Arabidopsis Clock-Associated Pseudo-Response Regulators PRR9, PRR7 and PRR5 Coordinately and Positively Regulate Flowering Time through the Canonical CONSTANS-Dependent Photoperiodic Pathway. [Plant Cell Physiol] Journal article | | Title | Arabidopsis Clock-Associated Pseudo-Response Regulators PRR9, PRR7 and PRR5 Coordinately and Positively Regulate Flowering Time through the Canonical CONSTANS-Dependent Photoperiodic Pathway. | | Author(s) | Nakamichi N, Kita M, Niimura K, Ito S, Yamashino T, Mizoguchi T, Mizuno T | | Institution | Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-ku, Nagoya 464-8602, Japan. | | Source | Plant Cell Physiol 2007 May 15. | | Abstract | Photoperiodism allows organisms to measure daylength, or external photoperiod, and to anticipate coming seasons. Daylength measurement requires the integration of light signal and temporal information by circadian clock. In the long-day plant Arabidopsis thaliana, CONSTANS (CO) plays a crucial role to integrate the circadian rhythm and environmental light signals into the photoperiodic flowering pathway. Nevertheless, the molecular mechanism by which the circadian clock modulates the cyclic expression profile of CO is poorly understood. Here, we first showed that the clock-associated genes PSEUDO-RESPONSE REGULATOR (PRR) PRR9, PRR7, and PRR5 are involved in activation of CO expression during the daytime. Then, extensive genetic studies using CIRCADIAN CLOCK ASSOCIATED1 (CCA1)/LATE ELONGATED HYPOCOTYL (LHY) double mutants (cca1/lhy) and prr7/prr5 were conducted. The results suggested that PRRs coordinately act in a manner parallel with and antagonistic to CCA/LHY, upstream of the canonical CO-FT photoperiodic flowering pathway. Finally, we provided evidence to propose a model, in which CCA1/LHY repress CO through GIGANTEA (GI), while PRR9, PRR7 and PRR5 activate CO predominantly by repressing CYCLING DOF FACTOR1 (CDF1) encoding a DNA-binding transcriptional repressor. | | Language | ENG | | Pub Type(s) | JOURNAL ARTICLE
| | PubMed ID | 17504813 |
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