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Freytes SN, Gobbini ML, Cerdán PD. The Plant Mediator Complex in the Initiation of Transcription by RNA Polymerase II. ANNUAL REVIEW OF PLANT BIOLOGY 2024; 75:211-237. [PMID: 38277699 DOI: 10.1146/annurev-arplant-070623-114005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2024]
Abstract
Thirty years have passed since the discovery of the Mediator complex in yeast. We are witnessing breakthroughs and advances that have led to high-resolution structural models of yeast and mammalian Mediators in the preinitiation complex, showing how it is assembled and how it positions the RNA polymerase II and its C-terminal domain (CTD) to facilitate the CTD phosphorylation that initiates transcription. This information may be also used to guide future plant research on the mechanisms of Mediator transcriptional control. Here, we review what we know about the subunit composition and structure of plant Mediators, the roles of the individual subunits and the genetic analyses that pioneered Mediator research, and how transcription factors recruit Mediators to regulatory regions adjoining promoters. What emerges from the research is a Mediator that regulates transcription activity and recruits hormonal signaling modules and histone-modifying activities to set up an off or on transcriptional state that recruits general transcription factors for preinitiation complex assembly.
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Affiliation(s)
| | | | - Pablo D Cerdán
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina; , ,
- Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Buenos Aires, Argentina
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2
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Blomberg J, Tasselius V, Vergara A, Karamat F, Imran QM, Strand Å, Rosvall M, Björklund S. Pseudomonas syringae infectivity correlates to altered transcript and metabolite levels of Arabidopsis mediator mutants. Sci Rep 2024; 14:6771. [PMID: 38514763 PMCID: PMC10958028 DOI: 10.1038/s41598-024-57192-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Accepted: 03/15/2024] [Indexed: 03/23/2024] Open
Abstract
Rapid metabolic responses to pathogens are essential for plant survival and depend on numerous transcription factors. Mediator is the major transcriptional co-regulator for integration and transmission of signals from transcriptional regulators to RNA polymerase II. Using four Arabidopsis Mediator mutants, med16, med18, med25 and cdk8, we studied how differences in regulation of their transcript and metabolite levels correlate to their responses to Pseudomonas syringae infection. We found that med16 and cdk8 were susceptible, while med25 showed increased resistance. Glucosinolate, phytoalexin and carbohydrate levels were reduced already before infection in med16 and cdk8, but increased in med25, which also displayed increased benzenoids levels. Early after infection, wild type plants showed reduced glucosinolate and nucleoside levels, but increases in amino acids, benzenoids, oxylipins and the phytoalexin camalexin. The Mediator mutants showed altered levels of these metabolites and in regulation of genes encoding key enzymes for their metabolism. At later stage, mutants displayed defective levels of specific amino acids, carbohydrates, lipids and jasmonates which correlated to their infection response phenotypes. Our results reveal that MED16, MED25 and CDK8 are required for a proper, coordinated transcriptional response of genes which encode enzymes involved in important metabolic pathways for Arabidopsis responses to Pseudomonas syringae infections.
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Affiliation(s)
- Jeanette Blomberg
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87, Umeå, Sweden
| | - Viktor Tasselius
- Department of Physics, Umeå University, 901 87, Umeå, Sweden
- Biostatistics, School of Public Health and Community Medicine, Gothenburg University, P.O. Box 463, 405 30, Gothenburg, Sweden
| | | | - Fazeelat Karamat
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87, Umeå, Sweden
| | - Qari Muhammad Imran
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87, Umeå, Sweden
| | - Åsa Strand
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, 901 87, Umeå, Sweden
| | - Martin Rosvall
- Department of Physics, Umeå University, 901 87, Umeå, Sweden
| | - Stefan Björklund
- Department of Medical Biochemistry and Biophysics, Umeå University, 901 87, Umeå, Sweden.
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3
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Chen J, Yang S, Fan B, Zhu C, Chen Z. The Mediator Complex: A Central Coordinator of Plant Adaptive Responses to Environmental Stresses. Int J Mol Sci 2022; 23:ijms23116170. [PMID: 35682844 PMCID: PMC9181133 DOI: 10.3390/ijms23116170] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Revised: 05/22/2022] [Accepted: 05/28/2022] [Indexed: 01/25/2023] Open
Abstract
As sessile organisms, plants are constantly exposed to a variety of environmental stresses and have evolved adaptive mechanisms, including transcriptional reprogramming, in order to survive or acclimate under adverse conditions. Over the past several decades, a large number of gene-specific transcription factors have been identified in the transcriptional regulation of plant adaptive responses. The Mediator complex plays a key role in transducing signals from gene-specific transcription factors to the transcription machinery to activate or repress target gene expression. Since its first purification about 15 years ago, plant Mediator complex has been extensively analyzed for its composition and biological functions. Mutants of many plant Mediator subunits are not lethal but are compromised in growth, development and response to biotic and abiotic stress, underscoring a particularly important role in plant adaptive responses. Plant Mediator subunits also interact with partners other than transcription factors and components of the transcription machinery, indicating the complexity of the regulation of gene expression by plant Mediator complex. Here, we present a comprehensive discussion of recent analyses of the structure and function of plant Mediator complex, with a particular focus on its roles in plant adaptive responses to a wide spectrum of environmental stresses and associated biological processes.
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Affiliation(s)
- Jialuo Chen
- College of Life Sciences, China Jiliang University, Hangzhou 310018, China; (J.C.); (S.Y.)
| | - Su Yang
- College of Life Sciences, China Jiliang University, Hangzhou 310018, China; (J.C.); (S.Y.)
| | - Baofang Fan
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA;
| | - Cheng Zhu
- College of Life Sciences, China Jiliang University, Hangzhou 310018, China; (J.C.); (S.Y.)
- Correspondence: (C.Z.); (Z.C.); Tel.: +86-571-8683-6090 (C.Z.); +1-765-494-4657 (Z.C.)
| | - Zhixiang Chen
- College of Life Sciences, China Jiliang University, Hangzhou 310018, China; (J.C.); (S.Y.)
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA;
- Correspondence: (C.Z.); (Z.C.); Tel.: +86-571-8683-6090 (C.Z.); +1-765-494-4657 (Z.C.)
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4
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Giustozzi M, Freytes SN, Jaskolowski A, Lichy M, Mateos J, Falcone Ferreyra ML, Rosano GL, Cerdán P, Casati P. Arabidopsis mediator subunit 17 connects transcription with DNA repair after UV-B exposure. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 110:1047-1067. [PMID: 35220621 DOI: 10.1111/tpj.15722] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 02/22/2022] [Accepted: 02/24/2022] [Indexed: 06/14/2023]
Abstract
Mediator 17 (MED17) is a subunit of the Mediator complex that regulates transcription initiation in eukaryotic organisms. In yeast and humans, MED17 also participates in DNA repair, physically interacting with proteins of the nucleotide excision DNA repair system, but this function in plants has not been investigated. We studied the role of MED17 in Arabidopsis plants exposed to UV-B radiation. Our results demonstrate that med17 and OE MED17 plants have altered responses to UV-B, and that MED17 participates in various aspects of the DNA damage response (DDR). Comparison of the med17 transcriptome with that of wild-type (WT) plants showed that almost one-third of transcripts with altered expression in med17 plants were also changed by UV-B exposure in WT plants. Increased sensitivity to DNA damage after UV-B in med17 plants could result from the altered regulation of UV-B responsive transcripts but MED17 also physically interacts with DNA repair proteins, suggesting a direct role of this Mediator subunit during repair. Finally, we show that MED17 is necessary to regulate the DDR activated by ataxia telangiectasia and Rad3 related (ATR), and that programmed cell death 5 (PDCD5) overexpression reverts the deficiencies in DDR shown in med17 mutants. Our data demonstrate that MED17 is an important regulator of DDR after UV-B irradiation in Arabidopsis.
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Affiliation(s)
- Marisol Giustozzi
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), CONICET, Universidad Nacional de Rosario, 2000, Rosario, Argentina
| | | | - Aime Jaskolowski
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
| | - Micaela Lichy
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
| | - Julieta Mateos
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
| | - María Lorena Falcone Ferreyra
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), CONICET, Universidad Nacional de Rosario, 2000, Rosario, Argentina
| | - Germán L Rosano
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biologia Molecular y Celular de Rosario (IBR), CONICET, Universidad Nacional de Rosario, 2000, Rosario, Argentina
| | - Pablo Cerdán
- Fundación Instituto Leloir, IIBBA-CONICET, Buenos Aires, Argentina
- Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Buenos Aires, Argentina
| | - Paula Casati
- Facultad de Ciencias Bioquímicas y Farmacéuticas, Centro de Estudios Fotosintéticos y Bioquímicos (CEFOBI), CONICET, Universidad Nacional de Rosario, 2000, Rosario, Argentina
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He H, Denecker J, Van Der Kelen K, Willems P, Pottie R, Phua SY, Hannah MA, Vertommen D, Van Breusegem F, Mhamdi A. The Arabidopsis mediator complex subunit 8 regulates oxidative stress responses. THE PLANT CELL 2021; 33:2032-2057. [PMID: 33713138 PMCID: PMC8290281 DOI: 10.1093/plcell/koab079] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 03/10/2021] [Indexed: 05/13/2023]
Abstract
Signaling events triggered by hydrogen peroxide (H2O2) regulate plant growth and defense by orchestrating a genome-wide transcriptional reprogramming. However, the specific mechanisms that govern H2O2-dependent gene expression are still poorly understood. Here, we identify the Arabidopsis Mediator complex subunit MED8 as a regulator of H2O2 responses. The introduction of the med8 mutation in a constitutive oxidative stress genetic background (catalase-deficient, cat2) was associated with enhanced activation of the salicylic acid pathway and accelerated cell death. Interestingly, med8 seedlings were more tolerant to oxidative stress generated by the herbicide methyl viologen (MV) and exhibited transcriptional hyperactivation of defense signaling, in particular salicylic acid- and jasmonic acid-related pathways. The med8-triggered tolerance to MV was manipulated by the introduction of secondary mutations in salicylic acid and jasmonic acid pathways. In addition, analysis of the Mediator interactome revealed interactions with components involved in mRNA processing and microRNA biogenesis, hence expanding the role of Mediator beyond transcription. Notably, MED8 interacted with the transcriptional regulator NEGATIVE ON TATA-LESS, NOT2, to control the expression of H2O2-inducible genes and stress responses. Our work establishes MED8 as a component regulating oxidative stress responses and demonstrates that it acts as a negative regulator of H2O2-driven activation of defense gene expression.
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Affiliation(s)
- Huaming He
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
| | - Jordi Denecker
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
- Present address: Illumina Cambridge Ltd, Cambridge, CB21 6DF, UK; Present address: Sciensano, 1050 Brussels, Belgium
| | - Katrien Van Der Kelen
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
- Present address: Illumina Cambridge Ltd, Cambridge, CB21 6DF, UK; Present address: Sciensano, 1050 Brussels, Belgium
| | - Patrick Willems
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
| | - Robin Pottie
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
| | - Su Yin Phua
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
| | - Matthew A Hannah
- BASF Belgium Coordination Center, Innovation Center Gent, 9052 Gent, Belgium
| | - Didier Vertommen
- de Duve Institute, Université Catholique de Louvain, 1200 Brussels, Belgium
| | - Frank Van Breusegem
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
| | - Amna Mhamdi
- Department of Plant Biotechnology and Bioinformatics, Ghent University, 9052 Gent, Belgium
- Center for Plant Systems Biology, VIB, 9052 Gent, Belgium
- Author for correspondence: (A.M.)
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Hu L, Liu J, Zhang W, Wang T, Zhang N, Lee YH, Lu H. FUNCTIONAL METABOLOMICS DECIPHER BIOCHEMICAL FUNCTIONS AND ASSOCIATED MECHANISMS UNDERLIE SMALL-MOLECULE METABOLISM. MASS SPECTROMETRY REVIEWS 2020; 39:417-433. [PMID: 31682024 DOI: 10.1002/mas.21611] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2019] [Revised: 10/08/2019] [Accepted: 10/10/2019] [Indexed: 06/10/2023]
Abstract
Metabolism is the collection of biochemical reactions enabled by chemically diverse metabolites, which facilitate different physiological processes to exchange substances and synthesize energy in diverse living organisms. Metabolomics has emerged as a cutting-edge method to qualify and quantify the metabolites in different biological matrixes, and it has the extraordinary capacity to interrogate the biological significance that underlies metabolic modification and modulation. Liquid chromatography combined with mass spectrometry (LC/MS), as a robust platform for metabolomics analysis, has increased in popularity over the past 10 years due to its excellent sensitivity, throughput, and versatility. However, metabolomics investigation currently provides us with only phenotype data without revealing the biochemical functions and associated mechanisms. This limitation indeed weakens the core value of metabolomics data in a broad spectrum of the life sciences. In recent years, the scientific community has actively explored the functional features of metabolomics and translated this cutting-edge approach to be used to solve key multifaceted questions, such as disease pathogenesis, the therapeutic discovery of drugs, nutritional issues, agricultural problems, environmental toxicology, and microbial evolution. Here, we are the first to briefly review the history and applicable progression of LC/MS-based metabolomics, with an emphasis on the applications of metabolic phenotyping. Furthermore, we specifically highlight the next era of LC/MS-based metabolomics to target functional metabolomes, through which we can answer phenotype-related questions to elucidate biochemical functions and associated mechanisms implicated in dysregulated metabolism. Finally, we propose many strategies to enhance the research capacity of functional metabolomics by enabling the combination of contemporary omics technologies and cutting-edge biochemical techniques. The main purpose of this review is to improve the understanding of LC/MS-based metabolomics, extending beyond the conventional metabolic phenotype toward biochemical functions and associated mechanisms, to enhance research capability and to enlarge the applicable scope of functional metabolomics in small-molecule metabolism in different living organisms.
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Affiliation(s)
- Longlong Hu
- Laboratory for Functional Metabolomics Science, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Jingjing Liu
- Laboratory for Functional Metabolomics Science, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Wenhua Zhang
- Laboratory for Functional Metabolomics Science, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, 200240, China
- Department of Pharmacognosy, College of Pharmacy, Heilongjiang University of Chinese Medicine, Harbin, 150040, China
| | - Tianyu Wang
- Laboratory for Functional Metabolomics Science, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, 200240, China
| | - Ning Zhang
- Department of Pharmacognosy, College of Pharmacy, Heilongjiang University of Chinese Medicine, Harbin, 150040, China
- Department of Pharmaceutical Analysis, College of Jiamusi, Heilongjiang University of Chinese Medicine, Harbin, 121000, China
| | - Yie Hou Lee
- Translational 'Omics and Biomarkers Group, KK Research Centre, KK Women's and Children's Hospital, Singapore, 229899, Singapore
- OBGYN-Academic Clinical Program, Duke-NUS Medical School, Singapore, 169857, Singapore
| | - Haitao Lu
- Laboratory for Functional Metabolomics Science, Key Laboratory of Systems Biomedicine (Ministry of Education), Shanghai Center for Systems Biomedicine, Shanghai Jiao Tong University, Shanghai, 200240, China
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Crawford T, Karamat F, Lehotai N, Rentoft M, Blomberg J, Strand Å, Björklund S. Specific functions for Mediator complex subunits from different modules in the transcriptional response of Arabidopsis thaliana to abiotic stress. Sci Rep 2020; 10:5073. [PMID: 32193425 PMCID: PMC7081235 DOI: 10.1038/s41598-020-61758-w] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Accepted: 02/26/2020] [Indexed: 11/22/2022] Open
Abstract
Adverse environmental conditions are detrimental to plant growth and development. Acclimation to abiotic stress conditions involves activation of signaling pathways which often results in changes in gene expression via networks of transcription factors (TFs). Mediator is a highly conserved co-regulator complex and an essential component of the transcriptional machinery in eukaryotes. Some Mediator subunits have been implicated in stress-responsive signaling pathways; however, much remains unknown regarding the role of plant Mediator in abiotic stress responses. Here, we use RNA-seq to analyze the transcriptional response of Arabidopsis thaliana to heat, cold and salt stress conditions. We identify a set of common abiotic stress regulons and describe the sequential and combinatorial nature of TFs involved in their transcriptional regulation. Furthermore, we identify stress-specific roles for the Mediator subunits MED9, MED16, MED18 and CDK8, and putative TFs connecting them to different stress signaling pathways. Our data also indicate different modes of action for subunits or modules of Mediator at the same gene loci, including a co-repressor function for MED16 prior to stress. These results illuminate a poorly understood but important player in the transcriptional response of plants to abiotic stress and identify target genes and mechanisms as a prelude to further biochemical characterization.
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Affiliation(s)
- Tim Crawford
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, 901 87, Sweden
- Institute for Biochemistry and Biology, University of Potsdam, Potsdam, Germany
| | - Fazeelat Karamat
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, 901 87, Sweden
| | - Nóra Lehotai
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, 901 87, Sweden
| | - Matilda Rentoft
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, 901 87, Sweden
| | - Jeanette Blomberg
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, 901 87, Sweden
| | - Åsa Strand
- Umeå Plant Science Centre, Department of Plant Physiology, Umeå University, Umeå, 901 87, Sweden
| | - Stefan Björklund
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, 901 87, Sweden.
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Mao X, Weake VM, Chapple C. Mediator function in plant metabolism revealed by large-scale biology. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:5995-6003. [PMID: 31504746 DOI: 10.1093/jxb/erz372] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Accepted: 08/07/2019] [Indexed: 05/16/2023]
Abstract
Mediator is a multisubunit transcriptional co-regulator that is involved in the regulation of an array of processes including plant metabolism. The pathways regulated by Mediator-dependent processes include those for the synthesis of phenylpropanoids (MED5), cellulose (MED16), lipids (MED15 and CDK8), and the regulation of iron homeostasis (MED16 and MED25). Traditional genetic and biochemical approaches laid the foundation for our understanding of Mediator function, but recent transcriptomic and metabolomic studies have provided deeper insights into how specific subunits cooperate in the regulation of plant metabolism. In this review, we highlight recent developments in the investigation of Mediator and plant metabolism, with particular emphasis on the large-scale biology studies of med mutants.
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Affiliation(s)
- Xiangying Mao
- Department of Biochemistry, Purdue University, West Lafayette, IN, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, USA
| | - Vikki M Weake
- Department of Biochemistry, Purdue University, West Lafayette, IN, USA
- Purdue University Center for Cancer Research, Purdue University, West Lafayette, IN, USA
| | - Clint Chapple
- Department of Biochemistry, Purdue University, West Lafayette, IN, USA
- Purdue Center for Plant Biology, Purdue University, West Lafayette, IN, USA
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9
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Pérez-Martín F, Yuste-Lisbona FJ, Pineda B, García-Sogo B, Olmo ID, de Dios Alché J, Egea I, Flores FB, Piñeiro M, Jarillo JA, Angosto T, Capel J, Moreno V, Lozano R. Developmental role of the tomato Mediator complex subunit MED18 in pollen ontogeny. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 96:300-315. [PMID: 30003619 DOI: 10.1111/tpj.14031] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 06/17/2018] [Accepted: 06/26/2018] [Indexed: 05/06/2023]
Abstract
Pollen development is a crucial step in higher plants, which not only makes possible plant fertilization and seed formation, but also determines fruit quality and yield in crop species. Here, we reported a tomato T-DNA mutant, pollen deficient1 (pod1), characterized by an abnormal anther development and the lack of viable pollen formation, which led to the production of parthenocarpic fruits. Genomic analyses and the characterization of silencing lines proved that pod1 mutant phenotype relies on the tomato SlMED18 gene encoding the subunit 18 of Mediator multi-protein complex involved in RNA polymerase II transcription machinery. The loss of SlMED18 function delayed tapetum degeneration, which resulted in deficient microspore development and scarce production of viable pollen. A detailed histological characterization of anther development proved that changes during microgametogenesis and a significant delay in tapetum degeneration are associated with a high proportion of degenerated cells and, hence, should be responsible for the low production of functional pollen grains. Expression of pollen marker genes indicated that SlMED18 is essential for the proper transcription of a subset of genes specifically required to pollen formation and fruit development, revealing a key role of SlMED18 in male gametogenesis of tomato. Additionally, SlMED18 is able to rescue developmental abnormalities of the Arabidopsis med18 mutant, indicating that most biological functions have been conserved in both species.
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Affiliation(s)
- Fernando Pérez-Martín
- Centro de Investigación en Biotecnología Agroalimentaria (BITAL), Universidad de Almería, 04120, Almería, Spain
| | - Fernando J Yuste-Lisbona
- Centro de Investigación en Biotecnología Agroalimentaria (BITAL), Universidad de Almería, 04120, Almería, Spain
| | - Benito Pineda
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-CSIC, 46022, Valencia, Spain
| | - Begoña García-Sogo
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-CSIC, 46022, Valencia, Spain
| | - Iván Del Olmo
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo UPM, 28223, Pozuelo de Alarcón (Madrid), Spain
| | - Juan de Dios Alché
- Departamento de Bioquímica, Biología Celular y Molecular de Plantas, EEZ-CSIC, 18008, Granada, Spain
| | - Isabel Egea
- Departamento de Biología del Estrés y Patología Vegetal, CEBAS-CSIC, 30100, Espinardo-Murcia, Spain
| | - Francisco B Flores
- Departamento de Biología del Estrés y Patología Vegetal, CEBAS-CSIC, 30100, Espinardo-Murcia, Spain
| | - Manuel Piñeiro
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo UPM, 28223, Pozuelo de Alarcón (Madrid), Spain
| | - José A Jarillo
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM) - Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA), Campus Montegancedo UPM, 28223, Pozuelo de Alarcón (Madrid), Spain
| | - Trinidad Angosto
- Centro de Investigación en Biotecnología Agroalimentaria (BITAL), Universidad de Almería, 04120, Almería, Spain
| | - Juan Capel
- Centro de Investigación en Biotecnología Agroalimentaria (BITAL), Universidad de Almería, 04120, Almería, Spain
| | - Vicente Moreno
- Instituto de Biología Molecular y Celular de Plantas, Universidad Politécnica de Valencia-CSIC, 46022, Valencia, Spain
| | - Rafael Lozano
- Centro de Investigación en Biotecnología Agroalimentaria (BITAL), Universidad de Almería, 04120, Almería, Spain
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