title: Light-dependent destabilization of PHL in Arabidopsis.
abstract: Plants sense environmental stimuli such as light to regulate their flowering time. In Arabidopsis, phytochrome B (phyB) is the major photoreceptor that perceives red and far-red light, and destabilizes transcriptional regulator CONSTANS (CO) protein. However the mechanism that links photoreceptor and CO protein degradation is largely unknown. We recently showed that PHYTOCHROME-DEPENDENT LATE-FLOWERING (PHL) protein inhibits phyB signaling through direct protein-protein interaction. Here, we report that light exposure destabilizes PHL protein as is the case with CO. Fluorescence from PHL-YFP fusion protein expressed under the control of Cauliflower Mosaic Virus (CaMV) 35S promoter (35S::PHL-YFP) almost disappeared after four-hour treatment of white light. Furthermore, the similar results were also obtained from the analysis of PHL-GUS fusion protein expressed by PHL promoter (PHLpro::PHL-GUS phl-1). These results highlight the importance of post-transcriptional regulation in phyB-mediated flowering regulation and will give us hints how phyB regulates CO protein amount.
authors.affiliation: Division of Integrated Life Science; Graduate School of Biostudies; Kyoto University; Kyoto, Japan.
authors.forename: Motomu
authors.initials: M
authors.lastname: Endo
authors.affiliation: Division of Integrated Life Science; Graduate School of Biostudies; Kyoto University; Kyoto, Japan.
authors.forename: Daiki
authors.initials: D
authors.lastname: Kudo
authors.affiliation: Division of Integrated Life Science; Graduate School of Biostudies; Kyoto University; Kyoto, Japan.
authors.forename: Tomoko
authors.initials: T
authors.lastname: Koto
authors.affiliation: Division of Integrated Life Science; Graduate School of Biostudies; Kyoto University; Kyoto, Japan.
authors.forename: Hanako
authors.initials: H
authors.lastname: Shimizu
authors.affiliation: Division of Integrated Life Science; Graduate School of Biostudies; Kyoto University; Kyoto, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Araki
mesh_terms: D017360:Arabidopsis / Q000378:metabolism / Q000528:radiation effects*; D029681:Arabidopsis Proteins / Q000378:metabolism / Q000528:radiation effects*; D004268:DNA-Binding Proteins / Q000378:metabolism; D008027:Light; D009687:Nuclear Proteins / Q000528:radiation effects*; D051939:Phytochrome B / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C092776:CONSTANS protein, Arabidopsis; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; C585477:PHL protein, Arabidopsis; D014157:Transcription Factors; D051939:Phytochrome B
keywords: Arabidopsis; CO; FT; PHL; florigen; flowering; photoperiod; phyB; phytochrome