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Flores-Tornero M, Becker JD. 50 years of sperm cell isolations: from structural to omic studies. JOURNAL OF EXPERIMENTAL BOTANY 2023:erad117. [PMID: 37025026 DOI: 10.1093/jxb/erad117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Indexed: 06/19/2023]
Abstract
The fusion of male and female gametes is a fundamental process in the perpetuation and diversification of species. During the last 50 years, significant efforts have been made to isolate and characterize sperm cells from flowering plants, and to identify how these cells interact with female gametes to achieve double fertilization. The first techniques and analytical approaches not only provided structural and biochemical characterizations of plant sperm cells but also paved the way for in vitro fertilization studies. Further technological advances then led to unique insights into sperm biology at transcriptomic, proteomic and epigenetic level. Starting with a historical overview of sperm cell isolation techniques, we provide examples of how these contributed to create our current knowledge of sperm cell biology, and point out remaining challenges.
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Affiliation(s)
- María Flores-Tornero
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, Oeiras, 2780-157 Portugal
| | - Jörg D Becker
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Av. da República, Oeiras, 2780-157 Portugal
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2
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Shunmugam ASK, Bollina V, Dukowic-Schulze S, Bhowmik PK, Ambrose C, Higgins JD, Pozniak C, Sharpe AG, Rozwadowski K, Kagale S. MeioCapture: an efficient method for staging and isolation of meiocytes in the prophase I sub-stages of meiosis in wheat. BMC PLANT BIOLOGY 2018; 18:293. [PMID: 30463507 PMCID: PMC6249822 DOI: 10.1186/s12870-018-1514-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2018] [Accepted: 10/31/2018] [Indexed: 05/21/2023]
Abstract
BACKGROUND Molecular analysis of meiosis has been hindered by difficulties in isolating high purity subpopulations of sporogenous cells representing the succeeding stages of meiosis. Isolation of purified male meiocytes from defined meiotic stages is crucial in discovering meiosis specific genes and associated regulatory networks. RESULTS We describe an optimized method termed MeioCapture for simultaneous isolation of uncontaminated male meiocytes from wheat (Triticum spp.), specifically from the pre-meiotic G2 and the five sub-stages of meiotic prophase I. The MeioCapture protocol builds on the traditional anther squash technique and the capillary collection method, and involves extrusion of intact sporogenous archesporial columns (SACs) containing meiocytes. This improved method exploits the natural meiotic synchrony between anthers of the same floret, the correlation between the length of anthers and meiotic stage, and the occurrence of meiocytes in intact SACs largely free of somatic cells. The main advantage of MeioCapture, compared to previous methods, is that it allows simultaneous collection of meiocytes from different sub-stages of prophase I at a very high level of purity, through correlation of stages with anther sizes. A detailed description is provided for all steps, including the collection of tissue, isolation and size sorting of anthers, extrusion of intact SACs, and staging of meiocytes. Precautions for individual steps throughout the procedure are also provided to facilitate efficient isolation of pure meiocytes. The proof-of-concept was successfully established in wheat, and a light microscopic atlas of meiosis, encompassing all stages from pre-meiosis to telophase II, was developed. CONCLUSION The MeioCapture method provides an essential technique to study the molecular basis of chromosome pairing and exchange of genetic information in wheat, leading to strategies for manipulating meiotic recombination frequencies. The method also provides a foundation for similar studies in other crop species.
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Affiliation(s)
| | | | | | | | - Chris Ambrose
- Department of Biology, University of Saskatchewan, Saskatoon, SK Canada
| | - James D. Higgins
- Department of Genetics and Genome Biology, University of Leicester, Leicester, UK
| | - Curtis Pozniak
- Department of Plant Sciences, University of Saskatchewan, Saskatoon, Canada
| | - Andrew G. Sharpe
- National Research Council Canada, Saskatoon, SK Canada
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, Canada
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Santos MR, Bispo C, Becker JD. Isolation of Arabidopsis Pollen, Sperm Cells, and Vegetative Nuclei by Fluorescence-Activated Cell Sorting (FACS). Methods Mol Biol 2017; 1669:193-210. [PMID: 28936660 DOI: 10.1007/978-1-4939-7286-9_16] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Efficient methods to isolate highly purified Arabidopsis thaliana pollen and the subcellular components of the male gametophyte (the vegetative nucleus and two sperm cells) have enabled genome-scale studies revealing a highly dynamic reprogramming of the transcriptome and epigenome during pollen development. Here, we describe the isolation of uninucleate microspores, mature pollen, as well as sperm cells and vegetative nuclei by Fluorescence-Activated Cell Sorting.
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Affiliation(s)
- Mário R Santos
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande Nº6, 2780-156, Oeiras, Portugal
| | - Cláudia Bispo
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande Nº6, 2780-156, Oeiras, Portugal
- UCSF Flow Cytometry Core Facility, 513 Parnassus Ave., San Francisco, CA, 94143, USA
| | - Jörg D Becker
- Instituto Gulbenkian de Ciência, Rua da Quinta Grande Nº6, 2780-156, Oeiras, Portugal.
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Russell SD, Jones DS. The male germline of angiosperms: repertoire of an inconspicuous but important cell lineage. FRONTIERS IN PLANT SCIENCE 2015; 6:173. [PMID: 25852722 PMCID: PMC4367165 DOI: 10.3389/fpls.2015.00173] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2014] [Accepted: 03/03/2015] [Indexed: 05/03/2023]
Abstract
The male germline of flowering plants constitutes a specialized lineage of diminutive cells initiated by an asymmetric division of the initial microspore cell that sequesters the generative cell from the pollen vegetative cell. The generative cell subsequently divides to form the two male gametes (non-motile sperm cells) that fuse with the two female gametophyte target cells (egg and central cells) to form the zygote and endosperm. Although these male gametes can be as little as 1/800th of the volume of their female counterpart, they encode a highly distinctive and rich transcriptome, translate proteins, and display a novel suite of gamete-distinctive control elements that create a unique chromatin environment in the male lineage. Sperm-expressed transcripts also include a high proportion of transposable element-related sequences that may be targets of non-coding RNA including miRNA and silencing elements from peripheral cells. The number of sperm-encoded transcripts is somewhat fewer than the number present in the egg cell, but are remarkably distinct compared to other cell types according to principal component and other analyses. The molecular role of the male germ lineage cells is just beginning to be understood and appears more complex than originally anticipated.
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Affiliation(s)
- Scott D. Russell
- *Correspondence: Scott D. Russell, Department of Microbiology and Plant Biology, University of Oklahoma, Norman, 770 Van Vleet Oval, OK 73019, USA
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5
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Techniques of cell type-specific transcriptome analysis and applications in researches of sexual plant reproduction. ACTA ACUST UNITED AC 2011. [DOI: 10.1007/s11515-011-1090-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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6
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Perumal P, Selvaraju S, Selvakumar S, Barik AK, Mohanty DN, Das S, Das RK, Mishra PC. Effect of Pre-freeze Addition of Cysteine Hydrochloride and Reduced Glutathione in Semen of Crossbred Jersey Bulls on Sperm Parameters and Conception Rates. Reprod Domest Anim 2010; 46:636-41. [DOI: 10.1111/j.1439-0531.2010.01719.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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7
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Xin H, Sun M. What we have learned from transcript profile analyses of male and female gametes in flowering plants. SCIENCE CHINA-LIFE SCIENCES 2010; 53:927-33. [PMID: 20821291 DOI: 10.1007/s11427-010-4033-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2010] [Accepted: 06/21/2010] [Indexed: 11/30/2022]
Abstract
Double fertilization is one of the predominant features of sexual reproduction in flowering plants but, because of the physical inaccessibility of gametes, the essential molecular mechanisms in these processes are largely unknown. Based on the techniques for isolating highly purified gametes from several species and well-developed methods for manipulating RNA from limited quantities of gametes, genome-wide investigations of gamete transcription profiles were recently conducted in flowering plants. In this review, we survey the accumulated knowledge on gamete collection and purification, cDNA library construction, and transcript profile analysis to assess our understanding of the molecular mechanisms of gamete specialization and fertilization.
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Affiliation(s)
- HaiPing Xin
- Key Laboratory of the Ministry of Education for Plant Developmental Biology, College of Life Science, Wuhan University, Wuhan, China
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8
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Hirano T, Hoshino Y. Sperm dimorphism in terms of nuclear shape and microtubule accumulation in Cyrtanthus mackenii. ACTA ACUST UNITED AC 2009; 23:153-62. [DOI: 10.1007/s00497-009-0123-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2009] [Accepted: 11/04/2009] [Indexed: 10/20/2022]
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Gou X, Yuan T, Wei X, Russell SD. Gene expression in the dimorphic sperm cells of Plumbago zeylanica: transcript profiling, diversity, and relationship to cell type. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2009; 60:33-47. [PMID: 19500307 DOI: 10.1111/j.1365-313x.2009.03934.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Plumbago zeylanica produces cytoplasmically dimorphic sperm cells that target the egg and central cell during fertilization. In mature pollen, the larger sperm cell contains numerous mitochondria, is associated with the vegetative nucleus (S(vn)), and fuses preferentially with the central cell, forming endosperm. The other, plastid-enriched sperm cell (S(ua)) fuses with the egg cell, forming the zygote and embryo. Sperm expressed genes were investigated using ESTs produced from each sperm type; differential expression was validated through suppression subtractive hybridization, custom microarrays, real-time RT-PCR and in situ hybridization. The expression profiles of dimorphic sperm cells reflect a diverse and broad complement of genes, including high proportions of conserved and unknown genes, as well as distinct patterns of expression. A number of genes were highly up-regulated in the male germ line, including some genes that were differentially expressed in either the S(ua) or the S(vn). Differentially up-regulated genes in the egg-targeted S(ua) showed increased expression in transcription and translation categories, whereas the central cell-targeted S(vn) displayed expanded expression in the hormone biosynthesis category. Interestingly, the up-regulated genes expressed in the sperm cells appeared to reflect the expected post-fusion profiles of the future embryo and endosperm. As sperm cytoplasm is known to be transmitted during fertilization in this plant, sperm-contributed mRNAs are probably transported during fertilization, which could influence early embryo and endosperm development.
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Affiliation(s)
- Xiaoping Gou
- Department of Botany, University of Oklahoma, Norman, OK 73019, USA
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Borg M, Brownfield L, Twell D. Male gametophyte development: a molecular perspective. JOURNAL OF EXPERIMENTAL BOTANY 2009; 60:1465-78. [PMID: 19213812 DOI: 10.1093/jxb/ern355] [Citation(s) in RCA: 215] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Pollen grains represent the highly reduced haploid male gametophyte generation in flowering plants, consisting of just two or three cells when released from the anthers. Their role is to deliver twin sperm cells to the embryo sac to undergo fusion with the egg and central cell. This double fertilization event along with the functional specialization of the male gametophyte, are considered to be key innovations in the evolutionary success of flowering plants. This review encompasses important recent advances in our understanding of the molecular mechanisms controlling male gametophyte development. A brief overview of pollen development is presented, followed by a discussion of genome-wide transcriptomic studies of haploid gene expression. The progress achieved through genetic analysis of landmark events of male gametogenesis is discussed, with a focus on sperm cell production, and an emerging model of the regulatory network governing male germline development is presented. The review concludes with a perspective of the impact these data will have on future research strategies to further develop our understanding of the gametophytic control of pollen development.
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Affiliation(s)
- Michael Borg
- Department of Biology, University of Leicester, UK
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12
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Chen SH, Liao JP, Kuang AX, Tian HQ. Isolation of two populations of sperm cells from the pollen tube of Torenia fournieri. PLANT CELL REPORTS 2006; 25:1138-42. [PMID: 16786313 DOI: 10.1007/s00299-006-0189-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2006] [Revised: 05/08/2006] [Accepted: 05/28/2006] [Indexed: 05/10/2023]
Abstract
The two sperm cells of Torenia fournieri are dimorphic. The dimorphic character suggests that they might be preferentially involved in fertilization during in vivo fusion with the egg cell and central cell. To probe the mechanism of preferential fertilization, it is necessary to use the most current molecular techniques. For this purpose, populations of >1000 individuals of the two dimorphic sperm cells, Sua (unassociated with the vegetative nucleus) and Svn (associated with the vegetative nucleus) were isolated from pollen tubes that had grown out of the cut ends of the styles. The two sperm cells released from pollen tubes remained attached to one another. When the two attached sperm cells were transferred into a solution containing 0.01% cellulose, 0.01% pectinase, and 5% mannitol, the connection between the two cells disappeared, and they were easily separated using a micromanipulator. The collection of these two individual populations containing over a thousand cells will permit research on gametic recognition at the molecular level.
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Affiliation(s)
- Su Hong Chen
- South China Botanical Garden, The Chinese Academy of Sciences, Guangzhou, 510650, China
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Wei X, Gou X, Yuan T, Russell SD. A highly efficient in vitro plant regeneration system and Agrobacterium-mediated transformation in Plumbago zeylanica. PLANT CELL REPORTS 2006; 25:513-21. [PMID: 16470412 DOI: 10.1007/s00299-006-0114-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2005] [Revised: 12/08/2005] [Accepted: 12/14/2005] [Indexed: 05/06/2023]
Abstract
Plumbago zeylanica is a unique model for studying flowering plant gametogenesis, heterospermy, and preferential fertilization, yet understanding the control of related molecular mechanisms is impossible without efficient and reproducible regeneration and stable genetic transformation. We found three key factors for enhancing successful regeneration: (1) tissue source of explants, (2) combination and concentration of growth regulators, and (3) culture conditions. The highest frequency of shoot regeneration was achieved using hypocotyl segments cultured on MS basal medium supplemented with BA 2.0 mg/l, NAA 0.75 mg/l, adenine 50 mg/l and 10% (v/v) coconut milk under subdued light at 25+/-2 degrees C; under these conditions, each hypocotyl segment produced over 30 shoots, arising primarily through direct organogenesis after 3 weeks of culture. Regenerated shoots rooted easily on half-strength basal MS medium and were successfully established in the greenhouse. Using this tissue culture protocol, reporter gene GUS under the constitutive CaMV 35S promoter was introduced into P. zeylanica cells of petiole, cotyledon and hypocotyl with A. tumefaciens strains AGL1 and LBA4404. Transient expression was observed in all recipient tissues. Stable transgenic calli originating from petiole were obtained.
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Affiliation(s)
- Xiaoping Wei
- Department of Botany and Microbiology, University of Oklahoma, Norman, OK 73019, USA
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14
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Russell SD, Strout GW. Microgametogenesis in Plumbago zeylanica (Plumbaginaceae). 2. Quantitative cell and organelle dynamics of the male reproductive cell lineage. ACTA ACUST UNITED AC 2005. [DOI: 10.1007/s00497-005-0005-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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15
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Isolation of two populations of sperm cells and microelectrophoresis of pairs of sperm cells from pollen tubes of tobacco (Nicotiana tabacum). ACTA ACUST UNITED AC 2005. [DOI: 10.1007/s00497-005-0248-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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16
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Rotman N, Durbarry A, Wardle A, Yang WC, Chaboud A, Faure JE, Berger F, Twell D. A novel class of MYB factors controls sperm-cell formation in plants. Curr Biol 2005; 15:244-8. [PMID: 15694308 DOI: 10.1016/j.cub.2005.01.013] [Citation(s) in RCA: 170] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2004] [Revised: 11/18/2004] [Accepted: 11/19/2004] [Indexed: 11/23/2022]
Abstract
In contrast to animals, the plant male germline is established after meiosis in distinctive haploid structures, termed pollen grains. The germline arises by a distinct asymmetric division of the meiotic products . The fates of the resulting vegetative and generative cells are distinct. In contrast to the larger vegetative cell, arrested in the G1 phase of the cell cycle, the smaller generative cell divides once to produce the two male gametes or sperm cells. Sperm cells are delivered to the female gametes by the pollen tube, which develops from the vegetative cell. In spite of recent efforts to understand pollen development , the molecular pathway controlling sperm-cell ontogenesis is unknown. Here, we present the isolation of DUO1, a novel R2R3 MYB gene of Arabidopsis, as the first gene shown to control male gamete formation in plants. DUO1 is specifically expressed in the male germline, and DUO1 protein accumulates in sperm-cell nuclei. Mutations in DUO1 produce a single larger diploid sperm cell unable to perform fertilization. DUO1 appears to be evolutionarily conserved in several plant species and defines a new subfamily of pollen-specific MYB genes.
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Affiliation(s)
- Nicolas Rotman
- Reproduction et Développement des Plantes, Unité Mixte de Recherche 5667, Institut Fédératif de Recherche 128, Centre National de la Recherche Scientifique, Université Claude Bernard Lyon I, 46 allée d'Italie, F-69364 Lyon Cedex 07, France
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Honys D, Twell D. Transcriptome analysis of haploid male gametophyte development in Arabidopsis. Genome Biol 2004; 5:R85. [PMID: 15535861 PMCID: PMC545776 DOI: 10.1186/gb-2004-5-11-r85] [Citation(s) in RCA: 541] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2004] [Revised: 09/17/2004] [Accepted: 09/28/2004] [Indexed: 12/12/2022] Open
Abstract
A transcriptome analysis of male gametophyte development in Arabidopsis uncovers distinct temporal classes of gene expression and opens the door to detailed studies of the regulatory pathways involved. Background The haploid male gametophyte generation of flowering plants consists of two- or three-celled pollen grains. This functional specialization is thought to be a key factor in the evolutionary success of flowering plants. Moreover, pollen ontogeny is also an attractive model in which to dissect cellular networks that control cell growth, asymmetric cell division and cellular differentiation. Our objective, and an essential step towards the detailed understanding of these processes, was to comprehensively define the male haploid transcriptome throughout development. Results We have developed staged spore isolation procedures for Arabidopsis and used Affymetrix ATH1 genome arrays to identify a total of 13,977 male gametophyte-expressed mRNAs, 9.7% of which were male-gametophyte-specific. The transition from bicellular to tricellular pollen was accompanied by a decline in the number of diverse mRNA species and an increase in the proportion of male gametophyte-specific transcripts. Expression profiles of regulatory proteins and distinct clusters of coexpressed genes were identified that could correspond to components of gametophytic regulatory networks. Moreover, integration of transcriptome and experimental data revealed the early synthesis of translation factors and their requirement to support pollen tube growth. Conclusions The progression from proliferating microspores to terminally differentiated pollen is characterized by large-scale repression of early program genes and the activation of a unique late gene-expression program in maturing pollen. These data provide a quantum increase in knowledge concerning gametophytic transcription and lay the foundations for new genomic-led studies of the regulatory networks and cellular functions that operate to specify male gametophyte development.
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Affiliation(s)
- David Honys
- Institute of Experimental Botany AS CR, Rozvojová 135, CZ-165 02, Praha 6, Czech Republic
- Department of Plant Physiology, Faculty of Sciences, Charles University, Viničná 5, CZ-128 44, Praha 2, Czech Republic
| | - David Twell
- Department of Biology, University of Leicester, University Road, Leicester LE1 7RH, UK
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Faure JE, Rusche ML, Thomas A, Keim P, Dumas C, Mogensen HL, Rougier M, Chaboud A. Double fertilization in maize: the two male gametes from a pollen grain have the ability to fuse with egg cells. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2003; 33:1051-1062. [PMID: 12631329 DOI: 10.1046/j.1365-313x.2003.01692.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In flowering plants, two male gametes from a single pollen grain fuse with two female gametes, the egg and central cells, to form the embryo and endosperm, respectively. The question then arises whether the two male gametes fuse randomly with the egg and central cells. We investigated this question using two nearly isogenic maize lines with supernumerary B chromosomes (TB10L18) or without (r-tester). B chromosomes regularly undergo non-disjunction at the second pollen mitosis, producing one sperm cell with zero B chromosomes and one with two. We first confirmed earlier studies showing an excess of transmission of the B chromosomes to the embryo rather than to the endosperm. We then tested the possibility of a directed fertilization. For TB10L18 pollen, we could demonstrate the existence of a size dimorphism between the two sperm cells, correlated to the content in B chromosomes, as detected by fluorescence in situ hybridization (FISH). However, no directed fusion of B chromosome containing sperm to egg cells could be detected when using in vitro fertilization. The absence of directed fusion in vitro could also be demonstrated for control lines. We conclude that both male gametes have the capacity to fuse with the egg cell in maize, although sexual reproduction results in a preferential transmission of supernumerary B chromosomes.
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Affiliation(s)
- Jean-Emmanuel Faure
- Ecole Normale Supérieure de Lyon, Laboratory of Plant Reproduction and Development (UMR 5667 CNRS-INRA-ENS Lyon-UCB Lyon I), Lyon, France
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Faure JE. Double fertilization in flowering plants: discovery, study methods and mechanisms. COMPTES RENDUS DE L'ACADEMIE DES SCIENCES. SERIE III, SCIENCES DE LA VIE 2001; 324:551-8. [PMID: 11455878 DOI: 10.1016/s0764-4469(01)01325-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The double fertilization of flowering plants was discovered a century ago. The cytology of the gametes is now well known. However the description of the fertilization steps is still poor and most of the cellular and molecular mechanisms involved are unknown. Recent research using in vitro fertilization demonstrated that the early steps of fertilization share some homology with those in animal species. In particular, gamete fusion is followed by a cytosolic calcium increase in the fertilized egg as well as a calcium influx. Further understanding of fertilization also comes from the analysis of mutants isolated in Arabidopsis thaliana. Important new ideas have already emerged from these studies such as the importance of the female gametophyte in embryo development, and an early silencing of the male genome during the first days following gamete fusion.
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Affiliation(s)
- J E Faure
- Ecole normale supérieure, Laboratory of Plant Reproduction and Development, UMR 5667 CNRS-Inra-ENS-Lyon-UCB-Lyon-I, 69364 Lyon, France.
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Abstract
The pollen grain and the pollen tube that grows from it are complex entities which must respond to a diverse array of signals to carry out their roles in sexual reproduction. Research is beginning to reveal the nature both of the signals and of the signal transduction machinery that converts these signals into directional, polarized growth.
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Affiliation(s)
- R E Pruitt
- Department of Molecular and Cellular Biology, Harvard University, 16 Divinity Avenue, Cambridge, MA 02138, USA.
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