title: Phot1 and phot2 mediate blue light regulation of stomatal opening.
abstract: The stomatal pores of higher plants allow for gaseous exchange into and out of leaves. Situated in the epidermis, they are surrounded by a pair of guard cells which control their opening in response to many environmental stimuli, including blue light. Opening of the pores is mediated by K(+) accumulation in guard cells through a K(+) channel and driven by an inside-negative electrical potential. Blue light causes phosphorylation and activation of the plasma membrane H(+)-ATPase that creates this potential. Thus far, no blue light receptor mediating stomatal opening has been identified, although the carotenoid, zeaxanthin, has been proposed. Arabidopsis mutants deficient in specific blue-light-mediated responses have identified four blue light receptors, cryptochrome 1 (cry1), cryptochrome 2 (cry2), phot1 and phot2. Here we show that in a double mutant of phot1 and phot2 stomata do not respond to blue light although single mutants are phenotypically normal. These results demonstrate that phot1 and phot2 act redundantly as blue light receptors mediating stomatal opening.
authors.affiliation: Department of Biology, Faculty of Science, Kyushu University, Ropponmatsu, Fukuoka 810-8560, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kinoshita
authors.forename: M
authors.initials: M
authors.lastname: Doi
authors.forename: N
authors.initials: N
authors.lastname: Suetsugu
authors.forename: T
authors.initials: T
authors.lastname: Kagawa
authors.forename: M
authors.initials: M
authors.lastname: Wada
authors.forename: K
authors.initials: K
authors.lastname: Shimazaki
mesh_terms: D017360:Arabidopsis; D029681:Arabidopsis Proteins / Q000235:genetics / Q000502:physiology*; D002462:Cell Membrane / Q000201:enzymology / Q000528:radiation effects; D008027:Light; D009154:Mutation; D010750:Phosphoproteins / Q000235:genetics / Q000502:physiology*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000235:genetics; D019441:Plant Epidermis / Q000502:physiology* / Q000528:radiation effects; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000502:physiology; D006180:Proton-Translocating ATPases / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D029681:Arabidopsis Proteins; C423903:PHOT2 protein, Arabidopsis; D010750:Phosphoproteins; D045322:Photosynthetic Reaction Center Complex Proteins; C103646:NPH1 protein, Arabidopsis; D017346:Protein Serine-Threonine Kinases; D006180:Proton-Translocating ATPases