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Liu XQ, Shi JJ, Fan H, Jiao J, Gao L, Tan L, Nagawa S, Wang DY. Nuclear DNA replicates during zygote development in Arabidopsis and Torenia fournieri. PLANT PHYSIOLOGY 2021; 185:137-145. [PMID: 33631800 PMCID: PMC8133679 DOI: 10.1093/plphys/kiaa014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/23/2020] [Indexed: 06/02/2023]
Abstract
The progression of the cell cycle is continuous in most cells, but gametes (sperm and egg cells) exhibit an arrest of the cell cycle to await fertilization to form a zygote, which then continues through the subsequent phases to complete cell division. The phase in which gametes of flowering plants arrest has been a matter of debate, since different phases have been reported for the gametes of different species. In this study, we reassessed the phase of cell-cycle arrest in the gametes of two species, Arabidopsis (Arabidopsis thaliana) and Torenia fournieri. We first showed that 4', 6-diamidino-2-phenylindole staining was not feasible to detect changes in gametic nuclear DNA in T. fournieri. Next, using 5-ethynyl-2'-deoxyuridine (EdU) staining that detects DNA replication by labeling the EdU absorbed by deoxyribonucleic acid, we found that the replication of nuclear DNA did not occur during gamete development but during zygote development, revealing that the gametes of these species have a haploid nuclear DNA content before fertilization. We thus propose that gametes in the G1 phase participate in the fertilization event in Arabidopsis and T. fournieri.
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Affiliation(s)
- Xue-Qiong Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi’an 710069, China
| | - Jiao-Jiao Shi
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi’an 710069, China
| | - Hua Fan
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi’an 710069, China
| | - Jiao Jiao
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi’an 710069, China
| | - Long Gao
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi’an 710069, China
| | - Li Tan
- Plant Stress Center, CAS Center for Excellence in Molecular Plant Sciences, Shanghai 201602, China
| | - Shingo Nagawa
- Plant Stress Center, CAS Center for Excellence in Molecular Plant Sciences, Shanghai 201602, China
- FAFU-UCR Joint Center Horticulture, Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou 350002, 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 710069, China
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Bittencourt Júnior NS. Evidence for post-zygotic self-incompatibility in Handroanthus impetiginosus (Bignoniaceae). PLANT REPRODUCTION 2017; 30:69-79. [PMID: 28303339 DOI: 10.1007/s00497-017-0300-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 03/08/2017] [Indexed: 06/06/2023]
Abstract
Late-acting self-incompatibility (LSI) has been defined as a genetically controlled self-sterility mechanism that prevents seed set by selfing, despite normal pollen tube growth and ovule penetration in self-pollinated pistils. In species of the Bignoniaceae with LSI, such as Handroanthus impetiginosus, the selfed pistils are characterized by a marked delay in ovule penetration, fertilization, and endosperm initiation, followed by uniform pistil abscission. This highlights the contentious possibility of a post-zygotic self-incompatibility system. However, previous studies were unable to confirm fusion of the sperm and egg cell nuclei in selfed ovules. In the present study, the cytology of the embryo sac, double fertilization, and pistil longevity was investigated in H. impetiginosus using comparative nuclei microspectrofluorometry of DAPI-stained sections of self- vs. unpollinated pistils. Differences in both pistil longevity and ovary size between self- and unpollinated flowers at the time of pistil abscission were significant. Zygotes with double the DNA content in their nuclei relative to unfertilized egg cell nuclei were verified in selfed ovules from the first day after pollination onward, and G1 karyogamy appeared to have occurred. Our cytological analysis clearly indicates that ovules of self-pollinated pistils in H. impetiginosus are fertilized before pistil abscission but no embryogenesis initiation occurs, which strongly supports the idea of a post-zygotic self-incompatibility mechanism.
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Affiliation(s)
- Nelson Sabino Bittencourt Júnior
- Departamento de Zoologia e Botânica, Instituto de Biociências Letras e Ciências Exatas, Universidade Estadual Paulista "Júlio de Mesquita Filho", Rua Cristóvão Colombo 2265, Jardim Nazareth, CEP 15054-000, São José do Rio Preto, São Paulo, Brazil.
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3
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Relationship between double fertilization and the cell cycle in male and female gametes of tobacco. ACTA ACUST UNITED AC 2004. [DOI: 10.1007/s00497-004-0233-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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RASCH E, WOODARD JW. Basic proteins of plant nuclei during normal and pathological cell growth. J Biophys Biochem Cytol 1998; 6:263-76. [PMID: 14436319 PMCID: PMC2229794 DOI: 10.1083/jcb.6.2.263] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Histone proteins were studied by microphotometry of plant tissue sections stained with fast green at pH 8.1. For comparative purposes the Feulgen reaction was used for deoxyribose nuclei acid (DNA); the Sakaguchi reaction for arginine; and the Millon reaction for estimates of total protein. Analysis of Tradescantia tissues indicated that amounts of nuclear histone fell into approximate multiples of the gametic (egg or sperm) quantity except in dividing tissues, where amounts intermediate between multiples were found. In differentiated tissues of lily, corn, onion, and broad bean, histones occurred in constant amounts per nucleus, characteristic of the species, as was found also for DNA. Unlike the condition in several animal species, the basic proteins of sperm nuclei in these higher plants were of the histone type; no evidence of protamine was found. In a plant neoplasm, crown gall of broad bean, behavior of the basic nuclear proteins closely paralleled that of DNA. Thus, alterations of DNA levels in tumor tissues were accompanied by quantitatively similar changes in histone levels to maintain the same Feulgen/fast green ratios found in homologous normal tissues.
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Interaction of nucleus and cytoplasm during oogenesis in
Pteridium aquilinum
(L.) Kuhn. ACTA ACUST UNITED AC 1997. [DOI: 10.1098/rspb.1961.0010] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
By means of auto-radiography, the synthesis of deoxyribonucleic acid has been followed throughout oogenesis in
Pteridium aquilinum
, the deoxyribonucleic acid having first been made radioactive by feeding the gametophyte with tritiated thymidine. It has been found that in the mature egg the deoxyribonucleic acid is dispersed throughout the whole cell. The failure of the nucleus of the mature egg to stain with the Feulgen reagent at this stage is believed to be a consequence of this dispersal of the deoxyribonucleic acid. Quantitative comparisons have been made of the amounts of radioactivity in the egg and in various nuclei of the archegonium which were expected on developmental grounds to contain the same amount of labelled deoxyribonucleic acid. Evidence is presented that the egg contains twice as much deoxyribonucleic acid as the non-gametic nuclei, and it is suggested that its chromosomes have entered the prophase condition.
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Carmichael JS, Friedman WE. Double Fertilization in Gnetum gnemon: The Relationship between the Cell Cycle and Sexual Reproduction. THE PLANT CELL 1995; 7:1975-1988. [PMID: 12242365 PMCID: PMC161055 DOI: 10.1105/tpc.7.12.1975] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Gnetum gnemon, a nonflowering seed plant and member of the Gnetales, expresses a rudimentary pattern of double fertilization that results in the formation of two zygotes per pollen tube. The process of double fertilization in G. gnemon was examined with light and fluorescence microscopy, and the DNA content of various nuclei involved in sexual reproduction was quantified with 4[prime],6-diamidino-2-phenylindole microspectrofluorometry.Male and female gamete nuclei pass through the synthesis phase of the cell cycle and increase their DNA content from 1C to 2C before fertilization. Each of the two zygotes found in association with a pollen tube is diploid and contains the 4C quantity of DNA at inception. Based on these results as well as previous studies of nuclear DNA content in plant sperm, eggs, and zygotes, three fundamental and distinct patterns of gamete karyogamy among seed plants can be circumscribed: (1) G1 karyogamy, in which male and female gametes contain the 1C quantity of DNA throughout karyogamy and the zygote undergoes DNA replication; (2) S-phase karyogamy, in which gamete nuclei initiate fusion at 1C but pass through the S phase of the cell cycle before completely fusing; and (3) G2 karyogamy, in which male and female gamete nuclei pass through the S phase of the cell cycle before the onset of fertilization. Our results show definitively a pattern of G2 karyogamy in G. gnemon.
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Affiliation(s)
- J. S. Carmichael
- Department of Biology, University of North Dakota, Grand Forks, North Dakota 58202
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Mogensen HL, Holm PB. Dynamics of Nuclear DNA Quantities during Zygote Development in Barley. THE PLANT CELL 1995; 7:487-494. [PMID: 12242375 PMCID: PMC160798 DOI: 10.1105/tpc.7.4.487] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Quantities of DNA were estimated in the nuclei of mechanically isolated egg and zygote protoplasts in two cultivars of barley using 4[prime],6-diamidino-2-phenylindole staining and microfluorometry. Unlike many previous studies on DNA amounts within the sex cells of flowering plants, we obtained consistent and unambiguous results indicating that the egg and sperm nuclei are at the 1C DNA level (basic haploid amount) at the time of karyogamy. Karyogamy was initiated within 60 min postpollination, and the male chromatin became completely integrated into the egg nucleus within 6 to 7 hr postpollination (hpp). Zygotic nuclear DNA levels began to increase at ~9 to 12 hpp in cultivar Alexis and at 12 to 15 hpp in cultivar Igri. The 4C DNA complement was reached in most zygotes by 22 to 26 hpp in cultivar Alexis and by 23 to 29 hpp in cultivar Igri. These data are fundamental to a better understanding of fertilization and zygote maturation in flowering plants. They are also relevant to studies in which the timing of zygotic DNA replication is of interest, such as ongoing investigations on genetic transformations in barley using the microinjection technique.
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Affiliation(s)
- H. L. Mogensen
- Department of Biological Science, Box 5640, Northern Arizona University, Flagstaff, Arizona 86011
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Faure JE, Mogensen HL, Dumas C, Lorz H, Kranz E. Karyogamy after Electrofusion of Single Egg and Sperm Cell Protoplasts from Maize: Cytological Evidence and Time Course. THE PLANT CELL 1993; 5:747-755. [PMID: 12271085 PMCID: PMC160313 DOI: 10.1105/tpc.5.7.747] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
In maize, in vitro fusion of isolated male gametes with isolated egg cell protoplasts can be induced by electric pulses. Until now, karyogamy has not been demonstrated. In this study, we cytologically examined fusion products fixed at different times after electrofusion with phase contrast microscopy and transmission electron microscopy. We obtained a precise timetable from 23 samples studied during the first 3 hr. The sperm nucleus was integrated within the egg cell protoplast, migrated toward the egg cell nucleus, and fused with it within 1 hr, as demonstrated by ultrastructural observations, three-dimensional reconstructions of nuclei, and subsequent nuclear volume estimates. Fusion of nuclei occurred before zygotic mitosis, as is the case in vivo. These findings demonstrate karyogamy during in vitro fertilization of maize.
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Affiliation(s)
- J. E. Faure
- Reconnaissance Cellulaire et Amelioration des Plantes, UMR 9938 CNRS-INRA, Ecole Normale Superieure de Lyon, 69364 Lyon Cedex 07, France
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Kowyama Y. Cell-cycle dependency of radiosensitivity and mutagenesis in fertilized egg cells of rice, Oryza sativa L. : 1. Autoradiographic determination of the first DNA synthetic phase. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 1983; 65:303-308. [PMID: 24263540 DOI: 10.1007/bf00276569] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/1982] [Indexed: 06/02/2023]
Abstract
To determine the time and duration of the first and second DNA synthetic phases in fertilized egg cells and central cells of rice, a total of 753 ovules were sampled at 2 h intervals during the first 30 h after pollination and exposed to (3)H-thymidine for 2 h at 25 °C. Autoradiographic observation of labeled nuclei was made for fertilized egg cells, as well as for central and antipodal cells. The first and second DNA synthetic phases in fertilized egg cells were found 8-12 h and 21-25 h after pollination, respectively. The durations of each cell-cycle phase in the egg cell were estimated to be 4-6 h for G1, 4 h vor S and for G2, and 2 h for M. In the central cell, the first DNA synthesis took place at 3-4 h after pollination, i.e., immediately after fertilization, followed by the formation of the primary endosperm nucleus. Antipodal cells also showed labeled nuclei in the early stages after fertilization. The first divisions of fertilized egg cell and primary endosperm nucleus were observed at 16-18h and at 4-6 h after pollination, respectively. The present observations suggest that sperm and egg nuclei participate in fertilization with haploid amount (1C) of DNA and fertilized egg cell originates thus in 2C state.
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Affiliation(s)
- Y Kowyama
- Plant Breeding Laboratory, Faculty of Agriculture, Mie University, 514, Tsu, Japan
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10
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Radiation-induced chromosomal aberrations in the plant Tradescantia: Dose-response curves I. Preliminary considerations. ACTA ACUST UNITED AC 1975. [DOI: 10.1016/s0033-7560(75)80001-9] [Citation(s) in RCA: 58] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Pipkin J, Larson D. Changing patterns of nucleic acids, basic and acidic proteins in generative and vegetative nuclei during pollen germination and pollen tube growth in Hippeastrum belladonna. Exp Cell Res 1973. [DOI: 10.1016/0014-4827(73)90486-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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12
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Scheuermann W, Klaffke-Lobsien G. On the infleunce of 5-amino uracil on the cell cycle of root tip meristems. Exp Cell Res 1973; 76:428-36. [PMID: 4685356 DOI: 10.1016/0014-4827(73)90395-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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13
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Pipkin JL, Larson DA. Characterization of the "very" lysine-rich histones of active and quiescent anther tissues of Hippeastrum belladonna. Exp Cell Res 1972; 71:249-60. [PMID: 4114671 DOI: 10.1016/0014-4827(72)90290-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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14
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Woodcock CL, Bell PR. The distribution of deoxyribonucleic acid in the female gametophyte of Myosurus minimus. HISTOCHEMIE. HISTOCHEMISTRY. HISTOCHIMIE 1968; 12:289-301. [PMID: 4173187 DOI: 10.1007/bf00278301] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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15
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