title: Cryptochrome photoreceptors cry1 and cry2 antagonistically regulate primary root elongation in Arabidopsis thaliana.
abstract: Cryptochromes are blue-light receptors controlling multiple aspects of plant growth and development. They are flavoproteins with significant homology to photolyases, but instead of repairing DNA they function by transducing blue light energy into a signal that can be recognized by the cellular signaling machinery. Here we report the effect of cry1 and cry2 blue light receptors on primary root growth in Arabidopsis thaliana seedlings, through analysis of both cryptochrome-mutant and cryptochrome-overexpressing lines. Cry1 mutant seedlings show reduced root elongation in blue light while overexpressing seedlings show significantly increased elongation as compared to wild type controls. By contrast, the cry2 mutation has the opposite effect on root elongation growth as does cry1, demonstrating that cry1 and cry2 act antagonistically in this response pathway. The site of cryptochrome signal perception is within the shoot, and the inhibitor of auxin transport, 1-N-naphthylphthalamic acid, abolishes the differential effect of cryptochromes on root growth, suggesting the blue-light signal is transmitted from the shoot to the root by a mechanism that involves auxin. Primary root elongation in blue light may thereby involve interaction between cryptochrome and auxin signaling pathways.
authors.affiliation: Université de Paris VI, PCMP, Casier 156, 4 Place Jussieu, 75005 Paris, France.
authors.forename: Roberto C
authors.initials: RC
authors.lastname: Canamero
authors.forename: Nadia
authors.initials: N
authors.lastname: Bakrim
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Bouly
authors.forename: Alvaro
authors.initials: A
authors.lastname: Garay
authors.forename: Elizabeth E
authors.initials: EE
authors.lastname: Dudkin
authors.forename: Yvette
authors.initials: Y
authors.lastname: Habricot
authors.forename: Margaret
authors.initials: M
authors.lastname: Ahmad
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development*; D029681:Arabidopsis Proteins; D056931:Cryptochromes; D046508:Culture Techniques; D005420:Flavoproteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D015870:Gene Expression; D007210:Indoleacetic Acids / Q000378:metabolism; D008027:Light; D009154:Mutation; D018517:Plant Roots / Q000254:growth & development*; D036226:Seedlings / Q000254:growth & development*
chemical_list: D029681:Arabidopsis Proteins; C538962:CRY1 protein, Arabidopsis; D056931:Cryptochromes; D005420:Flavoproteins; D007210:Indoleacetic Acids