title: Verification at the protein level of the PIF4-mediated external coincidence model for the temperature-adaptive photoperiodic control of plant growth in Arabidopsis thaliana.
abstract: Plant circadian clock controls a wide variety of physiological and developmental events, which include the short-days (SDs)-specific promotion of the elongation of hypocotyls during de-etiolation and also the elongation of petioles during vegetative growth. In A. thaliana, the PIF4 gene encoding a phytochrome-interacting basic helix-loop-helix (bHLH) transcription factor plays crucial roles in this photoperiodic control of plant growth. According to the proposed external coincidence model, the PIF4 gene is transcribed precociously at the end of night specifically in SDs, under which conditions the protein product is stably accumulated, while PIF4 is expressed exclusively during the daytime in long days (LDs), under which conditions the protein product is degraded by the light-activated phyB and also the residual proteins are inactivated by the DELLA family of proteins. A number of previous reports provided solid evidence to support this coincidence model mainly at the transcriptional level of the PIF 4 and PIF4-traget genes. Nevertheless, the diurnal oscillation profiles of PIF4 proteins, which were postulated to be dependent on photoperiod and ambient temperature, have not yet been demonstrated. Here we present such crucial evidence on PIF4 protein level to further support the external coincidence model underlying the temperature-adaptive photoperiodic control of plant growth in A. thaliana.
authors.affiliation: Laboratory of Molecular and Functional Genomics; School of Agriculture; Nagoya University; Nagoya, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Yamashino
authors.forename: Yuji
authors.initials: Y
authors.lastname: Nomoto
authors.forename: Séverine
authors.initials: S
authors.lastname: Lorrain
authors.forename: Miki
authors.initials: M
authors.lastname: Miyachi
authors.forename: Shogo
authors.initials: S
authors.lastname: Ito
authors.forename: Norihito
authors.initials: N
authors.lastname: Nakamichi
authors.forename: Christian
authors.initials: C
authors.lastname: Fankhauser
authors.forename: Takeshi
authors.initials: T
authors.lastname: Mizuno
mesh_terms: D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D057906:Circadian Clocks / Q000235:genetics; D002940:Circadian Rhythm / Q000235:genetics; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D008027:Light; D008954:Models, Biological; D017440:Photoperiod; D010834:Phytochrome / Q000378:metabolism; D051939:Phytochrome B / Q000235:genetics / Q000378:metabolism; D063245:Plant Development / Q000235:genetics; D018547:Plant Stems / Q000254:growth & development* / Q000378:metabolism; D015398:Signal Transduction; D013696:Temperature
chemical_list: D029681:Arabidopsis Proteins; D051792:Basic Helix-Loop-Helix Proteins; D010834:Phytochrome; D051939:Phytochrome B; C109555:GAI protein, Arabidopsis; C497952:PHYB protein, Arabidopsis; C459466:PIF4 protein, Arabidopsis
keywords: arabidopsis thaliana; circadian clock; external coincidence model; light signaling; photomorphogenesis