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Zhong S, Zhao P, Peng X, Li HJ, Duan Q, Cheung AY. From gametes to zygote: Mechanistic advances and emerging possibilities in plant reproduction. PLANT PHYSIOLOGY 2024; 195:4-35. [PMID: 38431529 PMCID: PMC11060694 DOI: 10.1093/plphys/kiae125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 02/13/2024] [Accepted: 02/13/2024] [Indexed: 03/05/2024]
Affiliation(s)
- Sheng Zhong
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, New Cornerstone Science Laboratory, College of Life Sciences, Peking University, Beijing 100871, China
| | - Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Xiongbo Peng
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Hong-Ju Li
- Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Center for Molecular Agrobiology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qiaohong Duan
- College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an, Shandong 271018, China
| | - Alice Y Cheung
- Department of Biochemistry and Molecular Biology, Molecular and Cellular Biology Program, Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
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2
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Lin C, Guo X, Yu X, Li S, Li W, Yu X, An F, Zhao P, Ruan M. Genome-Wide Survey of the RWP-RK Gene Family in Cassava ( Manihot esculenta Crantz) and Functional Analysis. Int J Mol Sci 2023; 24:12925. [PMID: 37629106 PMCID: PMC10454212 DOI: 10.3390/ijms241612925] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 08/12/2023] [Accepted: 08/16/2023] [Indexed: 08/27/2023] Open
Abstract
The plant-specific RWP-RK transcription factor family plays a central role in the regulation of nitrogen response and gametophyte development. However, little information is available regarding the evolutionary relationships and characteristics of the RWP-RK family genes in cassava, an important tropical crop. Herein, 13 RWP-RK proteins identified in cassava were unevenly distributed across 9 of the 18 chromosomes (Chr), and these proteins were divided into two clusters based on their phylogenetic distance. The NLP subfamily contained seven cassava proteins including GAF, RWP-RK, and PB1 domains; the RKD subfamily contained six cassava proteins including the RWP-RK domain. Genes of the NLP subfamily had a longer sequence and more introns than the RKD subfamily. A large number of hormone- and stress-related cis-acting elements were found in the analysis of RWP-RK promoters. Real-time quantitative PCR revealed that all MeNLP1-7 and MeRKD1/3/5 genes responded to different abiotic stressors (water deficit, cold temperature, mannitol, polyethylene glycol, NaCl, and H2O2), hormonal treatments (abscisic acid and methyl jasmonate), and nitrogen starvation. MeNLP3/4/5/6/7 and MeRKD3/5, which can quickly and efficiently respond to different stresses, were found to be important candidate genes for further functional assays in cassava. The MeRKD5 and MeNLP6 proteins were localized to the cell nucleus in tobacco leaf. Five and one candidate proteins interacting with MeRKD5 and MeNLP6, respectively, were screened from the cassava nitrogen starvation library, including agamous-like mads-box protein AGL14, metallothionein 2, Zine finger FYVE domain containing protein, glyceraldehyde-3-phosphate dehydrogenase, E3 Ubiquitin-protein ligase HUWE1, and PPR repeat family protein. These results provided a solid basis to understand abiotic stress responses and signal transduction mediated by RWP-RK genes in cassava.
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Affiliation(s)
- Chenyu Lin
- School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China; (C.L.); (X.G.); (X.Y.)
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; (S.L.); (W.L.); (X.Y.)
| | - Xin Guo
- School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China; (C.L.); (X.G.); (X.Y.)
| | - Xiaohui Yu
- School of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China; (C.L.); (X.G.); (X.Y.)
| | - Shuxia Li
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; (S.L.); (W.L.); (X.Y.)
| | - Wenbin Li
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; (S.L.); (W.L.); (X.Y.)
| | - Xiaoling Yu
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; (S.L.); (W.L.); (X.Y.)
| | - Feng An
- Hainan Danzhou Agro-Ecosystem National Observation and Research Station, Rubber Research Institute of Chinese Academy of Tropical Agricultural Sciences, Danzhou 571737, China;
| | - Pingjuan Zhao
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; (S.L.); (W.L.); (X.Y.)
| | - Mengbin Ruan
- Key Laboratory of Biology and Genetic Resources of Tropical Crops, Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China; (S.L.); (W.L.); (X.Y.)
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3
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Alaniz-Fabián J, Orozco-Nieto A, Abreu-Goodger C, Gillmor CS. Hybridization alters maternal and paternal genome contributions to early plant embryogenesis. Development 2022; 149:281772. [PMID: 36314727 DOI: 10.1242/dev.201025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022]
Abstract
After fertilization, zygotic genome activation results in a transcriptionally competent embryo. Hybrid transcriptome experiments in Arabidopsis have concluded that the maternal and paternal genomes make equal contributions to zygotes and embryos, yet embryo defective (emb) mutants in the Columbia (Col) ecotype display early maternal effects. Here, we show that hybridization of Col with Landsberg erecta (Ler) or Cape Verde Islands (Cvi) ecotypes decreases the maternal effects of emb mutants. Reanalysis of Col/Ler and Col/Cvi transcriptomes confirmed equal parental contributions in Col/Cvi early embryos. By contrast, thousands of genes in Col/Ler zygotes and one-cell embryos were biallelic in one cross and monoallelic in the reciprocal cross, with analysis of intron reads pointing to active transcription as responsible for this parent-of-origin bias. Our analysis shows that, contrary to previous conclusions, the maternal and paternal genomes in Col/Ler zygotes are activated in an asymmetric manner. The decrease in maternal effects in hybrid embryos compared with those in isogenic Col along with differences in genome activation between Col/Cvi and Col/Ler suggest that neither of these hybrids accurately reflects the general trends of parent-of-origin regulation in Arabidopsis embryogenesis.
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Affiliation(s)
- Jaime Alaniz-Fabián
- Langebio, Unidad de Genómica Avanzada, CINVESTAV-IPN, Irapuato 36824, México
| | - Axel Orozco-Nieto
- Langebio, Unidad de Genómica Avanzada, CINVESTAV-IPN, Irapuato 36824, México
| | - Cei Abreu-Goodger
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - C Stewart Gillmor
- Langebio, Unidad de Genómica Avanzada, CINVESTAV-IPN, Irapuato 36824, México
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4
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Zhao P, Shi C, Wang L, Sun MX. The parental contributions to early plant embryogenesis and the concept of maternal-to-zygotic transition in plants. CURRENT OPINION IN PLANT BIOLOGY 2022; 65:102144. [PMID: 34823206 DOI: 10.1016/j.pbi.2021.102144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 10/20/2021] [Accepted: 10/21/2021] [Indexed: 06/13/2023]
Abstract
The maternal-to-zygotic transition (MZT) is a major developmental transition in the life cycles of animals. It consists of two associated processes: maternal transcript clearance and zygotic genome activation (ZGA). The concept of MZT has been controversially discussed in plants. In this short review, we summarize recent advances in understanding the timing of ZGA and the similarities and differences between ZGA in eudicots and monocots. We discuss the parental contributions to the transcriptome of the proembryo and parental control of early embryogenesis, and we examine distinct differences in the ZGA between animals and plants, update relevant concepts on MZT, and highlight outstanding questions in this field.
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Affiliation(s)
- Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China; Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Ce Shi
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Ling Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China.
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5
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Kao P, Schon MA, Mosiolek M, Enugutti B, Nodine MD. Gene expression variation in Arabidopsis embryos at single-nucleus resolution. Development 2021; 148:dev199589. [PMID: 34142712 PMCID: PMC8276985 DOI: 10.1242/dev.199589] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2021] [Accepted: 05/24/2021] [Indexed: 12/17/2022]
Abstract
Soon after fertilization of egg and sperm, plant genomes become transcriptionally activated and drive a series of coordinated cell divisions to form the basic body plan during embryogenesis. Early embryonic cells rapidly diversify from each other, and investigation of the corresponding gene expression dynamics can help elucidate underlying cellular differentiation programs. However, current plant embryonic transcriptome datasets either lack cell-specific information or have RNA contamination from surrounding non-embryonic tissues. We have coupled fluorescence-activated nuclei sorting together with single-nucleus mRNA-sequencing to construct a gene expression atlas of Arabidopsis thaliana early embryos at single-cell resolution. In addition to characterizing cell-specific transcriptomes, we found evidence that distinct epigenetic and transcriptional regulatory mechanisms operate across emerging embryonic cell types. These datasets and analyses, as well as the approach we devised, are expected to facilitate the discovery of molecular mechanisms underlying pattern formation in plant embryos. This article has an associated 'The people behind the papers' interview.
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Affiliation(s)
- Ping Kao
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Bio Center (VBC), Dr Bohr-Gasse 3, 1030 Vienna, Austria
| | - Michael A. Schon
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Bio Center (VBC), Dr Bohr-Gasse 3, 1030 Vienna, Austria
| | - Magdalena Mosiolek
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Bio Center (VBC), Dr Bohr-Gasse 3, 1030 Vienna, Austria
| | - Balaji Enugutti
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Bio Center (VBC), Dr Bohr-Gasse 3, 1030 Vienna, Austria
| | - Michael D. Nodine
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Bio Center (VBC), Dr Bohr-Gasse 3, 1030 Vienna, Austria
- Laboratory of Molecular Biology, Wageningen University, Wageningen 6708 PB, The Netherlands
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de Folter S. Plant Biology: Gynoecium Development with Style. Curr Biol 2021; 30:R1420-R1422. [PMID: 33290708 DOI: 10.1016/j.cub.2020.10.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The gynoecium is the female reproductive part of the flower and is essential for plant sexual reproduction. A new study shows a novel angiosperm-specific gene family that fine tunes the architecture of the stigma and style in Arabidopsis.
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Affiliation(s)
- Stefan de Folter
- Unidad de Genómica Avanzada (UGA-LANGEBIO), Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Km 9.6 Libramiento Norte, Carretera Irapuato-León, C.P. 36824 Irapuato, México.
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Khanday I, Sundaresan V. Plant zygote development: recent insights and applications to clonal seeds. CURRENT OPINION IN PLANT BIOLOGY 2021; 59:101993. [PMID: 33422964 DOI: 10.1016/j.pbi.2020.101993] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/11/2020] [Accepted: 12/15/2020] [Indexed: 05/22/2023]
Abstract
In flowering plants, haploid gametes - an egg cell and a sperm cell fuse to form the first diploid cell - the zygote. The zygote is the progenitor stem cell that gives rise to all the embryonic and post embryonic tissues and organs. Unlike animals, both maternal and paternal gene products participate in the initial development of zygotes in plants. Here, we discuss recent advances in understanding of the zygotic transition and embryo initiation in angiosperms, including the role of parental contributions to gene expression in the zygote. We further discuss utilization of this knowledge in agricultural biotechnology through synthetic apomixis. Parthenogenesis obtained by manipulation of embryogenic factors, combined with mutations that bypass meiosis, enables clonal propagation of hybrid crops through seeds.
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Affiliation(s)
- Imtiyaz Khanday
- Department of Plant Biology, University of California, Davis, CA, USA; Innovative Genomics Institute, University of California, Berkeley, CA, USA
| | - Venkatesan Sundaresan
- Department of Plant Biology, University of California, Davis, CA, USA; Innovative Genomics Institute, University of California, Berkeley, CA, USA; Department of Plant Sciences, University of California, Davis, CA, USA.
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Three STIGMA AND STYLE STYLISTs Pattern the Fine Architectures of Apical Gynoecium and Are Critical for Male Gametophyte-Pistil Interaction. Curr Biol 2020; 30:4780-4788.e5. [PMID: 33007250 DOI: 10.1016/j.cub.2020.09.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 08/02/2020] [Accepted: 09/03/2020] [Indexed: 11/22/2022]
Abstract
The gynoecium is derived from the fusion of carpels and is considered to have evolved from a simple setup followed by adaptive adjustment in cell type and tissue distribution to facilitate efficient sexual reproduction [1, 2]. As a sequence of the adjustment, the apical gynoecium differentiates into a stigma and a style. Both the structural patterning and functional specification of the apical gynoecium are critical for plant fertility [3, 4]. However, how the fine structures of the apical gynoecium are established at the interface interacting with pollen and pollen tubes remain to be elucidated. Here, we report a novel angiosperm-specific gene family, STIGMA AND STYLE STYLIST 1-3 (SSS1, SSS2, and SSS3). The SSS1 expresses predominately in the transmitting tract tissue of style, SSS2 expresses intensively in stigma, and SSS3 expresses mainly in stylar peripheral region round the transmitting tract. SSSs coregulate the patterning of the apical gynoecium via controlling cell expansion or elongation. Both the architecture and function of apical gynoecium can be affected by the alteration of SSS expression, indicating their critical roles in the establishment of a proper female interface for communication with pollen tubes. The NGATHA3 (NGA3) transcription factor [5, 6] can directly bind to SSSs promoter and control SSSs expression. Overexpression of SSSs could rescue the stylar defect of nga1nga3 double mutant, indicating their context in the same regulatory pathway. Our findings reveal a novel molecular mechanism responsible for patterning the fine architecture of apical gynoecium and establishing a proper interface for pollen tube growth, which is therefore crucial for plant sexual reproduction.
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9
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Kimata Y, Ueda M. Intracellular dynamics and transcriptional regulations in plant zygotes: a case study of Arabidopsis. PLANT REPRODUCTION 2020; 33:89-96. [PMID: 32322957 DOI: 10.1007/s00497-020-00389-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Accepted: 04/09/2020] [Indexed: 06/11/2023]
Abstract
Recent understandings ofArabidopsiszygote. Body axis formation is essential for the proper development of multicellular organisms. The apical-basal axis in Arabidopsis thaliana is determined by the asymmetric division of the zygote, following its cellular polarization. However, the regulatory mechanism of zygote polarization is unclear due to technical issues. The zygote is located deep in the seed (ovule) in flowers, which prevents the living dynamics of zygotes from being observed. In addition, elucidation of molecular pathways by conventional forward genetic screens was not enough because of high gene redundancy in early development. Here, we present a review introducing two new methods, which have been developed to overcome these problems. Method 1: the two-photon live-cell imaging method provides a new system to visualize the dynamics of intracellular structures in Arabidopsis zygotes, such as cytoskeletons and vacuoles. Microtubules form transverse rings and control zygote elongation, while vacuoles dynamically change their shapes along longitudinal actin filaments and support polar nuclear migration. Method 2: the transcriptome method uses isolated Arabidopsis zygotes and egg cells to reveal the gene expression profiles before and after fertilization. This approach revealed that de novo transcription occurs extensively and immediately after fertilization. Moreover, inhibition of the de novo transcription was shown to sufficiently block the zygotic division, thus indicating a strong possibility that yet unidentified zygote regulators can be found using this transcriptome approach. These new strategies in Arabidopsis will help to further our understanding of the fundamental principles regarding the proper formation of plant bodies from unicellular zygotes.
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Affiliation(s)
- Yusuke Kimata
- Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan
| | - Minako Ueda
- Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601, Japan.
- Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602, Japan.
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Wang K, Chen H, Miao Y, Bayer M. Square one: zygote polarity and early embryogenesis in flowering plants. CURRENT OPINION IN PLANT BIOLOGY 2020; 53:128-133. [PMID: 31727540 DOI: 10.1016/j.pbi.2019.10.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/27/2019] [Accepted: 10/07/2019] [Indexed: 06/10/2023]
Abstract
In the last two decades, work on auxin signaling has helped to understand many aspects of the fundamental process underlying the specification of tissue types in the plant embryo. However, the immediate steps after fertilization including the polarization of the zygote and the initial body axis formation remained poorly understood. Valuable insight into these enigmatic processes has been gained by studying fertilization in grasses. Recent technical advances in transcriptomics of developing embryos with high spatial and temporal resolution give an emerging picture of the rapid changes of the zygotic developmental program. Together with the use of live imaging of novel fluorescent marker lines, these data are now the basis of unraveling the very first steps of the embryonic patterning process.
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Affiliation(s)
- Kai Wang
- Max Planck Institute for Developmental Biology, Department of Cell Biology, Max-Planck-Ring 5, 72076 Tübingen, Germany
| | - Houming Chen
- Max Planck Institute for Developmental Biology, Department of Cell Biology, Max-Planck-Ring 5, 72076 Tübingen, Germany
| | - Yingjing Miao
- Max Planck Institute for Developmental Biology, Department of Cell Biology, Max-Planck-Ring 5, 72076 Tübingen, Germany
| | - Martin Bayer
- Max Planck Institute for Developmental Biology, Department of Cell Biology, Max-Planck-Ring 5, 72076 Tübingen, Germany.
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11
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Abstract
Zygotic embryogenesis is one of key processes for fertile seed development and therefore has gained great attention for decades in the field of plant developmental biology. However, this process is deeply embedded in the maternal tissues. The inaccessibility of tiny early embryos has greatly hindered the study of early embryogenesis, especially limits direct observation and accurate omics investigations. In order to investigate the molecular mechanism regulating embryo development with modern technologies, it is necessary to develop a reliable method to isolate living embryos at different stages. For this purpose, plant scientists have been trying to develop different methods for isolating zygotes and early embryos in different plants such as maize, wheat, rice, and tobacco during past decades. Nicotiana tabacum has long been considered as an ideal model eudicot for the study of embryogenesis, which displays a traceable and predictable cell division pattern, spanning from the first zygotic division to the mature embryo formation. Here, we provide a detailed protocol for isolating living embryos from zygote to cotyledon embryo. Isolated living zygotes and early embryos could be used for several important studies such as cell type-specific transcriptome construction and clear GFP observation.
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Affiliation(s)
- Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China.
| | - Xuemei Zhou
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Ce Shi
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
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Kao P, Nodine MD. Transcriptional Activation of Arabidopsis Zygotes Is Required for Initial Cell Divisions. Sci Rep 2019; 9:17159. [PMID: 31748673 PMCID: PMC6868190 DOI: 10.1038/s41598-019-53704-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 11/04/2019] [Indexed: 11/10/2022] Open
Abstract
Commonly referred to as the maternal-to-zygotic transition, the shift of developmental control from maternal-to-zygotic genomes is a key event during animal and plant embryogenesis. Together with the degradation of parental gene products, the increased transcriptional activities of the zygotic genome remodels the early embryonic transcriptome during this transition. Although evidence from multiple flowering plants suggests that zygotes become transcriptionally active soon after fertilization, the timing and developmental requirements of zygotic genome activation in Arabidopsis thaliana (Arabidopsis) remained a matter of debate until recently. In this report, we optimized an expansion microscopy technique for robust immunostaining of Arabidopsis ovules and seeds. This enabled the detection of marks indicative of active transcription in zygotes before the first cell division. Moreover, we employed a live-imaging culture system together with transcriptional inhibitors to demonstrate that such active transcription is physiologically required in zygotes and early embryos. Our results indicate that zygotic genome activation occurs soon after fertilization and is required for the initial zygotic divisions in Arabidopsis.
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Affiliation(s)
- Ping Kao
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Michael D Nodine
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030, Vienna, Austria.
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13
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Zhang L, Zhao T, Sun X, Wang Y, Du C, Zhu Z, Gichuki DK, Wang Q, Li S, Xin H. Overexpression of VaWRKY12, a transcription factor from Vitis amurensis with increased nuclear localization under low temperature, enhances cold tolerance of plants. PLANT MOLECULAR BIOLOGY 2019; 100:95-110. [PMID: 0 DOI: 10.1007/s11103-019-00846-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Accepted: 02/18/2019] [Indexed: 05/23/2023]
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14
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Armenta-Medina A, Gillmor CS. Genetic, molecular and parent-of-origin regulation of early embryogenesis in flowering plants. Curr Top Dev Biol 2019; 131:497-543. [DOI: 10.1016/bs.ctdb.2018.11.008] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/05/2022]
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Fehér A. Callus, Dedifferentiation, Totipotency, Somatic Embryogenesis: What These Terms Mean in the Era of Molecular Plant Biology? FRONTIERS IN PLANT SCIENCE 2019; 10:536. [PMID: 31134106 PMCID: PMC6524723 DOI: 10.3389/fpls.2019.00536] [Citation(s) in RCA: 109] [Impact Index Per Article: 21.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2018] [Accepted: 04/08/2019] [Indexed: 05/18/2023]
Abstract
Recent findings call for the critical overview of some incorrectly used plant cell and tissue culture terminology such as dedifferentiation, callus, totipotency, and somatic embryogenesis. Plant cell and tissue culture methods are efficient means to preserve and propagate genotypes with superior germplasm as well as to increase genetic variability for breading. Besides, they are useful research tools and objects of plant developmental biology. The history of plant cell and tissue culture dates back to more than a century. Its basic methodology and terminology were formulated preceding modern plant biology. Recent progress in molecular and cell biology techniques allowed unprecedented insights into the underlying processes of plant cell/tissue culture and regeneration. The main aim of this review is to provide a theoretical framework supported by recent experimental findings to reconsider certain historical, even dogmatic, statements widely used by plant scientists and teachers such as "plant cells are totipotent" or "callus is a mass of dedifferentiated cells," or "somatic embryos have a single cell origin." These statements are based on a confused terminology. Clarification of it might help to avoid further misunderstanding and to overcome potential "terminology-raised" barriers in plant research.
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Affiliation(s)
- Attila Fehér
- Department of Plant Biology, University of Szeged, Szeged, Hungary
- Institute of Plant Biology, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary
- *Correspondence: Attila Fehér, ;
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Gao L, Guo X, Liu XQ, Zhang L, Huang J, Tan L, Lin Z, Nagawa S, Wang DY. Changes in mitochondrial DNA levels during early embryogenesis in Torenia fournieri and Arabidopsis thaliana. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 95:785-795. [PMID: 29882345 DOI: 10.1111/tpj.13987] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Revised: 05/29/2018] [Accepted: 06/01/2018] [Indexed: 05/18/2023]
Abstract
Changes in the amount of mitochondrial DNA (mtDNA) have never been investigated in plant zygotes or early plant embryos due to the difficulty in isolating these cells, although such changes have been investigated in mammalian embryos. Using the single-cell quantitative real-time polymerase chain reaction (PCR) and laser confocal microscopy, we surveyed the changes in mtDNA levels during early embryogenesis in Torenia fournieri and Arabidopsis thaliana. In contrast with the amount of mtDNA in early mammalian embryos, which does not change, we found that mtDNA doubling occurred during zygotic development in T. fournieri and during two-cell proembryo development in A. thaliana. These findings reveal that mtDNA doubling occurs during early embryogenesis in T. fournieri and A. thaliana, indicating that the dynamics of mtDNA in early plant embryos differs from that in early mammalian embryos.
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Affiliation(s)
- Long Gao
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi'an, Shaanxi, 710069, China
| | - Xue Guo
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi'an, Shaanxi, 710069, China
| | - Xue-Qiong Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi'an, Shaanxi, 710069, China
| | - Li Zhang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi'an, Shaanxi, 710069, China
| | - Jilei Huang
- Instrumental Analysis and Research Center, South China Agricultural University, Guangzhou, Guangdong, 510642, China
| | - Li Tan
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, 201602, China
| | - Zhen Lin
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi'an, Shaanxi, 710069, China
| | - Shingo Nagawa
- Shanghai Center for Plant Stress Biology, Chinese Academy of Sciences, Shanghai, 201602, China
| | - Dan-Yang Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi'an, Shaanxi, 710069, China
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17
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Toda E, Ohnishi Y, Okamoto T. An imbalanced parental genome ratio affects the development of rice zygotes. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:2609-2619. [PMID: 29538694 PMCID: PMC5920335 DOI: 10.1093/jxb/ery094] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2017] [Accepted: 03/06/2018] [Indexed: 05/25/2023]
Abstract
Upon double fertilization, one sperm cell fuses with the egg cell to form a zygote with a 1:1 maternal-to-paternal genome ratio (1m:1p), and another sperm cell fuses with the central cell to form a triploid primary endosperm cell with a 2m:1p ratio, resulting in formation of the embryo and the endosperm, respectively. The endosperm is known to be considerably sensitive to the ratio of the parental genomes. However, the effect of an imbalance of the parental genomes on zygotic development and embryogenesis has not been well studied, because it is difficult to reproduce the parental genome-imbalanced situation in zygotes and to monitor the developmental profile of zygotes without external effects from the endosperm. In this study, we produced polyploid zygotes with an imbalanced parental genome ratio by electro-fusion of isolated rice gametes and observed their developmental profiles. Polyploid zygotes with an excess maternal gamete/genome developed normally, whereas approximately half to three-quarters of polyploid zygotes with a paternal excess showed developmental arrests. These results indicate that paternal and maternal genomes synergistically serve zygote development with distinct functions, and that genes with monoallelic expression play important roles during zygotic development and embryogenesis.
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Affiliation(s)
- Erika Toda
- Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa, Hachioji, Tokyo, Japan
- Plant Breeding Innovation Laboratory, RIKEN Innovation Center, Tsurumi-ku, Yokohama, Japan
| | - Yukinosuke Ohnishi
- Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa, Hachioji, Tokyo, Japan
| | - Takashi Okamoto
- Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa, Hachioji, Tokyo, Japan
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18
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Peng X, Sun MX. The suspensor as a model system to study the mechanism of cell fate specification during early embryogenesis. PLANT REPRODUCTION 2018; 31:59-65. [PMID: 29473100 PMCID: PMC5845063 DOI: 10.1007/s00497-018-0326-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2017] [Accepted: 02/14/2018] [Indexed: 05/24/2023]
Abstract
The advances in the suspensor. During early embryogenesis, the proembryo consists of two domains, the embryo proper and the suspensor. Unlike the embryo proper, which has been investigated extensively, research on the suspensor has been limited in past decades. Recent studies have revealed that the suspensor plays an important role in early embryogenesis and the process of suspensor formation and degeneration may provide a unique model for studies on cell division pattern, cell fate determination, and cell death. In this review, we briefly summarize the advances in research on the suspensor, which provide new insight in our understanding of the mechanism of early embryogenesis and show great potential for a unique model for future investigations.
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Affiliation(s)
- Xiongbo Peng
- State Key Laboratory of Hybrid Rice, College of Life Science, Wuhan University, Wuhan, 430072, China
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Science, Wuhan University, Wuhan, 430072, China.
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19
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Zhou X, Guo Y, Zhao P, Sun MX. Comparative Analysis of WUSCHEL-Related Homeobox Genes Revealed Their Parent-of-Origin and Cell Type-Specific Expression Pattern During Early Embryogenesis in Tobacco. FRONTIERS IN PLANT SCIENCE 2018; 9:311. [PMID: 29662495 PMCID: PMC5890105 DOI: 10.3389/fpls.2018.00311] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 02/22/2018] [Indexed: 05/05/2023]
Abstract
WUSCHEL-related homeobox (WOX) gene is a plant-specific clade of homeobox transcription factors. Increasing evidences reveal that WOXs play critical roles in early embryogenesis, which involves zygote development, initiation of zygote division, and apical or basal cell lineage establishment. However, how WOXs regulate these developmental events remains largely unknown, and even detailed expression pattern in gametes and early proembryos is not yet available. Here, 13 WOX family genes were identified in Nicotiana tabacum genome. Comparative analysis of 13 WOX family genes with their homologs in Arabidopsis thaliana reveals relatively conserved expression pattern of WUS and WOX5 in shoot/root apical meristem. Whereas variations were also found, e.g., lacking homolog of WOX8 (a marker for suspensor cell) in tobacco genome and the expression of WOX2/WOX9 in both apical cell and basal cell. Transient transcriptional activity analysis revealed that WOXs in WUS clade have repressive activities for their target's transcription, whereas WOXs in ancient and intermediate clade have activation activities, giving a molecular basis for the phylogenetic classification of tobacco WOXs into three major clades. Expression pattern analysis revealed that some WOXs (e.g., WOX 13a) expressed in both male and female gametes and some WOXs (e.g., WOX 11 and WOX 13b) displayed the characteristics of parent-of-origin genes. Interestingly, some WOXs (e.g., WOX2 and WOX9), which are essential for early embryo patterning, were de novo transcribed in zygote, indicating relevant mechanism for embryo pattern formation is only established in zygote right after fertilization and not carried in by gametes. We also found that most WOXs displayed a stage-specific and cell type-specific expression pattern. Taken together, this work provides a detailed landscape of WOXs in tobacco during fertilization and early embryogenesis, which will facilitate the understanding of their specific roles in these critical developmental processes of embryogenesis.
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20
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Qu LH, Zhou X, Li X, Li SS, Zhao J, Zhao P, Liu Y, Sun MX. The autonomous cell fate specification of basal cell lineage: the initial round of cell fate specification occurs at the two-celled proembryo stage. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 91:1051-1063. [PMID: 28671744 DOI: 10.1111/tpj.13629] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2017] [Revised: 06/16/2017] [Accepted: 06/23/2017] [Indexed: 06/07/2023]
Abstract
In angiosperms, the first zygotic division usually gives rise to two daughter cells with distinct morphologies and developmental fates, which is critical for embryo pattern formation; however, it is still unclear when and how these distinct cell fates are specified, and whether the cell specification is related to cytoplasmic localization or polarity. Here, we demonstrated that when isolated from both maternal tissues and the apical cell, a single basal cell could only develop into a typical suspensor, but never into an embryo in vitro. Morphological, cytological and gene expression analyses confirmed that the resulting suspensor in vitro is highly similar to its undisturbed in vivo counterpart. We also demonstrated that the isolated apical cell could develop into a small globular embryo, both in vivo and in vitro, after artificial dysfunction of the basal cell; however, these growing apical cell lineages could never generate a new suspensor. These findings suggest that the initial round of cell fate specification occurs at the two-celled proembryo stage, and that the basal cell lineage is autonomously specified towards the suspensor, implying a polar distribution of cytoplasmic contents in the zygote. The cell fate transition of the basal cell lineage to the embryo in vivo is actually a conditional cell specification process, depending on the developmental signals from both the apical cell lineage and maternal tissues connected to the basal cell lineage.
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Affiliation(s)
- Liang-Huan Qu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xuemei Zhou
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Xinbo Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Shi-Sheng Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Jing Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Yuan Liu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
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21
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Bogaert KA, Beeckman T, De Clerck O. Two-step cell polarization in algal zygotes. NATURE PLANTS 2017; 3:16221. [PMID: 28112726 DOI: 10.1038/nplants.2016.221] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 12/19/2016] [Indexed: 06/06/2023]
Abstract
In most complex eukaryotes, development starts with the establishment of cell polarity determining the first axis of the body plan. This polarity axis is established by the asymmetrical distribution of intrinsic factors1-3, which breaks the symmetry in a single step. Zygotes of the brown alga Fucus, which unlike land plant and animal zygotes4,5 do not possess a maternally predetermined polarity axis, serve as models to study polarity establishment6,7. Here, we studied this process in Dictyota, and concluded that sense and direction of the cell polarization vector are established in two mechanistically and temporally distinct phases that are under control of different life cycle stages. On egg activation, the zygote elongates rapidly according to a maternally predetermined direction expressing the first phase of cell polarization. Which of the two poles of the resulting prolate spheroidal zygote will acquire the basal cell fate is subsequently environmentally determined. The second phase is accompanied by and dependent on zygotic transcription instead of relying uniquely on maternal factors8. Cell polarization, whereby determination of direction and sense of the polarization vector are temporally and mechanistically uncoupled, is unique and represents a favourable system to gain insight into the processes underlying cell polarity establishment in general.
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Affiliation(s)
- Kenny A Bogaert
- Department of Biology, Ghent University, Krijgslaan 281 S8, 9000 Ghent, Belgium
| | - Tom Beeckman
- VIB-UGent Center for Plant Systems Biology, Technologiepark 927, B-9052 Ghent, Belgium
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Technologiepark 927, B-9052 Ghent, Belgium
| | - Olivier De Clerck
- Department of Biology, Ghent University, Krijgslaan 281 S8, 9000 Ghent, Belgium
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22
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Englhart M, Šoljić L, Sprunck S. Manual Isolation of Living Cells from the Arabidopsis thaliana Female Gametophyte by Micromanipulation. Methods Mol Biol 2017; 1669:221-234. [PMID: 28936662 DOI: 10.1007/978-1-4939-7286-9_18] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The few-celled female gametophyte, or embryo sac, of flowering plants is not easily accessible as it is buried within the sporophytic tissues of the ovule. Nevertheless, it has become an attractive model system to study the molecular mechanisms underlying patterning and cell type specification, as well as fertilization of the two female gametes, the egg and the central cell. While female gametes, zygotes, and early embryos can be manually isolated from the embryo sacs in maize, wheat, tobacco, and rice by micromanipulation, this approach had been considered impossible for the much smaller embryo sac of the model plant Arabidopsis thaliana. Here, we describe a method to isolate living cells from the Arabidopsis female gametophyte by micromanipulation. The manual isolation of egg cells, central cells, and synergid cells is a technique that enables a number of important studies such as cell-type-specific transcriptional profiling or the analysis of DNA methylation profiles. It also offers the possibility to use isolated female gametes for in vitro fertilization studies.
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Affiliation(s)
- Maria Englhart
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitaetsstrasse 31, 93053, Regensburg, Germany
| | - Lucija Šoljić
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitaetsstrasse 31, 93053, Regensburg, Germany
| | - Stefanie Sprunck
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, Universitaetsstrasse 31, 93053, Regensburg, Germany.
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23
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Zhao J, Xin H, Cao L, Huang X, Shi C, Zhao P, Fu Y, Sun MX. NtDRP is necessary for accurate zygotic division orientation and differentiation of basal cell lineage toward suspensor formation. THE NEW PHYTOLOGIST 2016; 212:598-612. [PMID: 27348863 DOI: 10.1111/nph.14060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Accepted: 05/14/2016] [Indexed: 05/08/2023]
Abstract
Plant embryogenesis begins with an asymmetric division of the zygote, producing apical and basal cells with distinct cell fates. The asymmetric zygote division is thought to be critical for embryo pattern formation; however, the molecular mechanisms regulating this process, especially maintaining the accurate position and proper orientation of cell division plane, remain poorly understood. Here, we report that a dynamin-related protein in Nicotiana tabacum, NtDRP, plays a critical role in maintaining orientation of zygotic division plane. Down-regulation of NtDRP caused zygotic cell division to occur in different, incorrect orientations and resulted in disruption of suspensor formation, and even development of twin embryos. The basal cell lineage totally integrated with the apical cell lineage into an embryo-like structure, suggesting that NtDRP is essential to accurate zygotic division orientation and differentiation of basal cell lineage toward suspensor formation. We also reveal that NtDRP plays its role by modulating microtubule spatial organization and spindle orientation during early embryogenesis. Thus, we revealed that NtDRP is involved in orientation of the asymmetric zygotic division and differentiation of distinct suspensor and embryo domains, as well as subsequent embryo pattern formation.
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Affiliation(s)
- Jing Zhao
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Haiping Xin
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden, The Chinese Academy of Sciences, Wuhan, 430074, China
| | - Lingyan Cao
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Xiaorong Huang
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Ce Shi
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Peng Zhao
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China
| | - Ying Fu
- State Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Meng-Xiang Sun
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072, China.
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24
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Palovaara J, de Zeeuw T, Weijers D. Tissue and Organ Initiation in the Plant Embryo: A First Time for Everything. Annu Rev Cell Dev Biol 2016; 32:47-75. [PMID: 27576120 DOI: 10.1146/annurev-cellbio-111315-124929] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Land plants can grow to tremendous body sizes, yet even the most complex architectures are the result of iterations of the same developmental processes: organ initiation, growth, and pattern formation. A central question in plant biology is how these processes are regulated and coordinated to allow for the formation of ordered, 3D structures. All these elementary processes first occur in early embryogenesis, during which, from a fertilized egg cell, precursors for all major tissues and stem cells are initiated, followed by tissue growth and patterning. Here we discuss recent progress in our understanding of this phase of plant life. We consider the cellular basis for multicellular development in 3D and focus on the genetic regulatory mechanisms that direct specific steps during early embryogenesis.
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Affiliation(s)
- Joakim Palovaara
- Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands;
| | - Thijs de Zeeuw
- Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands;
| | - Dolf Weijers
- Laboratory of Biochemistry, Wageningen University, 6703 HA Wageningen, The Netherlands;
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25
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Koi S, Hisanaga T, Sato K, Shimamura M, Yamato KT, Ishizaki K, Kohchi T, Nakajima K. An Evolutionarily Conserved Plant RKD Factor Controls Germ Cell Differentiation. Curr Biol 2016; 26:1775-1781. [PMID: 27345165 DOI: 10.1016/j.cub.2016.05.013] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 05/02/2016] [Accepted: 05/04/2016] [Indexed: 11/30/2022]
Abstract
In contrast to animals, in which the germ cell lineage is established during embryogenesis, plant germ cells are generated in reproductive organs via reprogramming of somatic cells. The factors that control germ cell differentiation and reprogramming in plants are poorly understood. Members of the RKD subfamily of plant-specific RWP-RK transcription factors have been implicated in egg cell formation in Arabidopsis based on their expression patterns and ability to cause an egg-like transcriptome upon ectopic expression [1]; however, genetic evidence of their involvement is lacking, due to possible genetic redundancy, haploid lethality, and the technical difficulty of analyzing egg cell differentiation in angiosperms. Here we analyzed the factors that govern germ cell formation in the liverwort Marchantia polymorpha. This recently revived model bryophyte has several characteristics that make it ideal for studies of germ cell formation, such as low levels of genetic redundancy, readily accessible germ cells, and the ability to propagate asexually via gemma formation [2, 3]. Our analyses revealed that MpRKD, a single RWP-RK factor closely related to angiosperm RKDs, is preferentially expressed in developing eggs and sperm precursors in M. polymorpha. Targeted disruption of MpRKD had no effect on the gross morphology of the vegetative and reproductive organs but led to striking defects in egg and sperm cell differentiation, demonstrating that MpRKD is an essential regulator of germ cell differentiation. Together with previous findings [1, 4-6], our results suggest that RKD factors are evolutionarily conserved regulators of germ cell differentiation in land plants.
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Affiliation(s)
- Satoshi Koi
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan; Faculty of Science, Osaka City University, 2000 Kisaichi, Katano, Osaka 576-0004, Japan
| | - Tetsuya Hisanaga
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Katsutoshi Sato
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan
| | - Masaki Shimamura
- Department of Biological Science, Graduate School of Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8526, Japan
| | - Katsuyuki T Yamato
- Faculty of Biology-Oriented Science and Technology, Kinki University, 930 Nishimitani, Kinokawa, Wakayama 649-6493, Japan
| | - Kimitsune Ishizaki
- Graduate School of Science, Kobe University, 1-1 Rokkodai, Nada-ku, Kobe, Hyogo 657-8501, Japan; Graduate School of Biostudies, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan
| | - Takayuki Kohchi
- Graduate School of Biostudies, Kyoto University, Kitashirakawa-Oiwake, Sakyo-ku, Kyoto 606-8502, Japan
| | - Keiji Nakajima
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192, Japan; PRESTO, Japan Science and Technology Agency, 4-1-8, Honcho, Kawaguchi, Saitama 332-0012, Japan.
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26
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Del Toro-De León G, Lepe-Soltero D, Gillmor CS. Zygotic genome activation in isogenic and hybrid plant embryos. CURRENT OPINION IN PLANT BIOLOGY 2016; 29:148-53. [PMID: 26802806 DOI: 10.1016/j.pbi.2015.12.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2015] [Revised: 12/11/2015] [Accepted: 12/18/2015] [Indexed: 05/24/2023]
Abstract
Zygotic genome activation (ZGA) is the onset of large-scale transcription that occurs after fertilization. In animal embryos, ZGA occurs after a period of transcriptional quiescence that varies between species. In plants, the timing of ZGA may also vary between species, and may or may not occur in a parent-of-origin dependent manner: some studies have shown a maternal bias in mRNA transcripts and gene activity in early embryogenesis, while other experiments have found the contribution of maternal and paternal genomes to be equal. In order to differentiate between maternal and paternal mRNAs, RNA sequencing studies of ZGA in plants have used embryos hybrid for polymorphic accessions. A recent genetic assay in Arabidopsis demonstrated significant variation in paternal allele activity between some hybrid combinations and isogenic embryos, as well as between different hybrid combinations, suggesting a possible source for conflicting results obtained by various experiments on paternal genome activation. We review recent literature on paternal genome activation studies in the zygote in both isogenic and hybrid embryos, and discuss possible explanations for the effects of hybridization on gene expression in early embryogenesis in plants.
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Affiliation(s)
- Gerardo Del Toro-De León
- Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Irapuato, Guanajuato 36821, México
| | - Daniel Lepe-Soltero
- Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Irapuato, Guanajuato 36821, México
| | - C Stewart Gillmor
- Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Unidad de Genómica Avanzada, Centro de Investigación y de Estudios Avanzados del Instituto Politécnico Nacional (CINVESTAV-IPN), Irapuato, Guanajuato 36821, México.
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27
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Embryogenesis and Plant Regeneration from Isolated Wheat Zygotes. Methods Mol Biol 2015; 1359:503-14. [PMID: 26619884 DOI: 10.1007/978-1-4939-3061-6_29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Wheat zygotes can be mechanically isolated and cultivated to continue their development in vitro. Since each zygote needs to be individually isolated, only relatively few of these cells are available per experiment. To facilitate embryonic growth despite of this limitation, the zygotes are kept within a culture insert placed in a larger dish which itself contains embryogenic pollen cocultivated for continuous medium conditioning. This setup ensures that the two cultures, while being physically separated from one another, can exchange essential intercellular signal molecules passing through the bottom of the insert which is made of a permeable membrane. Thanks to the natural fate of zygotes, which is to form an embryo followed by the generation of a plant, embryogenesis and plant regeneration are achieved at much higher efficiency as compared to other single-cell systems. While the method is largely independent of the genotype, it allows for the nondestructive observation, manipulation, and individual analysis of zygotes and very young embryos.
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28
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Baroux C, Grossniklaus U. The Maternal-to-Zygotic Transition in Flowering Plants: Evidence, Mechanisms, and Plasticity. Curr Top Dev Biol 2015; 113:351-71. [PMID: 26358878 DOI: 10.1016/bs.ctdb.2015.06.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
The maternal-to-zygotic transition (MZT) defines a developmental phase during which the embryo progressively emancipates itself from a developmental control relying largely on maternal information. The MZT is a functional readout of two processes: the clearance of maternally derived information and the de novo expression of the inherited, parental alleles enabled by zygotic genome activation (ZGA). In plants, for many years the debate about whether the MZT exists at all focused on the ZGA alone. However, several recent studies provide evidence for a progressive alleviation of the maternal control over embryogenesis that is correlated with a gradual ZGA, a process that is itself maternally controlled. Yet, several examples of zygotic genes that are expressed and/or functionally required early in embryogenesis demonstrate a certain flexibility in the dynamics and kinetics of the MZT among plant species and also intraspecific hybrids.
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Affiliation(s)
- Célia Baroux
- Institute of Plant Biology & Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Ueli Grossniklaus
- Institute of Plant Biology & Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland.
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29
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Zhao P, Sun MX. The Maternal-to-Zygotic Transition in Higher Plants: Available Approaches, Critical Limitations, and Technical Requirements. Curr Top Dev Biol 2015; 113:373-98. [PMID: 26358879 DOI: 10.1016/bs.ctdb.2015.06.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Fertilization marks the turnover from the gametophyte to sporophyte generation in higher plants. After fertilization, sporophytic development undergoes genetic turnover from maternal to zygotic control: the maternal-to-zygotic transition (MZT). The MZT is thought to be critical for early embryogenesis; however, little is known about the time course or developmental impact of the MZT in higher plants. Here, we discuss what is known in the field and focus on techniques used in relevant studies and their limitations. Some significant questions and technical requirements for further investigations are also discussed.
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Affiliation(s)
- Peng Zhao
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, China
| | - Meng-Xiang Sun
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, China.
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Ohnishi Y, Okamoto T. Karyogamy in rice zygotes: Actin filament-dependent migration of sperm nucleus, chromatin dynamics, and de novo gene expression. PLANT SIGNALING & BEHAVIOR 2015; 10:e989021. [PMID: 25723729 PMCID: PMC4622960 DOI: 10.4161/15592324.2014.989021] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Accepted: 09/18/2014] [Indexed: 05/29/2023]
Abstract
In angiosperms, the fusion of a sperm cell with an egg cell, termed plasmogamy, triggers egg activation. Then, karyogamy, migration of the sperm nucleus toward the egg nucleus and their subsequent nuclear fusion, progresses, and de novo gene expression from the zygotic genome is initiated for early embryogenesis. Therefore, karyogamy is an important post-fusion event that bridges egg activation and de novo gene expression in fused gametes/zygotes. In this study, we monitored the progression of karyogamy in rice zygotes produced by in vitro fusion. The results indicated that the sperm nucleus migrated adjacent to the egg nucleus via an actin cytoskeleton, and the egg chromatin then appeared to move unidirectionally into the sperm nucleus through a possible nuclear connection. An enlargement of the sperm nucleus accompanied this possible chromatin remodeling. Then, 30-70 min after fusion, the sperm chromatin began to decondense, and karyogamy was completed. The development of early rice zygotes from plasmogamy to karyogamy could be divided into eight stages, and paternal and de novo synthesized transcripts were separately detectable in zygotes at early and late karyogamy stages, respectively, by RT-PCR using zygotes at each karyogamy stage.
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Affiliation(s)
- Yukinosuke Ohnishi
- Department of Biological Sciences; Tokyo Metropolitan University; Tokyo, Japan
| | - Takashi Okamoto
- Department of Biological Sciences; Tokyo Metropolitan University; Tokyo, Japan
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Kuang Q, Yu X, Peng X, Sun MX. The isolation of early nuclear endosperm of Oryza sativa to facilitate gene expression analysis and screening imprinted genes. PLANT METHODS 2015; 11:49. [PMID: 26500689 PMCID: PMC4618753 DOI: 10.1186/s13007-015-0092-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2015] [Accepted: 10/13/2015] [Indexed: 05/16/2023]
Abstract
BACKGROUND Since the quality and yield of rice production depends on endosperm development, previous studies have focused on the molecular mechanism that regulates this developmental process. Recently, how this process is epigenetically regulated has become an important topic. However, the gene expression analysis and screening imprinted genes during early endosperm development remain challenging since the isolation of early endosperm has not been possible. Here, we report a procedure for the isolation of endosperm at 24 or 48 HAP (hours after pollination) during the free nuclear stage of endosperm development. RESULTS This technique allows for rapid and convenient collection of pure free nuclear endosperm. Early endosperm RNA can then be extracted from the isolated endosperm cells using dynabeads. Our results showed that the quality of RNA is satisfactory for gene expression analysis and screening the parental-of-origin specific genes in early endosperm. CONCLUSIONS Thus, we offer a reliable method to overcome one of the major obstacles in the investigation of the molecular mechanisms of early endosperm development. Our approach can be used for accurate gene expression analysis and screening of imprinted genes, and facilitates the confirmation of endosperm-specific gene expression at the very early stages of endosperm development. This method could also be used in other species to collect early free nuclear endosperm.
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Affiliation(s)
- Quan Kuang
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072 China
| | - Xiaobo Yu
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072 China
| | - Xiongbo Peng
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072 China
| | - Meng-xiang Sun
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, 430072 China
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Non-equivalent contributions of maternal and paternal genomes to early plant embryogenesis. Nature 2014; 514:624-7. [PMID: 25209660 DOI: 10.1038/nature13620] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 06/27/2014] [Indexed: 11/08/2022]
Abstract
Zygotic genome activation in metazoans typically occurs several hours to a day after fertilization, and thus maternal RNAs and proteins drive early animal embryo development. In plants, despite several molecular studies of post-fertilization transcriptional activation, the timing of zygotic genome activation remains a matter of debate. For example, two recent reports that used different hybrid ecotype combinations for RNA sequence profiling of early Arabidopsis embryo transcriptomes came to divergent conclusions. One identified paternal contributions that varied by gene, but with overall maternal dominance, while the other found that the maternal and paternal genomes are transcriptionally equivalent. Here we assess paternal gene activation functionally in an isogenic background, by performing a large-scale genetic analysis of 49 EMBRYO DEFECTIVE genes and testing the ability of wild-type paternal alleles to complement phenotypes conditioned by mutant maternal alleles. Our results demonstrate that wild-type paternal alleles for nine of these genes are completely functional 2 days after pollination, with the remaining 40 genes showing partial activity beginning at 2, 3 or 5 days after pollination. Using our functional assay, we also demonstrate that different hybrid combinations exhibit significant variation in paternal allele activation, reconciling the apparently contradictory results of previous transcriptional studies. The variation in timing of gene function that we observe confirms that paternal genome activation does not occur in one early discrete step, provides large-scale functional evidence that maternal and paternal genomes make non-equivalent contributions to early plant embryogenesis, and uncovers an unexpectedly profound effect of hybrid genetic backgrounds on paternal gene activity.
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Zhao P, Zhou XM, Zou J, Wang W, Wang L, Peng XB, Sun MX. Comprehensive analysis of cystatin family genes suggests their putative functions in sexual reproduction, embryogenesis, and seed formation. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:5093-107. [PMID: 24996653 PMCID: PMC4144781 DOI: 10.1093/jxb/eru274] [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] [Indexed: 05/22/2023]
Abstract
Cystatins are tightly bound and reversible inhibitors of cysteine proteases in C1A and C13 peptidase families, which have been identified in several species and shown to function in vegetative development and response to biotic/abiotic stresses in plants. Recent work revealed their critical role in regulating programmed cell death during embryogenesis in tobacco and suggested their more comprehensive roles in the process of sexual plant reproduction, although little is known about cystatin family genes in the processes. Here, 10 cystatin family genes in Nicotiana tabacum were identified using an expressed sequence tag (EST)-based gene clone strategy. Analysis of their biochemical properties showed that nine of them have the potency to inhibit the activities of both commercial cathepsin L-like proteases and extracted cysteine proteases from seeds, but with different K i values depending on the types of proteases and the developmental stages of the seed tested. This suggests that cystatin-dependent cathepsin L-like proteolytic pathways are probably important for early seed development. Comprehensive expression profile analysis revealed that cystatin family genes showed manifold variations in their transcription levels in different plant cell types, including the sperm, egg, and zygote, especially in the embryo and seed at different developmental stages. More interestingly, intracellular localization analysis of each cystatin revealed that most members of cystatin families are recognized as secretory proteins with signal peptides that direct them to the endoplasmic reticulum. These results suggest their widespread roles in cell fate determination and cell-cell communication in the process of sexual reproduction, especially in gamete and embryo development, as well as in seed formation.
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Affiliation(s)
- Peng Zhao
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Plant Hybrid rice, Wuhan University, Wuhan 430072, China
| | - Xue-mei Zhou
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Plant Hybrid rice, Wuhan University, Wuhan 430072, China
| | - Jie Zou
- Molecular Genetics Key Laboratory of China Tobacco, Guizhou Academy of Tobacco Science, Guiyang 550081, China
| | - Wei Wang
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Plant Hybrid rice, Wuhan University, Wuhan 430072, China
| | - Lu Wang
- Key Laboratory of Plant Germplasm Enhancement and Specialty Agriculture, Wuhan Botanical Garden of the Chinese Academy of Sciences, Wuhan 430074, China
| | - Xiong-bo Peng
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Plant Hybrid rice, Wuhan University, Wuhan 430072, China
| | - Meng-xiang Sun
- Department of Cell and Developmental Biology, College of Life Sciences, State Key Laboratory of Plant Hybrid rice, Wuhan University, Wuhan 430072, China
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Ohnishi Y, Hoshino R, Okamoto T. Dynamics of Male and Female Chromatin during Karyogamy in Rice Zygotes. PLANT PHYSIOLOGY 2014; 165:1533-1543. [PMID: 24948834 PMCID: PMC4119036 DOI: 10.1104/pp.114.236059] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2014] [Accepted: 06/14/2014] [Indexed: 05/20/2023]
Abstract
In angiosperms, the conversion of an egg cell into a zygote involves two sequential gametic processes: plasmogamy, the fusion of the plasma membranes of male and female gametes, and karyogamy, the fusion of the gametic nuclei. In this study, the nuclei and nuclear membranes of rice (Oryza sativa) gametes were fluorescently labeled using histones 2B-green fluorescent protein/red fluorescent protein and Sad1/UNC-84-domain protein2-green fluorescent protein, respectively, which were heterologously expressed. These gametes were fused in vitro to produce zygotes, and the nuclei and nuclear membranes in the zygotes were observed during karyogamy. The results indicated that the sperm nucleus migrates adjacent to the egg nucleus 5 to 10 min after plasmogamy via an actin cytoskelton, and the egg chromatin then appears to move unidirectionally into the sperm nucleus through a possible nuclear connection. The enlargement of the sperm nucleus accompanies this possible chromatin remodeling. Then, 30 to 70 min after fusion, the sperm chromatin begins to decondense with the completion of karyogamy. Based on these observations, the development of early rice zygotes from plasmogamy to karyogamy was divided into eight stages, and using reverse transcription PCR analyses, paternal and de novo synthesized transcripts were separately detected in zygotes at early and late karyogamy stages, respectively.
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Affiliation(s)
- Yukinosuke Ohnishi
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Rina Hoshino
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Takashi Okamoto
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0397, Japan
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Luo A, Shi C, Zhang L, Sun MX. The expression and roles of parent-of-origin genes in early embryogenesis of angiosperms. FRONTIERS IN PLANT SCIENCE 2014; 5:729. [PMID: 25566300 PMCID: PMC4267172 DOI: 10.3389/fpls.2014.00729] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Accepted: 12/01/2014] [Indexed: 05/03/2023]
Abstract
Uniparental transcripts during embryogenesis may arise due to gamete delivery during fertilization or genomic imprinting. Such transcripts have been found in a number of plant species and appear critical for the early development of embryo or endosperm in seeds. Although the regulatory expression mechanism and function of these genes in embryogenesis require further elucidation, recent studies suggest stage-specific and highly dynamic features that might be essential for critical developmental events such as zygotic division and cell fate determination during embryogenesis. Here, we summarize the current work in this field and discuss future research directions.
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Affiliation(s)
- An Luo
- State Key Laboratory of Hybrid Rice, Department of Cell and Developmental Biology, College of Life Sciences, Wuhan UniversityWuhan, China
- College of Life Sciences, Yangtze UniversityJingzhou, China
| | - Ce Shi
- State Key Laboratory of Hybrid Rice, Department of Cell and Developmental Biology, College of Life Sciences, Wuhan UniversityWuhan, China
| | - Liyao Zhang
- State Key Laboratory of Hybrid Rice, Department of Cell and Developmental Biology, College of Life Sciences, Wuhan UniversityWuhan, China
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, Department of Cell and Developmental Biology, College of Life Sciences, Wuhan UniversityWuhan, China
- *Correspondence: Meng-Xiang Sun, State Key Laboratory of Hybrid Rice, Department of Cell and Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, Hubei, China e-mail:
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Leljak-Levanić D, Juranić M, Sprunck S. De novo zygotic transcription in wheat (Triticum aestivum L.) includes genes encoding small putative secreted peptides and a protein involved in proteasomal degradation. PLANT REPRODUCTION 2013; 26:267-85. [PMID: 23912470 DOI: 10.1007/s00497-013-0229-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 07/10/2013] [Indexed: 05/12/2023]
Abstract
Wheat is one of the world's most important crops, and increasing grain yield is a major challenge for the future. Still, our knowledge about the molecular machineries responsible for early post-fertilization events such as zygotic reprogramming, the initial cell-specification events during embryogenesis, and the intercellular communication between the early embryo and the developing endosperm is very limited. Here, we describe the identification of de novo transcribed genes in the wheat zygote. We used wheat ovaries of defined post-fertilization stages to isolate zygotes and early embryos, and identified genes that are specifically induced in these particular stages. Importantly, we observed that some of the zygotic-induced genes encode proteins with similarity to secreted signaling peptides such as TAPETUM DETERMINANT 1 and EGG APPARATUS 1, and to MATH-BTB proteins which are known substrate-binding adaptors for the Cullin3-based ubiquitin E3 ligase. This suggests that both cell-cell signaling and targeted proteasomal degradation may be important molecular events during zygote formation and the progression of early embryogenesis.
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Affiliation(s)
- Dunja Leljak-Levanić
- Department of Molecular Biology, Faculty of Science and Mathematics, University of Zagreb, Horvatovac 102a, 10000, Zagreb, Croatia
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Zhao P, Zhou XM, Zhang LY, Wang W, Ma LG, Yang LB, Peng XB, Bozhkov PV, Sun MX. A bipartite molecular module controls cell death activation in the Basal cell lineage of plant embryos. PLoS Biol 2013; 11:e1001655. [PMID: 24058297 PMCID: PMC3769231 DOI: 10.1371/journal.pbio.1001655] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2013] [Accepted: 08/01/2013] [Indexed: 11/19/2022] Open
Abstract
Plant zygote divides asymmetrically into an apical cell that develops into the embryo proper and a basal cell that generates the suspensor, a vital organ functioning as a conduit of nutrients and growth factors to the embryo proper. After the suspensor has fulfilled its function, it is removed by programmed cell death (PCD) at the late stages of embryogenesis. The molecular trigger of this PCD is unknown. Here we use tobacco (Nicotiana tabacum) embryogenesis as a model system to demonstrate that the mechanism triggering suspensor PCD is based on the antagonistic action of two proteins: a protease inhibitor, cystatin NtCYS, and its target, cathepsin H-like protease NtCP14. NtCYS is expressed in the basal cell of the proembryo, where encoded cystatin binds to and inhibits NtCP14, thereby preventing precocious onset of PCD. The anti-cell death effect of NtCYS is transcriptionally regulated and is repressed at the 32-celled embryo stage, leading to increased NtCP14 activity and initiation of PCD. Silencing of NtCYS or overexpression of NtCP14 induces precocious cell death in the basal cell lineage causing embryonic arrest and seed abortion. Conversely, overexpression of NtCYS or silencing of NtCP14 leads to profound delay of suspensor PCD. Our results demonstrate that NtCYS-mediated inhibition of NtCP14 protease acts as a bipartite molecular module to control initiation of PCD in the basal cell lineage of plant embryos.
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Affiliation(s)
- Peng Zhao
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
| | - Xue-mei Zhou
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
| | - Li-yao Zhang
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
| | - Wei Wang
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
| | - Li-gang Ma
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
| | - Li-bo Yang
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
| | - Xiong-bo Peng
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
| | - Peter V. Bozhkov
- Department of Plant Biology and Forest Genetics, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala, Sweden
| | - Meng-xiang Sun
- Department of Cell and Developmental Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan, China
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Abiko M, Maeda H, Tamura K, Hara-Nishimura I, Okamoto T. Gene expression profiles in rice gametes and zygotes: identification of gamete-enriched genes and up- or down-regulated genes in zygotes after fertilization. JOURNAL OF EXPERIMENTAL BOTANY 2013; 64:1927-40. [PMID: 23570690 PMCID: PMC3638821 DOI: 10.1093/jxb/ert054] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
In angiosperms, fertilization and subsequent zygotic development occur in embryo sacs deeply embedded in the ovaries; therefore, these processes are poorly elucidated. In this study, microarray-based transcriptome analyses were conducted on rice sperm cells, egg cells, and zygotes isolated from flowers to identify candidate genes involved in gametic and/or early zygotic development. Cell type-specific transcriptomes were obtained, and up- or down-regulated genes in zygotes after fertilization were identified, in addition to genes enriched in male and female gametes. A total of 325 putatively up-regulated and 94 putatively down-regulated genes in zygotes were obtained. Interestingly, several genes encoding homeobox proteins or transcription factors were identified as highly up-regulated genes after fertilization, and the gene ontology for up-regulated genes was highly enriched in functions related to chromatin/DNA organization and assembly. Because a gene encoding methyltransferase 1 was identified as a highly up-regulated gene in zygotes after fertilization, the effect of an inhibitor of this enzyme on zygote development was monitored. The inhibitor appeared partially to affect polarity or division asymmetry in rice zygotes, but it did not block normal embryo generation.
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Affiliation(s)
- Mafumi Abiko
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo 192–0397, Japan
| | - Hiroki Maeda
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo 192–0397, Japan
| | - Kentaro Tamura
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606–8502, Japan
| | - Ikuko Hara-Nishimura
- Department of Botany, Graduate School of Science, Kyoto University, Kyoto 606–8502, Japan
| | - Takashi Okamoto
- Department of Biological Sciences, Tokyo Metropolitan University, Hachioji, Tokyo 192–0397, Japan
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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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Ueda M, Laux T. The origin of the plant body axis. CURRENT OPINION IN PLANT BIOLOGY 2012; 15:578-84. [PMID: 22921364 DOI: 10.1016/j.pbi.2012.08.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 08/01/2012] [Accepted: 08/07/2012] [Indexed: 05/11/2023]
Abstract
During embryogenesis, the basic body plan of an organism develops from a unicellular zygote. In most flowering plants, the polar zygote divides asymmetrically, making visible the apical-basal axis in the early embryo. The molecular mechanisms governing how the zygote polarizes and how this polarity is linked to embryo axis formation have been obscure, mainly owing to the difficulties to access the zygote that is deeply embedded in the maternal tissue. In this review, we summarize recent findings identifying key regulators in Arabidopsis and developing novel approaches in various plant species, which altogether set the stage for unraveling embryo axis formation.
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Affiliation(s)
- Minako Ueda
- Laboratory of Plant Growth Regulation, Graduate School of Biological Sciences, Nara Institute of Science and Technology, Takayamacho 8916-5, Ikoma, Nara 630-0192, Japan.
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Wu JJ, Peng XB, Li WW, He R, Xin HP, Sun MX. Mitochondrial GCD1 dysfunction reveals reciprocal cell-to-cell signaling during the maturation of Arabidopsis female gametes. Dev Cell 2012; 23:1043-58. [PMID: 23085019 DOI: 10.1016/j.devcel.2012.09.011] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2011] [Revised: 06/11/2012] [Accepted: 09/17/2012] [Indexed: 12/27/2022]
Abstract
Cell-to-cell communication in embryo sacs is thought to regulate the development of female gametes in flowering plants, but the details remain poorly understood. Here, we report a mitochondrial protein, GAMETE CELL DEFECTIVE 1 (GCD1), enriched in gametophytes that is essential for final maturation of female gametes. Using Arabidopsis gcd1 mutants, we found that final maturation of the egg and central cells is not required for double fertilization but is necessary for embryogenesis initiation and endosperm development. Furthermore, nonautonomous effects, observed when GCD1 or AAC2 function is disrupted, suggest that mitochondrial function influences reciprocal signaling between central and egg cells to regulate maturation of the partner (egg or central) cell. Our findings confirm that cell-to-cell communication is important in functional maturation of female gametic cells and suggest that both egg and central cells sense and transmit their mitochondrial metabolic status as an important cue that regulates the coordination of gamete maturation.
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Affiliation(s)
- Jian-Jun Wu
- Department of Cell and Development Biology, College of Life Science, State Key Laboratory of Plant Hybrid Rice, Wuhan University, Wuhan 430072, China
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Xin HP, Zhao J, Sun MX. The maternal-to-zygotic transition in higher plants. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2012; 54:610-5. [PMID: 22731521 DOI: 10.1111/j.1744-7909.2012.01138.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
During early embryogenesis in mammals and higher plants, the maternal-to-zygotic transition (MZT) marks the turnover of developmental control from maternal products to de novo zygotic genome transcripts. Intensive studies in animals indicate that early embryonic development is largely maternally controlled. In recent years, the MZT has drawn the attention of botanists, as it is important for understanding the mechanism of embryogenesis and hybrid vigor. In this study, we present a brief overview of some aspects of the MZT in flowering plants. Based on what we have learned from Nicotiana tabacum, we hypothesize that the MZT occurs before zygotic cell division and that the development of the fertilized egg cell in flowering plants can be divided into two phases: the zygote stage, which is mainly controlled maternally, and the one-celled proembryo stage, in which zygotic genome activation (ZGA) occurs and is required for zygote division.
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Affiliation(s)
- Hai-Ping Xin
- Department of Cell and Developmental Biology, College of Life Sciences, Wuhan University, Wuhan 430072, China
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Yu M, Zhao J. The cytological changes of tobacco zygote and proembryo cells induced by beta-glucosyl Yariv reagent suggest the involvement of arabinogalactan proteins in cell division and cell plate formation. BMC PLANT BIOLOGY 2012; 12:126. [PMID: 22853005 PMCID: PMC3487971 DOI: 10.1186/1471-2229-12-126] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 07/12/2012] [Indexed: 05/21/2023]
Abstract
BACKGROUND In dicotyledonous plant, the first asymmetric zygotic division and subsequent several cell divisions are crucial for proembryo pattern formation and later embryo development. Arabinogalactan proteins (AGPs) are a family of extensively glycosylated cell surface proteins that are thought to have important roles in various aspects of plant growth and development, including embryogenesis. Previous results from our laboratory show that AGPs are concerned with tobacco egg cell fertilization and zygotic division. However, how AGPs interact with other factors involved in zygotic division and proembryo development remains unknown. RESULTS In this study, we used the tobacco in vitro zygote culture system and series of meticulous cell biology techniques to investigate the roles of AGPs in zygote and proembryo cell division. For the first time, we examined tobacco proembryo division patterns detailed to every cell division. The bright-field images and statistical results both revealed that with the addition of an exogenous AGPs inhibitor, beta-glucosyl Yariv (beta-GlcY) reagent, the frequency of aberrant division increased remarkably in cultured tobacco zygotes and proembryos, and the cell plate specific locations of AGPs were greatly reduced after beta-GlcY treatment. In addition, the accumulations of new cell wall materials were also significantly affected by treating with beta-GlcY. Detection of cellulose components by Calcofluor white stain showed that strong fluorescence was located in the newly formed wall of daughter cells after the zygotic division of in vivo samples and the control samples from in vitro culture without beta-GlcY treatment; while there was only weak fluorescence in the newly formed cell walls with beta-GlcY treatment. Immunocytochemistry examination with JIM5 and JIM7 respectively against the low- and high-esterified pectins displayed that these two pectins located in opposite positions of zygotes and proembryos in vivo and the polarity was not affected by beta-GlcY. Furthermore, FM4-64 staining revealed that endosomes were distributed in the cell plates of proembryos, and the localization pattern was also affected by beta-GlcY treatment. These results were further confirmed by subsequent observation with transmission electron microscopy. Moreover, the changes to proembryo cell-organelles induced by beta-GlcY reagent were also observed using fluorescent dye staining technique. CONCLUSIONS These results imply that AGPs may not only relate to cell plate position decision, but also to the location of new cell wall components. Correlated with other factors, AGPs further influence the zygotic division and proembryo pattern establishment in tobacco.
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Affiliation(s)
- Miao Yu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Jie Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
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Niedojadło K, Pięciński S, Smoliński DJ, Bednarska-Kozakiewicz E. Transcriptional activity of Hyacinthus orientalis L. female gametophyte cells before and after fertilization. PLANTA 2012; 236:153-69. [PMID: 22293855 PMCID: PMC3382649 DOI: 10.1007/s00425-012-1599-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 01/05/2012] [Indexed: 05/19/2023]
Abstract
We characterized three phases of Hyacinthus orientalis L. embryo sac development, in which the transcriptional activity of the cells differed using immunolocalization of incorporated 5′-bromouracil, the total RNA polymerase II pool and the hypo- (initiation) and hyperphosphorylated (elongation) forms of RNA Pol II. The first stage, which lasts from the multinuclear stage to cellularization, is a period of high transcriptional activity, probably related to the maturation of female gametophyte cells. The second stage, encompassing the period of embryo sac maturity and the progamic phase, involves the transcriptional silencing of cells that will soon undergo fusion with male gametes. During this period in the hyacinth egg cell, there are almost no newly formed transcripts, and only a small pool of RNA Pol II is present in the nucleus. The transcriptional activity of the central cell is only slightly higher than that observed in the egg cell. The post-fertilization stage is related to the transcriptional activation of the zygote and the primary endosperm cell. The rapid increase in the pool of newly formed transcripts in these cells is accompanied by an increase in the pool of RNA Pol II, and the pattern of enzyme distribution in the zygote nucleus is similar to that observed in the somatic cells of the ovule. Our data, together with the earlier results of Pięciński et al. (2008), indicate post-fertilization synthesis and the maturation of numerous mRNA transcripts, suggesting that fertilization in H. orientalis induces the activation of the zygote and endosperm genomes.
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Affiliation(s)
- Katarzyna Niedojadło
- Department of Cell Biology, Institute of General and Molecular Biology, Nicolaus Copernicus University, Gagarina 9, 87-100 Toruń, Poland.
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Maternal and paternal genomes contribute equally to the transcriptome of early plant embryos. Nature 2012; 482:94-7. [PMID: 22266940 DOI: 10.1038/nature10756] [Citation(s) in RCA: 161] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2011] [Accepted: 12/01/2011] [Indexed: 01/28/2023]
Abstract
In animals, maternal gene products deposited into eggs regulate embryonic development before activation of the zygotic genome. In plants, an analogous period of prolonged maternal control over embryogenesis is thought to occur based on some gene-expression studies. However, other gene-expression studies and genetic analyses show that some transcripts must derive from the early zygotic genome, implying that the prevailing model does not fully explain the nature of zygotic genome activation in plants. To determine the maternal, paternal and zygotic contributions to the early embryonic transcriptome, we sequenced the transcripts of hybrid embryos from crosses between two polymorphic inbred lines of Arabidopsis thaliana and used single-nucleotide polymorphisms diagnostic of each parental line to quantify parental contributions. Although some transcripts seemed to be either inherited from primarily one parent or transcribed from imprinted loci, the vast majority of transcripts were produced in near-equal amounts from both maternal and paternal alleles, even during the initial stages of embryogenesis. Results of reporter experiments and analyses of transcripts from genes that are not expressed in sperm and egg indicate early and widespread zygotic transcription. Thus, in contrast to early animal embryogenesis, early plant embryogenesis is mostly under zygotic control.
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Lau S, Slane D, Herud O, Kong J, Jürgens G. Early embryogenesis in flowering plants: setting up the basic body pattern. ANNUAL REVIEW OF PLANT BIOLOGY 2012; 63:483-506. [PMID: 22224452 DOI: 10.1146/annurev-arplant-042811-105507] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Early embryogenesis is the critical developmental phase during which the basic features of the plant body are established: the apical-basal axis of polarity, different tissue layers, and both the root pole and the shoot pole. Polarization of the zygote correlates with the generation of apical and basal (embryonic and extraembryonic) cell fates. Whereas mechanisms of zygote polarization are still largely unknown, distinct expression domains of WOX family transcription factors as well as directional auxin transport and local auxin response are known to be involved in early apical-basal patterning. Radial patterning of tissue layers appears to be mediated by cell-cell communication involving both peptide signaling and transcription factor movement. Although the initiation of the shoot pole is still unclear, the apical organization of the embryo depends on both the proper establishment of transcription factor expression domains and, for cotyledon initiation, upward auxin flow in the protoderm. Here we focus on the essential patterning processes, drawing mainly on data from Arabidopsis thaliana and also including relevant data from other species if available.
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Affiliation(s)
- Steffen Lau
- Department of Cell Biology, Max Planck Institute for Developmental Biology, Tübingen, Germany
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Hu TX, Yu M, Zhao J. Comparative transcriptional analysis reveals differential gene expression between asymmetric and symmetric zygotic divisions in tobacco. PLoS One 2011; 6:e27120. [PMID: 22069495 PMCID: PMC3206072 DOI: 10.1371/journal.pone.0027120] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Accepted: 10/11/2011] [Indexed: 11/24/2022] Open
Abstract
Asymmetric cell divisions occur widely during many developmental processes in plants. In most angiosperms, the first zygotic cell division is asymmetric resulting in two daughter cells of unequal size and with distinct fates. However, the critical molecular mechanisms regulating this division remain unknown. Previously we showed that treatment of tobacco zygotes with beta-glucosyl Yariv (βGlcY) could dramatically alter the first zygotic asymmetric division to produce symmetric two-celled proembryos. In the present study, we isolated zygotes and two-celled asymmetric proembryos in vivo by micromanipulation, and obtained symmetric, two-celled proembryos by in vitro cell cultures. Using suppression-subtractive hybridization (SSH) and macroarray analysis differential gene expression between the zygote and the asymmetric and symmetric two-celled proembryos was investigated. After sequencing of the differentially expressed clones, a total of 1610 EST clones representing 685 non-redundant transcripts were obtained. Gene ontology (GO) term analysis revealed that these transcripts include those involved in physiological processes such as response to stimulus, regulation of gene expression, and localization and formation of anatomical structures. A homology search against known genes from Arabidopsis indicated that some of the above transcripts are involved in asymmetric cell division and embryogenesis. Quantitative real-time PCR confirmed the up- or down-regulation of the selected candidate transcripts during zygotic division. A few of these transcripts were expressed exclusively in the zygote, or in either type of the two-celled proembryos. Expression analyses of select genes in different tissues and organs also revealed potential roles of these transcripts in fertilization, seed maturation and organ development. The putative roles of few of the identified transcripts in the regulation of zygotic division are discussed. Further functional work on these candidate transcripts will provide important information for understanding asymmetric zygotic division, generation of apical-basal polarity and cell fate decisions during early embryogenesis.
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Affiliation(s)
- Tian-Xiang Hu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Miao Yu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Jie Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
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Zhang JE, Luo A, Xin HP, Zhao J, Li SS, Qu LH, Ma LG, Scholten S, Sun MX. Genes of both parental origins are differentially involved in early embryogenesis of a tobacco interspecies hybrid. PLoS One 2011; 6:e23153. [PMID: 21829711 PMCID: PMC3150392 DOI: 10.1371/journal.pone.0023153] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Accepted: 07/12/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND In animals, early embryonic development is largely dependent on maternal transcripts synthesized during gametogenesis. However, in higher plants, the extent of maternal control over zygote development and early embryogenesis is not fully understood yet. Nothing is known about the activity of the parental genomes during seed formation of interspecies hybrids. METHODOLOGY/PRINCIPAL FINDINGS Here, we report that an interspecies hybridization system between SR1 (Nicotiana tabacum) and Hamayan (N. rustica) has been successfully established. Based on the system we selected 58 genes that have polymorphic sites between SR1 and Hamayan, and analyzed the allele-specific expression of 28 genes in their hybrid zygotes (Hamayan x SR1). Finally the allele-specific expressions of 8 genes in hybrid zygotes were repeatedly confirmed. Among them, 4 genes were of paternal origin, 1 gene was of maternal origin and 3 genes were of biparental origin. These results revealed obvious biparental involvement and differentially contribution of parental-origin genes to zygote development in the interspecies hybrid. We further detected the expression pattern of the genes at 8-celled embryo stage found that the involvement of the parental-origin genes may change at different stages of embryogenesis. CONCLUSIONS/SIGNIFICANCE We reveal that genes of both parental origins are differentially involved in early embryogenesis of a tobacco interspecies hybrid and functions in a developmental stage-dependent manner. This finding may open a window to seek for the possible molecular mechanism of hybrid vigor.
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Affiliation(s)
- Jun-E Zhang
- Key Laboratory of Ministry of Education for Plant Development Biology, College of Life Science, Wuhan University, Wuhan, China
- College of Life Science, Jiangxi Normal University, Nanchang, China
| | - An Luo
- Key Laboratory of Ministry of Education for Plant Development Biology, College of Life Science, Wuhan University, Wuhan, China
| | - Hai-Ping Xin
- Key Laboratory of Ministry of Education for Plant Development Biology, College of Life Science, Wuhan University, Wuhan, China
| | - Jing Zhao
- Key Laboratory of Ministry of Education for Plant Development Biology, College of Life Science, Wuhan University, Wuhan, China
| | - Shi-Sheng Li
- Key Laboratory of Ministry of Education for Plant Development Biology, College of Life Science, Wuhan University, Wuhan, China
| | - Liang-Huan Qu
- Key Laboratory of Ministry of Education for Plant Development Biology, College of Life Science, Wuhan University, Wuhan, China
| | - Li-Gang Ma
- Key Laboratory of Ministry of Education for Plant Development Biology, College of Life Science, Wuhan University, Wuhan, China
| | - Stefan Scholten
- Biocenter Klein Flottbek, Developmental Biology and Biotechnology, University of Hamburg, Hamburg, Germany
| | - Meng-Xiang Sun
- Key Laboratory of Ministry of Education for Plant Development Biology, College of Life Science, Wuhan University, Wuhan, China
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