Molecular bases for the constitutive photomorphogenic phenotypes in Arabidopsis.
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ABSTRACT:
SUBMITTER: Pham VN
PROVIDER: S-EPMC6288388 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Interaction between light signaling and stress response has been recently reported in plants. Here, we investigated the role of CONSTITUTIVE PHOTOMORPHOGENIC 1 (COP1), a key regulator of light signaling, in endoplasmic reticulum (ER) stress response in Arabidopsis. The cop1-4 mutant Arabidopsis plants were highly sensitive to ER stress induced by treatment with tunicarmycin (Tm). Interestingly, the abundance of nuclear-localized COP1 increased under ER stress conditions. Complementation of cop1-4 mutant plants with the wild-type or variant types of COP1 revealed that the nuclear localization and dimerization of COP1 are essential for its function in plant ER stress response. Moreover, the protein amount of ELONGATED HYPOCOTYL 5 (HY5), which inhibits bZIP28 to activate the unfolded protein response (UPR), decreased under ER stress conditions in a COP1-dependent manner. Accordingly, the binding of bZIP28 to the BIP3 promoter was reduced in cop1-4 plants and increased in hy5 plants compared with the wild type. Furthermore, introduction of the hy5 mutant locus into the cop1-4 mutant background rescued its ER stress-sensitive phenotype. Altogether, our results suggest that COP1, a negative regulator of light signaling, positively controls ER stress response by partially degrading HY5 in the nucleus.
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Project description:Under favorable moisture, temperature, and light conditions, gibberellin (GA) biosynthesis is induced and triggers seed germination. A major mechanism by which GA promotes seed germination is by promoting the degradation of the DELLA protein RGA-LIKE 2 (RGL2), a major repressor of germination in Arabidopsis (Arabidopsis thaliana) seeds. Analysis of seed germination phenotypes of constitutive photomorphogenic 1 (cop1) mutants and complemented COP1-OX/cop1-4 lines in response to GA and paclobutrazol (PAC) suggested a positive role for COP1 in seed germination and a relation with GA signaling. cop1-4 mutant seeds showed PAC hypersensitivity, but transformation with a COP1 overexpression construct rendered them PAC insensitive, with a phenotype similar to that of rgl2 mutant (rgl2-SK54) seeds. Furthermore, cop1-4 rgl2-SK54 double mutants showed a PAC-insensitive germination phenotype like that of rgl2-SK54, identifying COP1 as an upstream negative regulator of RGL2. COP1 interacted directly with RGL2, and in vivo this interaction was strongly enhanced by SUPPRESSOR OF PHYA-105 1. COP1 directly ubiquitinated RGL2 to promote its degradation. Moreover, GA stabilized COP1 with consequent RGL2 destabilization. By uncovering this COP1-RGL2 regulatory module, we reveal a mechanism whereby COP1 positively regulates seed germination and controls the expression of germination-promoting genes.
| S-EPMC9237706 | biostudies-literature
Project description:In Arabidopsis, CONSTITUTIVE PHOTOMORPHOGENIC/DE-ETIOLATED/FUSCA (COP/DET/FUS) genes act in repression of photomorphogenesis in darkness, and recent reports revealed that some of these genes, such as COP1 and DET1, also have important roles in controlling flowering time and circadian rhythm. The COP/DET/FUS protein COP10 interacts with DET1 and DNA DAMAGE-BINDING PROTEIN 1 (DDB1) to form a CDD complex and represses photomorphogenesis in darkness. The cop10-4 mutants flower normally in inductive long days (LD) but early in non-inductive short days (SD) compared with wild type (WT); however, the role of COP10 remains unknown. Here, we investigate the role of COP10 in SD-dependent floral repression. Reverse transcription-quantitative PCR revealed that in SD, expression of the LD-dependent floral inducers GI, FKF1, and FT significantly increased in cop10-4 mutants, compared with WT. This suggests that COP10 mainly regulates FT expression in a CO-independent manner. We also show that COP10 interacts with GI in vitro and in vivo, suggesting that COP10 could also affect GI function at the posttranslational level. Moreover, FLC expression was repressed drastically in cop10-4 mutants and COP10 interacts with MULTICOPY SUPPRESSOR OF IRA1 4 (MSI4)/FVE (MSI4/FVE), which epigenetically inhibits FLC expression. These data suggest that COP10 contributes to delaying flowering in the photoperiod and autonomous pathways by downregulating FT expression under SD.
| S-EPMC4661828 | biostudies-literature
Project description:Light is both a source of energy and a critically important environmental signal for plant development. Through decades of research, 2 groups of photomorphogenic repressors have been identified. The first group is CONSTITUTIVE PHOTOMORPHOGENIC/DE-ETIOLATED/FUSCA (COP/DET/FUS), which were first identified by genetic screening and then by purification of protein complexes. Another group is the Phytochrome-Interacting Factors (PIFs), which were identified by yeast 2-hybrid screens using phyB as bait. How so many factors work together to repress photomorphogenesis has long been an interesting question. Previously, we demonstrated that CULLIN4 (CUL4) works as a core factor connecting the COP1-SPA complexes, the COP9 signalosome (CSN), and the COP10-DDB1-DET1 (CDD) complex. Recently, we showed that DET1 represses photomorphogenesis through positively regulating the abundance of PIF proteins in the dark. Dr. Huq and his colleagues reported that PIFs may enhance the function of COP1-SPA complexes to promote the degradation of HY5, and thus they synergistically repress photomorphogenesis in the dark. Though much work still needs to be done, these recent breakthroughs shed light on the regulatory relationships among these multiple photomorphogenic repressors.
| S-EPMC4622545 | biostudies-other
Project description:We report the application of ribosome profiling method to map ribosome locations on transcripts in de-etiolating Arabidopsis seedlings
2013-11-08 | GSE43703 | GEO
Project description:This application is from a NERC-funded consortium (Mark MacNair, Nick Smirnoff, Exeter) and (Brian Ford-Lloyd, John Newbury, Birmingham). Metal tolerance is one of the classic examples of micro-evolution. Despite extensive research the physiological bases of the adaptation in plants are largely unknown. Arabidopsis halleri is a zinc tolerant, zinc accumulating species whereas Arabidopsis petraea is non-accumulating and non-tolerant. The objective of our programme is to identify: a) those key genes that act to determine Zn tolerance and accumulation in Arabidopsis (and which account for the difference in performance of A. halleri and A. petraea grown in the presence of elevated Zn), and b) those _downstream_ genes that are expressed as part of the tolerance or accumulation response. Phase 1: Total of 24 chips: Material ready by May 2003. The results will: a) tell us how effectively material derived from other Arabidopsis species hybridises to the chips, and b) identify genes that are differentially expressed in the two species in the presence and absence of Zn stress (thus providing initial lists of genes that may be responsible for Zn tolerance or accumulation- (but see phase 2). A. halleri exposed to low and high Zn; root and leaf mRNAs extracted: 3 replicates of each: = 12 slides. A. petraea exposed to low and high Zn; root and leaf mRNAs extracted: 3 replicates of each: = 12 slides. Phase 2: Total of 48 chips: Material ready by September 2003. The results will tell us which genes, identified as having appropriate expression patterns, co-segregate with the Zn tolerance or accumulation phenotype and will provide firmer candidate genes for intensive study. Bulks will be produced from F3 progeny (from the halleri x petraea cross) following phentoypic analyses for Zn tolerance and accumulation. A bulk of F3 progeny all exhibiting high Zn tolerance: exposed to low and high Zn; leaf and root mRNAs: 3 replicates: = 12 slides. A bulk of F3 progeny all exhibiting low Zn tolerance: exposed to low and high Zn; leaf and root mRNAs: 3 replicates: = 12 slides. A bulk of F3 progeny all exhibiting high Zn accumulation: exposed to low and high Zn; leaf and root mRNAs: 3 replicates: = 12 slides. A bulk of F3 progeny all exhibiting low Zn accumulation: exposed to low and high Zn; leaf and root mRNAs: 3 replicates: = 12 slides. Experimenter name = H. John Newbury Experimenter phone = 0121 414 5581 Experimenter fax = 0121 414 5925 Experimenter institute = University of Birmingham Experimenter address = School of Biosciences Experimenter address = University of Birmingham Experimenter address = Edgbaston Experimenter address = Birmingham Experimenter zip/postal_code = B15 2TT Experimenter country = UK Keywords: stimulus_or_stress_design; organism_part_comparison_design; strain_or_line_design
2007-01-08 | GSE5738 | GEO
Project description:Plants use light as a source of information via a suite of photomorphogenic photoreceptors to optimize growth in response to their light environment. Growth-promoting hormones such as brassinosteroids also can modulate many of these responses. BAS1 and SOB7 are brassinosteroid-catabolizing P450s in Arabidopsis thaliana that synergistically/redundantly modulate photomorphogenic traits such as flowering time. The role of BAS1 and SOB7 in photomorphogenesis has been investigated by studying null-mutant genetic interactions with the photoreceptors phyA, phyB, and cry1 with regard to seed germination and flowering time. The removal of BAS1 and/or SOB7 rescued the low germination rate of the phyA-211 phyB-9 double-null mutant. With regard to floral induction, bas1-2 and sob7-1 showed a complex set of genetic interactions with photoreceptor-null mutants. Histochemical analysis of transgenic plants harboring BAS1:BAS1-GUS and SOB7:SOB7-GUS translational fusions under the control of their endogenous promoters revealed overlapping and distinct expression patterns. BAS1's expression in the shoot apex increases during the phase transition from short-to-long-day growth conditions and requires phyB in red light. In summary, BAS1 and SOB7 displayed both simple and complex genetic interactions with the phytochromes in a plant-stage specific manner.
| S-EPMC3516480 | biostudies-literature
Project description:In Arabidopsis, ultraviolet (UV)-B-induced photomorphogenesis is initiated by a unique photoreceptor UV resistance locus 8 (UVR8) which utilizes its tryptophan residues as internal chromophore to sense UV-B. As a result of UV-B light perception, the UVR8 homodimer shaped by its arginine residues undergoes a conformational switch of monomerization. Then UVR8 associates with the constitutively photomorphogenic 1-suppressor of PHYA (COP1-SPA) core complex(es) that is released from the cullin 4-damaged dna binding protein 1 (CUL4-DDB1) E3 apparatus. This association, in turn, causes COP1 to convert from a repressor to a promoter of photomorphogenesis. It is not fully understood, however, regarding the biological significance of light-absorbing and dimer-stabilizing residues for UVR8 activity in photomorphogenic UV-B signaling. Here, we take advantage of transgenic UVR8 variants to demonstrate that two light-absorbing tryptophans, W233 and W285, and two dimer-stabilizing arginines, R286 and R338, play pivotal roles in UV-B-induced photomorphogenesis. Mutation of each residue results in alterations in UV-B light perception, UVR8 monomerization and UVR8-COP1 association in response to photomorphogenic UV-B. We also identify and functionally characterize two constitutively active UVR8 variants, UVR8W285A and UVR8R338A, whose photobiological activities are enhanced by the repression of CUL4, a negative regulator in this pathway. Based on our molecular and biochemical evidence, we propose that the UVR8-COP1 affinity in plants critically determines the photomorphogenic UV-B signal transduction coupling with UVR8-mediated UV-B light perception.
| S-EPMC3961177 | biostudies-literature
Project description:BackgroundPost-transcriptional control of gene expression mediated by small regulatory RNAs (sRNAs) is vital for growth and development of diverse organisms. The biogenesis of sRNAs is regulated by both positive and negative regulators known to regulate photomorphogenic development. Two microRNAs (miRNAs), miR157 and miR319, also regulate photomorphogenesis. However, genome-wide profiling of sRNAs and their regulation of target genes during photomorphogenesis has been missing. We provide a comprehensive view of sRNA-controlled gene expression in this developmental process.ResultsBy profiling sRNAs and the 5' ends of degraded mRNAs during the first 24 h of photomorphogenic development in Arabidopsis, we identified 335 sRNA-mediated mRNA cleavage events in de-etiolating seedlings. These cleavage events are primarily resulted from actions of highly expressed miRNAs and irrelevant to the abundance of target mRNAs. In the light, the expression of the slicer protein gene ARGONAUTE1 in the miRNA functioning pathway could be fine-tuned by miRNA168a/b. We also found that miR396a/b positively regulates de-etiolation by suppressing GROWTH REGULATING FACTORs. Our results suggest that the miRNAs are required to tune down the target mRNAs and regulate photomorphogenesis.ConclusionsRNAs may have a broad impact on gene expression regulation for optimized photomorphogenic development. With both positive and negative regulators under the control of sRNAs, young Arabidopsis seedlings can have a timely but not exaggerated developmental adaptation to light.
| S-EPMC5525271 | biostudies-literature
Project description:This application is from a NERC-funded consortium (Mark MacNair, Nick Smirnoff, Exeter) and (Brian Ford-Lloyd, John Newbury, Birmingham). Metal tolerance is one of the classic examples of micro-evolution. Despite extensive research the physiological bases of the adaptation in plants are largely unknown. Arabidopsis halleri is a zinc tolerant, zinc accumulating species whereas Arabidopsis petraea is non-accumulating and non-tolerant. The objective of our programme is to identify a) those key genes that act to determine Zn tolerance and accumulation in Arabidopsis (and which account for the difference in performance of A. halleri and A. petraea grown in the presence of elevated Zn) and b) those _downstream_ genes that are expressed as part of the tolerance or accumulation response. Phase 1: Total of 24 chips: Material ready by May 2003 The results will a) tell us how effectively material derived from other Arabidopsis species hybridises to the chips, and b) identify genes that are differentially expressed in the two species in the presence and absence of Zn stress (thus providing initial lists of genes that may be responsible for Zn tolerance or accumulation- but see phase 2)· A. halleri exposed to low and high Zn; root and leaf mRNAs extracted: 3 replicates of each: = 12 slides· A. petraea exposed to low and high Zn; root and leaf mRNAs extracted: 3 replicates of each: = 12 slides Phase 2: Total of 48 chips: Material ready by September 2003 The results will tell us which genes, identified as having appropriate expression patterns, co-segregate with the Zn tolerance or accumulation phenotype and will provide firmer candidate genes for intensive study. Bulks will be produced from F3 progeny (from the halleri x petraea cross) following phentoypic analyses for Zn tolerance and accumulation.· A bulk of F3 progeny all exhibiting high Zn tolerance: exposed to low and high Zn; leaf and root mRNAs: 3 replicates: = 12 slides· A bulk of F3 progeny all exhibiting low Zn tolerance: exposed to low and high Zn; leaf and root mRNAs: 3 replicates: = 12 slides· A bulk of F3 progeny all exhibiting high Zn accumulation: exposed to low and high Zn; leaf and root mRNAs: 3 replicates: = 12 slides· A bulk of F3 progeny all exhibiting low Zn accumulation: exposed to low and high Zn; leaf and root mRNAs: 3 replicates: = 12 slides Experimenter name = H. John Newbury Experimenter phone = 0121 414 5581 Experimenter fax = 0121 414 5925 Experimenter department = Newbury lab Experimenter institute = University of Birmingham Experimenter address = School of Biosciences Experimenter address = University of Birmingham Experimenter address = Edgbaston Experimenter address = Birmingham Experimenter zip/postal_code = B15 2TT Experimenter country = UK Keywords: stimulus_or_stress_design; organism_part_comparison_design; strain_or_line_design
2007-01-08 | GSE5613 | GEO