20 results on '"Bou-Torrent J"'
Search Results
2. The bHLH proteins BEE and BIM positively modulate the shade avoidance syndrome in Arabidopsis seedlings
- Author
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Cifuentes-Esquivel N, Bou-Torrent J, Galstyan A, Gallemí M, Sessa G, Salla Martret M, Roig-Villanova I, Ruberti I, and Martínez-García JF.
- Published
- 2013
3. The bHLH proteins BEE and BIM positively modulate the shade avoidance syndrome in Arabidopsis seedlings
- Author
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Cifuentes-Esquivel N (1), Bou-Torrent J (1), Galstyan A (1), Gallemí M (1), Sessa G (2), Salla Martret M (1), Roig-Villanova I (1), Ruberti I (2), Martínez-García JF (1, Consejo Superior de Investigaciones Científicas (España), Ministerio de Economía y Competitividad (España), Ministerio de Educación y Ciencia (España), Gobierno de Chile, Ministero dell'Economia e delle Finanze, Generalitat de Catalunya, and European Commission
- Subjects
Arabidopsis thaliana ,Light ,Arabidopsis ,Plant Science ,transcriptional co-factors ,Shade avoidance ,chemistry.chemical_compound ,shade avoidance syndrome ,Gene Expression Regulation, Plant ,Brassinosteroids ,Botany ,Gene expression ,Basic Helix-Loop-Helix Transcription Factors ,Genetics ,Brassinosteroid ,Transcription factor ,BEEs and BIMs ,biology ,Phytochrome ,Basic helix-loop-helix ,Arabidopsis Proteins ,hypocotyl elongation ,fungi ,Nuclear Proteins ,food and beverages ,Cell Biology ,biology.organism_classification ,PAR1 ,Hypocotyl ,Cell biology ,DNA-Binding Proteins ,chemistry ,Seedlings ,basic helix-loop-helix ,Mutation - Abstract
The shade avoidance syndrome (SAS) refers to a set of plant responses initiated after perception by the phytochromes of light with a reduced red to far-red ratio, indicative of vegetation proximity or shade. These responses, including elongation growth, anticipate eventual shading from potential competitor vegetation by overgrowing neighboring plants or flowering to ensure production of viable seeds for the next generation. In Arabidopsis thaliana seedlings, the SAS includes dramatic changes in gene expression, such as induction of PHYTOCHROME RAPIDLY REGULATED 1 (PAR1), encoding an atypical basic helix-loop-helix (bHLH) protein that acts as a transcriptional co-factor to repress hypocotyl elongation. Indeed, PAR1 has been proposed to act fundamentally as a dominant negative antagonist of conventional bHLH transcription factors by forming heterodimers with them to prevent their binding to DNA or other transcription factors. Here we report the identification of PAR1-interacting factors, including the brassinosteroid signaling components BR-ENHANCED EXPRESSION (BEE) and BES1-INTERACTING MYC-LIKE (BIM), and characterize their role as networked positive regulators of SAS hypocotyl responses. We provide genetic evidence that these bHLH transcriptional regulators not only control plant growth and development under shade and non-shade conditions, but are also redundant in the control of plant viability. Our results suggest that SAS responses are initiated as a consequence of a new balance of transcriptional regulators within the pre-existing bHLH network triggered by plant proximity, eventually causing hypocotyls to elongate., Fellowships or contracts were provided by CSIC (J.B.–T. and M.S.–M.), the Ministerio de Educación (A.G.), the Ministerio de Economía y Competitividad (I.R.–V, and M.G.) and the Gobierno de Chile (N.C.–E.). Research in our laboratories is supported by grants to I.R. from the Italian Ministry of Economy and Finance (Project FaReBio di Qualità) and to J.F.M.–G.'s laboratory (XRB, 2009-SGR697 from the Generalitat de Catalunya and CSD2007-00036, BIO2005-00154, BIO2008-00169 and BIO2011-23489 from Ministerio de Economía y Competitividad/Fondo Europeo de Desarrollo Regional funds).
- Published
- 2013
4. PAR1 and PAR2, two novel and atypical bHLH transcription factors, connect shade avoidance and hormone pathways
- Author
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Roig-Villanova, I., primary, Bou-Torrent, J., additional, Galstyan, A., additional, Rodríguez-Concepción, M., additional, and Martínez-García, J., additional
- Published
- 2007
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5. Spatial regulation of early phytochrome signalling components
- Author
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Bou-Torrent, J., primary, Roig-Villanova, I., additional, and Martinez-Garcia, J., additional
- Published
- 2007
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- View/download PDF
6. Correction to: Regulation of Carotenoid Biosynthesis by Shade Relies on Specific Subsets of Antagonistic Transcription Factors and Cofactors.
- Author
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Bou-Torrent J, Toledo-Ortiz G, Ortiz-Alcaide M, Cifuentes-Esquivel N, Halliday KJ, Martinez-García JF, and Rodriguez-Concepcion M
- Published
- 2022
- Full Text
- View/download PDF
7. Regulation of Carotenoid Biosynthesis by Shade Relies on Specific Subsets of Antagonistic Transcription Factors and Cofactors.
- Author
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Bou-Torrent J, Toledo-Ortiz G, Ortiz-Alcaide M, Cifuentes-Esquivel N, Halliday KJ, Martinez-García JF, and Rodriguez-Concepcion M
- Subjects
- Arabidopsis genetics, Arabidopsis Proteins genetics, Promoter Regions, Genetic, Seedlings, Transcription Factors, Arabidopsis metabolism, Arabidopsis Proteins metabolism, Carotenoids biosynthesis, Gene Expression Regulation, Plant physiology, Light
- Abstract
Carotenoids are photosynthetic pigments essential for the protection against excess light. During deetiolation, their production is regulated by a dynamic repression-activation module formed by PHYTOCHROME-INTERACTING FACTOR1 (PIF1) and LONG HYPOCOTYL5 (HY5). These transcription factors directly and oppositely control the expression of the gene encoding PHYTOENE SYNTHASE (PSY), the first and main rate-determining enzyme of the carotenoid pathway. Antagonistic modules also regulate the responses of deetiolated plants to vegetation proximity and shade (i.e. to the perception of far-red light-enriched light filtered through or reflected from neighboring plants). These responses, aimed to adapt to eventual shading from plant competitors, include a reduced accumulation of carotenoids. Here, we show that PIF1 and related photolabile PIFs (but not photostable PIF7) promote the shade-triggered decrease in carotenoid accumulation. While HY5 does not appear to be required for this process, other known PIF antagonists were found to modulate the expression of the Arabidopsis (Arabidopsis thaliana) PSY gene and the biosynthesis of carotenoids early after exposure to shade. In particular, PHYTOCHROME-RAPIDLY REGULATED1, a transcriptional cofactor that prevents the binding of true transcription factors to their target promoters, was found to interact with PIF1 and hence directly induce PSY expression. By contrast, a change in the levels of the transcriptional cofactor LONG HYPOCOTYL IN FAR RED1, which also binds to PIF1 and other PIFs to regulate shade-related elongation responses, did not impact PSY expression or carotenoid accumulation. Our data suggest that the fine-regulation of carotenoid biosynthesis in response to shade relies on specific modules of antagonistic transcriptional factors and cofactors., (© 2015 American Society of Plant Biologists. All Rights Reserved.)
- Published
- 2015
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8. Mathematical modelling of the diurnal regulation of the MEP pathway in Arabidopsis.
- Author
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Pokhilko A, Bou-Torrent J, Pulido P, Rodríguez-Concepción M, and Ebenhöh O
- Subjects
- Arabidopsis radiation effects, Circadian Clocks, Erythritol metabolism, Metabolic Networks and Pathways, Models, Biological, Photosynthesis, Arabidopsis metabolism, Circadian Rhythm, Erythritol analogs & derivatives, Sugar Phosphates metabolism
- Abstract
Isoprenoid molecules are essential elements of plant metabolism. Many important plant isoprenoids, such as chlorophylls, carotenoids, tocopherols, prenylated quinones and hormones are synthesised in chloroplasts via the 2-C-methyl-d-erythritol 4-phosphate (MEP) pathway. Here we develop a mathematical model of diurnal regulation of the MEP pathway in Arabidopsis thaliana. We used both experimental and theoretical approaches to integrate mechanisms potentially involved in the diurnal control of the pathway. Our data show that flux through the MEP pathway is accelerated in light due to the photosynthesis-dependent supply of metabolic substrates of the pathway and the transcriptional regulation of key biosynthetic genes by the circadian clock. We also demonstrate that feedback regulation of both the activity and the abundance of the first enzyme of the MEP pathway (1-deoxy-D-xylulose 5-phosphate synthase, DXS) by pathway products stabilizes the flux against changes in substrate supply and adjusts the flux according to product demand under normal growth conditions. These data illustrate the central relevance of photosynthesis, the circadian clock and feedback control of DXS for the diurnal regulation of the MEP pathway., (© 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.)
- Published
- 2015
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9. The HY5-PIF regulatory module coordinates light and temperature control of photosynthetic gene transcription.
- Author
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Toledo-Ortiz G, Johansson H, Lee KP, Bou-Torrent J, Stewart K, Steel G, Rodríguez-Concepción M, and Halliday KJ
- Subjects
- Arabidopsis metabolism, Arabidopsis Proteins biosynthesis, Carotenoids biosynthesis, Chlorophyll biosynthesis, G-Box Binding Factors genetics, Gene Expression Regulation, Plant, Photoperiod, Promoter Regions, Genetic, Receptors, Peptide biosynthesis, Seasons, Temperature, Transcription, Genetic, Arabidopsis growth & development, Arabidopsis Proteins genetics, Basic Helix-Loop-Helix Transcription Factors genetics, Basic-Leucine Zipper Transcription Factors genetics, Nuclear Proteins genetics, Photosynthesis genetics, Transcriptional Activation genetics
- Abstract
The ability to interpret daily and seasonal alterations in light and temperature signals is essential for plant survival. This is particularly important during seedling establishment when the phytochrome photoreceptors activate photosynthetic pigment production for photoautotrophic growth. Phytochromes accomplish this partly through the suppression of phytochrome interacting factors (PIFs), negative regulators of chlorophyll and carotenoid biosynthesis. While the bZIP transcription factor long hypocotyl 5 (HY5), a potent PIF antagonist, promotes photosynthetic pigment accumulation in response to light. Here we demonstrate that by directly targeting a common promoter cis-element (G-box), HY5 and PIFs form a dynamic activation-suppression transcriptional module responsive to light and temperature cues. This antagonistic regulatory module provides a simple, direct mechanism through which environmental change can redirect transcriptional control of genes required for photosynthesis and photoprotection. In the regulation of photopigment biosynthesis genes, HY5 and PIFs do not operate alone, but with the circadian clock. However, sudden changes in light or temperature conditions can trigger changes in HY5 and PIFs abundance that adjust the expression of common target genes to optimise photosynthetic performance and growth.
- Published
- 2014
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10. Plant proximity perception dynamically modulates hormone levels and sensitivity in Arabidopsis.
- Author
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Bou-Torrent J, Galstyan A, Gallemí M, Cifuentes-Esquivel N, Molina-Contreras MJ, Salla-Martret M, Jikumaru Y, Yamaguchi S, Kamiya Y, and Martínez-García JF
- Subjects
- Adaptation, Physiological drug effects, Adaptation, Physiological radiation effects, Arabidopsis drug effects, Arabidopsis genetics, Arabidopsis radiation effects, Arabidopsis Proteins genetics, Arabidopsis Proteins metabolism, Brassinosteroids pharmacology, Gene Expression Regulation, Plant drug effects, Gene Expression Regulation, Plant radiation effects, Genes, Plant, Hypocotyl drug effects, Hypocotyl physiology, Hypocotyl radiation effects, Indoleacetic Acids pharmacology, Light, Mutation genetics, Oligonucleotide Array Sequence Analysis, Plant Growth Regulators pharmacology, Arabidopsis physiology, Plant Growth Regulators metabolism
- Abstract
The shade avoidance syndrome (SAS) refers to a set of plant responses initiated after perception by the phytochromes of light enriched in far-red colour reflected from or filtered by neighbouring plants. These varied responses are aimed at anticipating eventual shading from potential competitor vegetation. In Arabidopsis thaliana, the most obvious SAS response at the seedling stage is the increase in hypocotyl elongation. Here, we describe how plant proximity perception rapidly and temporally alters the levels of not only auxins but also active brassinosteroids and gibberellins. At the same time, shade alters the seedling sensitivity to hormones. Plant proximity perception also involves dramatic changes in gene expression that rapidly result in a new balance between positive and negative factors in a network of interacting basic helix-loop-helix proteins, such as HFR1, PAR1, and BIM and BEE factors. Here, it was shown that several of these factors act as auxin- and BR-responsiveness modulators, which ultimately control the intensity or degree of hypocotyl elongation. It was deduced that, as a consequence of the plant proximity-dependent new, dynamic, and local balance between hormone synthesis and sensitivity (mechanistically resulting from a restructured network of SAS regulators), SAS responses are unleashed and hypocotyls elongate., (© The Author 2014. Published by Oxford University Press on behalf of the Society for Experimental Biology.)
- Published
- 2014
- Full Text
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11. ATHB4 and HAT3, two class II HD-ZIP transcription factors, control leaf development in Arabidopsis.
- Author
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Bou-Torrent J, Salla-Martret M, Brandt R, Musielak T, Palauqui JC, Martínez-García JF, and Wenkel S
- Subjects
- Arabidopsis genetics, Arabidopsis Proteins genetics, Cotyledon genetics, Cotyledon growth & development, Cotyledon metabolism, Gene Expression Regulation, Plant genetics, Gene Expression Regulation, Plant physiology, Homeodomain Proteins genetics, Plant Leaves genetics, Plants, Genetically Modified genetics, Plants, Genetically Modified growth & development, Plants, Genetically Modified metabolism, Transcription Factors genetics, Arabidopsis growth & development, Arabidopsis metabolism, Arabidopsis Proteins metabolism, Homeodomain Proteins metabolism, Plant Leaves growth & development, Plant Leaves metabolism, Transcription Factors metabolism
- Abstract
In response to plant proximity or canopy shade, plants can react by altering elongation growth and development. Several members of the class II homeodomain-leucine zipper (HD-ZIPII) transcription factor family have been shown to play an instrumental role in the responses to shade. HD-ZIP members of the class III (HD-ZIPIII), by contrast, are involved in basic patterning processes. We recently showed that REVOLUTA (REV), a member of the HD-ZIPIII family, directly and positively regulates the expression of several genes involved in shade-induced growth, such as those encoding HD-ZIPII factors HAT2, HAT3, ATHB2/HAT4 and ATHB4, and of the components of the auxin biosynthesis pathway YUCCA5 and TAA1. Furthermore, we could demonstrate a novel role for HD-ZIPIII in shade-induced promotion of growth. Here we show that besides responding to shade, ATHB4 and HAT3 have a critical role in establishing the dorso-ventral axis in cotyledons and developing leaves. Loss-of-function mutations in these two HD-ZIPII genes (athb4 hat3) results in severely abaxialized, entirely radialized leaves. Conversely, overexpression of HAT3 results in adaxialized leaf development. Taken together, our findings unravel a so far unappreciated role for an HD-ZIPII/HD-ZIPIII module required for dorso-ventral patterning of leaves. The finding that HD-ZIPII/HD-ZIPIII also function in shade avoidance suggests that this module is at the nexus of patterning and growth promotion.
- Published
- 2012
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12. Genome-wide binding-site analysis of REVOLUTA reveals a link between leaf patterning and light-mediated growth responses.
- Author
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Brandt R, Salla-Martret M, Bou-Torrent J, Musielak T, Stahl M, Lanz C, Ott F, Schmid M, Greb T, Schwarz M, Choi SB, Barton MK, Reinhart BJ, Liu T, Quint M, Palauqui JC, Martínez-García JF, and Wenkel S
- Subjects
- Adaptation, Physiological, Arabidopsis cytology, Arabidopsis growth & development, Arabidopsis radiation effects, Arabidopsis Proteins metabolism, Binding Sites, Chromatin Immunoprecipitation, Gene Expression Regulation, Developmental, Gene Expression Regulation, Plant, Genome, Plant genetics, Homeodomain Proteins metabolism, Hypocotyl cytology, Hypocotyl genetics, Hypocotyl growth & development, Hypocotyl radiation effects, In Situ Hybridization, Indoleacetic Acids analysis, Indoleacetic Acids metabolism, Light, Mutation, Phylogeny, Plant Leaves cytology, Plant Leaves genetics, Plant Leaves growth & development, Plant Leaves radiation effects, Sequence Analysis, DNA, Signal Transduction, Transcription Factors metabolism, Arabidopsis genetics, Arabidopsis Proteins genetics, Body Patterning, Homeodomain Proteins genetics, Transcription Factors genetics
- Abstract
Unlike the situation in animals, the final morphology of the plant body is highly modulated by the environment. During Arabidopsis development, intrinsic factors provide the framework for basic patterning processes. CLASS III HOMEODOMAIN LEUCINE ZIPPER (HD-ZIPIII) transcription factors are involved in embryo, shoot and root patterning. During vegetative growth HD-ZIPIII proteins control several polarity set-up processes such as in leaves and the vascular system. We have identified several direct target genes of the HD-ZIPIII transcription factor REVOLUTA (REV) using a chromatin immunoprecipitation/DNA sequencing (ChIP-Seq) approach. This analysis revealed that REV acts upstream of auxin biosynthesis and affects directly the expression of several class II HD-ZIP transcription factors that have been shown to act in the shade-avoidance response pathway. We show that, as well as involvement in basic patterning, HD-ZIPIII transcription factors have a critical role in the control of the elongation growth that is induced when plants experience shade. Leaf polarity is established by the opposed actions of HD-ZIPIII and KANADI transcription factors. Finally, our study reveals that the module that consists of HD-ZIPIII/KANADI transcription factors controls shade growth antagonistically and that this antagonism is manifested in the opposed regulation of shared target genes., (© 2012 The Authors. The Plant Journal © 2012 Blackwell Publishing Ltd.)
- Published
- 2012
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13. A dual mechanism controls nuclear localization in the atypical basic-helix-loop-helix protein PAR1 of Arabidopsis thaliana.
- Author
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Galstyan A, Bou-Torrent J, Roig-Villanova I, and Martínez-García JF
- Subjects
- Amino Acid Sequence, Arabidopsis Proteins chemistry, Basic Helix-Loop-Helix Transcription Factors chemistry, Molecular Sequence Data, Mutant Proteins chemistry, Mutant Proteins metabolism, Mutation genetics, Nuclear Localization Signals metabolism, Phenotype, Protein Multimerization, Protein Structure, Tertiary, Protein Transport, Sequence Alignment, Structure-Activity Relationship, Arabidopsis cytology, Arabidopsis metabolism, Arabidopsis Proteins metabolism, Basic Helix-Loop-Helix Transcription Factors metabolism, Cell Nucleus metabolism
- Abstract
PAR1 is an atypical basic-helix-loop-helix (bHLH) protein that negatively regulates the shade avoidance syndrome in Arabidopsis thaliana acting as a transcriptional cofactor. Consistently with this function, PAR1 has to be in the nucleus to display biological activity. Previous structure-function analyses revealed that the N-terminal region of PAR1 drives the protein to the nucleus. However, truncated forms of PAR1 lacking this region still display biological activity, implying that PAR1 has additional mechanisms to localize into the nucleus. In this work, we compared the primary structure of PAR1 and various related and unrelated plant bHLH proteins, which led us to suggest that PAR1 contains a non-canonical nuclear localization signal (NLS) in the N-terminal region. By overexpressing truncated and mutated derivatives of PAR1, we have also investigated the importance of other regions of PAR1, such as the acidic and the extended HLH dimerization domains, for its nuclear localization. We found that, in the absence of the N-terminal region, a functional HLH domain is required for nuclear localization. Our results suggest the existence of a dual mechanism for PAR1 nuclear localization: (1) one mediated by the N-terminal non-consensus NLS and (2) a second one that involves interaction with other proteins via the dimerization domain.
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- 2012
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14. A DELLA in disguise: SPATULA restrains the growth of the developing Arabidopsis seedling.
- Author
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Josse EM, Gan Y, Bou-Torrent J, Stewart KL, Gilday AD, Jeffree CE, Vaistij FE, Martínez-García JF, Nagy F, Graham IA, and Halliday KJ
- Subjects
- Alleles, Arabidopsis drug effects, Arabidopsis genetics, Arabidopsis radiation effects, Arabidopsis Proteins genetics, Basic Helix-Loop-Helix Transcription Factors genetics, Cotyledon drug effects, Cotyledon genetics, Cotyledon growth & development, Cotyledon radiation effects, Gene Expression Regulation, Plant, Genes, Plant genetics, Gibberellins pharmacology, Hypocotyl drug effects, Hypocotyl genetics, Hypocotyl growth & development, Hypocotyl radiation effects, Light, Models, Biological, Mutation genetics, Oligonucleotide Array Sequence Analysis, Phenotype, Phytochrome B metabolism, Repressor Proteins genetics, Seedlings drug effects, Seedlings genetics, Seedlings radiation effects, Arabidopsis growth & development, Arabidopsis Proteins metabolism, Basic Helix-Loop-Helix Transcription Factors metabolism, Repressor Proteins metabolism, Seedlings growth & development
- Abstract
The period following seedling emergence is a particularly vulnerable stage in the plant life cycle. In Arabidopsis thaliana, the phytochrome-interacting factor (PIF) subgroup of basic-helix-loop-helix transcription factors has a pivotal role in regulating growth during this early phase, integrating environmental and hormonal signals. We previously showed that SPATULA (SPT), a PIF homolog, regulates seed dormancy. In this article, we establish that unlike PIFs, which mainly promote hypocotyl elongation, SPT is a potent regulator of cotyledon expansion. Here, SPT acts in an analogous manner to the gibberellin-dependent DELLAs, REPRESSOR OF GA1-3 and GIBBERELLIC ACID INSENSITIVE, which restrain cotyledon expansion alongside SPT. However, although DELLAs are not required for SPT action, we demonstrate that SPT is subject to negative regulation by DELLAs. Cross-regulation of SPT by DELLAs ensures that SPT protein levels are limited when DELLAs are abundant but rise following DELLA depletion. This regulation provides a means to prevent excessive growth suppression that would result from the dual activity of SPT and DELLAs, yet maintain growth restraint under DELLA-depleted conditions. We present evidence that SPT and DELLAs regulate common gene targets and illustrate that the balance of SPT and DELLA action depends on light quality signals in the natural environment.
- Published
- 2011
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15. The shade avoidance syndrome in Arabidopsis: a fundamental role for atypical basic helix-loop-helix proteins as transcriptional cofactors.
- Author
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Galstyan A, Cifuentes-Esquivel N, Bou-Torrent J, and Martinez-Garcia JF
- Subjects
- Arabidopsis genetics, Arabidopsis metabolism, Arabidopsis Proteins genetics, Basic Helix-Loop-Helix Transcription Factors genetics, DNA-Binding Proteins genetics, Gene Expression Regulation, Plant, Hypocotyl radiation effects, Nuclear Proteins genetics, Plants, Genetically Modified genetics, Plants, Genetically Modified metabolism, Plants, Genetically Modified radiation effects, Transcription, Genetic, Transgenes, Arabidopsis radiation effects, Arabidopsis Proteins metabolism, Basic Helix-Loop-Helix Transcription Factors metabolism, DNA-Binding Proteins metabolism, Nuclear Proteins metabolism
- Abstract
The shade avoidance syndrome (SAS) refers to a set of plant responses aimed at anticipating eventual shading by potential competitors. The SAS is initiated after perception of nearby vegetation as a reduction in the red to far-red ratio (R:FR) of the incoming light. Low R:FR light is perceived by the phytochromes, triggering dramatic changes in gene expression that, in seedlings, eventually result in an increased hypocotyl elongation to overgrow competitors. This response is inhibited by genes such as PHYTOCHROME RAPIDLY REGULATED 1 (PAR1), PAR2 and LONG HYPOCOTYL IN FR 1 (HFR1), which are transcriptionally induced by low R:FR. Although PAR1/PAR2 and HFR1 proteins belong to different groups of basic helix-loop-helix (bHLH) transcriptional regulators, they all lack a typical basic domain required for binding to E-box and G-box motifs in the promoter of target genes. By overexpressing derivatives of PAR1 and HFR1 we show that these proteins are actually transcriptional cofactors that do not need to bind DNA to directly regulate transcription. We conclude that protein-protein interactions involving the HLH domain of PAR1 and HFR1 are a fundamental aspect of the mechanism by which these proteins regulate gene expression, most likely through interaction with true transcription factors that do bind to the target genes and eventually unleash the observed SAS responses., (© 2011 The Authors. The Plant Journal © 2011 Blackwell Publishing Ltd.)
- Published
- 2011
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16. Gibberellin A1 metabolism contributes to the control of photoperiod-mediated tuberization in potato.
- Author
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Bou-Torrent J, Martínez-García JF, García-Martínez JL, and Prat S
- Subjects
- Amino Acid Sequence, Biosynthetic Pathways, Circadian Rhythm, Gene Expression Regulation, Enzymologic, Gene Expression Regulation, Plant, Isoenzymes classification, Isoenzymes genetics, Isoenzymes metabolism, Mixed Function Oxygenases classification, Mixed Function Oxygenases genetics, Mixed Function Oxygenases metabolism, Molecular Sequence Data, Phylogeny, Plant Components, Aerial enzymology, Plant Components, Aerial genetics, Plant Components, Aerial metabolism, Plant Leaves enzymology, Plant Leaves genetics, Plant Leaves metabolism, Plant Tubers genetics, Plants, Genetically Modified, Reverse Transcriptase Polymerase Chain Reaction, Sequence Homology, Amino Acid, Solanum tuberosum enzymology, Solanum tuberosum genetics, Time Factors, Gibberellins metabolism, Photoperiod, Plant Tubers metabolism, Solanum tuberosum metabolism
- Abstract
Some potato species require a short-day (SD) photoperiod for tuberization, a process that is negatively affected by gibberellins (GAs). Here we report the isolation of StGA3ox2, a gene encoding a GA 3-oxidase, whose expression is increased in the aerial parts and is repressed in the stolons after transfer of photoperiod-dependent potato plants to SD conditions. Over-expression of StGA3ox2 under control of constitutive or leaf-specific promoters results in taller plants which, in contrast to StGA20ox1 over-expressers previously reported, tuberize earlier under SD conditions than the controls. By contrast, StGA3ox2 tuber-specific over-expression results in non-elongated plants with slightly delayed tuber induction. Together, our experiments support that StGA3ox2 expression and gibberellin metabolism significantly contribute to the tuberization time in strictly photoperiod-dependent potato plants.
- Published
- 2011
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17. ATHB4, a regulator of shade avoidance, modulates hormone response in Arabidopsis seedlings.
- Author
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Sorin C, Salla-Martret M, Bou-Torrent J, Roig-Villanova I, and Martínez-García JF
- Subjects
- Arabidopsis metabolism, Arabidopsis radiation effects, Arabidopsis Proteins genetics, Gene Expression Regulation, Plant, Genes, Plant, Indoleacetic Acids metabolism, Leucine Zippers, Light, Plant Growth Regulators metabolism, Plants, Genetically Modified genetics, Plants, Genetically Modified metabolism, Plants, Genetically Modified radiation effects, RNA, Plant genetics, Seedlings genetics, Seedlings metabolism, Seedlings radiation effects, Transcription Factors genetics, Arabidopsis genetics, Arabidopsis Proteins metabolism, Photoreceptors, Plant metabolism, Transcription Factors metabolism
- Abstract
Plants sense the presence of competing neighboring vegetation as a change in light quality: i.e. they sense the reduced ratio of red light to far-red light. The responses to shade are generally referred to as the shade avoidance syndrome (SAS), and involve various developmental changes intended to outgrow or outcompete the neighboring plants. Here, we analyze the function of ATHB4, a gene encoding a homeodomain-leucine zipper (HD-Zip) class-II transcription factor from Arabidopsis thaliana, the expression of which is rapidly and directly upregulated after proximity perception by the phytochrome photoreceptors. ATHB4 acts redundantly with other members of the HD-Zip class-II transcription factors. The expression of these genes is regulated by other members of the same class, forming a small transcriptional network of factors in which homeostasis is mutually controlled. Our results suggest that some members of this small gene subfamily can modulate SAS responses by controlling auxin, brassinosteroid and gibberellin molecular and/or physiological responsiveness. In particular, we propose ATHB4 as a new shade signaling component that participates in integrating shade perception and hormone-mediated growth.
- Published
- 2009
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18. PAR1 and PAR2 integrate shade and hormone transcriptional networks.
- Author
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Bou-Torrent J, Roig-Villanova I, Galstyan A, and Martínez-García JF
- Abstract
PHYTOCHROME RAPIDLY REGULATED1 (PAR1) and PAR2 are two negative regulators of shade avoidance syndrome (SAS) responses in Arabidopsis. PAR1 and PAR2 belong to the bHLH family of transcription factors and act as direct transcriptional repressors of auxin- and brassinosteroid-responsive genes. These observations led us to propose that PAR1 and PAR2 might integrate shade and hormone signals. After plant proximity perception by the phytochrome photoreceptors, the expression of PAR1, PAR2 and dozens of additional PAR genes is affected, initiating a complex web of transcriptional events instrumental for the establishment of the SAS responses. Studying the organization of this complex transcriptional network, that is, the interactions amongst the different PAR factors involved and how they are connected with the endogenous hormone-regulated transcriptional networks, seems therefore fundamental to understand how SAS is modulated.
- Published
- 2008
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19. Light signaling: back to space.
- Author
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Bou-Torrent J, Roig-Villanova I, and Martínez-García JF
- Subjects
- Models, Biological, Seedlings genetics, Seedlings growth & development, Seedlings radiation effects, Gene Expression Regulation, Plant radiation effects, Light
- Abstract
Recent work has increased our understanding of the molecular and cellular mechanisms of the phytochrome family of photoreceptors in controlling plant photomorphogenesis. However, the importance of long-distance communication in controlling light responses has received relatively little attention and is poorly understood. In this article, by taking a closer look at old and new experiments that extend the analysis of light signaling beyond the limits of the plant cell, we offer to look at the field in a new light. Furthermore, we discuss how intercellular and inter-organ communication might integrate with the transcriptional networks controlling light-regulated responses in plants, a novel view that might help to re-assess the parameters by which we screen for photomorphogenic mutants in the future.
- Published
- 2008
- Full Text
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20. Interaction of shade avoidance and auxin responses: a role for two novel atypical bHLH proteins.
- Author
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Roig-Villanova I, Bou-Torrent J, Galstyan A, Carretero-Paulet L, Portolés S, Rodríguez-Concepción M, and Martínez-García JF
- Subjects
- 2,4-Dichlorophenoxyacetic Acid pharmacology, Adaptation, Biological, Amino Acid Sequence, Arabidopsis anatomy & histology, Arabidopsis drug effects, Arabidopsis metabolism, Arabidopsis Proteins metabolism, Basic Helix-Loop-Helix Transcription Factors metabolism, Cycloheximide pharmacology, DNA, Plant genetics, Dexamethasone pharmacology, Glucocorticoids pharmacology, Herbicides pharmacology, Indoleacetic Acids metabolism, Molecular Sequence Data, Phenotype, Plants, Genetically Modified anatomy & histology, Plants, Genetically Modified drug effects, Plants, Genetically Modified genetics, Plants, Genetically Modified metabolism, Protein Synthesis Inhibitors pharmacology, Sequence Analysis, DNA, Arabidopsis genetics, Arabidopsis Proteins genetics, Basic Helix-Loop-Helix Transcription Factors genetics, Sunlight
- Abstract
Plants sense the presence of potentially competing nearby individuals as a reduction in the red to far-red ratio of the incoming light. In anticipation of eventual shading, a set of plant responses known as the shade avoidance syndrome (SAS) is initiated soon after detection of this signal by the phytochrome photoreceptors. Here we analyze the function of PHYTOCHROME RAPIDLY REGULATED1 (PAR1) and PAR2, two Arabidopsis thaliana genes rapidly upregulated after simulated shade perception. These genes encode two closely related atypical basic helix-loop-helix proteins with no previously assigned function in plant development. Using reverse genetic approaches, we show that PAR1 and PAR2 act in the nucleus to broadly control plant development, acting as negative regulators of a variety of SAS responses, including seedling elongation and photosynthetic pigment accumulation. Molecularly, PAR1 and PAR2 act as direct transcriptional repressors of two auxin-responsive genes, SMALL AUXIN UPREGULATED15 (SAUR15) and SAUR68. Additional results support that PAR1 and PAR2 function in integrating shade and hormone transcriptional networks, rapidly connecting phytochrome-sensed light changes with auxin responsiveness.
- Published
- 2007
- Full Text
- View/download PDF
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