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Bellino C, Herrera FE, Rodrigues D, Garay AS, Huck SV, Reinheimer R. Molecular Evolution of RAMOSA1 (RA1) in Land Plants. Biomolecules 2024; 14:550. [PMID: 38785957 PMCID: PMC11117814 DOI: 10.3390/biom14050550] [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: 03/16/2024] [Revised: 04/29/2024] [Accepted: 04/30/2024] [Indexed: 05/25/2024] Open
Abstract
RAMOSA1 (RA1) is a Cys2-His2-type (C2H2) zinc finger transcription factor that controls plant meristem fate and identity and has played an important role in maize domestication. Despite its importance, the origin of RA1 is unknown, and the evolution in plants is only partially understood. In this paper, we present a well-resolved phylogeny based on 73 amino acid sequences from 48 embryophyte species. The recovered tree topology indicates that, during grass evolution, RA1 arose from two consecutive SUPERMAN duplications, resulting in three distinct grass sequence lineages: RA1-like A, RA1-like B, and RA1; however, most of these copies have unknown functions. Our findings indicate that RA1 and RA1-like play roles in the nucleus despite lacking a traditional nuclear localization signal. Here, we report that copies diversified their coding region and, with it, their protein structure, suggesting different patterns of DNA binding and protein-protein interaction. In addition, each of the retained copies diversified regulatory elements along their promoter regions, indicating differences in their upstream regulation. Taken together, the evidence indicates that the RA1 and RA1-like gene families in grasses underwent subfunctionalization and neofunctionalization enabled by gene duplication.
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Affiliation(s)
- Carolina Bellino
- Fellow of Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina (CONICET), Instituto de Agrobiotecnología del Litoral, Universidad Nacional del Litoral, CONICET, CCT-Santa Fe, Ruta Nacional N° 168 Km 0, s/n, Paraje el Pozo, Santa Fe S3000, Argentina;
| | - Fernando E. Herrera
- Member of Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina (CONICET), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Ciudad Universitaria, Paraje El Pozo, Santa Fe S3000, Argentina; (F.E.H.); (D.R.)
| | - Daniel Rodrigues
- Member of Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina (CONICET), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Ciudad Universitaria, Paraje El Pozo, Santa Fe S3000, Argentina; (F.E.H.); (D.R.)
| | - A. Sergio Garay
- Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Ciudad Universitaria, Paraje El Pozo, Santa Fe S3000, Argentina;
| | - Sofía V. Huck
- Fellow of Agencia Nacional de Promoción de la Investigación, el Desarrollo Tecnológico y la Innovación, Instituto de Agrobiotecnología del Litoral, Universidad Nacional del Litoral, CONICET, CCT-Santa Fe, Ruta Nacional N° 168 Km 0, s/n, Paraje el Pozo, Santa Fe S3000, Argentina;
| | - Renata Reinheimer
- Member of Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina (CONICET), Instituto de Agrobiotecnología del Litoral, Universidad Nacional del Litoral, FCA, CONICET, CCT-Santa Fe, Ruta Nacional N° 168 Km 0, s/n, Paraje el Pozo, Santa Fe S3000, Argentina
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Jia HH, Xu YT, Yin ZJ, Qing M, Xie KD, Guo WW, Wu XM. Genome-wide identification of the C2H2-Zinc finger gene family and functional validation of CsZFP7 in citrus nucellar embryogenesis. PLANT REPRODUCTION 2023; 36:287-300. [PMID: 37247027 DOI: 10.1007/s00497-023-00470-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 05/15/2023] [Indexed: 05/30/2023]
Abstract
KEY MESSAGE Genome-wide identification of C2H2-ZF gene family in the poly- and mono-embryonic citrus species and validation of the positive role of CsZFP7 in sporophytic apomixis. The C2H2 zinc finger (C2H2-ZF) gene family is involved in plant vegetative and reproductive development. Although a large number of C2H2 zinc-finger proteins (C2H2-ZFPs) have been well characterized in some horticultural plants, little is known about the C2H2-ZFPs and their function in citrus. In this work, we performed a genome-wide sequence analysis and identified 97 and 101 putative C2H2-ZF gene family members in the genomes of sweet orange (C. sinensis, poly-embryonic) and pummelo (C. grandis, mono-embryonic), respectively. Phylogenetic analysis categorized citrus C2H2-ZF gene family into four clades, and their possible functions were inferred. According to the numerous regulatory elements on promoter, citrus C2H2-ZFPs can be divided into five different regulatory function types that indicate functional differentiation. RNA-seq data revealed 20 differentially expressed C2H2-ZF genes between poly-embryonic and mono-embryonic ovules at two stages of citrus nucellar embryogenesis, among them CsZFP52 specifically expressed in mono-embryonic pummelo ovules, while CsZFP7, 37, 44, 45, 67 and 68 specifically expressed in poly-embryonic sweet orange ovules. RT-qPCR further validated that CsZFP7 specifically expressed at higher levels in poly-embryonic ovules, and down-regulation of CsZFP7 in the poly-embryonic mini citrus (Fortunella hindsii) increased rate of mono-embryonic seeds compared with the wild type, indicating the regulatory potential of CsZFP7 in nucellar embryogenesis of citrus. This work provided a comprehensive analysis of C2H2-ZF gene family in citrus, including genome organization and gene structure, phylogenetic relationships, gene duplications, possible cis-elements on promoter regions and expression profiles, especially in the poly- and mono-embryogenic ovules, and suggested that CsZFP7 is involved in nucellar embryogenesis.
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Affiliation(s)
- Hui-Hui Jia
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yuan-Tao Xu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhu-Jun Yin
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Mei Qing
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Kai-Dong Xie
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Wen-Wu Guo
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xiao-Meng Wu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, College of Horticulture and Forestry Sciences, Huazhong Agricultural University, Wuhan, 430070, China.
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Zhang M, Zhou E, Li M, Tian S, Xiao H. A SUPERMAN-like Gene Controls the Locule Number of Tomato Fruit. PLANTS (BASEL, SWITZERLAND) 2023; 12:3341. [PMID: 37765505 PMCID: PMC10535046 DOI: 10.3390/plants12183341] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 09/19/2023] [Accepted: 09/20/2023] [Indexed: 09/29/2023]
Abstract
Tomato (Solanum lycopersicum) fruits are derived from fertilized ovaries formed during flower development. Thus, fruit morphology is tightly linked to carpel number and identity. The SUPERMAN (SUP) gene is a key transcription repressor to define the stamen-carpel boundary and to control floral meristem determinacy. Despite SUP functions having been characterized in a few plant species, its functions have not yet been explored in tomato. In this study, we identified and characterized a fascinated and multi-locule fruit (fmf) mutant in Solanum pimpinellifolium background harboring a nonsense mutation in the coding sequence of a zinc finger gene orthologous to SUP. The fmf mutant produces supersex flowers containing increased numbers of stamens and carpels and sets malformed seedless fruits with complete flowers frequently formed on the distal end. fmf alleles in cultivated tomato background created by CRISPR-Cas9 showed similar floral and fruit phenotypes. Our results provide insight into the functional conservation and diversification of SUP members in different species. We also speculate the FMF gene may be a potential target for yield improvement in tomato by genetic engineering.
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Affiliation(s)
- Mi Zhang
- University of Chinese Academy of Sciences, 19A Yuquan Rd, Beijing 100049, China; (M.Z.); (E.Z.); (S.T.)
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Rd., Shanghai 200032, China;
| | - Enbai Zhou
- University of Chinese Academy of Sciences, 19A Yuquan Rd, Beijing 100049, China; (M.Z.); (E.Z.); (S.T.)
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Rd., Shanghai 200032, China;
| | - Meng Li
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Rd., Shanghai 200032, China;
| | - Shenglan Tian
- University of Chinese Academy of Sciences, 19A Yuquan Rd, Beijing 100049, China; (M.Z.); (E.Z.); (S.T.)
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Rd., Shanghai 200032, China;
| | - Han Xiao
- National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, 300 Fenglin Rd., Shanghai 200032, China;
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Liu H, Jiang L, Wen Z, Yang Y, Singer SD, Bennett D, Xu W, Su Z, Yu Z, Cohn J, Chae H, Que Q, Liu Y, Liu C, Liu Z. Rice RS2-9, which is bound by transcription factor OSH1, blocks enhancer-promoter interactions in plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 109:541-554. [PMID: 34773305 PMCID: PMC9303810 DOI: 10.1111/tpj.15574] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 11/02/2021] [Indexed: 05/13/2023]
Abstract
Insulators characterized in Drosophila and mammals have been shown to play a key role in the restriction of promiscuous enhancer-promoter interactions, as well as reshaping the topological landscape of chromosomes. Yet the role of insulators in plants remains poorly understood, in large part because of a lack of well-characterized insulators and binding factor(s). In this study, we isolated a 1.2-kb RS2-9 insulator from the Oryza sativa (rice) genome that can, when interposed between an enhancer and promoter, efficiently block the activation function of both constitutive and floral organ-specific enhancers in transgenic Arabidopsis and Nicotiana tabacum (tobacco). In the rice genome, the genes flanking RS2-9 exhibit an absence of mutual transcriptional interactions, as well as a lack of histone modification spread. We further determined that O. sativa Homeobox 1 (OSH1) bound two regions of RS2-9, as well as over 50 000 additional sites in the rice genome, the majority of which resided in intergenic regions. Mutation of one of the two OSH1-binding sites in RS2-9 impaired insulation activity by up to 60%, whereas the mutation of both binding sites virtually abolished insulator function. We also demonstrated that OSH1 binding sites were associated with 72% of the boundaries of topologically associated domains (TADs) identified in the rice genome, which is comparable to the 77% of TAD boundaries bound by the insulator CCCTC-binding factor (CTCF) in mammals. Taken together, our findings indicate that OSH1-RS2-9 acts as a true insulator in plants, and highlight a potential role for OSH1 in gene insulation and topological organization in plant genomes.
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Affiliation(s)
- Huawei Liu
- USDA‐ARS, Appalachian Fruit Research StationKearneysvilleWest Virginia25430USA
- College of Food Science and TechnologyNanjing Agricultural UniversityNanjing210095China
| | - Li Jiang
- USDA‐ARS, Appalachian Fruit Research StationKearneysvilleWest Virginia25430USA
- College of Food Science and TechnologyNanjing Agricultural UniversityNanjing210095China
| | - Zhifeng Wen
- USDA‐ARS, Appalachian Fruit Research StationKearneysvilleWest Virginia25430USA
- College of HorticultureFujian Agriculture and Forestry UniversityFuzhou350002China
| | - Yingjun Yang
- USDA‐ARS, Appalachian Fruit Research StationKearneysvilleWest Virginia25430USA
- Forestry CollegeHenan University of Science and TechnologyLuoyang471023China
| | - Stacy D. Singer
- Agriculture and Agri‐Food CanadaLethbridge Research and Development CentreLethbridgeAlbertaT1J 4B1Canada
| | - Dennis Bennett
- USDA‐ARS, Appalachian Fruit Research StationKearneysvilleWest Virginia25430USA
| | - Wenying Xu
- State Key Laboratory of Plant Physiology and BiochemistryCollege of Biological SciencesChina Agricultural UniversityBeijing100193China
| | - Zhen Su
- State Key Laboratory of Plant Physiology and BiochemistryCollege of Biological SciencesChina Agricultural UniversityBeijing100193China
| | - Zhifang Yu
- College of Food Science and TechnologyNanjing Agricultural UniversityNanjing210095China
| | - Jonathan Cohn
- Syngenta Crop ProtectionLLCResearch Triangle ParkNorth Carolina27709USA
| | - Hyunsook Chae
- Syngenta Crop ProtectionLLCResearch Triangle ParkNorth Carolina27709USA
| | - Qiudeng Que
- Syngenta Crop ProtectionLLCResearch Triangle ParkNorth Carolina27709USA
| | - Yue Liu
- College of HorticultureQingdao Agricultural UniversityQingdao266109China
| | - Chang Liu
- Department of EpigeneticsUniversity of HohenheimStuttgart70599Germany
| | - Zongrang Liu
- USDA‐ARS, Appalachian Fruit Research StationKearneysvilleWest Virginia25430USA
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Li J, Zhang L, Yuan Y, Wang Q, Elbaiomy RG, Zhou W, Wu H, Soaud SA, Abbas M, Chen B, Zhao D, El-Sappah AH. In Silico Functional Prediction and Expression Analysis of C2H2 Zinc-Finger Family Transcription Factor Revealed Regulatory Role of ZmZFP126 in Maize Growth. Front Genet 2021; 12:770427. [PMID: 34804129 PMCID: PMC8602080 DOI: 10.3389/fgene.2021.770427] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 10/21/2021] [Indexed: 11/16/2022] Open
Abstract
The C2H2-zinc finger proteins (ZFP) comprise a large family of transcription factors with various functions in biological processes. In maize, the function regulation of C2H2- zine finger (ZF) genes are poorly understood. We conducted an evolution analysis and functional prediction of the maize C2H2-ZF gene family. Furthermore, the ZmZFP126 gene has been cloned and sequenced for further favorable allelic variation discovery. The phylogenetic analysis of the C2H2-ZF domain indicated that the position and sequence of the C2H2-ZF domain of the poly-zinc finger gene are relatively conserved during evolution, and the C2H2-ZF domain with the same position is highly conserved. The expression analysis of the C2H2-ZF gene family in 11 tissues at different growth stages of B73 inbred lines showed that genes with multiple transcripts were endowed with more functions. The expression analysis of the C2H2-ZF gene in P1 and P2 inbred lines under drought conditions showed that the C2H2-ZF genes were mainly subjected to negative regulation under drought stress. Functional prediction indicated that the maize C2H2-ZF gene is mainly involved in reproduction and development, especially concerning the formation of important agronomic traits in maize yield. Furthermore, sequencing and correlation analysis of the ZmZFP126 gene indicated that this gene was significantly associated with the SDW-NAP and TDW-NAP. The analysis of the relationship between maize C2H2-ZF genes and C2H2-ZF genes with known functions indicated that the functions of some C2H2-ZF genes are relatively conservative, and the functions of homologous genes in different species are similar.
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Affiliation(s)
- Jia Li
- Faculty of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, China
| | - Litian Zhang
- State Key Laboratory of Plateau Ecology and Agriculture, Academy of Animal Science and Veterinary Medicine of Qinghai University, Xining, China
| | - Yibing Yuan
- Maize Research Institute, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture, Chengdu, China
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Chengdu, China
| | - Qi Wang
- Maize Research Institute, Sichuan Agricultural University, Chengdu, China
- Key Laboratory of Biology and Genetic Improvement of Maize in Southwest Region, Ministry of Agriculture, Chengdu, China
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Chengdu, China
| | | | - Wanhai Zhou
- Faculty of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, China
| | - Hui Wu
- Faculty of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, China
| | - Salma A. Soaud
- Genetics Department, Faculty of Agriculture, Zagazig University, Zagazig, Egypt
| | - Manzar Abbas
- Faculty of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, China
| | - Bo Chen
- Faculty of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, China
| | - Deming Zhao
- Yibin Academy of Agricultural Sciences, Yibin, China
| | - Ahmed H. El-Sappah
- Faculty of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, China
- Genetics Department, Faculty of Agriculture, Zagazig University, Zagazig, Egypt
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Rodas AL, Roque E, Hamza R, Gómez-Mena C, Minguet EG, Wen J, Mysore KS, Beltrán JP, Cañas LA. MtSUPERMAN plays a key role in compound inflorescence and flower development in Medicago truncatula. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 105:816-830. [PMID: 33176041 DOI: 10.1111/tpj.15075] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/18/2020] [Accepted: 09/23/2020] [Indexed: 06/11/2023]
Abstract
Legumes have unique features, such as compound inflorescences and a complex floral ontogeny. Thus, the study of regulatory genes in these species during inflorescence and floral development is essential to understand their role in the evolutionary origin of developmental novelties. The SUPERMAN (SUP) gene encodes a C2H2 zinc-finger transcriptional repressor that regulates the floral organ number in the third and fourth floral whorls of Arabidopsis thaliana. In this work, we present the functional characterization of the Medicago truncatula SUPERMAN (MtSUP) gene based on gene expression analysis, complementation and overexpression assays, and reverse genetic approaches. Our findings provide evidence that MtSUP is the orthologous gene of SUP in M. truncatula. We have unveiled novel functions for a SUP-like gene in eudicots. MtSUP controls not only the number of floral organs in the inner two whorls, but also in the second whorl of the flower. Furthermore, MtSUP regulates the activity of the secondary inflorescence meristem, thus controlling the number of flowers produced. Our work provides insight into the regulatory network behind the compound inflorescence and flower development in this angiosperm family.
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Affiliation(s)
- Ana L Rodas
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Ciudad Politécnica de la Innovación, Edf. 8E. C/Ingeniero Fausto Elio s/n. E-46022, Valencia, Spain
| | - Edelín Roque
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Ciudad Politécnica de la Innovación, Edf. 8E. C/Ingeniero Fausto Elio s/n. E-46022, Valencia, Spain
| | - Rim Hamza
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Ciudad Politécnica de la Innovación, Edf. 8E. C/Ingeniero Fausto Elio s/n. E-46022, Valencia, Spain
| | - Concepción Gómez-Mena
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Ciudad Politécnica de la Innovación, Edf. 8E. C/Ingeniero Fausto Elio s/n. E-46022, Valencia, Spain
| | - Eugenio G Minguet
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Ciudad Politécnica de la Innovación, Edf. 8E. C/Ingeniero Fausto Elio s/n. E-46022, Valencia, Spain
| | - Jiangqi Wen
- Plant Biology Division, Noble Research Institute, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - Kirankumar S Mysore
- Plant Biology Division, Noble Research Institute, 2510 Sam Noble Parkway, Ardmore, OK, 73401, USA
| | - José P Beltrán
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Ciudad Politécnica de la Innovación, Edf. 8E. C/Ingeniero Fausto Elio s/n. E-46022, Valencia, Spain
| | - Luis A Cañas
- Instituto de Biología Molecular y Celular de Plantas (CSIC-UPV), Ciudad Politécnica de la Innovación, Edf. 8E. C/Ingeniero Fausto Elio s/n. E-46022, Valencia, Spain
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Prunet N, Duncan K. Imaging flowers: a guide to current microscopy and tomography techniques to study flower development. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:2898-2909. [PMID: 32383442 PMCID: PMC7260710 DOI: 10.1093/jxb/eraa094] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 05/06/2020] [Indexed: 05/20/2023]
Abstract
Developmental biology relies heavily on our ability to generate three-dimensional images of live biological specimens through time, and to map gene expression and hormone response in these specimens as they undergo development. The last two decades have seen an explosion of new bioimaging technologies that have pushed the limits of spatial and temporal resolution and provided biologists with invaluable new tools. However, plant tissues are difficult to image, and no single technology fits all purposes; choosing between many bioimaging techniques is not trivial. Here, we review modern light microscopy and computed projection tomography methods, their capabilities and limitations, and we discuss their current and potential applications to the study of flower development and fertilization.
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Affiliation(s)
| | - Keith Duncan
- Donald Danforth Plant Science Center, St. Louis, MO, USA
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Chen X, Schï Nberger B, Menz J, Ludewig U. Plasticity of DNA methylation and gene expression under zinc deficiency in Arabidopsis roots. PLANT & CELL PHYSIOLOGY 2018; 59:1790-1802. [PMID: 29800330 DOI: 10.1093/pcp/pcy100] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2017] [Accepted: 05/10/2018] [Indexed: 05/24/2023]
Abstract
DNA methylation is a heritable chromatin modification that maintains chromosome stability, regulates transposon silencing and appears to be involved in gene expression in response to environmental conditions. Environmental stress alters DNA methylation patterns that are correlated with gene expression differences. Here, genome-wide differential DNA methylation was identified upon prolonged zinc (Zn) deficiency, leading to hypo- and hypermethylated chromosomal regions. Preferential CpG methylation changes occurred in gene promoters and gene bodies, but did not overlap with transcriptional start sites. Methylation changes were also prominent in transposable elements. In contrast, non-CpG methylation differences were exclusively found in promoters of protein-coding genes and in transposable elements. Strongly Zn deficiency-induced genes and their promoters were mostly non-methylated, irrespective of Zn supply. Differential DNA methylation in the CpG and CHG, but not in the CHH context, was found close to a few up-regulated Zn deficiency genes. However, the transcriptional Zn deficiency response in roots appeared little correlated with associated DNA methylation changes in promoters or gene bodies. Furthermore, under Zn deficiency, developmental defects were identified in an Arabidopsis mutant lacking non-CpG methylation. The root methylome thus responds specifically to a micronutrient deficiency and is important for efficient Zn utilization at low availability, but the relationship of differential methylation and differentially expressed genes is surprisingly poor.
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Affiliation(s)
- Xiaochao Chen
- Institute of Crop Science, Nutritional Crop Physiology, University of Hohenheim, Fruwirthstr. 20, Stuttgart, Germany
| | - Brigitte Schï Nberger
- Institute of Crop Science, Nutritional Crop Physiology, University of Hohenheim, Fruwirthstr. 20, Stuttgart, Germany
| | - Jochen Menz
- Institute of Crop Science, Nutritional Crop Physiology, University of Hohenheim, Fruwirthstr. 20, Stuttgart, Germany
| | - Uwe Ludewig
- Institute of Crop Science, Nutritional Crop Physiology, University of Hohenheim, Fruwirthstr. 20, Stuttgart, Germany
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The DNA Methylome and Association of Differentially Methylated Regions with Differential Gene Expression during Heat Stress in Brassica rapa. Int J Mol Sci 2018; 19:ijms19051414. [PMID: 29747401 PMCID: PMC5983725 DOI: 10.3390/ijms19051414] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 04/16/2018] [Accepted: 04/29/2018] [Indexed: 01/04/2023] Open
Abstract
Cytosine DNA methylation is a critical epigenetic mechanism in the silencing of transposable elements, imprinting and regulating gene expression. However, little is known about the potential role of mC in response to heat stress. To determine and explore the functions of the dynamic DNA methylome during heat stress, we characterized single-base resolution methylome maps of Brassica rapa and assessed the dynamic changes of mC under heat stress using whole genome bisulfite sequencing. On average, the DNA methylation levels of CG, CHG and CHH are 39.3%, 15.38% and 5.24% in non-heading Chinese cabbage (NHCC), respectively. We found that the patterns of methylation are similar to other eudicot plants, but with higher CHH methylation levels. Further comparative analysis revealed varying patterns for three sequence contexts (mCG, mCHG and mCHH) under heat stress indicating context- and position-dependent methylation regulation. DNA methylation near the TSS and TES may be closely associated with methylation-dependent transcriptional silencing. Association analysis of differential methylation and differential gene expression revealed a different set of methDEGs involved at early and late stages under heat stress. The systemic characterization of the dynamic DNA methylome during heat stress will improve our understanding of the mechanism of epigenetic regulation under heat stress.
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Xu K, Wang L, Liu N, Xie X, Zhu Y. Characterization of a SUPERMAN-like Gene, MdSUP11, in apple (Malus × domestica Borkh.). PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2018; 125:136-142. [PMID: 29448155 DOI: 10.1016/j.plaphy.2017.12.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 12/03/2017] [Accepted: 12/03/2017] [Indexed: 06/08/2023]
Abstract
Arabidopsis SUPERMAN and its family members of its family play important roles in plant growth and floral organ development; yet much less is known about their functions expanding in apple tree development. Previous work has identified 12 SUP-like genes in the apple (Malus × domestica Borkh.) genome, and the MdSUP11 which is expressed in both vegetative and reproductive organs of apple. However, the function of MdSUP11 remains obscure. In this study, the β-glucuronidase expression driven by the MdSUP11 native promoter was detected in roots, young leaves, and floral organs of transgenic Arabidopsis. In transgenic tobacco, overexpression of MdSUP11 lead to dwarfism, aberrant leaf shapes, and morphological changes of floral organs. Endogenous concentrations of auxin (indole-3-acetic acid), abscisic acid, isopentenyl adenosine and zeatin riboside were significantly higher in young MdSUP11-transformed tobacco plants than in non-transformed plants. Gene expression analysis using real-time quantitative PCR showed up-regulation of NtDFR2 and NtANS1 expression in unopened transgenic flowers, whereas NtCHS expression was not changed significantly. Together, these results suggest that MdSUP11 is associated with apple's vegetative and reproductive development. Its overexpression in tobacco affects leaf and flower organ development and plant height; potentially by changing NtDFR2 and NtANS1 expression and endogenous levels of indole-3-acetic acid, cytokinins and abscisic acid.
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Affiliation(s)
- Ke Xu
- Department of Pomology, College of Horticulture, China Agricultural University, Yuanmingyuan West Road No. 2, Haidian District, Beijing 100193, PR China.
| | - LiMin Wang
- Department of Pomology, College of Horticulture, China Agricultural University, Yuanmingyuan West Road No. 2, Haidian District, Beijing 100193, PR China.
| | - Na Liu
- Department of Pomology, College of Horticulture, China Agricultural University, Yuanmingyuan West Road No. 2, Haidian District, Beijing 100193, PR China.
| | - Xuan Xie
- Department of Pomology, College of Horticulture, China Agricultural University, Yuanmingyuan West Road No. 2, Haidian District, Beijing 100193, PR China.
| | - YuanDi Zhu
- Department of Pomology, College of Horticulture, China Agricultural University, Yuanmingyuan West Road No. 2, Haidian District, Beijing 100193, PR China.
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11
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Uemura A, Yamaguchi N, Xu Y, Wee W, Ichihashi Y, Suzuki T, Shibata A, Shirasu K, Ito T. Regulation of floral meristem activity through the interaction of AGAMOUS, SUPERMAN, and CLAVATA3 in Arabidopsis. PLANT REPRODUCTION 2018; 31:89-105. [PMID: 29218596 DOI: 10.1007/s00497-017-0315-0] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Accepted: 11/28/2017] [Indexed: 05/23/2023]
Abstract
Floral meristem size is redundantly controlled by CLAVATA3, AGAMOUS , and SUPERMAN in Arabidopsis. The proper regulation of floral meristem activity is key to the formation of optimally sized flowers with a fixed number of organs. In Arabidopsis thaliana, multiple regulators determine this activity. A small secreted peptide, CLAVATA3 (CLV3), functions as an important negative regulator of stem cell activity. Two transcription factors, AGAMOUS (AG) and SUPERMAN (SUP), act in different pathways to regulate the termination of floral meristem activity. Previous research has not addressed the genetic interactions among these three genes. Here, we quantified the floral developmental stage-specific phenotypic consequences of combining mutations of AG, SUP, and CLV3. Our detailed phenotypic and genetic analyses revealed that these three genes act in partially redundant pathways to coordinately modulate floral meristem sizes in a spatial and temporal manner. Analyses of the ag sup clv3 triple mutant, which developed a mass of undifferentiated cells in its flowers, allowed us to identify downstream targets of AG with roles in reproductive development and in the termination of floral meristem activity. Our study highlights the role of AG in repressing genes that are expressed in organ initial cells to control floral meristem activity.
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Affiliation(s)
- Akira Uemura
- Biological Sciences, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, 630-0192, Japan
| | - Nobutoshi Yamaguchi
- Biological Sciences, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, 630-0192, Japan
- Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, 4-1-8, Honcho, Kawaguchi-shi, Saitama, 332-0012, Japan
| | - Yifeng Xu
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Republic of Singapore
| | - WanYi Wee
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore, 117604, Republic of Singapore
| | - Yasunori Ichihashi
- Precursory Research for Embryonic Science and Technology, Japan Science and Technology Agency, 4-1-8, Honcho, Kawaguchi-shi, Saitama, 332-0012, Japan
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan
| | - Takamasa Suzuki
- Department of Biological Chemistry, College of Bioscience and Biotechnology, Chubu University, 1200 Matsumoto-cho, Kasugai, Aichi, 487-8501, Japan
| | - Arisa Shibata
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan
| | - Ken Shirasu
- RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro, Tsurumi, Yokohama, Kanagawa, 230-0045, Japan
- Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, 113-0033, Japan
| | - Toshiro Ito
- Biological Sciences, Nara Institute of Science and Technology, 8916-5, Takayama, Ikoma, Nara, 630-0192, Japan.
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12
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SUPERMAN prevents class B gene expression and promotes stem cell termination in the fourth whorl of Arabidopsis thaliana flowers. Proc Natl Acad Sci U S A 2017. [PMID: 28634297 DOI: 10.1073/pnas.1705977114] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The molecular and genetic networks underlying the determination of floral organ identity are well studied, but much less is known about how the flower is partitioned into four developmentally distinct whorls. The SUPERMAN gene is required for proper specification of the boundary between stamens in whorl 3 and carpels in whorl 4, as superman mutants exhibit supernumerary stamens but usually lack carpels. However, it has remained unclear whether extra stamens in superman mutants originate from an organ identity change in whorl 4 or the overproliferation of whorl 3. Using live confocal imaging, we show that the extra stamens in superman mutants arise from cells in whorl 4, which change their fate from female to male, while floral stem cells proliferate longer, allowing for the production of additional stamens.
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13
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Breuil-Broyer S, Trehin C, Morel P, Boltz V, Sun B, Chambrier P, Ito T, Negrutiu I. Analysis of the Arabidopsis superman allelic series and the interactions with other genes demonstrate developmental robustness and joint specification of male-female boundary, flower meristem termination and carpel compartmentalization. ANNALS OF BOTANY 2016; 117:905-23. [PMID: 27098089 PMCID: PMC4845806 DOI: 10.1093/aob/mcw023] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Revised: 12/14/2015] [Accepted: 01/26/2016] [Indexed: 05/24/2023]
Abstract
BACKGROUND AND AIMS SUPERMAN is a cadastral gene controlling the sexual boundary in the flower. The gene's functions and role in flower development and evolution have remained elusive. The analysis of a contrasting SUP allelic series (for which the names superman, superwoman and supersex have been coined) makes it possible to distinguish early vs. late regulatory processes at the flower meristem centre to which SUP is an important contributor. Their understanding is essential in further addressing evolutionary questions linking bisexuality and flower meristem homeostasis. METHODS Inter-allelic comparisons were carried out and SUP interactions with other boundary factors and flower meristem patterning and homeostasis regulators (such as CLV, WUS, PAN, CUC, KNU, AG, AP3/PI, CRC and SPT) have been evaluated at genetic, molecular, morphological and histological levels. KEY RESULTS Early SUP functions include mechanisms of male-female (sexual) boundary specification, flower mersitem termination and control of stamen number. A SUP-dependent flower meristem termination pathway is identified and analysed. Late SUP functions play a role in organ morphogenesis by controlling intra-whorl organ separation and carpel medial region formation. By integrating early and late SUP functions, and by analyzing in one single experiment a series of SUP genetic interactions, the concept of meristematic 'transference' (cascade) - a regulatory bridging process redundantly and sequentially co-ordinating the triggering and completion of flower meristem termination, and carpel margin meristem and placenta patterning - is proposed. CONCLUSIONS Taken together, the results strongly support the view that SUP(-type) function(s) have been instrumental in resolving male/female gradients into sharp male and female identities (whorls, organs) and in enforcing flower homeostasis during evolution. This has probably been achieved by incorporating the meristem patterning system of the floral axis into the female/carpel programme.
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Key Words
- Arabidopsis
- SUPERMAN gene: superman, clark-kent/superwoman, supersex, AG, CLV, CRC, CUC2, KNU, PAN, SPT, WUS
- allelic series
- carpel
- evo-devo
- flower homeostasis
- flower meristem determinacy
- flower pattern
- meristematic ‘cascade’/transference
- pistillody/carpelloidy
- placenta
- stamen
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Affiliation(s)
| | - Christophe Trehin
- Plant Reproduction and Development, ENS de Lyon, UCBL, INRA, CNRS 69364, France
| | - Patrice Morel
- Plant Reproduction and Development, ENS de Lyon, UCBL, INRA, CNRS 69364, France
| | - Véronique Boltz
- Plant Reproduction and Development, ENS de Lyon, UCBL, INRA, CNRS 69364, France
| | - Bo Sun
- School of Life Sciences, Nanjing University, Nanjing City, Jiangsu Province, China 210093 Temasek Life Sciences Laboratory 1 Research Link National University of Singapore Singapore 117604
| | - Pierre Chambrier
- Plant Reproduction and Development, ENS de Lyon, UCBL, INRA, CNRS 69364, France
| | - Toshiro Ito
- Temasek Life Sciences Laboratory 1 Research Link National University of Singapore Singapore 117604 Nara Institute of Science and Technology 8916-5 Takayama, Ikoma, Japan
| | - Ioan Negrutiu
- Plant Reproduction and Development, ENS de Lyon, UCBL, INRA, CNRS 69364, France
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Charlier JB, Polese C, Nouet C, Carnol M, Bosman B, Krämer U, Motte P, Hanikenne M. Zinc triggers a complex transcriptional and post-transcriptional regulation of the metal homeostasis gene FRD3 in Arabidopsis relatives. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:3865-78. [PMID: 25900619 PMCID: PMC4473987 DOI: 10.1093/jxb/erv188] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In Arabidopsis thaliana, FRD3 (FERRIC CHELATE REDUCTASE DEFECTIVE 3) plays a central role in metal homeostasis. FRD3 is among a set of metal homeostasis genes that are constitutively highly expressed in roots and shoots of Arabidopsis halleri, a zinc hyperaccumulating and hypertolerant species. Here, we examined the regulation of FRD3 by zinc in both species to shed light on the evolutionary processes underlying the evolution of hyperaccumulation in A. halleri. We combined gene expression studies with the use of β-glucuronidase and green fluorescent protein reporter constructs to compare the expression profile and transcriptional and post-transcriptional regulation of FRD3 in both species. The AtFRD3 and AhFRD3 genes displayed a conserved expression profile. In A. thaliana, alternative transcription initiation sites from two promoters determined transcript variants that were differentially regulated by zinc supply in roots and shoots to favour the most highly translated variant under zinc-excess conditions. In A. halleri, a single transcript variant with higher transcript stability and enhanced translation has been maintained. The FRD3 gene thus undergoes complex transcriptional and post-transcriptional regulation in Arabidopsis relatives. Our study reveals that a diverse set of mechanisms underlie increased gene dosage in the A. halleri lineage and illustrates how an environmental challenge can alter gene regulation.
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Affiliation(s)
- Jean-Benoit Charlier
- Functional Genomics and Plant Molecular Imaging, Center for Protein Engineering (CIP), Department of Life Sciences, University of Liège, B-4000 Liège, Belgium
| | - Catherine Polese
- Functional Genomics and Plant Molecular Imaging, Center for Protein Engineering (CIP), Department of Life Sciences, University of Liège, B-4000 Liège, Belgium
| | - Cécile Nouet
- Functional Genomics and Plant Molecular Imaging, Center for Protein Engineering (CIP), Department of Life Sciences, University of Liège, B-4000 Liège, Belgium
| | - Monique Carnol
- Laboratory of Plant and Microbial Ecology, Department of Biology, Ecology, Evolution, University of Liège, B-4000 Liège, Belgium
| | - Bernard Bosman
- Laboratory of Plant and Microbial Ecology, Department of Biology, Ecology, Evolution, University of Liège, B-4000 Liège, Belgium
| | - Ute Krämer
- Department of Plant Physiology, Ruhr University Bochum, D-44801 Bochum, Germany
| | - Patrick Motte
- Functional Genomics and Plant Molecular Imaging, Center for Protein Engineering (CIP), Department of Life Sciences, University of Liège, B-4000 Liège, Belgium PhytoSYSTEMS, University of Liège, B-4000 Liège, Belgium
| | - Marc Hanikenne
- Functional Genomics and Plant Molecular Imaging, Center for Protein Engineering (CIP), Department of Life Sciences, University of Liège, B-4000 Liège, Belgium PhytoSYSTEMS, University of Liège, B-4000 Liège, Belgium
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15
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Sun B, Looi LS, Guo S, He Z, Gan ES, Huang J, Xu Y, Wee WY, Ito T. Timing mechanism dependent on cell division is invoked by Polycomb eviction in plant stem cells. Science 2014; 343:1248559. [PMID: 24482483 DOI: 10.1126/science.1248559] [Citation(s) in RCA: 147] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Plant floral stem cells divide a limited number of times before they stop and terminally differentiate, but the mechanisms that control this timing remain unclear. The precise temporal induction of the Arabidopsis zinc finger repressor KNUCKLES (KNU) is essential for the coordinated growth and differentiation of floral stem cells. We identify an epigenetic mechanism in which the floral homeotic protein AGAMOUS (AG) induces KNU at ~2 days of delay. AG binding sites colocalize with a Polycomb response element in the KNU upstream region. AG binding to the KNU promoter causes the eviction of the Polycomb group proteins from the locus, leading to cell division-dependent induction. These analyses demonstrate that floral stem cells measure developmental timing by a division-dependent epigenetic timer triggered by Polycomb eviction.
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Affiliation(s)
- Bo Sun
- Temasek Life Sciences Laboratory, 1 Research Link, National University of Singapore, Singapore 117604, Republic of Singapore
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16
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Abstract
The generation of dominant gain-of-function mutants through activation tagging is a forward genetic approach that complements the screening of loss-of-function mutants and that has been successfully applied to studying the mechanisms of flower development. In addition, the functions of genes of interest can be further analyzed through reverse genetics. A commonly used method is gene overexpression, where strong, often ectopic expression can result in an opposite phenotype to that caused by a loss-of-function mutation. When overexpression is detrimental, the misexpression of a gene using tissue-specific promoters can be useful to study spatial-specific function. As flower development is a multistep process, it can be advantageous to control gene expression, or its protein product activity, in a temporal and/or spatial manner. This has been made possible through several inducible promoter systems, as well as by constructing chimeric fusions between the ligand binding domain of the glucocorticoid receptor (GR) and the protein of interest. Upon treatment with a steroid hormone at a specific time point, the fusion protein can enter the nucleus and activate downstream target genes. All these methods allow us to genetically manipulate gene expression during flower development. In this chapter, we describe methods to produce the expression constructs, method of screening, and more general applications of the techniques.
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Affiliation(s)
- Yifeng Xu
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore, Singapore
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17
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Immink RGH, Posé D, Ferrario S, Ott F, Kaufmann K, Valentim FL, de Folter S, van der Wal F, van Dijk ADJ, Schmid M, Angenent GC. Characterization of SOC1's central role in flowering by the identification of its upstream and downstream regulators. PLANT PHYSIOLOGY 2012; 160:433-49. [PMID: 22791302 PMCID: PMC3440217 DOI: 10.1104/pp.112.202614] [Citation(s) in RCA: 146] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2012] [Accepted: 07/10/2012] [Indexed: 05/18/2023]
Abstract
The transition from vegetative to reproductive development is one of the most important phase changes in the plant life cycle. This step is controlled by various environmental signals that are integrated at the molecular level by so-called floral integrators. One such floral integrator in Arabidopsis (Arabidopsis thaliana) is the MADS domain transcription factor SUPPRESSOR OF OVEREXPRESSION OF CONSTANS1 (SOC1). Despite extensive genetic studies, little is known about the transcriptional control of SOC1, and we are just starting to explore the network of genes under the direct control of SOC1 transcription factor complexes. Here, we show that several MADS domain proteins, including SOC1 heterodimers, are able to bind SOC1 regulatory sequences. Genome-wide target gene analysis by ChIP-seq confirmed the binding of SOC1 to its own locus and shows that it also binds to a plethora of flowering-time regulatory and floral homeotic genes. In turn, the encoded floral homeotic MADS domain proteins appear to bind SOC1 regulatory sequences. Subsequent in planta analyses revealed SOC1 repression by several floral homeotic MADS domain proteins, and we show that, mechanistically, this depends on the presence of the SOC1 protein. Together, our data show that SOC1 constitutes a major hub in the regulatory networks underlying floral timing and flower development and that these networks are composed of many positive and negative autoregulatory and feedback loops. The latter seems to be crucial for the generation of a robust flower-inducing signal, followed shortly after by repression of the SOC1 floral integrator.
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Affiliation(s)
- Richard G H Immink
- Plant Research International, Bioscience, 6708 PB Wageningen, The Netherlands.
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18
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Makhzoum A, Petit-Paly G, St Pierre B, Bernards MA. Functional analysis of the DAT gene promoter using transient Catharanthus roseus and stable Nicotiana tabacum transformation systems. PLANT CELL REPORTS 2011; 30:1173-82. [PMID: 21308469 DOI: 10.1007/s00299-011-1025-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 01/18/2011] [Accepted: 01/24/2011] [Indexed: 05/23/2023]
Abstract
The Catharanthus roseus DAT gene encodes the enzyme acetyl-CoA:deacetylvindoline-4-O-acetyltransferase involved in the last step of the indole alkaloid pathway leading to vindoline. This gene is characterized by specific cell type expression in idioblasts and laticifers. To understand the specific transcriptional regulation mechanism(s) of DAT, several DAT promoter GUS constructs were cloned into pCAMBIA1305.1. Agroinfiltration of different explant types of C. roseus resulted in organ-specific accumulation of GUS, albeit at various levels. Heterologous accumulation of GUS in transgenic tobacco revealed both general and non-specific expression with the exception of a stomata-specific expression when 2.3 kb of the DAT promoter was coupled with a portion of the DAT ORF. These results suggest that in addition to the 2.3 kb upstream of the DAT transcriptional start site, additional cis-acting elements may be responsible for the specific spatial expression of DAT in vivo. Furthermore, hairy roots transformed with DAT promoter GUS constructs demonstrated GUS expression in root tissues (visualized through GUS enzyme activity), even though DAT is repressed in non-transformed roots.
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Affiliation(s)
- Abdullah Makhzoum
- Department of Biology and The Biotron, The University of Western Ontario, London, ON, Canada.
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19
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Ronse De Craene L, Tréhin C, Morel P, Negrutiu I. Carpeloidy in flower evolution and diversification: a comparative study in Carica papaya and Arabidopsis thaliana. ANNALS OF BOTANY 2011; 107:1453-63. [PMID: 21504912 PMCID: PMC3108808 DOI: 10.1093/aob/mcr087] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2010] [Revised: 01/04/2011] [Accepted: 02/23/2011] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIMS Bisexual flowers of Carica papaya range from highly regular flowers to morphs with various fusions of stamens to the ovary. Arabidopsis thaliana sup1 mutants have carpels replaced by chimeric carpel-stamen structures. Comparative analysis of stamen to carpel conversions in the two different plant systems was used to understand the stage and origin of carpeloidy when derived from stamen tissues, and consequently to understand how carpeloidy contributes to innovations in flower evolution. METHODS Floral development of bisexual flowers of Carica was studied by scanning electron microscopy and was compared with teratological sup mutants of A. thaliana. KEY RESULTS In Carica development of bisexual flowers was similar to wild (unisexual) forms up to locule initiation. Feminization ranges from fusion of stamen tissue to the gynoecium to complete carpeloidy of antepetalous stamens. In A. thaliana, partial stamen feminization occurs exclusively at the flower apex, with normal stamens forming at the periphery. Such transformations take place relatively late in development, indicating strong developmental plasticity of most stamen tissues. These results are compared with evo-devo theories on flower bisexuality, as derived from unisexual ancestors. The Arabidopsis data highlight possible early evolutionary events in the acquisition of bisexuality by a patchy transformation of stamen parts into female parts linked to a flower axis-position effect. The Carica results highlight tissue-fusion mechanisms in angiosperms leading to carpeloidy once bisexual flowers have evolved. CONCLUSIONS We show two different developmental routes leading to stamen to carpel conversions by late re-specification. The process may be a fundamental aspect of flower development that is hidden in most instances by developmental homeostasis.
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20
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Nibau C, Di Stilio VS, Wu HM, Cheung AY. Arabidopsis and Tobacco superman regulate hormone signalling and mediate cell proliferation and differentiation. JOURNAL OF EXPERIMENTAL BOTANY 2011; 62:949-61. [PMID: 20980362 PMCID: PMC3022392 DOI: 10.1093/jxb/erq325] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2010] [Revised: 09/23/2010] [Accepted: 09/23/2010] [Indexed: 05/19/2023]
Abstract
Arabidopsis thaliana superman (SUP) plays an important role during flower development by maintaining the boundary between stamens and carpels in the inner two whorls. It was proposed that SUP maintains this boundary by regulating cell proliferation in both whorls, as loss-of-function superman mutants produce more stamens at the expense of carpels. However, the cellular mechanism that underlies SUP function remains unknown. Here Arabidopsis or tobacco (Nicotiana tabacum) SUP was overexpressed in tobacco plants to substantiate SUP's role as a regulator of cell proliferation and boundary definition and provide evidence that its biological role may be mediated via hormonal changes. It was found that moderate levels of SUP stimulated cell growth and proliferation, whereas high levels were inhibitory. SUP stimulated auxin- and cytokinin-regulated processes, and cells overexpressing SUP displayed reduced hormone dependency for proliferation and regeneration into plants. SUP also induced proliferation of female traits in the second and third flower whorls and promoted differentiation of petaloid properties in sepals, further supporting a role for SUP as a boundary regulator. Moreover, cytokinin suppressed stamen development and promoted differentiation of carpeloid tissues, suggesting that SUP may regulate male and female development via its effect on cytokinin signalling. Taken together, these observations suggest a model whereby the effect of SUP on cell growth and proliferation involves the modulation of auxin- and cytokinin-regulated processes. Furthermore, differential SUP expression or different sensitivities of different cell types to SUP may determine whether SUP stimulates or suppresses their proliferation.
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Affiliation(s)
- Candida Nibau
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA
- Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Verónica S. Di Stilio
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA
- Department of Biology, University of Washington, Seattle, WA 98195-1800, USA
| | - Hen-ming Wu
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA
- Molecular Cell Biology Program, University of Massachusetts, Amherst, MA 01003, USA
| | - Alice Y. Cheung
- Department of Biochemistry and Molecular Biology, University of Massachusetts, Amherst, MA 01003, USA
- Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
- Molecular Cell Biology Program, University of Massachusetts, Amherst, MA 01003, USA
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21
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Gardiner J, Donner TJ, Scarpella E. Simultaneous activation of SHR and ATHB8 expression defines switch to preprocambial cell state in Arabidopsis leaf development. Dev Dyn 2010; 240:261-70. [DOI: 10.1002/dvdy.22516] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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22
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Zhang M, Kimatu JN, Xu K, Liu B. DNA cytosine methylation in plant development. J Genet Genomics 2010; 37:1-12. [PMID: 20171573 DOI: 10.1016/s1673-8527(09)60020-5] [Citation(s) in RCA: 111] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2009] [Revised: 11/15/2009] [Accepted: 11/30/2009] [Indexed: 10/19/2022]
Abstract
Cytosine bases of the nuclear genome in higher plants are often extensively methylated. Cytosine methylation has been implicated in the silencing of both transposable elements (TEs) and endogenous genes, and loss of methylation may have severe functional consequences. The recent methylation profiling of the entire Arabidopsis genome has provided novel insights into the extent and pattern of cytosine methylation and its relationships with gene activity. In addition, the fresh studies also revealed the more dynamic nature of this epigenetic modification across plant development than previously believed. Cytosine methylation of gene promoter regions usually inhibits transcription, but methylation in coding regions (gene-body methylation) does not generally affect gene expression. Active demethylation (though probably act synergistically with passive loss of methylation) of promoters by the 5-methyl cytosine DNA glycosylase or DEMETER (DME) is required for the uni-parental expression of imprinting genes in endosperm, which is essential for seed viability. The opinion that cytosine methylation is indispensible for normal plant development has been reinforced by using single or combinations of diverse loss-of-function mutants for DNA methyltransferases, DNA glycosylases, components involved in siRNA biogenesis and chromatin remodeling factors. Patterns of cytosine methylation in plants are usually faithfully maintained across organismal generations by the concerted action of epigenetic inheritance and progressive correction of strayed patterns. However, some variant methylation patterns may escape from being corrected and hence produce novel epialleles in the affected somatic cells. This, coupled with the unique property of plants to produce germline cells late during development, may enable the newly acquired epialleles to be inherited to future generations, which if visible to selection may contribute to adaptation and evolution.
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Affiliation(s)
- Meishan Zhang
- Key Laboratory of Molecular Epigenetics of MOE and Institute of Genetics and Cytology, Northeast Normal University, Changchun 130024, China
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23
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Mahfouz MM. RNA-directed DNA methylation: mechanisms and functions. PLANT SIGNALING & BEHAVIOR 2010; 5:806-16. [PMID: 20421728 PMCID: PMC3115029 DOI: 10.4161/psb.5.7.11695] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Accepted: 03/03/2010] [Indexed: 05/21/2023]
Abstract
Epigenetic RNA based gene silencing mechanisms play a major role in genome stability and control of gene expression. Transcriptional gene silencing via RNA-directed DNA methylation (RdDM) guides the epigenetic regulation of the genome in response to disease states, growth, developmental and stress signals. RdDM machinery is composed of proteins that produce and modify 24-nt- long siRNAs, recruit the RdDM complex to genomic targets, methylate DNA and remodel chromatin. The final DNA methylation pattern is determined by either DNA methyltransferase alone or by the combined action of DNA methyltransferases and demethylases. The dynamic interaction between RdDM and demethylases may render the plant epigenome plastic to growth, developmental, and environmental cues. The epigenome plasticity may allow the plant genome to assume many epigenomes and to have the right epigenome at the right time in response to intracellular or extracellular stimuli. This review discusses recent advances in RdDM research and considers future perspectives.
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Affiliation(s)
- Magdy M Mahfouz
- Center for Plant Stress Genomics & Technology, 4700 King Abdullah University of Science & Technology, Kingdom of Saudi Arabia.
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Abstract
During early flower development in Arabidopsis, floral stem cells proliferate and produce a sufficient amount of cells that are recruited for organogenesis. However, after the central organ primordia initiate, stem cell activity in the floral meristem is terminated to ensure the differentiation of a fixed number of floral organs. Underlying this process, the genetic programme regulating the fate of floral meristems undergoes a shift from a spatially balanced signalling scheme for stem cell maintenance to a temporally controlled transcriptional scheme for stem cell termination. Precise timing of stem cell termination is a key issue for flower development, which is secured by the orchestration of multiple regulators in transcriptional and epigenetic regulation.
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Ng KH, Yu H, Ito T. AGAMOUS controls GIANT KILLER, a multifunctional chromatin modifier in reproductive organ patterning and differentiation. PLoS Biol 2009; 7:e1000251. [PMID: 19956801 PMCID: PMC2774341 DOI: 10.1371/journal.pbio.1000251] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Accepted: 10/16/2009] [Indexed: 11/18/2022] Open
Abstract
The floral, homeotic protein AGAMOUS coordinates multiple downstream genes through direct transcriptional regulation of the nuclear matrix attachment region binding protein GIANT KILLER. The Arabidopsis homeotic protein AGAMOUS (AG), a MADS domain transcription factor, specifies reproductive organ identity during flower development. Using a binding assay and expression analysis, we identified a direct target of AG, GIANT KILLER (GIK), which fine-tunes the expression of multiple genes downstream of AG. The GIK protein contains an AT-hook DNA binding motif that is widely found in chromosomal proteins and that binds to nuclear matrix attachment regions of DNA elements. Overexpression and loss of function of GIK cause wide-ranging defects in patterning and differentiation of reproductive organs. GIK directly regulates the expression of several key transcriptional regulators, including ETTIN/AUXIN RESPONSE FACTOR 3 (ETT/ARF3) that patterns the gynoecium, by binding to the matrix attachment regions of target promoters. Overexpression of GIK causes a swift and dynamic change in repressive histone modification in the ETT promoter. We propose that GIK acts as a molecular node downstream of the homeotic protein AG, regulating patterning and differentiation of reproductive organs through chromatin organization. Multicellular development depends on proper expression of thousands of genes. Master regulators, such as homeotic proteins, code for transcription factors in both plants and animals and are thought to act by regulating other genes. Recent genomic studies in the plant Arabidopsis have shown that over 1,000 genes are regulated by homeotic proteins that directly control various target genes, including different classes of transcriptional regulators. It is not known, however, how expression of so many genes is coordinated by a single homeotic gene to form functional organs and tissues. Here we identified a transcriptional target of the plant homeotic protein AGAMOUS using bioinformatics analysis and showed that AGAMOUS directly controls GIANT KILLER, a multifunctional chromatin modifier. GIANT KILLER then binds to the upstream regions of multiple genes involved in patterning and differentiation in the AGAMOUS pathway and fine-tunes the expression of these genes. These data therefore provide a possible mechanism by which a homeotic gene coordinates multiple downstream targets in plants.
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Affiliation(s)
- Kian-Hong Ng
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore
| | - Hao Yu
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore
| | - Toshiro Ito
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore
- Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore
- PRESTO, Japan Science and Technology Agency, Saitama, Japan
- * E-mail:
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Sun B, Xu Y, Ng KH, Ito T. A timing mechanism for stem cell maintenance and differentiation in the Arabidopsis floral meristem. Genes Dev 2009; 23:1791-804. [PMID: 19651987 DOI: 10.1101/gad.1800409] [Citation(s) in RCA: 213] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Developmental regulation of the floral meristem ensures that plants of the same species have similarly sized flowers with a fixed number of floral organs. The maintenance of stem cells in the floral meristem is terminated after the production of a fixed number of floral organ primordia. Precise repression of the Arabidopsis thaliana homeobox gene WUSCHEL (WUS) by the floral homeotic protein AGAMOUS (AG) plays a major part in this process. Here we show that KNUCKLES (KNU) mediates the repression of WUS in floral meristem determinacy control. AG directly induces the transcription of KNU, which encodes a C2H2-type zinc finger protein with a conserved transcriptional repression motif. In turn, KNU represses WUS transcription to abolish stem cell activity. We also show that the timing of KNU induction is key in balancing proliferation and differentiation in flower development. Delayed KNU expression results in an indeterminate meristem, whereas ectopic KNU expression prematurely terminates the floral meristem. Furthermore, KNU induction by AG is preceded by changes in repressive histone modification at the KNU locus, which occurs in an AG-dependent manner. This study provides a mechanistic link between transcriptional feedback and epigenetic regulation in plant stem cell proliferation.
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Affiliation(s)
- Bo Sun
- Temasek Life Sciences Laboratory (TLL), National University of Singapore, Singapore, Singapore
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27
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Kazama Y, Fujiwara MT, Koizumi A, Nishihara K, Nishiyama R, Kifune E, Abe T, Kawano S. A SUPERMAN-like gene is exclusively expressed in female flowers of the dioecious plant Silene latifolia. PLANT & CELL PHYSIOLOGY 2009; 50:1127-41. [PMID: 19406862 DOI: 10.1093/pcp/pcp064] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
To elucidate the mechanism(s) underlying dioecious flower development, the present study analyzed a SUPERMAN (SUP) homolog, SlSUP, which was identified in Silene latifolia. The sex of this plant is determined by heteromorphic X and Y sex chromosomes. It was revealed that SlSUP is a single-copy autosomal gene expressed exclusively in female flowers. Introduction of a genomic copy of SlSUP into the Arabidopsis thaliana sup (sup-2) mutant complemented the excess-stamen and infertile phenotypes of sup-2, and the overexpression of SlSUP in transgenic Arabidopsis plants resulted in reduced stamen numbers as well as the suppression of petal elongation. During the development of the female flower in S. latifolia, the expression of SlSUP is first detectable in whorls 2 and 3 when the normal expression pattern of the B-class flowering genes was already established and persisted in the stamen primordia until the ovule had matured completely. In addition, significant expression of SlSUP was detected in the ovules, suggestive of the involvement of this gene in ovule development. Furthermore, it was revealed that the de-suppression of stamen development by infection of the S. latifolia female flower with Microbotryum violaceum was accompanied by a significant reduction in SlSUP transcript levels in the induced organs. Taken together, these results demonstrate that SlSUP is a female flower-specific gene and suggest that SlSUP has a positive role in the female flower developmental pathways of S. latifolia.
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Affiliation(s)
- Yusuke Kazama
- RIKEN Nishina Center, 2-1 Hirosawa, Wako, Saitama, Japan
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28
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Skinner DJ, Gasser CS. Expression-based discovery of candidate ovule development regulators through transcriptional profiling of ovule mutants. BMC PLANT BIOLOGY 2009; 9:29. [PMID: 19291320 PMCID: PMC2664812 DOI: 10.1186/1471-2229-9-29] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Accepted: 03/16/2009] [Indexed: 05/05/2023]
Abstract
BACKGROUND Arabidopsis ovules comprise four morphologically distinct parts: the nucellus, which contains the embryo sac, two integuments that become the seed coat, and the funiculus that anchors the ovule within the carpel. Analysis of developmental mutants has shown that ovule morphogenesis relies on tightly regulated genetic interactions that can serve as a model for developmental regulation. Redundancy, pleiotropic effects and subtle phenotypes may preclude identification of mutants affecting some processes in screens for phenotypic changes. Expression-based gene discovery can be used access such obscured genes. RESULTS Affymetrix microarrays were used for expression-based gene discovery to identify sets of genes expressed in either or both integuments. The genes were identified by comparison of pistil mRNA from wild type with mRNA from two mutants; inner no outer (ino, which lacks the outer integument), and aintegumenta (ant, which lacks both integuments). Pools of pistils representing early and late stages of ovule development were evaluated and data from the three genotypes were used to designate genes that were predominantly expressed in the integuments using pair-wise and cluster analyses. Approximately two hundred genes were found to have a high probability of preferential expression in these structures, and the predictive nature of the expression classes was confirmed with reverse transcriptase polymerase chain reaction and in situ hybridization. CONCLUSION The results showed that it was possible to use a mutant, ant, with broad effects on plant phenotype to identify genes expressed specifically in ovules, when coupled with predictions from known gene expression patterns, or in combination with a more specific mutant, ino. Robust microarray averaging (RMA) analysis of array data provided the most reliable comparisons, especially for weakly expressed genes. The studies yielded an over-abundance of transcriptional regulators in the identified genes, and these form a set of candidate genes for evaluation of roles in ovule development using reverse genetics.
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Affiliation(s)
- Debra J Skinner
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
- Department of Crop Science, University of Illinois, Urbana, IL 61801, USA
| | - Charles S Gasser
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616, USA
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29
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Ito T, Ng KH, Lim TS, Yu H, Meyerowitz EM. The homeotic protein AGAMOUS controls late stamen development by regulating a jasmonate biosynthetic gene in Arabidopsis. THE PLANT CELL 2007; 19:3516-29. [PMID: 17981996 PMCID: PMC2174883 DOI: 10.1105/tpc.107.055467] [Citation(s) in RCA: 147] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2007] [Revised: 10/07/2007] [Accepted: 10/10/2007] [Indexed: 05/18/2023]
Abstract
The Arabidopsis thaliana floral homeotic gene AGAMOUS (AG) plays a central role in reproductive organ (stamen and carpel) development. AG RNA is expressed in the center of floral primordia from a time prior to the initiation of stamen and carpel primordia until late in flower development. While early AG expression acts in specification of stamens and carpels, the role, if any, of continued AG expression in later flower development is unknown. To examine the timing of AG action and its possible late-stage functions, we performed a series of time-course experiments using a transgenic line with inducible AG activity in an ag homozygous mutant background. We show that AG controls late-stage stamen development, including anther morphogenesis and dehiscence, as well as filament formation and elongation. We further show that AG coordinates late stamen maturation by controlling a biosynthetic gene of the lipid-derived phytohormone jasmonic acid (JA). Expression analysis and in vivo binding of AG indicate that AG directly regulates the transcription of a catalytic enzyme of JA, DEFECTIVE IN ANTHER DEHISCENCE1. Our results indicate that stamen identity and differentiation control by AG is achieved by the regulation of different transcriptional cascades in different floral stages, with organ specification induced early, followed by phytohormone biosynthesis to coordinate stamen maturation.
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Affiliation(s)
- Toshiro Ito
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore 117604, Singapore.
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30
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Godiard L, Niebel A, Micheli F, Gouzy J, Ott T, Gamas P. Identification of new potential regulators of the Medicago truncatula-Sinorhizobium meliloti symbiosis using a large-scale suppression subtractive hybridization approach. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2007; 20:321-32. [PMID: 17378435 DOI: 10.1094/mpmi-20-3-0321] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
We set up a large-scale suppression subtractive hybridization (SSH) approach to identify Medicago truncatula genes differentially expressed at different stages of the symbiotic interaction with Sinorhizobium meliloti, with a particular interest for regulatory genes. We constructed 7 SSH libraries covering successive stages from Nod factor signal transduction to S. meliloti infection, nodule organogenesis, and functioning. Over 26,000 clones were differentially screened by two rounds of macroarray hybridizations. In all, 3,340 clones, corresponding to genes whose expression was potentially affected, were selected, sequenced, and ordered into 2,107 tentative gene clusters, including 767 MtS clusters corresponding to new M. truncatula genes. In total, 52 genes encoding potential regulatory proteins, including transcription factors (TFs) and other elements of signal transduction cascades, were identified. The expression pattern of some of them was analyzed by quantitative reverse-transcription polymerase chain reaction in wild-type and in Nod- M. truncatula mutants blocked before or after S. meliloti infection. Three genes, coding for TFs of the bHLH and WRKY families and a C2H2 zinc-finger protein, respectively, were found to be upregulated, following S. meliloti inoculation, in the infection-defective mutant lin, whereas the bHLH gene also was expressed in the root-hair-curling mutant hcl. The potential role of these genes in early symbiotic steps is discussed.
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Affiliation(s)
- Laurence Godiard
- Laboratoire des Interactions Plantes Micro-organismes (LIPM), UMR CNRS-INRA 2594/441, BP 52627, F- 31 326 Castanet Tolosan, France.
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31
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Soltani BM, Ehlting J, Douglas CJ. Genetic analysis and epigenetic silencing of At4CL1 and At4CL2 expression in transgenic Arabidopsis. Biotechnol J 2007; 1:1124-36. [PMID: 17004303 DOI: 10.1002/biot.200600140] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
4-coumarate::CoA ligase (4CL) gene family members are involved in channeling carbon flow into branch pathways of phenylpropanoid metabolism. Transgenic Arabidopsis plants containing the At4CL1 or At4CL2 promoter fused to the beta-glucuronidase (GUS) reporter gene show developmentally regulated GUS expression in the xylem tissues of the root and shoot. To identify regulatory genes involved in the developmental regulation of At4CL and other phenylpropanoid-specific genes, we generated ethyl methyl sulfate mutagenized populations of At4CL1::GUS and At4CL2::GUS transgenic lines and screened approximately 16,000 progeny for reduced or altered GUS expression. Several lines with reproducible patterns of reduced GUS expression were identified. However, the GUS-expression phenotype segregated in a non-Mendelian manner in all of the identified lines. Also, GUS expression was restored by 5-azacytidine (aza) treatment, suggesting inhibitory DNA methylation of the transgene. Southern analysis confirmed DNA methylation of the proximal promoter sequences of the transgene only in the mutant lines. In addition, retransformation of At4CL::GUS lines with further At4CL promoter constructs enhanced the GUS-silencing phenotype. Taken together, these results suggest that the isolated mutants are epimutants. Apparently, two different modes of silencing were engaged in the At4CL1::GUS and At4CL2::GUS silenced lines. While silencing in the seedlings of the At4CL1::GUS lines was root specific in seedlings, it affected all organs in the At4CL2::GUS lines. Also, At4CL1::GUS transgene silencing was confined to the transgene but At4CL2::GUS silencing extended to the endogenous At4CL2 gene. Organ-specific silencing of the At4CL1::GUS transgene cannot be explained by current models in the literature.
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Affiliation(s)
- Bahram M Soltani
- Genetics Graduate Program, University of British Columbia, Vancouver, BC, Canada
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32
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Aida M, Tasaka M. Morphogenesis and patterning at the organ boundaries in the higher plant shoot apex. PLANT MOLECULAR BIOLOGY 2006; 60:915-28. [PMID: 16724261 DOI: 10.1007/s11103-005-2760-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/27/2004] [Accepted: 09/02/2005] [Indexed: 05/09/2023]
Abstract
Formation of lateral organ primordia from the shoot apical meristem creates boundaries that separate the primordium from surrounding tissue. Morphological and gene expression studies indicate the presence of a distinct set of cells that define the boundaries in the plant shoot apex. Cells at the boundary usually display reduced growth activity that results in separation of adjacent organs or tissues and this morphological boundary coincides with the border of different cell identities. Such morphogenetic and patterning events and their spatial coordination are controlled by a number of boundary-specific regulatory genes. The boundary may also act as a reference point for the generation of new meristems such as axillary meristems. Many of the genes involved in meristem initiation are expressed in the boundary. This review summarizes the cellular characters of the shoot organ boundary and the roles of regulatory genes that control different aspects of this unique region in plant development.
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Affiliation(s)
- Mitsuhiro Aida
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Nara, 630-0192, Japan.
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33
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Lee JY, Colinas J, Wang JY, Mace D, Ohler U, Benfey PN. Transcriptional and posttranscriptional regulation of transcription factor expression in Arabidopsis roots. Proc Natl Acad Sci U S A 2006; 103:6055-60. [PMID: 16581911 PMCID: PMC2111400 DOI: 10.1073/pnas.0510607103] [Citation(s) in RCA: 208] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Understanding how the expression of transcription factor (TF) genes is modulated is essential for reconstructing gene regulatory networks. There is increasing evidence that sequences other than upstream noncoding can contribute to modulating gene expression, but how frequently they do so remains unclear. Here, we investigated the regulation of TFs expressed in a tissue-enriched manner in Arabidopsis roots. For 61 TFs, we created GFP reporter constructs driven by each TF's upstream noncoding sequence (including the 5'UTR) fused to the GFP reporter gene alone or together with the TF's coding sequence. We compared the visually detectable GFP patterns with endogenous mRNA expression patterns, as defined by a genome-wide microarray root expression map. An automated image analysis method for quantifying GFP signals in different tissues was developed and used to validate our visual comparison method. From these combined analyses, we found that (i) the upstream noncoding sequence was sufficient to recapitulate the mRNA expression pattern for 80% (35/44) of the TFs, and (ii) 25% of the TFs undergo posttranscriptional regulation via microRNA-mediated mRNA degradation (2/24) or via intercellular protein movement (6/24). The results suggest that, for Arabidopsis TFs, upstream noncoding sequences are major contributors to mRNA expression pattern establishment, but modulation of transcription factor protein expression pattern after transcription is relatively frequent. This study provides a systematic overview of regulation of TF expression at a cellular level.
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Affiliation(s)
| | | | | | - Daniel Mace
- Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708
| | - Uwe Ohler
- Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708
| | - Philip N. Benfey
- *Department of Biology and
- Institute for Genome Sciences and Policy, Duke University, Durham, NC 27708
- To whom correspondence should be addressed. E-mail:
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34
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Linke B, Börner T. Mitochondrial effects on flower and pollen development. Mitochondrion 2005; 5:389-402. [PMID: 16275170 DOI: 10.1016/j.mito.2005.10.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Revised: 10/04/2005] [Accepted: 10/05/2005] [Indexed: 11/17/2022]
Affiliation(s)
- Bettina Linke
- Department of Biology, Humboldt University Berlin, Chausseestr. 117, D-10115 Berlin, Germany
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35
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Ranganath RM. Asymmetric cell divisions in flowering plants - one mother, "two-many" daughters. PLANT BIOLOGY (STUTTGART, GERMANY) 2005; 7:425-48. [PMID: 16163608 DOI: 10.1055/s-2005-865899] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Plant development shows a fascinating range of asymmetric cell divisions. Over the years, however, cellular differentiation has been interpreted mostly in terms of a mother cell dividing mitotically to produce two daughter cells of different fates. This popular view has masked the significance of an entirely different cell fate specification pathway, where the mother cell first becomes a coenocyte and then cellularizes to simultaneously produce more than two specialized daughter cells. The "one mother - two different daughters" pathways rely on spindle-assisted mechanisms, such as translocation of the nucleus/spindle to a specific cellular site and orientation of the spindle, which are coordinated with cell-specific allocation of cell fate determinants and cytokinesis. By contrast, during "coenocyte-cellularization" pathways, the spindle-assisted mechanisms are irrelevant since cell fate specification emerges only after the nuclear divisions are complete, and the number of specialized daughter cells produced depends on the developmental context. The key events, such as the formation of a coenocyte and migration of the nuclei to specific cellular locations, are coordinated with cellularization by unique types of cell wall formation. Both one mother - two different daughters and the coenocyte-cellularization pathways are used by higher plants in precise spatial and time windows during development. In both the pathways, epigenetic regulation of gene expression is crucial not only for cell fate specification but also for its maintenance through cell lineage. In this review, the focus is on the coenocyte-cellularization pathways in the context of our current understanding of the asymmetric cell divisions. Instances where cell differentiation does not involve an asymmetric division are also discussed to provide a comprehensive account of cell differentiation.
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Affiliation(s)
- R M Ranganath
- Cytogenetics and Developmental Biology Laboratory, Department of Botany, Bangalore University, India.
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36
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Radchuk VV, Sreenivasulu N, Radchuk RI, Wobus U, Weschke W. The methylation cycle and its possible functions in barley endosperm development. PLANT MOLECULAR BIOLOGY 2005; 59:289-307. [PMID: 16247558 DOI: 10.1007/s11103-005-8881-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2005] [Accepted: 06/16/2005] [Indexed: 05/05/2023]
Abstract
Barley endosperm development can be subdivided into the pre-storage, intermediate, storage and desiccation phase. Nothing is known about DNA methylation events involved in different endosperm-specific developmental programmes. A complete set of methylation cycle enzyme genes was identified and investigated by mRNA expression analysis. During the pre-storage phase, methionine synthase and S-adenosylmethionine (AdoMet) synthase genes are expressed at high levels, mainly to produce AdoMet, which might be used for methylation processes as indicated by high expression of methyltransferases HvMET1, HvCMT1 and HvDnmt3-1 as well as AdoHcy hydrolase genes. The methyltransferases, core histones and DNA-unwinding ATPases are co-expressed at the mRNA level. On the contrary, storage protein (prolamin) gene expression is repressed due to CpG methylation. Expression of genes responsible for starch biosynthesis is also developmentally regulated but not methylation-dependent. Thus, during pre-storage phase, activity of HvMET1 and HvCMT1 possibly maintains DNA replication and suppresses specific pathways of maturation. Besides, HvDnmt3-1 might be responsible for differentiation-specific de novo methylation. Expression of methyltransferases HvDnmt3-2 and HvCMT2 peaks during the onset of massive starch accumulation. The enzymes are likely responsible for DNA methylation involved in determining plastid division and amyloplast differentiation as concluded from the patterns of co-expressed genes. Levels of AdoMet decarboxylase mRNA, but not methyltransferase- and AdoHcy mRNA, increase at the beginning of desiccation together with methionine synthase and AdoMet synthase levels. This increase may be indicative for utilization of AdoMet in polyamine production protecting aleuron and embryo cell membranes during desiccation.
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Affiliation(s)
- Volodymyr V Radchuk
- Institut für Pflanzengenetik und Kulturpflanzenforschung (IPK), Molecular Genetics, Corrensstrasse 3, Gatersleben, 06466, Saxoinia-Anhalt, Germany
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37
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Chan SWL, Henderson IR, Jacobsen SE. Gardening the genome: DNA methylation in Arabidopsis thaliana. Nat Rev Genet 2005; 6:351-60. [PMID: 15861207 DOI: 10.1038/nrg1601] [Citation(s) in RCA: 678] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
DNA methylation has two essential roles in plants and animals - defending the genome against transposons and regulating gene expression. Recent experiments in Arabidopsis thaliana have begun to address crucial questions about how DNA methylation is established and maintained. One cardinal insight has been the discovery that DNA methylation can be guided by small RNAs produced through RNA-interference pathways. Plants and mammals use a similar suite of DNA methyltransferases to propagate DNA methylation, but plants have also developed a glycosylase-based mechanism for removing DNA methylation, and there are hints that similar processes function in other organisms.
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Affiliation(s)
- Simon W-L Chan
- Department of Molecular, Cell and Developmental Biology, University of California, Los Angeles, California 90095, USA
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38
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Ito T, Wellmer F, Yu H, Das P, Ito N, Alves-Ferreira M, Riechmann JL, Meyerowitz EM. The homeotic protein AGAMOUS controls microsporogenesis by regulation of SPOROCYTELESS. Nature 2004; 430:356-60. [PMID: 15254538 DOI: 10.1038/nature02733] [Citation(s) in RCA: 217] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2004] [Accepted: 06/07/2004] [Indexed: 11/08/2022]
Abstract
The Arabidopsis homeotic gene AGAMOUS (AG) is necessary for the specification of reproductive organs (stamens and carpels) during the early steps of flower development. AG encodes a transcription factor of the MADS-box family that is expressed in stamen and carpel primordia. At later stages of development, AG is expressed in distinct regions of the reproductive organs. This suggests that AG might function during the maturation of stamens and carpels, as well as in their early development. However, the developmental processes that AG might control during organogenesis and the genes that are regulated by this factor are largely unknown. Here we show that microsporogenesis, the process leading to pollen formation, is induced by AG through activation of the SPOROCYTELESS gene (SPL, also known as NOZZLE,NZZ), a regulator of sporogenesis. Furthermore, we demonstrate that SPL can induce microsporogenesis in the absence of AG function, suggesting that AG controls a specific process during organogenesis by activating another regulator that performs a subset of its functions.
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Affiliation(s)
- Toshiro Ito
- Division of Biology 156-29, California Institute of Technology, 1200 E. California Blvd, Pasadena, California 91125, USA
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