title: Cryptochrome blue-light photoreceptors of Arabidopsis implicated in phototropism.
abstract: Phototropism-bending towards the light-is one of the best known plant tropic responses. Despite being reported by Darwin and others over a century ago to be specifically under the control of blue light, the photoreceptors mediating phototropism have remained unknown. We have characterized a blue-light photoreceptor from Arabidopsis, named CRY1 for cryptochrome 1; this photoreceptor is a flavoprotein that mediates numerous blue-light-dependent responses. In Arabidopsis, HY4 (the gene encoding CRY1) is a member of a small gene family that also encodes a related photoreceptor, CRY2, which shares considerable functional overlap with CRY1. Here we report that mutant plants lacking both the CRY1 and the CRY2 blue-light photoreceptors are deficient in the phototropic response. Transgenic Arabidopsis plants overexpressing CRY1 or CRY2 show enhanced phototropic curvature. We conclude that cryptochrome is one of the photoreceptors mediating phototropism in plants.
authors.affiliation: Plant Science Institute, Department of Biology, University of Pennsylvania, Philadelphia 19104-6018, USA. mahmad@mail.sas.upenn.edu
authors.forename: M
authors.initials: M
authors.lastname: Ahmad
authors.forename: J A
authors.initials: JA
authors.lastname: Jarillo
authors.forename: O
authors.initials: O
authors.lastname: Smirnova
authors.forename: A R
authors.initials: AR
authors.lastname: Cashmore
mesh_terms: D000872:Anthocyanins / Q000378:metabolism; D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins; D056931:Cryptochromes; D029721:Drosophila Proteins; D005136:Eye Proteins; D005420:Flavoproteins / Q000235:genetics / Q000502:physiology*; D009154:Mutation; D010786:Photoreceptor Cells / Q000502:physiology*; D017956:Photoreceptor Cells, Invertebrate; D018524:Phototropism; D010940:Plant Proteins / Q000235:genetics / Q000502:physiology*; D030821:Plants, Genetically Modified; D043562:Receptors, G-Protein-Coupled
chemical_list: D000872:Anthocyanins; D029681:Arabidopsis Proteins; C538962:CRY1 protein, Arabidopsis; D056931:Cryptochromes; D029721:Drosophila Proteins; D005136:Eye Proteins; D005420:Flavoproteins; D010940:Plant Proteins; D043562:Receptors, G-Protein-Coupled; C119828:cry protein, Drosophila