The Circadian Clock in the Ageing Plant
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ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE242964 | GEO | 2024/11/21
REPOSITORIES: GEO
Similar Datasets
Project description:Plants are sessile organisms that have acquired highly plastic developmental strategies to adapt to the environment. Among these processes, the floral transition is essential to ensure reproductive success and is finely regulated by several internal and external genetic networks. The photoperiodic pathway, which controls the plant response to day length, is one of the most important pathways controlling flowering. In Arabidopsis photoperiodic flowering, CONSTANS (CO) is the central gene activating the expression of the florigen FLOWERING LOCUS T (FT) in the leaves at the end of a long day. CO expression is strongly regulated by the circadian clock. However, to date, no evidence has been reported regarding a feedback loop from the photoperiod pathway back to the circadian clock. Using transcriptional networks, we have identified relevant network motifs regulating the interplay between the circadian clock and the photoperiod pathway. Gene expression, chromatin immunoprecipitation experiments and phenotypic analysis allowed us to elucidate the role of CO over the circadian clock. Plants with altered CO expression showed a different internal clock period, measured by daily rhythmic movements in the leaves. We show that CO is able to activate key genes related to the circadian clock, such as CCA1, LHY, PRR5 and GI, at the end of a long day by binding to specific sites on their promoters. Moreover, a significant number of PRR5 repressed target genes are upregulated by CO, and this could explain the phase transition promoted by CO. The CO-PRR5 complex interacts with the bZIP transcription factor HY5 and helps to localize the complex in the promoters of clock genes. Our results indicate that there may be a feedback loop in which CO communicates back to the circadian clock, feeding seasonal information to the circadian system.
2024-01-01 | GSE222657 | GEO
Project description:Plants are sessile organisms that have acquired highly plastic developmental strategies to adapt to the environment. Among these processes, the floral transition is essential to ensure reproductive success and is finely regulated by several internal and external genetic networks. The photoperiodic pathway, which controls the plant response to day length, is one of the most important pathways controlling flowering. In Arabidopsis photoperiodic flowering, CONSTANS (CO) is the central gene activating the expression of the florigen FLOWERING LOCUS T (FT) in the leaves at the end of a long day. CO expression is strongly regulated by the circadian clock. However, to date, no evidence has been reported regarding a feedback loop from the photoperiod pathway back to the circadian clock. Using transcriptional networks, we have identified relevant network motifs regulating the interplay between the circadian clock and the photoperiod pathway. Gene expression, chromatin immunoprecipitation experiments and phenotypic analysis allowed us to elucidate the role of CO over the circadian clock. Plants with altered CO expression showed a different internal clock period, measured by daily rhythmic movements in the leaves. We show that CO is able to activate key genes related to the circadian clock, such as CCA1, LHY, PRR5 and GI, at the end of a long day by binding to specific sites on their promoters. Moreover, a significant number of PRR5 repressed target genes are upregulated by CO, and this could explain the phase transition promoted by CO. The CO-PRR5 complex interacts with the bZIP transcription factor HY5 and helps to localize the complex in the promoters of clock genes. Our results indicate that there may be a feedback loop in which CO communicates back to the circadian clock, feeding seasonal information to the circadian system.
2023-08-01 | GSE236178 | GEO
Project description:Flowering in plants is a very dynamic and synchronized process where various cues including age, day-length, temperature and endogenous hormones fine-tune the timing of flowering for reproductive success. Arabidopsis thaliana is a facultative long day plant where long-day (LD) photoperiod promotes flowering. Arabidopsis still flowers under short-day (SD) conditions, albeit much later than LD conditions. Although, factors regulating the photoperiodic LD pathway have been extensively investigated, the SD pathway is much less understood. Here we identified a critical transcription factor called bHLH93 (basic Helix-Loop-Helix 93) that is essential to induce flowering specifically under SD conditions in Arabidopsis. bhlh93 mutants do not flower from primary meristem under SD conditions, but flowers similar to wild type under LD conditions. The late flowering phenotype is rescued by exogenous application of GA, suggesting that bHLH93 acts upstream of GA pathway to promote flowering. Double mutant studies showed that bhlh93 is epistatic to phyB and soc1 genes under SD conditions. bHLH93 is expressed at the meristematic regions and its expression peaks at 8 hours after dawn under SD conditions. As expected, the bHLH93 is localized in the nucleus. Taken together, these data suggest that bHLH93 is a key transcription factor necessary for Arabidopsis thaliana to evolve as a facultative plant.
2011-12-31 | GSE29786 | GEO
Project description:Flowering in plants is a very dynamic and synchronized process where various cues including age, day-length, temperature and endogenous hormones fine-tune the timing of flowering for reproductive success. Arabidopsis thaliana is a facultative long day plant where long-day (LD) photoperiod promotes flowering. Arabidopsis still flowers under short-day (SD) conditions, albeit much later than LD conditions. Although, factors regulating the photoperiodic LD pathway have been extensively investigated, the SD pathway is much less understood. Here we identified a critical transcription factor called bHLH93 (basic Helix-Loop-Helix 93) that is essential to induce flowering specifically under SD conditions in Arabidopsis. bhlh93 mutants do not flower from primary meristem under SD conditions, but flowers similar to wild type under LD conditions. The late flowering phenotype is rescued by exogenous application of GA, suggesting that bHLH93 acts upstream of GA pathway to promote flowering. Double mutant studies showed that bhlh93 is epistatic to phyB and soc1 genes under SD conditions. bHLH93 is expressed at the meristematic regions and its expression peaks at 8 hours after dawn under SD conditions. As expected, the bHLH93 is localized in the nucleus. Taken together, these data suggest that bHLH93 is a key transcription factor necessary for Arabidopsis thaliana to evolve as a facultative plant. Stratified Col-0 and bhlh93-1 mutants seeds in cold for 4 days. Transferred to Short Day (8h light and 16h dark) chamber and harvested samples after 10days. Tissue was harvested 0 and 4 hour after light was turned on.
2011-12-31 | E-GEOD-29786 | biostudies-arrayexpress
Project description:Seasonal adaptation to changes in light:dark regimes (i.e., photoperiod) allows organisms living at temperate latitudes to anticipate environmental change and adjust their physiology and behavior accordingly. The circadian system has been implicated in measurement and response to changes in photoperiod in nearly all animals studied so far (Saunders, 2011). The use of both traditional and non-traditional model insects with robust seasonal responses has recently genetically demonstrated the central role that clock genes play in photoperiodic response. Yet, the molecular pathways involved in insect photoperiodic responses remain largely unknown. Here, using the Eastern North American monarch butterfly (Reppert et al, 2016; Denlinger et al, 2017), we identified the vitamin A pathway as a novel pathway downstream of the circadian clock mediating insect photoperiod responsiveness. We found that interrupting clock function by disrupting circadian activation and repression abolishes photoperiodic responses in reproductive output, providing a functional link between clock genes and photoperiodic responsiveness in the monarch. Through transcriptomic approaches, we identified a molecular signature of seasonal-specific rhythmic gene expression in the brain, the organ known to function in photoperiodic reception in both Lepidoptera and some flies (Bowen et al, 1984; Saunders & Cymborowski, 1996). Among genes differentially expressed between both long and short photoperiods and between seasonal forms, several were belonging to the vitamin A pathway. The rhythmic expression of all of these genes was abolished in clock-deficient mutants. We also showed that a CRISPR/Cas9-mediated loss-of-function mutation in the pathway’s rate-limiting enzyme, ninaB1, impaired the monarch ability to respond to the photoperiod independently of visual function in the compound eye and without affecting circadian rhythms. Our finding that the vitamin A pathway is a key mediator of photoperiodic responses in insects could have broad implications for understanding the molecular mechanisms underlying photoperiodism.
2019-11-13 | GSE126336 | GEO
Project description:Plants of Solanum tuberosum ssp andigena, which tuberize only under SD conditions, were grown in growth chambers under non-inductive LD conditions and half of the plants were transferred to inductive SD conditions for 1 or 15 days, whilst the rest of the plants were kept as controls in LD. Transgenic potato plants with reduced phyB levels, which tuberize irrespective of photoperiod, were also grown in LD conditions. All the plants, irrespective of treatment, were harvested 14 hours after the beggining of the photoperiod (i.e. immediately before dusk for plants on LD, and 8 hours after dusk for the plants on SD). A similar experimental protocol was used with plants of N. tabacum cv Hicks that flower at the same time irrespective of photoperiod and the isogenic line N. tabacum cv Hicks carrying the Maryland Mammoth mutant allele, which flower only on SD (i.e. the plants were grown under LD for 55 or 41 days in LD and then transferred for 1 or 15 days to SD conditions, respectively, whilst control plants were grown 56 days in LD). Finally, Nicotiana silvestris plants that flower only on LD were grown in non-inductive SD and then half of the plants were transferred to inductive LD conditions for 1 or 15 days. In all cases we harvested only the leaves, the organ in which daylength perception takes place and photoperiodic responses are initiated. SD conditions in this experiments were 8 hours of light/ 16 hours of darkness, 160 uEinstein, 22 °C. LD conditions were 16 hours of light/ 8 hours of darkness, 80 uEinstein, 22 °C. RNA was extracted with TRIZOL. Keywords: Direct comparison / Balanced Block Design
2007-09-01 | GSE8142 | GEO
Project description:The timing of reproductive development determines spike architecture and thus yield in temperate grasses such as barley (Hordeum vulgare L.). Reproductive development in barley is controlled by the photoperiod response gene Ppd-H1 which accelerates flowering time under long-day (LD) conditions. A natural mutation in Ppd-H1 prevalent in spring barley causes a reduced photoperiod response, and thus, late flowering under LD. However, it is not very well understood how LD and Ppd-H1 control pre-anthesis development, and thus spike architecture and yield in barley. We performed a detailed morphological analysis of the pre-anthesis development in the spring barley cultivar Scarlett and its wild barley derived introgression line S42-IL107, carrying the photoperiod responsive Ppd-H1 allele. Characterization of shoot apex development in these genotypes indicated that floral transition and initiation of floral primordia occurred under LD (16h light/ 8h dark) and short day (SD, 8h light/ 16h dark) conditions, while inflorescence and seed development strictly required LDs. Additionally, a fast photoperiod response in the presence of the dominant Ppd-H1 allele promoted floret fertility under LDs. To characterize the effects of the photoperiod and allelic variation at Ppd-H1 on gene expression during pre-anthesis development we performed RNA sequencing of leaves and developing main shoot apices during the vegetative phase and early stages of inflorescence development in Scarlett and S42-IL107 grown under SD and LD conditions. Main shoot apices of both genotypes were sampled at defined developmental stages, i.e. Waddington stage W0.5, W1.0, W2.0 and W3.5, respectively. Leaf samples were harvested from plants before (W1.0) and after floral transition (W2.0). We identified genes that were specifically regulated at floral transition independent of day-length and Ppd-H1 and thus may serve as markers for the staging of floral transition. Furthermore, we identified transcripts differentially expressed between photoperiods and between genotypes in leaves and in shoot apices. This set of transcripts might act as candidates downstream of Ppd-H1 and are correlated with the promotion of shoot apex development and higher floret fertility under LD and in the presence of the photoperiod responsive Ppd-H1 allele.
2015-03-10 | E-MTAB-4114 | biostudies-arrayexpress
Project description:Floral transition and flower development are regulated by numerous environmental and endogenous signals, which are integrated at a relatively small number of floral integrators, such as FLOWERING LOCUS T (FT) and SUPPRESSOR OF CONSTANS OVEREXPRESSION 1 (SOC1). Of the environmental factors, photoperiod is regarded the most important one in promoting floral transition in Arabidopsis thaliana and most labstrains will flower earlier under long day (LD) conditions than under short day (SD) conditions. Arabidopsis is therefore considered a facultative LD plant. To monitor gene expression changes during floral transition and early flower development plants were grown under SD (9 hr light, 15 hr dark) for 30 days. Plants were then shifted to LD (16 hr light, 8 hr dark) conditions to induce flowering. RNA was isolated from micro-dissected apical tissue harvested 0, 3, 5, and 7 days after the shift to LD and double-stranded cDNA was synthesized. Biotinylated cRNA probes were prepared and hybridized to the Affymetrix ATH1 array in duplicate (biological replicates). To study floral transition, we not only analyzed response of wildtype Landsberg erecta (Ler) plants, but also the effect of mutants in the flowering time genes CONSTANS (CO; co-2) and FT (ft-2). Early flower development was analyzed by comparing Col-0 wildtype plants with the meristem identity mutant lfy-12 (Col-0).
2022-11-20 | E-AFMX-8 | biostudies-arrayexpress
Project description:This study aim to understand how the long and short day flowering pathways are integrated and the mechanism of photoperiod perception in rice. Trascriptome at different time points under LD and SD conditions reveal that photoperiodism in rice is controlled by the evening complex. Mutants in LUX ARRYTHMO (LUX) and EARLY FLOWERING3 (ELF3) orthologs abolish flowering. We show that light causes a rapid and sustained degradation of ELF3-1, and this response is dependent on phyB. ChIP-seq of ELF3 and LUX reveal that EC controls both LD and SD flowering pathways by directly binding and suppressing the expression of key floral repressors, including PRR7 orthologs and Ghd7.
2022-05-24 | GSE181833 | GEO
Project description:This study aim to understand how the long and short day flowering pathways are integrated and the mechanism of photoperiod perception in rice. Trascriptome at different time points under LD and SD conditions reveal that photoperiodism in rice is controlled by the evening complex. Mutants in LUX ARRYTHMO (LUX) and EARLY FLOWERING3 (ELF3) orthologs abolish flowering. We show that light causes a rapid and sustained degradation of ELF3-1, and this response is dependent on phyB. ChIP-seq of ELF3 and LUX reveal that EC controls both LD and SD flowering pathways by directly binding and suppressing the expression of key floral repressors, including PRR7 orthologs and Ghd7.
2022-05-24 | GSE181831 | GEO