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Brownfield LR, Figueiredo DD, Borg M, Schmidt A. Editorial: Plant development and reproduction at single cell and cell type-specific resolution. FRONTIERS IN PLANT SCIENCE 2023; 14:1261685. [PMID: 37609522 PMCID: PMC10441578 DOI: 10.3389/fpls.2023.1261685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 07/27/2023] [Indexed: 08/24/2023]
Affiliation(s)
| | | | - Michael Borg
- Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Anja Schmidt
- Department of Plant Evolutionary Biology, Institute of Biology, University of Hohenheim, Stuttgart, Germany
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2
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Goel K, Kundu P, Sharma P, Zinta G. Thermosensitivity of pollen: a molecular perspective. PLANT CELL REPORTS 2023; 42:843-857. [PMID: 37029819 DOI: 10.1007/s00299-023-03003-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Accepted: 03/04/2023] [Indexed: 05/06/2023]
Abstract
A current trend in climate comprises adverse weather anomalies with more frequent and intense temperature events. Heatwaves are a serious threat to global food security because of the susceptibility of crop plants to high temperatures. Among various developmental stages of plants, even a slight rise in temperature during reproductive development proves detrimental, thus making sexual reproduction heat vulnerable. In this context, male gametophyte or pollen development stages are the most sensitive ones. High-temperature exposure induces pollen abortion, reducing pollen viability and germination rate with a concomitant effect on seed yield. This review summarizes the ultrastructural, morphological, biochemical, and molecular changes underpinning high temperature-induced aberrations in male gametophytes. Specifically, we highlight the temperature sensing cascade operating in pollen, involving reactive oxygen species (ROS), heat shock factors (HSFs), a hormones and transcriptional regulatory network. We also emphasize integrating various omics approaches to decipher the molecular events triggered by heat stress in pollen. The knowledge of genes, proteins, and metabolites conferring thermotolerance in reproductive tissues can be utilized to breed/engineer thermotolerant crops to ensure food security.
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Affiliation(s)
- Komal Goel
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology (IHBT), Palampur, Himachal Pradesh, 176061, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, 201002, India
| | - Pravesh Kundu
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology (IHBT), Palampur, Himachal Pradesh, 176061, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, 201002, India
| | - Paras Sharma
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology (IHBT), Palampur, Himachal Pradesh, 176061, India
| | - Gaurav Zinta
- Biotechnology Division, CSIR-Institute of Himalayan Bioresource Technology (IHBT), Palampur, Himachal Pradesh, 176061, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, Uttar Pradesh, 201002, India.
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3
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Ali MF, Kawashima T. Formins control dynamics of F-actin in the central cell of Arabidopsis thaliana. PLANT SIGNALING & BEHAVIOR 2021; 16:1920192. [PMID: 33944667 PMCID: PMC8244771 DOI: 10.1080/15592324.2021.1920192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/16/2021] [Accepted: 04/18/2021] [Indexed: 05/28/2023]
Abstract
In the female gamete of flowering plants, sperm nuclear migration is controlled by a constant inward movement of actin filaments (F-actin) for successful fertilization. This dynamic F-actin movement is ARP2/3-independent, raising the question of how actin nucleation and polymerization is controlled in the female gamete. Using confocal microscopy live-cell imaging in combination with a pharmacological approach, we assessed the involvement of another group of actin nucleators, formins, in F-actin inward movement in the central cell of Arabidopsis thaliana. We identify that the inhibition of the formin function, by formin inhibitor SMIFH2, significantly reduced the dynamic inward movement of F-actin in the central cell, indicating that formins play a major role in actin nucleation required for F-actin inward movement in the central cell.
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Affiliation(s)
- Mohammad Foteh Ali
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
| | - Tomokazu Kawashima
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
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Chaturvedi P, Wiese AJ, Ghatak A, Záveská Drábková L, Weckwerth W, Honys D. Heat stress response mechanisms in pollen development. THE NEW PHYTOLOGIST 2021; 231:571-585. [PMID: 33818773 PMCID: PMC9292940 DOI: 10.1111/nph.17380] [Citation(s) in RCA: 52] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Indexed: 05/03/2023]
Abstract
Being rooted in place, plants are faced with the challenge of responding to unfavourable local conditions. One such condition, heat stress, contributes massively to crop losses globally. Heatwaves are predicted to increase, and it is of vital importance to generate crops that are tolerant to not only heat stress but also to several other abiotic stresses (e.g. drought stress, salinity stress) to ensure that global food security is protected. A better understanding of the molecular mechanisms that underlie the temperature stress response in pollen will be a significant step towards developing effective breeding strategies for high and stable production in crop plants. While most studies have focused on the vegetative phase of plant growth to understand heat stress tolerance, it is the reproductive phase that requires more attention as it is more sensitive to elevated temperatures. Every phase of reproductive development is affected by environmental challenges, including pollen and ovule development, pollen tube growth, male-female cross-talk, fertilization, and embryo development. In this review we summarize how pollen is affected by heat stress and the molecular mechanisms employed during the stress period, as revealed by classical and -omics experiments.
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Affiliation(s)
- Palak Chaturvedi
- Molecular Systems Biology (MOSYS)Department of Functional and Evolutionary EcologyFaculty of Life SciencesUniversity of ViennaAlthanstrasse 14Vienna1090Austria
| | - Anna J. Wiese
- Laboratory of Pollen BiologyInstitute of Experimental Botany of the Czech Academy of SciencesRozvojová 263Prague 6165 02Czech Republic
| | - Arindam Ghatak
- Molecular Systems Biology (MOSYS)Department of Functional and Evolutionary EcologyFaculty of Life SciencesUniversity of ViennaAlthanstrasse 14Vienna1090Austria
| | - Lenka Záveská Drábková
- Laboratory of Pollen BiologyInstitute of Experimental Botany of the Czech Academy of SciencesRozvojová 263Prague 6165 02Czech Republic
| | - Wolfram Weckwerth
- Molecular Systems Biology (MOSYS)Department of Functional and Evolutionary EcologyFaculty of Life SciencesUniversity of ViennaAlthanstrasse 14Vienna1090Austria
- Vienna Metabolomics Center (VIME)University of ViennaAlthanstrasse 14Vienna1090Austria
| | - David Honys
- Laboratory of Pollen BiologyInstitute of Experimental Botany of the Czech Academy of SciencesRozvojová 263Prague 6165 02Czech Republic
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5
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Liu L, Wang T. Male gametophyte development in flowering plants: A story of quarantine and sacrifice. JOURNAL OF PLANT PHYSIOLOGY 2021; 258-259:153365. [PMID: 33548696 DOI: 10.1016/j.jplph.2021.153365] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 01/06/2021] [Accepted: 01/06/2021] [Indexed: 05/19/2023]
Abstract
Over 160 years ago, scientists made the first microscopic observations of angiosperm pollen. Unlike in animals, male meiosis in angiosperms produces a haploid microspore that undergoes one asymmetric division to form a vegetative cell and a generative cell. These two cells have distinct fates: the vegetative cell exits the cell cycle and elongates to form a tip-growing pollen tube; the generative cell divides once more in the pollen grain or within the growing pollen tube to form a pair of sperm cells. The concept that male germ cells are less active than the vegetative cell came from biochemical analyses and pollen structure anatomy early in the last century and is supported by the pollen transcriptome data of the last decade. However, the mechanism of how and when the transcriptional repression in male germ cells occurs is still not fully understood. In this review, we provide a brief account of the cytological and metabolic differentiation between the vegetative cell and male germ cells, with emphasis on the role of temporary callose walls, dynamic nuclear pore density, transcription repression, and histone variants. We further discuss the intercellular movement of small interfering RNA (siRNA) derived from transposable elements (TEs) and reexamine the function of TE expression in male germ cells.
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Affiliation(s)
- Lingtong Liu
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China.
| | - Tai Wang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China; College of Life Science, University of Chinese Academy of Sciences, Beijing 100049, China; Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing 100093, China.
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Xu Y, Jia H, Wu X, Koltunow AM, Deng X, Xu Q. Regulation of nucellar embryony, a mode of sporophytic apomixis in Citrus resembling somatic embryogenesis. CURRENT OPINION IN PLANT BIOLOGY 2021; 59:101984. [PMID: 33418404 DOI: 10.1016/j.pbi.2020.101984] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 11/28/2020] [Accepted: 12/02/2020] [Indexed: 06/12/2023]
Abstract
Apomixis, is an asexual mode of seed formation resulting in genetically identical or clonal seed with a maternal genotype. Apomixis has not been reported in seed crops where its flexible application in plant breeding could accelerate delivery of new varieties. By contrast, a sporophytic form of apomixis termed nucellar or adventitious embryony is common in the Rutaceae containing Citrus crop species. Here, multiple embryos develop from the maternal, somatic, nucellar cells of the ovule. They are incorporated into the enlarging embryo sac containing the sexually derived zygotic embryo and endosperm, which are products of double fertilization. Recent research has provided insights to the molecular basis for nucellar embryony. Here, we review the current understanding of the initiation, genetic basis and evolution of nucellar embryony in Citrus, and discuss prospects for future study and breeding applications of Citrus sporophytic apomixis.
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Affiliation(s)
- Yuantao Xu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Huihui Jia
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Xiaomeng Wu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Anna Mg Koltunow
- Centre for Crop Sciences, Queensland Alliance for Agriculture and Food Innovation (QAAFI), The University of Queensland, Brisbane, Queensland, 4702, Australia.
| | - Xiuxin Deng
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan, Hubei 430070, PR China
| | - Qiang Xu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan, Hubei 430070, PR China.
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Ali MF, Fatema U, Peng X, Hacker SW, Maruyama D, Sun MX, Kawashima T. ARP2/3-independent WAVE/SCAR pathway and class XI myosin control sperm nuclear migration in flowering plants. Proc Natl Acad Sci U S A 2020; 117:32757-32763. [PMID: 33288691 PMCID: PMC7768783 DOI: 10.1073/pnas.2015550117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
After eukaryotic fertilization, gamete nuclei migrate to fuse parental genomes in order to initiate development of the next generation. In most animals, microtubules control female and male pronuclear migration in the zygote. Flowering plants, on the other hand, have evolved actin filament (F-actin)-based sperm nuclear migration systems for karyogamy. Flowering plants have also evolved a unique double-fertilization process: two female gametophytic cells, the egg and central cells, are each fertilized by a sperm cell. The molecular and cellular mechanisms of how flowering plants utilize and control F-actin for double-fertilization events are largely unknown. Using confocal microscopy live-cell imaging with a combination of pharmacological and genetic approaches, we identified factors involved in F-actin dynamics and sperm nuclear migration in Arabidopsis thaliana (Arabidopsis) and Nicotiana tabacum (tobacco). We demonstrate that the F-actin regulator, SCAR2, but not the ARP2/3 protein complex, controls the coordinated active F-actin movement. These results imply that an ARP2/3-independent WAVE/SCAR-signaling pathway regulates F-actin dynamics in female gametophytic cells for fertilization. We also identify that the class XI myosin XI-G controls active F-actin movement in the Arabidopsis central cell. XI-G is not a simple transporter, moving cargos along F-actin, but can generate forces that control the dynamic movement of F-actin for fertilization. Our results provide insights into the mechanisms that control gamete nuclear migration and reveal regulatory pathways for dynamic F-actin movement in flowering plants.
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Affiliation(s)
- Mohammad Foteh Ali
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546-0312
| | - Umma Fatema
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546-0312
| | - Xiongbo Peng
- State Key Laboratory of Hybrid Rice, College of Life Science, Wuhan University, 430072 Wuhan, China
| | - Samuel W Hacker
- Agriculture and Medical Biotechnology Program, University of Kentucky, Lexington, KY 40546-0312
| | - Daisuke Maruyama
- Kihara Institute for Biological Research, Yokohama City University, 244-0813 Yokohama, Kanagawa, Japan
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Science, Wuhan University, 430072 Wuhan, China
| | - Tomokazu Kawashima
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY 40546-0312;
- Agriculture and Medical Biotechnology Program, University of Kentucky, Lexington, KY 40546-0312
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8
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Controlling Apomixis: Shared Features and Distinct Characteristics of Gene Regulation. Genes (Basel) 2020; 11:genes11030329. [PMID: 32245021 PMCID: PMC7140868 DOI: 10.3390/genes11030329] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/13/2020] [Accepted: 03/18/2020] [Indexed: 02/06/2023] Open
Abstract
In higher plants, sexual and asexual reproduction through seeds (apomixis) have evolved as alternative strategies. As apomixis leads to the formation of clonal offspring, its great potential for agricultural applications has long been recognized. However, the genetic basis and the molecular control underlying apomixis and its evolutionary origin are to date not fully understood. Both in sexual and apomictic plants, reproduction is tightly controlled by versatile mechanisms regulating gene expression, translation, and protein abundance and activity. Increasing evidence suggests that interrelated pathways including epigenetic regulation, cell-cycle control, hormonal pathways, and signal transduction processes are relevant for apomixis. Additional molecular mechanisms are being identified that involve the activity of DNA- and RNA-binding proteins, such as RNA helicases which are increasingly recognized as important regulators of reproduction. Together with other factors including non-coding RNAs, their association with ribosomes is likely to be relevant for the formation and specification of the apomictic reproductive lineage. Subsequent seed formation appears to involve an interplay of transcriptional activation and repression of developmental programs by epigenetic regulatory mechanisms. In this review, insights into the genetic basis and molecular control of apomixis are presented, also taking into account potential relations to environmental stress, and considering aspects of evolution.
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Zühl L, Volkert C, Ibberson D, Schmidt A. Differential activity of F-box genes and E3 ligases distinguishes sexual versus apomictic germline specification in Boechera. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:5643-5657. [PMID: 31294816 PMCID: PMC6812705 DOI: 10.1093/jxb/erz323] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2018] [Accepted: 07/01/2019] [Indexed: 05/22/2023]
Abstract
Germline specification is the first step during sexual and apomictic plant reproduction, and takes place in the nucellus of the ovule, a specialized domain of the reproductive flower tissues. In each case, a sporophytic cell is determined to form the sexual megaspore mother cell (MMC) or an apomictic initial cell (AIC). These differ in their developmental fates: while the MMC undergoes meiosis, the AIC modifies or omits meiosis to form the female gametophyte. Despite great interest in these distinct developmental processes, little is known about their gene regulatory basis. To elucidate the gene regulatory networks underlying germline specification, we conducted tissue-specific transcriptional profiling using laser-assisted microdissection and RNA sequencing to compare the transcriptomes of nucellar tissues between different sexual and apomictic Boechera accessions representing four species and two ploidy levels. This allowed us to distinguish between expression differences caused by genetic background or reproductive mode. Statistical data analysis revealed 45 genes that were significantly differentially expressed, and which potentially play a role for determination of the reproductive mode. Based on annotations, these included F-box genes and E3 ligases that most likely relate to genes previously described as regulators important for germline development. Our findings provide novel insights into the transcriptional basis of sexual and apomictic reproduction.
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Affiliation(s)
- Luise Zühl
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld, Heidelberg
- Present address: Max Planck Institute for Plant Breeding Research, Department of Comparative Development and Genetics, Carl-von-Linné-Weg 10, D-50829 Cologne
| | - Christopher Volkert
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld, Heidelberg
| | - David Ibberson
- Deep Sequencing Core Facility, CellNetworks Excellence Cluster, Heidelberg University, Im Neuenheimer Feld, Heidelberg
| | - Anja Schmidt
- Centre for Organismal Studies Heidelberg, Department of Biodiversity and Plant Systematics, Heidelberg University, Im Neuenheimer Feld, Heidelberg
- Correspondence:
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Shunmugam ASK, Bollina V, Dukowic-Schulze S, Bhowmik PK, Ambrose C, Higgins JD, Pozniak C, Sharpe AG, Rozwadowski K, Kagale S. MeioCapture: an efficient method for staging and isolation of meiocytes in the prophase I sub-stages of meiosis in wheat. BMC PLANT BIOLOGY 2018; 18:293. [PMID: 30463507 PMCID: PMC6249822 DOI: 10.1186/s12870-018-1514-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 10/31/2018] [Indexed: 05/21/2023]
Abstract
BACKGROUND Molecular analysis of meiosis has been hindered by difficulties in isolating high purity subpopulations of sporogenous cells representing the succeeding stages of meiosis. Isolation of purified male meiocytes from defined meiotic stages is crucial in discovering meiosis specific genes and associated regulatory networks. RESULTS We describe an optimized method termed MeioCapture for simultaneous isolation of uncontaminated male meiocytes from wheat (Triticum spp.), specifically from the pre-meiotic G2 and the five sub-stages of meiotic prophase I. The MeioCapture protocol builds on the traditional anther squash technique and the capillary collection method, and involves extrusion of intact sporogenous archesporial columns (SACs) containing meiocytes. This improved method exploits the natural meiotic synchrony between anthers of the same floret, the correlation between the length of anthers and meiotic stage, and the occurrence of meiocytes in intact SACs largely free of somatic cells. The main advantage of MeioCapture, compared to previous methods, is that it allows simultaneous collection of meiocytes from different sub-stages of prophase I at a very high level of purity, through correlation of stages with anther sizes. A detailed description is provided for all steps, including the collection of tissue, isolation and size sorting of anthers, extrusion of intact SACs, and staging of meiocytes. Precautions for individual steps throughout the procedure are also provided to facilitate efficient isolation of pure meiocytes. The proof-of-concept was successfully established in wheat, and a light microscopic atlas of meiosis, encompassing all stages from pre-meiosis to telophase II, was developed. CONCLUSION The MeioCapture method provides an essential technique to study the molecular basis of chromosome pairing and exchange of genetic information in wheat, leading to strategies for manipulating meiotic recombination frequencies. The method also provides a foundation for similar studies in other crop species.
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Affiliation(s)
| | | | | | | | - Chris Ambrose
- Department of Biology, University of Saskatchewan, Saskatoon, SK Canada
| | - James D. Higgins
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Curtis Pozniak
- Department of Plant Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Andrew G. Sharpe
- National Research Council Canada, Saskatoon, SK Canada
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, Canada
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Huang L, Dong H, Zhou D, Li M, Liu Y, Zhang F, Feng Y, Yu D, Lin S, Cao J. Systematic identification of long non-coding RNAs during pollen development and fertilization in Brassica rapa. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 96:203-222. [PMID: 29975432 DOI: 10.1111/tpj.14016] [Citation(s) in RCA: 68] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Revised: 06/18/2018] [Accepted: 06/26/2018] [Indexed: 05/21/2023]
Abstract
The importance of long non-coding RNAs (lncRNAs) in plant development has been established, but a systematic analysis of lncRNAs expressed during pollen development and fertilization has been elusive. We performed a time series of RNA-seq experiments at five developmental stages during pollen development and three different time points after pollination in Brassica rapa and identified 12 051 putative lncRNAs. A comprehensive view of dynamic lncRNA expression networks underpinning pollen development and fertilization was provided. B. rapa lncRNAs share many common characteristics of lncRNAs: relatively short length, low expression but specific in narrow time windows, and low evolutionary conservation. Gene modules and key lncRNAs regulating reproductive development such as exine formation were uncovered. Forty-seven cis-acting lncRNAs and 451 trans-acting lncRNAs were revealed to be highly coexpressed with their target protein-coding genes. Of particular importance are the discoveries of 14 lncRNAs that were highly coexpressed with 10 function-known pollen-associated coding genes. Fifteen lncRNAs were predicted as endogenous target mimics for 13 miRNAs, and two lncRNAs were proved to be functional target mimics for miR160 after experimental verification and shown to function in pollen development. Our study provides the systematic identification of lncRNAs during pollen development and fertilization in B. rapa and forms the foundation for future genetic, genomic, and evolutionary studies.
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Affiliation(s)
- Li Huang
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Hangzhou, 310058, China
| | - Heng Dong
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Hangzhou, 310058, China
| | - Dong Zhou
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Hangzhou, 310058, China
| | - Ming Li
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Hangzhou, 310058, China
| | - Yanhong Liu
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Hangzhou, 310058, China
| | - Fang Zhang
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Hangzhou, 310058, China
| | - Yaoyao Feng
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Hangzhou, 310058, China
| | - Dongliang Yu
- College of Life and Environmental Sciences, Hangzhou Normal University, Hangzhou, 310036, China
| | - Sue Lin
- Institute of Life Sciences, Wenzhou University, Wenzhou, 325000, China
| | - Jiashu Cao
- Laboratory of Cell & Molecular Biology, Institute of Vegetable Science, Zhejiang University, Hangzhou, 310058, China
- Key Laboratory of Horticultural Plant Growth, Development and Quality Improvement, Ministry of Agriculture/Zhejiang Provincial Key Laboratory of Horticultural Plant Integrative Biology, Hangzhou, 310058, China
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Abstract
The haploid female gametophyte (embryo sac) is an essential reproductive unit of flowering plants, usually comprising four specialized cell types, including the female gametes (egg cell and central cell). The differentiation of these cells relies on spatial signals which pattern the gametophyte along a proximal-distal axis, but the molecular and genetic mechanisms by which cell identities are determined in the embryo sac have long been a mystery. Recent identification of key genes for cell fate specification and their relationship to hormonal signaling pathways that act on positional cues has provided new insights into these processes. A model for differentiation can be devised with egg cell fate as a default state of the female gametophyte and with other cell types specified by the action of spatially regulated factors. Cell-to-cell communication within the gametophyte is also important for maintaining cell identity as well as facilitating fertilization of the female gametes by the male gametes (sperm cells).
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Affiliation(s)
- Debra J Skinner
- Department of Plant Biology, University of California-Davis, Davis, USA
| | - Venkatesan Sundaresan
- Department of Plant Biology, University of California-Davis, Davis, USA.,Department of Plant Sciences, University of California-Davis, Davis, USA
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Cell-Type Transcriptomes of the Multicellular Green Alga Volvox carteri Yield Insights into the Evolutionary Origins of Germ and Somatic Differentiation Programs. G3-GENES GENOMES GENETICS 2018; 8:531-550. [PMID: 29208647 PMCID: PMC5919742 DOI: 10.1534/g3.117.300253] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Germ-soma differentiation is a hallmark of complex multicellular organisms, yet its origins are not well understood. Volvox carteri is a simple multicellular green alga that has recently evolved a simple germ-soma dichotomy with only two cell-types: large germ cells called gonidia and small terminally differentiated somatic cells. Here, we provide a comprehensive characterization of the gonidial and somatic transcriptomes of V. carteri to uncover fundamental differences between the molecular and metabolic programming of these cell-types. We found extensive transcriptome differentiation between cell-types, with somatic cells expressing a more specialized program overrepresented in younger, lineage-specific genes, and gonidial cells expressing a more generalist program overrepresented in more ancient genes that shared striking overlap with stem cell-specific genes from animals and land plants. Directed analyses of different pathways revealed a strong dichotomy between cell-types with gonidial cells expressing growth-related genes and somatic cells expressing an altruistic metabolic program geared toward the assembly of flagella, which support organismal motility, and the conversion of storage carbon to sugars, which act as donors for production of extracellular matrix (ECM) glycoproteins whose secretion enables massive organismal expansion. V. carteri orthologs of diurnally controlled genes from C. reinhardtii, a single-celled relative, were analyzed for cell-type distribution and found to be strongly partitioned, with expression of dark-phase genes overrepresented in somatic cells and light-phase genes overrepresented in gonidial cells- a result that is consistent with cell-type programs in V. carteri arising by cooption of temporal regulons in a unicellular ancestor. Together, our findings reveal fundamental molecular, metabolic, and evolutionary mechanisms that underlie the origins of germ-soma differentiation in V. carteri and provide a template for understanding the acquisition of germ-soma differentiation in other multicellular lineages.
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Nakajima K. Be my baby: patterning toward plant germ cells. CURRENT OPINION IN PLANT BIOLOGY 2018; 41:110-115. [PMID: 29223127 DOI: 10.1016/j.pbi.2017.11.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Revised: 11/27/2017] [Accepted: 11/27/2017] [Indexed: 05/28/2023]
Abstract
In flowering plants, germ cells are formed via tightly coordinated patterning processes that facilitate specification of spore mother cells and meiosis during sporogenesis, as well as functional differentiation of germ cells in gametogenesis. Studies using the conventional Arabidopsis system and the newly emerged bryophyte system have revealed novel interactions between regulatory factors that restrict the number of spore mother cells, and evolutionarily conserved factors that promote germ cell differentiation. This short review summarizes recent advances in our understanding of the cellular events that lead to the formation of germ cells in plants, and highlights questions that remain to be addressed in the field.
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Affiliation(s)
- Keiji Nakajima
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan.
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15
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Liu Z, Miao L, Huo R, Song X, Johnson C, Kong L, Sundaresan V, Yu X. ARF2-ARF4 and ARF5 are Essential for Female and Male Gametophyte Development in Arabidopsis. PLANT & CELL PHYSIOLOGY 2018; 59:179-189. [PMID: 29145642 DOI: 10.1093/pcp/pcx174] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2017] [Accepted: 11/07/2017] [Indexed: 05/14/2023]
Abstract
The plant hormone auxin plays critical roles in plant growth and development. Auxin response factors (ARFs) are a class of transcription factors which regulate auxin-mediated gene expression. While the functions of ARFs in sporophytic development have been well characterized, their functions specific to gametophytic development have not been studied extensively. In this study, Arabidopsis ARF genes were selectively down-regulated in gametophytes by misexpression of targeted microRNAs (amiRARF234, amiRARFMP and MIR167a) to silence AtARF2-AtAEF4, AtARF5, AtARF6 and AtARF8. Embryo sacs in amiRARF234- and amiRARFMP-expressing plants exhibited identity defects in cells at the micropylar pole, such as formation of two cells with egg cell-like morphology, concomitant with loss of synergid marker expression and seed abortion. The pollen grains of the transgenic plants were morphologically aberrant and unviable, and the inclusions and nuclei were lost in the abnormal pollen grains. However, plants misexpressing MIR167a showed no obvious abnormal phenotypes in the embryo sacs and pollen grains. Overall, these results provide evidence that AtARF2-AtARF4 and AtARF5 play significant roles in regulating both female and male gametophyte development in Arabidopsis.
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MESH Headings
- Arabidopsis/genetics
- Arabidopsis/growth & development
- Arabidopsis Proteins/genetics
- Base Sequence
- DNA-Binding Proteins/genetics
- Down-Regulation
- Gametogenesis, Plant/genetics
- Gene Expression Regulation, Developmental
- Gene Expression Regulation, Plant
- Germ Cells, Plant/growth & development
- Germ Cells, Plant/metabolism
- Germ Cells, Plant/ultrastructure
- Microscopy, Electron, Transmission
- Nuclear Proteins/genetics
- Plants, Genetically Modified
- Repressor Proteins/genetics
- Seeds/genetics
- Seeds/growth & development
- Sequence Homology, Nucleic Acid
- Transcription Factors/genetics
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Affiliation(s)
- Zhenning Liu
- Institute of Vegetable Science, Zhejiang University, Hangzhou 310058, China
- College of Agriculture and Forestry Sciences, Linyi University, Linyi, Shandong 276000, China
- Department of Plant Biology, University of California, Davis, CA 95616, USA
| | - Liming Miao
- Institute of Vegetable Science, Zhejiang University, Hangzhou 310058, China
| | - Ruxue Huo
- College of Agriculture and Forestry Sciences, Linyi University, Linyi, Shandong 276000, China
| | - Xiaoya Song
- Department of Plant Biology, University of California, Davis, CA 95616, USA
| | - Cameron Johnson
- Department of Plant Biology, University of California, Davis, CA 95616, USA
| | - Lijun Kong
- Institute of Vegetable Science, Zhejiang University, Hangzhou 310058, China
| | | | - Xiaolin Yu
- Institute of Vegetable Science, Zhejiang University, Hangzhou 310058, China
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16
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Park K, Frost JM, Adair AJ, Kim DM, Yun H, Brooks JS, Fischer RL, Choi Y. Optimized Methods for the Isolation of Arabidopsis Female Central Cells and Their Nuclei. Mol Cells 2016; 39:768-775. [PMID: 27788573 PMCID: PMC5104886 DOI: 10.14348/molcells.2016.0209] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Revised: 09/13/2016] [Accepted: 09/13/2016] [Indexed: 12/31/2022] Open
Abstract
The Arabidopsis female gametophyte contains seven cells with eight haploid nuclei buried within layers of sporophytic tissue. Following double fertilization, the egg and central cells of the gametophyte develop into the embryo and endosperm of the seed, respectively. The epigenetic status of the central cell has long presented an enigma due both to its inaccessibility, and the fascinating epigenome of the endosperm, thought to have been inherited from the central cell following activity of the DEMETER demethylase enzyme, prior to fertilization. Here, we present for the first time, a method to isolate pure populations of Arabidopsis central cell nuclei. Utilizing a protocol designed to isolate leaf mesophyll protoplasts, we systematically optimized each step in order to efficiently separate central cells from the female gametophyte. We use initial manual pistil dissection followed by the derivation of central cell protoplasts, during which process the central cell emerges from the micropylar pole of the embryo sac. Then, we use a modified version of the Isolation of Nuclei TAgged in specific Cell Types (INTACT) protocol to purify central cell nuclei, resulting in a purity of 75-90% and a yield sufficient to undertake downstream molecular analyses. We find that the process is highly dependent on the health of the original plant tissue used, and the efficiency of protoplasting solution infiltration into the gametophyte. By isolating pure central cell populations, we have enabled elucidation of the physiology of this rare cell type, which in the future will provide novel insights into Arabidopsis reproduction.
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Affiliation(s)
- Kyunghyuk Park
- Department of Biological Sciences, Seoul National University, Seoul 08826,
Korea
| | - Jennifer M. Frost
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720,
USA
| | - Adam James Adair
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720,
USA
| | - Dong Min Kim
- Department of Biological Sciences, Seoul National University, Seoul 08826,
Korea
| | - Hyein Yun
- Department of Biological Sciences, Seoul National University, Seoul 08826,
Korea
| | - Janie S. Brooks
- Department of Science, Seoul Foreign School, Seoul 09723,
Korea
| | - Robert L. Fischer
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720,
USA
| | - Yeonhee Choi
- Department of Biological Sciences, Seoul National University, Seoul 08826,
Korea
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17
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Schmid MW, Schmidt A, Grossniklaus U. The female gametophyte: an emerging model for cell type-specific systems biology in plant development. FRONTIERS IN PLANT SCIENCE 2015; 6:907. [PMID: 26579157 PMCID: PMC4630298 DOI: 10.3389/fpls.2015.00907] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2015] [Accepted: 10/10/2015] [Indexed: 05/03/2023]
Abstract
Systems biology, a holistic approach describing a system emerging from the interactions of its molecular components, critically depends on accurate qualitative determination and quantitative measurements of these components. Development and improvement of large-scale profiling methods ("omics") now facilitates comprehensive measurements of many relevant molecules. For multicellular organisms, such as animals, fungi, algae, and plants, the complexity of the system is augmented by the presence of specialized cell types and organs, and a complex interplay within and between them. Cell type-specific analyses are therefore crucial for the understanding of developmental processes and environmental responses. This review first gives an overview of current methods used for large-scale profiling of specific cell types exemplified by recent advances in plant biology. The focus then lies on suitable model systems to study plant development and cell type specification. We introduce the female gametophyte of flowering plants as an ideal model to study fundamental developmental processes. Moreover, the female reproductive lineage is of importance for the emergence of evolutionary novelties such as an unequal parental contribution to the tissue nurturing the embryo or the clonal production of seeds by asexual reproduction (apomixis). Understanding these processes is not only interesting from a developmental or evolutionary perspective, but bears great potential for further crop improvement and the simplification of breeding efforts. We finally highlight novel methods, which are already available or which will likely soon facilitate large-scale profiling of the specific cell types of the female gametophyte in both model and non-model species. We conclude that it may take only few years until an evolutionary systems biology approach toward female gametogenesis may decipher some of its biologically most interesting and economically most valuable processes.
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Affiliation(s)
| | | | - Ueli Grossniklaus
- Department of Plant & Microbial Biology and Zurich-Basel Plant Science Center, University of ZurichZurich, Switzerland
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18
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McClure CD, Southall TD. Getting Down to Specifics: Profiling Gene Expression and Protein-DNA Interactions in a Cell Type-Specific Manner. ADVANCES IN GENETICS 2015; 91:103-151. [PMID: 26410031 PMCID: PMC4604662 DOI: 10.1016/bs.adgen.2015.06.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The majority of multicellular organisms are comprised of an extraordinary range of cell types, with different properties and gene expression profiles. Understanding what makes each cell type unique and how their individual characteristics are attributed are key questions for both developmental and neurobiologists alike. The brain is an excellent example of the cellular diversity expressed in the majority of eukaryotes. The mouse brain comprises of approximately 75 million neurons varying in morphology, electrophysiology, and preferences for synaptic partners. A powerful process in beginning to pick apart the mechanisms that specify individual characteristics of the cell, as well as their fate, is to profile gene expression patterns, chromatin states, and transcriptional networks in a cell type-specific manner, i.e., only profiling the cells of interest in a particular tissue. Depending on the organism, the questions being investigated, and the material available, certain cell type-specific profiling methods are more suitable than others. This chapter reviews the approaches presently available for selecting and isolating specific cell types and evaluates their key features.
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Affiliation(s)
- Colin D. McClure
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, South Kensington Campus, London SW7 2AZ, United Kingdom
| | - Tony D. Southall
- Department of Life Sciences, Imperial College London, Sir Ernst Chain Building, South Kensington Campus, London SW7 2AZ, United Kingdom
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19
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Baroux C, Autran D. Chromatin dynamics during cellular differentiation in the female reproductive lineage of flowering plants. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 83:160-76. [PMID: 26031902 PMCID: PMC4502977 DOI: 10.1111/tpj.12890] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Revised: 05/12/2015] [Accepted: 05/22/2015] [Indexed: 05/05/2023]
Abstract
Sexual reproduction in flowering plants offers a number of remarkable aspects to developmental biologists. First, the spore mother cells - precursors of the plant reproductive lineage - are specified late in development, as opposed to precocious germline isolation during embryogenesis in most animals. Second, unlike in most animals where meiosis directly produces gametes, plant meiosis entails the differentiation of a multicellular, haploid gametophyte, within which gametic as well as non-gametic accessory cells are formed. These observations raise the question of the factors inducing and modus operandi of cell fate transitions that originate in floral tissues and gametophytes, respectively. Cell fate transitions in the reproductive lineage imply cellular reprogramming operating at the physiological, cytological and transcriptome level, but also at the chromatin level. A number of observations point to large-scale chromatin reorganization events associated with cellular differentiation of the female spore mother cells and of the female gametes. These include a reorganization of the heterochromatin compartment, the genome-wide alteration of the histone modification landscape, and the remodeling of nucleosome composition. The dynamic expression of DNA methyltransferases and actors of small RNA pathways also suggest additional, global epigenetic alterations that remain to be characterized. Are these events a cause or a consequence of cellular differentiation, and how do they contribute to cell fate transition? Does chromatin dynamics induce competence for immediate cellular functions (meiosis, fertilization), or does it also contribute long-term effects in cellular identity and developmental competence of the reproductive lineage? This review attempts to review these fascinating questions.
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Affiliation(s)
- Célia Baroux
- Institute of Plant Biology and Zürich-Basel Plant Science Center, University of ZürichZollikerstrasse 107, 8008, Zürich, Switzerland
- *For correspondence (e-mail )
| | - Daphné Autran
- Institut de Recherche pour le Développement (UMR DIADE 232), Centre National de la Recherche Scientifique (URL 5300), Université de Montpellier911 avenue Agropolis, 34000, Montpellier, France
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20
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Rutley N, Twell D. A decade of pollen transcriptomics. PLANT REPRODUCTION 2015; 28:73-89. [PMID: 25761645 PMCID: PMC4432081 DOI: 10.1007/s00497-015-0261-7] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2015] [Accepted: 02/24/2015] [Indexed: 05/19/2023]
Abstract
Overview of pollen transcriptome studies. Pollen development is driven by gene expression, and knowledge of the molecular events underlying this process has undergone a quantum leap in the last decade through studies of the transcriptome. Here, we outline historical evidence for male haploid gene expression and review the wealth of pollen transcriptome data now available. Knowledge of the transcriptional capacity of pollen has progressed from genetic studies to the direct analysis of RNA and from gene-by-gene studies to analyses on a genomic scale. Microarray and/or RNA-seq data can now be accessed for all phases and cell types of developing pollen encompassing 10 different angiosperms. These growing resources have accelerated research and will undoubtedly inspire new directions and the application of system-based research into the mechanisms that govern the development, function and evolution of angiosperm pollen.
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Affiliation(s)
- Nicholas Rutley
- Department of Biology, University of Leicester, Leicester, LE1 7RH UK
| | - David Twell
- Department of Biology, University of Leicester, Leicester, LE1 7RH UK
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21
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Schmidt A, Schmid MW, Grossniklaus U. Plant germline formation: common concepts and developmental flexibility in sexual and asexual reproduction. Development 2015; 142:229-41. [PMID: 25564620 DOI: 10.1242/dev.102103] [Citation(s) in RCA: 104] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The life cycle of flowering plants alternates between two heteromorphic generations: a diploid sporophytic generation and a haploid gametophytic generation. During the development of the plant reproductive lineages - the germlines - typically, single sporophytic (somatic) cells in the flower become committed to undergo meiosis. The resulting spores subsequently develop into highly polarized and differentiated haploid gametophytes that harbour the gametes. Recent studies have provided insights into the genetic basis and regulatory programs underlying cell specification and the acquisition of reproductive fate during both sexual reproduction and asexual (apomictic) reproduction. As we review here, these recent advances emphasize the importance of transcriptional, translational and post-transcriptional regulation, and the role of epigenetic regulatory pathways and hormonal activity.
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Affiliation(s)
- Anja Schmidt
- Institute of Plant Biology and Zürich-Basel Plant Science Centre, University of Zürich, Zollikerstrasse 107, Zürich CH-8008, Switzerland
| | - Marc W Schmid
- Institute of Plant Biology and Zürich-Basel Plant Science Centre, University of Zürich, Zollikerstrasse 107, Zürich CH-8008, Switzerland
| | - Ueli Grossniklaus
- Institute of Plant Biology and Zürich-Basel Plant Science Centre, University of Zürich, Zollikerstrasse 107, Zürich CH-8008, Switzerland
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22
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Mantegazza O, Gregis V, Chiara M, Selva C, Leo G, Horner DS, Kater MM. Gene coexpression patterns during early development of the native Arabidopsis reproductive meristem: novel candidate developmental regulators and patterns of functional redundancy. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2014; 79:861-77. [PMID: 24923650 DOI: 10.1111/tpj.12585] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Revised: 05/13/2014] [Accepted: 06/04/2014] [Indexed: 05/16/2023]
Abstract
During very early stages of flower development in Arabidopsis thaliana, a series of key decisions are taken. Indeed, the position and the basic patterning of new flowers are determined in less than 4 days. Given that the scientific literature provides hard evidence for the function of only 10% of A. thaliana genes, we hypothesized that although many essential genes have already been identified, many poorly characterized genes are likely to be involved in floral patterning. In the current study, we use high-throughput sequencing to describe the transcriptome of the native inflorescence meristem, the floral meristem and the new flower immediately after the start of organ differentiation. We provide evidence that our experimental system is reliable and less affected by experimental artefacts than a widely used floral induction system. Furthermore, we show how these data can be used to identify candidate genes for functional studies, and to generate hypotheses of functional redundancies and regulatory interactions.
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Affiliation(s)
- Otho Mantegazza
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133, Milano, Italy
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23
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Chettoor AM, Givan SA, Cole RA, Coker CT, Unger-Wallace E, Vejlupkova Z, Vollbrecht E, Fowler JE, Evans MM. Discovery of novel transcripts and gametophytic functions via RNA-seq analysis of maize gametophytic transcriptomes. Genome Biol 2014; 15:414. [PMID: 25084966 PMCID: PMC4309534 DOI: 10.1186/s13059-014-0414-2] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2014] [Accepted: 07/15/2014] [Indexed: 01/17/2023] Open
Abstract
BACKGROUND Plant gametophytes play central roles in sexual reproduction. A hallmark of the plant life cycle is that gene expression is required in the haploid gametophytes. Consequently, many mutant phenotypes are expressed in this phase. RESULTS We perform a quantitative RNA-seq analysis of embryo sacs, comparator ovules with the embryo sacs removed, mature pollen, and seedlings to assist the identification of gametophyte functions in maize. Expression levels were determined for annotated genes in both gametophytes, and novel transcripts were identified from de novo assembly of RNA-seq reads. Transposon-related transcripts are present in high levels in both gametophytes, suggesting a connection between gamete production and transposon expression in maize not previously identified in any female gametophytes. Two classes of small signaling proteins and several transcription factor gene families are enriched in gametophyte transcriptomes. Expression patterns of maize genes with duplicates in subgenome 1 and subgenome 2 indicate that pollen-expressed genes in subgenome 2 are retained at a higher rate than subgenome 2 genes with other expression patterns. Analysis of available insertion mutant collections shows a statistically significant deficit in insertions in gametophyte-expressed genes. CONCLUSIONS This analysis, the first RNA-seq study to compare both gametophytes in a monocot, identifies maize gametophyte functions, gametophyte expression of transposon-related sequences, and unannotated, novel transcripts. Reduced recovery of mutations in gametophyte-expressed genes is supporting evidence for their function in the gametophytes. Expression patterns of extant, duplicated maize genes reveals that selective pressures based on male gametophytic function have likely had a disproportionate effect on plant genomes.
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24
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Fang J, Schneider B. Laser microdissection: a sample preparation technique for plant micrometabolic profiling. PHYTOCHEMICAL ANALYSIS : PCA 2014; 25:307-13. [PMID: 24108508 DOI: 10.1002/pca.2477] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 08/16/2013] [Accepted: 08/19/2013] [Indexed: 05/03/2023]
Abstract
INTRODUCTION Unlike unicellular organisms, plants have evolved as complex organisms that are defined by their ability to distribute special vital functions to spatially separated organs and tissues. Current phytochemical approaches mostly ignore this fact by analysing samples that consist of different cell types and thus average the information obtained. A comprehensive metabolite analysis with high spatial resolution is essential to fully characterise the state of a certain tissue; hence, the analysis of metabolites occurring in specialised plant cells is of considerable interest in chemical ecology, plant natural product chemistry and other bioscience disciplines. Laser microdissection (LMD), including laser capture microdissection and laser microdissection and pressure catapulting, is a convenient sampling technique to harvest homogeneous cell types for the microanalysis of plant metabolites. OBJECTIVE The objective of this work is to provide an introduction to LMD methodology and a concise review of recent applications of LMD in the high-resolution analysis of metabolites in different plant materials. METHODS A step-by-step approach to LMD sampling techniques is described. How LMD can be used to sample cells or microscopic tissue pieces from different plant organs, such as leaves, stems, and seeds, is shown in detail. Finally, the future of LMD in plant metabolites analysis is discussed. RESULTS This review summarises studies over the past decade not only showing technical details but also indicating the wide application of this method for high-resolution plant metabolite analysis. CONCLUSION Laser microdissection is a powerful sampling technique for plant micrometabolic profiling and metabolomics research.
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Affiliation(s)
- Jingjing Fang
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Str. 8, Beutenberg Campus, 07745, Jena, Germany
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25
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Dukowic-Schulze S, Chen C. The meiotic transcriptome architecture of plants. FRONTIERS IN PLANT SCIENCE 2014; 5:220. [PMID: 24926296 PMCID: PMC4046320 DOI: 10.3389/fpls.2014.00220] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2014] [Accepted: 05/02/2014] [Indexed: 05/21/2023]
Abstract
Although a number of genes that play key roles during the meiotic process have been characterized in great detail, the whole process of meiosis is still not completely unraveled. To gain insight into the bigger picture, large-scale approaches like RNA-seq and microarray can help to elucidate the transcriptome landscape during plant meiosis, discover co-regulated genes, enriched processes, and highly expressed known and unknown genes which might be important for meiosis. These high-throughput studies are gaining more and more popularity, but their beginnings in plant systems reach back as far as the 1960's. Frequently, whole anthers or post-meiotic pollen were investigated, while less data is available on isolated cells during meiosis, and only few studies addressed the transcriptome of female meiosis. For this review, we compiled meiotic transcriptome studies covering different plant species, and summarized and compared their key findings. Besides pointing to consistent as well as unique discoveries, we finally draw conclusions what can be learned from these studies so far and what should be addressed next.
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Affiliation(s)
| | - Changbin Chen
- Department of Horticultural Science, University of MinnesotaSt. Paul, MN, USA
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26
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Ikram S, Durandet M, Vesa S, Pereira S, Guerche P, Bonhomme S. Functional redundancy and/or ongoing pseudogenization among F-box protein genes expressed in Arabidopsis male gametophyte. PLANT REPRODUCTION 2014; 27:95-107. [PMID: 24821062 DOI: 10.1007/s00497-014-0243-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Accepted: 04/25/2014] [Indexed: 05/21/2023]
Abstract
F-box protein genes family is one of the largest gene families in plants, with almost 700 predicted genes in the model plant Arabidopsis. F-box proteins are key components of the ubiquitin proteasome system that allows targeted protein degradation. Transcriptome analyses indicate that half of these F-box protein genes are found expressed in microspore and/or pollen, i.e., during male gametogenesis. To assess the role of F-box protein genes during this crucial developmental step, we selected 34 F-box protein genes recorded as highly and specifically expressed in pollen and isolated corresponding insertion mutants. We checked the expression level of each selected gene by RT-PCR and confirmed pollen expression for 25 genes, but specific expression for only 10 of the 34 F-box protein genes. In addition, we tested the expression level of selected F-box protein genes in 24 mutant lines and showed that 11 of them were null mutants. Transmission analysis of the mutations to the progeny showed that none of the single mutations was gametophytic lethal. These unaffected transmission efficiencies suggested leaky mutations or functional redundancy among F-box protein genes. Cytological observation of the gametophytes in the mutants confirmed these results. Combinations of mutations in F-box protein genes from the same subfamily did not lead to transmission defect either, further highlighting functional redundancy and/or a high proportion of pseudogenes among these F-box protein genes.
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Affiliation(s)
- Sobia Ikram
- Institut Jean-Pierre Bourgin, UMR1318 INRA-AgroParisTech, Route de Saint-Cyr (RD 10), 78026, Versailles Cedex, France
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27
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Dukowic-Schulze S, Sundararajan A, Ramaraj T, Mudge J, Chen C. Sequencing-based large-scale genomics approaches with small numbers of isolated maize meiocytes. FRONTIERS IN PLANT SCIENCE 2014; 5:57. [PMID: 24611068 PMCID: PMC3933774 DOI: 10.3389/fpls.2014.00057] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/26/2013] [Accepted: 02/05/2014] [Indexed: 05/06/2023]
Abstract
High-throughput sequencing has become the large-scale approach of choice to study global gene expression and the distribution of specific chromatin marks and features. However, the limited availability of large amounts of purified cells made it very challenging to apply sequencing-based techniques in plant meiosis research in the past. In this paper, we describe a method to isolate meiocytes from maize anthers and detailed protocols to successfully perform RNA-seq, smRNA-seq, H3K4me3-ChIP-seq, and DNA bisulfite conversion sequencing with 5000-30,000 isolated maize male meiotic cells. These methods can be adjusted for other flowering plant species as well.
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Affiliation(s)
| | | | | | - Joann Mudge
- National Center for Genome ResourcesSanta Fe, NM, USA
| | - Changbin Chen
- Department of Horticultural Science, University of MinnesotaSt. Paul, MN, USA
- *Correspondence: Changbin Chen, Department of Horticultural Science, University of Minnesota, 432 Alderman Hall, St. Paul, MN 55108, USA e-mail:
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28
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She W, Baroux C. Chromatin dynamics during plant sexual reproduction. FRONTIERS IN PLANT SCIENCE 2014; 5:354. [PMID: 25104954 PMCID: PMC4109563 DOI: 10.3389/fpls.2014.00354] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 07/03/2014] [Indexed: 05/19/2023]
Abstract
Plants have the remarkable ability to establish new cell fates throughout their life cycle, in contrast to most animals that define all cell lineages during embryogenesis. This ability is exemplified during sexual reproduction in flowering plants where novel cell types are generated in floral tissues of the adult plant during sporogenesis, gametogenesis, and embryogenesis. While the molecular and genetic basis of cell specification during sexual reproduction is being studied for a long time, recent works disclosed an unsuspected role of global chromatin organization and its dynamics. In this review, we describe the events of chromatin dynamics during the different phases of sexual reproduction and discuss their possible significance particularly in cell fate establishment.
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Affiliation(s)
| | - Célia Baroux
- *Correspondence: Célia Baroux, Institute of Plant Biology – Zürich-Basel Plant Science Center, University of Zürich, Zollikerstrasse 107, 8008 Zürich, Switzerland e-mail:
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29
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Comparative transcriptomics of early meiosis in Arabidopsis and maize. J Genet Genomics 2013; 41:139-52. [PMID: 24656234 DOI: 10.1016/j.jgg.2013.11.007] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 10/31/2013] [Accepted: 11/07/2013] [Indexed: 12/11/2022]
Abstract
Though sexually reproductive plants share the same principle and most processes in meiosis, there are distinct features detectable. To address the similarities and differences of early meiosis transcriptomes from the dicot model system Arabidopsis and monocot model system maize, we performed comparative analyses of RNA-seq data of isolated meiocytes, anthers and seedlings from both species separately and via orthologous genes. Overall gene expression showed similarities, such as an increased number of reads mapping to unannotated features, and differences, such as the amount of differentially expressed genes. We detected major similarities and differences in functional annotations of genes up-regulated in meiocytes, which point to conserved features as well as unique features. Transcriptional regulation seems to be quite similar in Arabidopsis and maize, and we could reveal known and novel transcription factors and cis-regulatory elements acting in early meiosis. Taken together, meiosis between Arabidopsis and maize is conserved in many ways, but displays key distinctions that lie in the patterns of gene expression.
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Gossmann TI, Schmid MW, Grossniklaus U, Schmid KJ. Selection-driven evolution of sex-biased genes is consistent with sexual selection in Arabidopsis thaliana. Mol Biol Evol 2013; 31:574-83. [PMID: 24273323 DOI: 10.1093/molbev/mst226] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Sex-biased genes are genes with a preferential or specific expression in one sex and tend to show an accelerated rate of evolution in animals. Various hypotheses--which are not mutually exclusive--have been put forth to explain observed patterns of rapid evolution. One possible explanation is positive selection, but this has been shown only in few animal species and mostly for male-specific genes. Here, we present a large-scale study that investigates evolutionary patterns of sex-biased genes in the predominantly self-fertilizing plant Arabidopsis thaliana. Unlike most animal species, A. thaliana does not possess sex chromosomes, its flowers develop both male and female sexual organs, and it is characterized by low outcrossing rates. Using cell-specific gene expression data, we identified genes whose expression is enriched in comparison with all other tissues in the male and female gametes (sperm, egg, and central cell), as well as in synergids, pollen, and pollen tubes, which also play an important role in reproduction. Genes specifically expressed in gametes and synergids show higher rates of protein evolution compared with the genome-wide average and no evidence for positive selection. In contrast, pollen- and pollen tube-specific genes not only have lower rates of protein evolution but also exhibit a higher proportion of adaptive amino acid substitutions. We show that this is the result of increased levels of purifying and positive selection among genes with pollen- and pollen tube-specific expression. The increased proportion of adaptive substitutions cannot be explained by the fact that pollen- and pollen tube-expressed genes are enriched in segmental duplications, are on average older, or have a larger effective population size. Our observations are consistent with prezygotic sexual selection as a result of interactions during pollination and pollen tube growth such as pollen tube competition.
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Affiliation(s)
- Toni I Gossmann
- Institute of Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, Stuttgart, Germany
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31
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Armenta-Medina A, Huanca-Mamani W, Sanchez-León N, Rodríguez-Arévalo I, Vielle-Calzada JP. Functional analysis of sporophytic transcripts repressed by the female gametophyte in the ovule of Arabidopsis thaliana. PLoS One 2013; 8:e76977. [PMID: 24194852 PMCID: PMC3806734 DOI: 10.1371/journal.pone.0076977] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2013] [Accepted: 08/28/2013] [Indexed: 01/07/2023] Open
Abstract
To investigate the genetic and molecular regulation that the female gametophyte could exert over neighboring sporophytic regions of the ovule, we performed a quantitative comparison of global expression in wild-type and nozzle/sporocyteless (spl) ovules of Arabidopsis thaliana (Arabidopsis), using Massively Parallel Signature Sequencing (MPSS). This comparison resulted in 1517 genes showing at least 3-fold increased expression in ovules lacking a female gametophyte, including those encoding 89 transcription factors, 50 kinases, 25 proteins containing a RNA-recognition motif (RRM), and 20 WD40 repeat proteins. We confirmed that eleven of these genes are either preferentially expressed or exclusive of spl ovules lacking a female gametophyte as compared to wild-type, and showed that six are also upregulated in determinant infertile1 (dif1), a meiotic mutant affected in a REC8-like cohesin that is also devoided of female gametophytes. The sporophytic misexpression of IOREMPTE, a WD40/transducin repeat gene that is preferentially expressed in the L1 layer of spl ovules, caused the arrest of female gametogenesis after differentiation of a functional megaspore. Our results show that in Arabidopsis, the sporophytic-gametophytic cross talk includes a negative regulation of the female gametophyte over specific genes that are detrimental for its growth and development, demonstrating its potential to exert a repressive control over neighboring regions in the ovule.
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Affiliation(s)
- Alma Armenta-Medina
- Grupo de Desarrollo Reproductivo y Apomixis, Laboratorio Nacional de Genómica para la Biodiversidad y Departamento de Ingeniería Genética de Plantas, CINVESTAV Irapuato, Irapuato, Mexico
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Ensuring Reproduction at High Temperatures: The Heat Stress Response during Anther and Pollen Development. PLANTS 2013; 2:489-506. [PMID: 27137389 PMCID: PMC4844380 DOI: 10.3390/plants2030489] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 06/28/2013] [Accepted: 07/03/2013] [Indexed: 01/01/2023]
Abstract
Sexual reproduction in flowering plants is very sensitive to environmental stresses, particularly to thermal insults which frequently occur when plants grow in field conditions in the warm season. Although abnormalities in both male and female reproductive organs due to high temperatures have been described in several crops, the failure to set fruits has mainly been attributed to the high sensitivity of developing anthers and pollen grains, particularly at certain developmental stages. A global view of the molecular mechanisms involved in the response to high temperatures in the male reproductive organs will be presented in this review. In addition, transcriptome and proteomic data, currently available, will be discussed in the light of physiological and metabolic changes occurring during anther and pollen development. A deep understanding of the molecular mechanisms involved in the stress response to high temperatures in flowers and, particularly, in the male reproductive organs will be a major step towards development of effective breeding strategies for high and stable production in crop plants.
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Tran F, Penniket C, Patel RV, Provart NJ, Laroche A, Rowland O, Robert LS. Developmental transcriptional profiling reveals key insights into Triticeae reproductive development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 74:971-88. [PMID: 23581995 DOI: 10.1111/tpj.12206] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 03/15/2013] [Accepted: 03/22/2013] [Indexed: 05/25/2023]
Abstract
Despite their importance, there remains a paucity of large-scale gene expression-based studies of reproductive development in species belonging to the Triticeae. As a first step to address this deficiency, a gene expression atlas of triticale reproductive development was generated using the 55K Affymetrix GeneChip(®) wheat genome array. The global transcriptional profiles of the anther/pollen, ovary and stigma were analyzed at concurrent developmental stages, and co-expressed as well as preferentially expressed genes were identified. Data analysis revealed both novel and conserved regulatory factors underlying Triticeae floral development and function. This comprehensive resource rests upon detailed gene annotations, and the expression profiles are readily accessible via a web browser.
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Affiliation(s)
- Frances Tran
- Agriculture and Agri-Food Canada, Eastern Cereal and Oilseed Research Centre, 960 Carling Avenue, Ottawa, ON K1A 0C6, Canada
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Domoki M, Szűcs A, Jäger K, Bottka S, Barnabás B, Fehér A. Identification of genes preferentially expressed in wheat egg cells and zygotes. PLANT CELL REPORTS 2013; 32:339-48. [PMID: 23160639 DOI: 10.1007/s00299-012-1367-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2012] [Revised: 09/28/2012] [Accepted: 10/31/2012] [Indexed: 05/14/2023]
Abstract
KEY MESSAGE : Wheat genes differentially expressed in the egg cell before and after fertilization were identified. The data support zygotic gene activation before the first cell division in wheat. To have an insight into fertilization-induced gene expression, cDNA libraries have been prepared from isolated wheat egg cells and one-celled zygotes. Two-hundred and twenty-six egg cell and 253 zygote-expressed EST sequences were determined. Most of the represented transcripts were detected in the wheat egg cell or zygote transcriptome at the first time. Expression analysis of fourteen of the identified genes and three controls was carried out by real-time quantitative PCR. The preferential expression of all investigated genes in the female gametophyte-derived samples (egg cells, zygotes, two-celled proembryos, and basal ovule parts with synergids) in comparison to the anthers, and the leaves were verified. Three genes with putative signaling/regulatory functions were expressed at a low level in the egg cell but exhibited increased (2-to-33-fold) relative expression in the zygote and the proembryo. Genes with high EST abundance in cDNA libraries exhibited strong expression in the egg cell and the zygote, while the ones coding for unknown or hypothetical proteins exhibited differential expression patterns with preferential transcript accumulation in egg cells and/or zygotes. The obtained data support the activation of the zygotic genome before the first cell division in wheat.
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Affiliation(s)
- Mónika Domoki
- Biological Research Centre, Institute of Plant Biology, Hungarian Academy of Sciences, Temesvári krt. 62, Szeged, 6726, Hungary
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35
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Coman D, Gruissem W, Hennig L. Transcript profiling in Arabidopsis with genome tiling microarrays. Methods Mol Biol 2013; 1067:35-49. [PMID: 23975784 DOI: 10.1007/978-1-62703-607-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Microarray technology is at present a standardized workflow for genome-wide expression analysis. Whole-genome tiling microarrays have emerged as an important platform for flexible and comprehensive expression profiling. In this chapter we describe a detailed standardized workflow for experiments assessing the transcriptome of Arabidopsis using tiling arrays and provide useful hints for critical steps from experimental design to data analysis. Although the protocol is optimized for AGRONOMICS1 arrays, it can readily be adapted to other tiling arrays. AGRONOMICS1 is the first platform that enables strand-specific expression analysis of the Arabidopsis genome with a single array. Moreover, it includes all perfect match probes from the original ATH1 array, allowing readily integration with the large existing ATH1 knowledge base. This workflow is designed for the analysis of raw data for any number of samples and it does not pose any particular hardware requirements.
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Affiliation(s)
- Diana Coman
- Plant Biotechnology, Department of Biology, ETH Zurich, Zurich, Switzerland
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Fernández-Aparicio M, Huang K, Wafula EK, Honaas LA, Wickett NJ, Timko MP, dePamphilis CW, Yoder JI, Westwood JH. Application of qRT-PCR and RNA-Seq analysis for the identification of housekeeping genes useful for normalization of gene expression values during Striga hermonthica development. Mol Biol Rep 2012; 40:3395-407. [DOI: 10.1007/s11033-012-2417-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Accepted: 12/18/2012] [Indexed: 12/11/2022]
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37
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Aharoni A, Brandizzi F. High-resolution measurements in plant biology. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2012; 70:1-4. [PMID: 22449038 DOI: 10.1111/j.1365-313x.2012.04987.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
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