title: FIONA1 is essential for regulating period length in the Arabidopsis circadian clock.
abstract: In plants, the circadian clock controls daily physiological cycles as well as daylength-dependent developmental processes such as photoperiodic flowering and seedling growth. Here, we report that FIONA1 (FIO1) is a genetic regulator of period length in the Arabidopsis thaliana circadian clock. FIO1 was identified by screening for a mutation in daylength-dependent flowering. The mutation designated fio1-1 also affects daylength-dependent seedling growth. fio1-1 causes lengthening of the free-running circadian period of leaf movement and the transcription of various genes, including the central oscillators CIRCADIAN CLOCK-ASSOCIATED1, LATE ELONGATED HYPOCOTYL, TIMING OF CAB EXPRESSION1, and LUX ARRHYTHMO. However, period lengthening is not dependent upon environmental light or temperature conditions, which suggests that FIO1 is not a simple input component of the circadian system. Interestingly, fio1-1 exerts a clear effect on the period length of circadian rhythm but has little effect on its amplitude and robustness. FIO1 encodes a novel nuclear protein that is highly conserved throughout the kingdoms. We propose that FIO1 regulates period length in the Arabidopsis circadian clock in a close association with the central oscillator and that the circadian period can be controlled separately from amplitude and robustness.
authors.affiliation: Division of Molecular and Life Sciences, Pohang University of Science and Technology, Hyoja-dong, Pohang, Gyungbuk 790-784, Republic of Korea.
authors.forename: Jeongsik
authors.initials: J
authors.lastname: Kim
authors.forename: Yumi
authors.initials: Y
authors.lastname: Kim
authors.forename: Miji
authors.initials: M
authors.lastname: Yeom
authors.forename: Jin-Hee
authors.initials: JH
authors.lastname: Kim
authors.forename: Hong Gil
authors.initials: HG
authors.lastname: Nam
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002940:Circadian Rhythm / Q000502:physiology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D035264:Flowers / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D018546:Hypocotyl / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D008969:Molecular Sequence Data; D009154:Mutation; D030821:Plants, Genetically Modified; D013696:Temperature; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C092776:CONSTANS protein, Arabidopsis; D004268:DNA-Binding Proteins; C530344:FIONA1 protein, Arabidopsis; D014157:Transcription Factors