GI is a repressor of ABA transcriptional responses and sensitivity in Arabidopsis
Ontology highlight
ABSTRACT:
ORGANISM(S): Arabidopsis thaliana
PROVIDER: GSE181083 | GEO | 2022/07/11
REPOSITORIES: GEO
Similar Datasets
Project description:Plants use their endogenous clock to regulate many physiological processes related to their survival and adaptability. GIGANTEA (GI), one of the clock proteins, contributes to the maintenance of circadian period length and amplitude and also regulates flowering time and hypocotyl growth in response to day length. In addition to GI, EARLY FLOWERING 4 (ELF4), another clock regulator, also contributes to these processes. However, little is known about the overall interactions between GI and ELF4 in Arabidopsis. In this study, we investigated the genetic interactions between GI and ELF4 in circadian output regulation. The results show that GI is dominant to ELF4 in flowering time determination, but ELF4 is dominant to GI in hypocotyl growth regulation. Moreover, GI and ELF4 have a synergistic effect on endogenous clock regulation. Further, gene expression profiling of gi-2, elf4, and gi-2 elf4 mutants confirmed that GI and ELF4 had differential dominant effects on circadian physiological outputs at dawn and dusk, respectively. This differential dominance of GI and ELF4 provides a potential means to achieve the diversity in the regulation of circadian physiological outputs including flowering time and hypocotyl growth. The genetic interactions between GI and ELF4 could be time-dependent functional dominance along a day, called temporal dominance hereafter. To test this hypothesis, we performed gene expression profiling of WT, gi-2, elf4 and gi elf4 plants at dawn (ZT1) and dusk (ZT16).
2012-06-30 | E-GEOD-32938 | biostudies-arrayexpress
Project description:Plants use their endogenous clock to regulate many physiological processes related to their survival and adaptability. GIGANTEA (GI), one of the clock proteins, contributes to the maintenance of circadian period length and amplitude and also regulates flowering time and hypocotyl growth in response to day length. In addition to GI, EARLY FLOWERING 4 (ELF4), another clock regulator, also contributes to these processes. However, little is known about the overall interactions between GI and ELF4 in Arabidopsis. In this study, we investigated the genetic interactions between GI and ELF4 in circadian output regulation. The results show that GI is dominant to ELF4 in flowering time determination, but ELF4 is dominant to GI in hypocotyl growth regulation. Moreover, GI and ELF4 have a synergistic effect on endogenous clock regulation. Further, gene expression profiling of gi-2, elf4, and gi-2 elf4 mutants confirmed that GI and ELF4 had differential dominant effects on circadian physiological outputs at dawn and dusk, respectively. This differential dominance of GI and ELF4 provides a potential means to achieve the diversity in the regulation of circadian physiological outputs including flowering time and hypocotyl growth.
2012-07-01 | GSE32938 | GEO
Project description:Histone H2B monoubiquitination (H2Bub1) has been implicated in several important physiological and developmental processes, but its role in the regulation of stress responses remains elusive. Here, we report that H2Bub1 is crucially involved in abscisic acid (ABA) signaling and drought response in rice. We found the rice (Oryza sativa) HISTONE MONOUBIQUITINATION2 (OsHUB2), an E3 ligase for H2Bub1, interacted with OsbZIP46, a key transcription factor regulating ABA signaling and drought response in rice. Genetic analyses suggest that OsHUB2, induced by drought and ABA, positively modulates ABA sensitivity and drought resistance. The H2Bub1 levels were increased in the promoters of OsbZIP46 target genes under the drought stress and ABA treatments, and the increased H2Bub1 levels were positively correlated to the increased expression levels of the target genes. Interestingly, MODD, a reported suppressor of ABA signaling and drought resistance through mediation of OsbZIP46 deactivation and degradation, can repress the H2Bub1 level in the promoters of OsbZIP46 target genes by recruiting a putative deubiquitinase OsOTLD1. Suppression of OsOTLD1 in vivo resulted in increased H2Bub1 levels and expression of drought-responsive genes targeted by OsbZIP46. These findings established an elaborate mechanism of histone monoubiquitination in the fine-turning of ABA signaling and drought response via balancing H2Bub1 deposition and removal.
2019-02-09 | GSE117047 | GEO
Project description:Using a yeast to hybrid screen, it was found that PHO2, a key regulator of phosphate homeostasis, could interact with GIGANTEA, a key regulator of flowering time. In addition, mutant analysis revealed that both the pho2 and gi mutants shared similar phenotypes, both at the phosphate and flowering time levels. We used microarrays to analyse the effects of each mutation (pho2 or gi) on global gene expression, and assessed the proportion of genes similalry regulated in both mutants, in both shoots and roots. Wild-type (Nipponbare), pho2 and gi knock-out rice plants were grown to 21-days before harvesting root and shoot separately.
2013-07-01 | E-GEOD-46867 | biostudies-arrayexpress
Project description:Using a yeast to hybrid screen, it was found that PHO2, a key regulator of phosphate homeostasis, could interact with GIGANTEA, a key regulator of flowering time. In addition, mutant analysis revealed that both the pho2 and gi mutants shared similar phenotypes, both at the phosphate and flowering time levels. We used microarrays to analyse the effects of each mutation (pho2 or gi) on global gene expression, and assessed the proportion of genes similalry regulated in both mutants, in both shoots and roots.
2013-07-01 | GSE46867 | GEO
Project description:Responses to drought in rice are regulated by transcription factor OsbZIP46 via ABA signaling. This work characterizes a protein MODD that negatively regulates OsbZIP46 activity and stability through HDAC-related chromatin remodeling and OsPUB70-mediated ubiquitination, respectively, to fine tune ABA signaling and drought resistance.
2016-09-07 | GSE83075 | GEO
Project description:Plants monitor and integrate temperature, photoperiod and light quality signals to respond to continuous changes in their environment. The GIGANTEA (GI) protein is central in diverse signaling pathways, including photoperiodic, sugar and light signaling pathways, stress responses and circadian clock regulation. Previously, GI was shown to activate expression of the key floral regulators CONSTANS (CO) and FLOWERING LOCUS T (FT) by facilitating degradation of a family of CYCLING DOF FACTOR (CDF) transcriptional repressors. However, whether CDFs are implicated in other processes regulated by GI remains unclear. We investigated the contribution of the GI-CDF module to traits that depend on GI. Transcriptome profiling indicated that mutations in GI and the CDFs have antagonistic effects on expression of a wider set of genes than CO and FT, whilst other genes are regulated by GI independently of the CDFs. Detailed expression studies followed by phenotypic assays showed that the CDFs function downstream of GI to control responses to freezing temperatures and growth, but are not necessary for proper clock function. Thus GI-mediated regulation of CDFs contributes to several processes in addition to flowering, but is not implicated in all of the phenotypes influenced by GI.
2015-07-31 | GSE59996 | GEO
Project description:Plants monitor and integrate temperature, photoperiod and light quality signals to respond to continuous changes in their environment. The GIGANTEA (GI) protein is central in diverse signaling pathways, including photoperiodic, sugar and light signaling pathways, stress responses and circadian clock regulation. Previously, GI was shown to activate expression of the key floral regulators CONSTANS (CO) and FLOWERING LOCUS T (FT) by facilitating degradation of a family of CYCLING DOF FACTOR (CDF) transcriptional repressors. However, whether CDFs are implicated in other processes regulated by GI remains unclear. We investigated the contribution of the GI-CDF module to traits that depend on GI. Transcriptome profiling indicated that mutations in GI and the CDFs have antagonistic effects on expression of a wider set of genes than CO and FT, whilst other genes are regulated by GI independently of the CDFs. Detailed expression studies followed by phenotypic assays showed that the CDFs function downstream of GI to control responses to freezing temperatures and growth, but are not necessary for proper clock function. Thus GI-mediated regulation of CDFs contributes to several processes in addition to flowering, but is not implicated in all of the phenotypes influenced by GI. Seedlings of Col-0, the cdf1-R cdf2-1 cdf3-1 cdf5-1 quadruple mutant, gi-100 and gi-100 cdf1-R cdf2-1 cdf3-1 cdf5-1 quintuple mutant were grown for 10 days under LD conditions (16h light/8h dark). The aerial part of the seedlings was collected at ZT12 and RNA was prepared from three biological replicas
2015-07-31 | E-GEOD-59996 | biostudies-arrayexpress
Project description:Results: In this study, the ears at the V9 stage, kernels and ear leaf at the 5DAP (days after pollination) stage of maize were used for morphological, physiological and comparative transcriptomics analysis to understand the different features of “sink” or “source” organs and the effects on kernel yield under drought stress conditions. The ABA-, NAC-mediate signaling pathway, osmotic protective substance synthesis and protein folding response were identified as common drought stress response in the three organs. Tissue-specific drought stress responses and the regulators were identified, they were highly correlated with growth, physiological adaptation and yield loss under drought stress. For ears, drought stress inhibited ear elongation, led to the abnormal differentiation of the paired spikelet, and auxin signaling involved in the regulation of cell division and growth and primordium development changes. In the kernels, reduced kernel size caused by drought stress was observed, and the obvious differences of auxin, BR and cytokine signaling transduction appeared, which indicated the modification in carbohydrate metabolism, cell differentiation and growth retardation. For the ear leaf, dramatically and synergistically reduced the expression of photosynthesis genes were observed when suffered from drought stress, the ABA- and NAC- mediate signaling pathway played important roles in the regulation of photosynthesis. Conclusions: Transcriptomic changes caused by drought were highly correlated with developmental and physiological adaptation, which was closely related to the final yield of maize, and a sketch of tissue- and developmental stage-specific responses to drought stress in maize was drafted.
2019-06-04 | GSE132113 | GEO
Project description:Pokhilko2013 - TOC1 signalling in Arabidopsis
circadian clock
In this model, Pokhilko
et al. has incorporated the negative transcriptional
regulations of the core clock genes by TOC1 and the up-regulation
of TOC1 expression by ABA signalling, to their previous model
BIOMD0000000412
This model is described in the article:
Modelling the widespread
effects of TOC1 signalling on the plant circadian clock and its
outputs.
Pokhilko A, Mas P, Millar AJ.
BMC Syst Biol 2013; 7: 23
Abstract:
BACKGROUND: 24-hour biological clocks are intimately
connected to the cellular signalling network, which complicates
the analysis of clock mechanisms. The transcriptional regulator
TOC1 (TIMING OF CAB EXPRESSION 1) is a founding component of
the gene circuit in the plant circadian clock. Recent results
show that TOC1 suppresses transcription of multiple target
genes within the clock circuit, far beyond its
previously-described regulation of the morning transcription
factors LHY (LATE ELONGATED HYPOCOTYL) and CCA1 (CIRCADIAN
CLOCK ASSOCIATED 1). It is unclear how this pervasive effect of
TOC1 affects the dynamics of the clock and its outputs. TOC1
also appears to function in a nested feedback loop that
includes signalling by the plant hormone Abscisic Acid (ABA),
which is upregulated by abiotic stresses, such as drought. ABA
treatments both alter TOC1 levels and affect the clock's timing
behaviour. Conversely, the clock rhythmically modulates
physiological processes induced by ABA, such as the closing of
stomata in the leaf epidermis. In order to understand the
dynamics of the clock and its outputs under changing
environmental conditions, the reciprocal interactions between
the clock and other signalling pathways must be integrated.
RESULTS: We extended the mathematical model of the plant clock
gene circuit by incorporating the repression of multiple clock
genes by TOC1, observed experimentally. The revised model more
accurately matches the data on the clock's molecular profiles
and timing behaviour, explaining the clock's responses in TOC1
over-expression and toc1 mutant plants. A simplified
representation of ABA signalling allowed us to investigate the
interactions of ABA and circadian pathways. Increased ABA
levels lengthen the free-running period of the clock,
consistent with the experimental data. Adding stomatal closure
to the model, as a key ABA- and clock-regulated downstream
process allowed to describe TOC1 effects on the rhythmic gating
of stomatal closure. CONCLUSIONS: The integrated model of the
circadian clock circuit and ABA-regulated environmental sensing
allowed us to explain multiple experimental observations on the
timing and stomatal responses to genetic and environmental
perturbations. These results crystallise a new role of TOC1 as
an environmental sensor, which both affects the pace of the
central oscillator and modulates the kinetics of downstream
processes.
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2013-03-22 | BIOMD0000000445 | BioModels