Circadian Timekeeping during Early Arabidopsis Development

Salomé, Patrice A.; Xie, Qiguang; McClung, C. Robertson

doi:10.1104/pp.108.117622

Cited by 63 publications

(71 citation statements)

References 75 publications

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“…The control output gene CAX1, a H ϩ /Ca 2ϩ antiporter (38) unrelated to chloroplast function, was also unaffected, suggesting that PIF1 and PIF3 function specifically in circadian control of genes involved in chloroplast development. A circadian clock has been shown to be functional in dark-grown Arabidopsis seedlings, with entrainment initiated through changes in temperature or imbibition (39), and can be observed just 2 d after imbibition (39) or even earlier (40). Moreover, the importance of this clock in controlling chloroplast development is supported by the observation that a range of clock mutants fail to green normally after transfer to WL (40).…”

Section: Pif1 and Pif3 Repress The Expression Of Key Chlorophyll Syntmentioning

confidence: 56%

PIF3 is a repressor of chloroplast development

Stephenson

Fankhauser

Terry

2009

Proc. Natl. Acad. Sci. U.S.A.

202

208

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The phytochrome-interacting factor PIF3 has been proposed to act as a positive regulator of chloroplast development. Here, we show that the pif3 mutant has a phenotype that is similar to the pif1 mutant, lacking the repressor of chloroplast development PIF1, and that a pif1pif3 double mutant has an additive phenotype in all respects. The pif mutants showed elevated protochlorophyllide levels in the dark, and etioplasts of pif mutants contained smaller prolamellar bodies and more prothylakoid membranes than corresponding wild-type seedlings, similar to previous reports of constitutive photomorphogenic mutants. Consistent with this observation, pif1, pif3, and pif1pif3 showed reduced hypocotyl elongation and increased cotyledon opening in the dark. Transfer of 4-d-old dark-grown seedlings to white light resulted in more chlorophyll synthesis in pif mutants over the first 2 h, and analysis of gene expression in dark-grown pif mutants indicated that key tetrapyrrole regulatory genes such as HEMA1 encoding the ratelimiting step in tetrapyrrole synthesis were already elevated 2 d after germination. Circadian regulation of HEMA1 in the dark also showed reduced amplitude and a shorter, variable period in the pif mutants, whereas expression of the core clock components TOC1, CCA1, and LHY was largely unaffected. Expression of both PIF1 and PIF3 was circadian regulated in dark-grown seedlings. PIF1 and PIF3 are proposed to be negative regulators that function to integrate light and circadian control in the regulation of chloroplast development.chlorophyll synthesis ͉ circadian regulation ͉ phytochrome ͉ etioplast ͉ light signaling

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Section: Pif1 and Pif3 Repress The Expression Of Key Chlorophyll Syntmentioning

confidence: 56%

PIF3 is a repressor of chloroplast development

Stephenson

Fankhauser

Terry

2009

Proc. Natl. Acad. Sci. U.S.A.

202

208

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“…We used toc1‐101 , prr5‐11 , prr7‐11 , and prr9‐10 as prr mutants (Ito et al , 2003; Yamamoto et al , 2003; Salome et al , 2008). SUC2 :: CO and SUC2 :: HA:CO have been previously described (An et al , 2004; Jang et al , 2009).…”

Section: Methodsmentioning

confidence: 99%

PSEUDO RESPONSE REGULATORs stabilize CONSTANS protein to promote flowering in response to day length

et al. 2017

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Seasonal reproduction in many organisms requires detection of day length. This is achieved by integrating information on the light environment with an internal photoperiodic time‐keeping mechanism. Arabidopsis thaliana promotes flowering in response to long days (LDs), and CONSTANS (CO) transcription factor represents a photoperiodic timer whose stability is higher when plants are exposed to light under LDs. Here, we show that PSEUDO RESPONSE REGULATOR (PRR) proteins directly mediate this stabilization. PRRs interact with and stabilize CO at specific times during the day, thereby mediating its accumulation under LDs. PRR‐mediated stabilization increases binding of CO to the promoter of FLOWERING LOCUS T (FT), leading to enhanced FT transcription and early flowering under these conditions. PRRs were previously reported to contribute to timekeeping by regulating CO transcription through their roles in the circadian clock. We propose an additional role for PRRs in which they act upon CO protein to promote flowering, directly coupling information on light exposure to the timekeeper and allowing recognition of LDs.

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“…As shown in Figure 7, the C1 OE and C3 OE seedlings grown on MS and subjected to LDHC conditions exhibited a significantly reduced LHY and CCA1 expression when compared with the wild-type ones. As a result of this reduction, it is expected that circadian clock outputs, such as the expression of CONSTANS-LIKE1 (COL1; Mizoguchi et al, 2002) and LHCB1.1 (Salomé et al, 2008) genes, should also be altered in the C1 OE and C3 OE plants. In addition to LHY and CCA1, the expression levels of the COL1 and LHCB1.1, on both the MS and 10 mM CuSO 4 , indeed decreased if compared with the wild type (Fig.…”

Section: Additional Phenotypes Associated With the Copt-overexpressinmentioning

confidence: 99%

Deregulated Copper Transport Affects Arabidopsis Development Especially in the Absence of Environmental Cycles

et al. 2010

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Copper is an essential cofactor for key processes in plants, but it exerts harmful effects when in excess. Previous work has shown that the Arabidopsis (Arabidopsis thaliana) COPT1 high-affinity copper transport protein participates in copper uptake through plant root tips. Here, we show that COPT1 protein localizes to the plasma membrane of Arabidopsis cells and the phenotypic effects of transgenic plants overexpressing either COPT1 or COPT3, the latter being another high-affinity copper transport protein family member. Both transgenic lines exhibit increased endogenous copper levels and are sensitive to the copper in the growth medium. Additional phenotypes include decreased hypocotyl growth in red light and differentially affected flowering times depending on the photoperiod. Furthermore, in the absence of environmental cycles, such as light and temperature, the survival of plants overexpressing COPT1 or COPT3 is compromised. Consistent with altered circadian rhythms, the expression of the nuclear circadian clock genes CIRCADIAN CLOCK-ASSOCIATED1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY) is substantially reduced in either COPT1-or COPT3-overexpressing plants. Copper affects the amplitude and the phase, but not the period, of the CCA1 and LHY oscillations in wild-type plants. Copper also drives a reduction in the expression of circadian clock output genes. These results reveal that the spatiotemporal control of copper transport is a key aspect of metal homeostasis that is required for Arabidopsis fitness, especially in the absence of environmental cues.

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Circadian Timekeeping during Early Arabidopsis Development

Cited by 63 publications

References 75 publications

PIF3 is a repressor of chloroplast development

PIF3 is a repressor of chloroplast development

PSEUDO RESPONSE REGULATORs stabilize CONSTANS protein to promote flowering in response to day length

Deregulated Copper Transport Affects Arabidopsis Development Especially in the Absence of Environmental Cycles

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