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Wang W, Malka R, Lindemeier M, Cyprys P, Tiedemann S, Sun K, Zhang X, Xiong H, Sprunck S, Sun MX. EGG CELL 1 contributes to egg-cell-dependent preferential fertilization in Arabidopsis. NATURE PLANTS 2024; 10:268-282. [PMID: 38287093 DOI: 10.1038/s41477-023-01616-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Accepted: 12/20/2023] [Indexed: 01/31/2024]
Abstract
During double fertilization in angiosperms, the pollen tube delivers two sperm cells into an embryo sac; one sperm cell fuses with an egg cell, and the other sperm cell fuses with the central cell. It has long been proposed that the preference for fusion with one or another female gamete cell depends on the sperm cells and occurs during gamete recognition. However, up to now, sperm-dependent preferential fertilization has not been demonstrated, and results on preferred fusion with either female gamete have remained conflicting. To investigate this topic, we generated Arabidopsis thaliana mutants that produce single sperm-like cells or whose egg cells are eliminated; we found that although the three different types of sperm-like cell are functionally equivalent in their ability to fertilize the egg and the central cell, each type of sperm-like cell fuses predominantly with the egg cell. This indicates that it is the egg cell that controls its preferential fertilization. We also found that sperm-activating small secreted EGG CELL 1 proteins are involved in the regulation of egg-cell-dependent preferential fertilization, revealing another important role for this protein family during double fertilization.
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Affiliation(s)
- Wei Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Raphael Malka
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Maria Lindemeier
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Philipp Cyprys
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Sophie Tiedemann
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Kaiting Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xuecheng Zhang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Hanxian Xiong
- School of Life Science and Technology, Wuhan Polytechnic University, Wuhan, China.
| | - Stefanie Sprunck
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany.
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China.
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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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Chen SY, Wang L, Jia PF, Yang WC, Sze H, Li HJ. Osmoregulation determines sperm cell geometry and integrity for double fertilization in flowering plants. MOLECULAR PLANT 2022; 15:1488-1496. [PMID: 35918896 DOI: 10.1016/j.molp.2022.07.013] [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: 02/24/2022] [Revised: 07/05/2022] [Accepted: 07/22/2022] [Indexed: 06/15/2023]
Abstract
Distinct from the motile flagellated sperm of animals and early land plants, the non-motile sperm cells of flowering plants are carried in the pollen grain to the female pistil. After pollination, a pair of sperm cells are delivered into the embryo sac by pollen tube growth and rupture. Unlike other walled plant cells with an equilibrium between internal turgor pressure and mechanical constraints of the cell walls, sperm cells wrapped inside the cytoplasm of a pollen vegetative cell have only thin and discontinuous cell walls. The sperm cells are uniquely ellipsoid in shape, although it is unclear how they maintain this shape within the pollen tubes and after release. In this study, we found that genetic disruption of three endomembrane-associated cation/H+ exchangers specifically causes sperm cells to become spheroidal in hydrated pollens of Arabidopsis. Moreover, the released mutant sperm cells are vulnerable and rupture before double fertilization, leading to failed seed set, which can be partially rescued by depletion of the sperm-expressed vacuolar water channel. These results suggest a critical role of cell-autonomous osmoregulation in adjusting the sperm cell shape for successful double fertilization in flowering plants.
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Affiliation(s)
- Shu-Yan Chen
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Lan Wang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Peng-Fei Jia
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Wei-Cai Yang
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Heven Sze
- Department of Cell Biology & Molecular Genetics, University of Maryland, College Park, MD 20742, USA
| | - Hong-Ju Li
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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Abstract
The isolation of male and female gametes is an effective method to study the fertilization mechanisms of higher plants. An osmotic shock method was used to rupture pollen grains of Allium tuberosum Roxb and release the pollen contents, including generative cells, which were mass collected. The pollinated styles were cut following 3 h of in vivo growth, and cultured in medium for 6-8 h, during which time pollen tubes grew out of the cut end of the style. After pollen tubes were transferred into a solution containing 6% mannitol, tubes burst and released pairs of sperm cells. Ovules of A. tuberosum were incubated in an enzyme solution for 30 min, and then dissected to remove the integuments. Following transfer to a dissecting solution free of enzymes, each nucellus was cut in the middle, and squeezed gently on the micropylar end, resulting in the liberation of the egg, zygote and proembryo from ovules at selected stages. These cells can be used to explore fertilization and embryonic development using molecular biological methods for each cell type and development stage.
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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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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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Márton ML, Dresselhaus T. A comparison of early molecular fertilization mechanisms in animals and flowering plants. ACTA ACUST UNITED AC 2008. [DOI: 10.1007/s00497-007-0062-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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Abstract
We derive an analytical model of the potential differences induced across plasma and internal organelle membranes in suspended cells exposed to oscillatory electric fields. Multiple shells are modeled using iterative applications of the single-shell calculation with mobile charges. This work is motivated, in part, by recent results suggesting the ability to use alternating current (ac) fields to noninvasively monitor enzyme activity within internal membranes, particularly the mitochondrial electron transport chain. Previous work, on induced transmembrane voltages in cells subjected to ac fields, has mainly been limited to oscillatory potentials across the plasma membrane. Here we first develop a three-membrane model, consisting of a plasma membrane surrounding inner and outer membranes representing an internal organelle, such as a mitochondrion. Frequency-dependent transmembrane potentials are modeled for spherical, weakly conducting membrane shells enclosing a conductive cytoplasm surrounding an idealized internal organelle. We then use a two-shell model to simulate induced ac membrane potentials of a suspended isolated mitochondrion in which the outer membrane is usually much more permeable than the inner membrane.
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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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In vitro fertilization as a tool for investigating sexual reproduction of angiosperms. ACTA ACUST UNITED AC 2006. [DOI: 10.1007/s00497-006-0029-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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