions. It was shown previously in the ascomycetous fungus Aspergillus nidulans that asexual sporulation is stimulated and sexual development repressed by red light. The effect was reminiscent of a phytochrome response, and indeed phytochrome-like proteins were detected in several fungal genomes. All fungal homologs are more similar to bacterial than plant phytochromes and have multifunctional domains where the phytochrome region and histidine kinase domain are combined in a single protein with a C-terminal response-regulator domain. Here, we show that the A. nidulans phytochrome FphA binds a biliverdin chromophore, acts as a red-light sensor, and represses sexual development under red-light conditions. FphA-GFP is cytoplasmic and excluded from the nuclei, suggesting that red-light photoperception occurs in the cytoplasm. This is the first phytochrome experimentally characterized outside the plant and bacterial kingdoms and the second type of fungal protein identified that functions in photoperception.
authors.affiliation: Max-Planck-Institute for Terrestrial Microbiology, Karl-von-Frisch-Str., D-35042 Marburg, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Blumenstein
authors.forename: Kay
authors.initials: K
authors.lastname: Vienken
authors.forename: Ronja
authors.initials: R
authors.lastname: Tasler
authors.forename: Janina
authors.initials: J
authors.lastname: Purschwitz
authors.forename: Daniel
authors.initials: D
authors.lastname: Veith
authors.forename: Nicole
authors.initials: N
authors.lastname: Frankenberg-Dinkel
authors.forename: Reinhard
authors.initials: R
authors.lastname: Fischer
mesh_terms: D000595:Amino Acid Sequence; D001233:Aspergillus nidulans / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001483:Base Sequence; D016000:Cluster Analysis; D003593:Cytoplasm / Q000378:metabolism; D040461:Gene Components; D008027:Light; D008969:Molecular Sequence Data; D018462:Photobiology; D010786:Photoreceptor Cells / Q000378:metabolism* / Q000502:physiology; D010802:Phylogeny; D010834:Phytochrome / Q000235:genetics / Q000378:metabolism*; D012100:Reproduction, Asexual / Q000502:physiology*; D017422:Sequence Analysis, DNA; D012741:Sexual Maturation / Q000502:physiology*
chemical_list: D010834:Phytochrome