title: From The Cover: A role for Arabidopsis cryptochromes and COP1 in the regulation of stomatal opening.
abstract: Cryptochromes (CRY) are blue light photoreceptors that mediate various light-induced responses in plants and animals. Arabidopsis CRY (CRY1 and CRY2) functions through negatively regulating constitutive photomorphogenic (COP) 1, a repressor of photomorphogenesis. Water evaporation and photosynthesis are regulated by the stomatal pores in plants, which are closed in darkness but open in response to blue light. There is evidence only for the phototropin blue light receptors (PHOT1 and PHOT2) in mediating blue light regulation of stomatal opening. Here, we report a previously uncharacterized role for Arabidopsis CRY and COP1 in the regulation of stomatal opening. Stomata of the cry1 cry2 double mutant showed reduced blue light response, whereas those of the CRY1-overexpressing plants showed hypersensitive response to blue light. In addition, stomata of the phot1 phot2 double mutant responded to blue light, but those of the cry1 cry2 phot1 phot2 quadruple mutant hardly responded. Strikingly, stomata of the cop1 mutant were constitutively open in darkness and stomata of the cry1 cry2 cop1 and phot1 phot2 cop1 triple mutants were open as wide as those of the cop1 single mutant under blue light. These results indicate that CRY functions additively with PHOT in mediating blue light-induced stomatal opening and that COP1 is a repressor of stomatal opening and likely acts downstream of CRY and PHOT signaling pathways.
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, 300 Fenglin Road, Shanghai 200032, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Mao
authors.forename: Yan-Chun
authors.initials: YC
authors.lastname: Zhang
authors.forename: Yi
authors.initials: Y
authors.lastname: Sang
authors.forename: Qing-Hua
authors.initials: QH
authors.lastname: Li
authors.forename: Hong-Quan
authors.initials: HQ
authors.lastname: Yang
mesh_terms: D017360:Arabidopsis / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D056931:Cryptochromes; D005420:Flavoproteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D008027:Light; D009154:Mutation / Q000235:genetics; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D018515:Plant Leaves / Q000166:cytology / Q000502:physiology*; D018526:Plant Transpiration / Q000235:genetics / Q000502:physiology*; D017346:Protein Serine-Threonine Kinases; D044767:Ubiquitin-Protein Ligases; D014867:Water / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C538962:CRY1 protein, Arabidopsis; D056931:Cryptochromes; D005420:Flavoproteins; C423903:PHOT2 protein, Arabidopsis; D010750:Phosphoproteins; D014867:Water; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases; C103646:NPH1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases