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Cheng T, Liu Z, Li H, Huang X, Wang W, Shi C, Zhang X, Chen H, Yao Z, Zhao P, Peng X, Sun MX. Sperm-origin paternal effects on root stem cell niche differentiation. Nature 2024:10.1038/s41586-024-07885-0. [PMID: 39198649 DOI: 10.1038/s41586-024-07885-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 07/30/2024] [Indexed: 09/01/2024]
Abstract
Fertilization introduces parental genetic information into the zygote to guide embryogenesis. Parental contributions to postfertilization development have been discussed for decades, and the data available show that both parents contribute to the zygotic transcriptome, suggesting a paternal role in early embryogenesis1-6. However, because the specific paternal effects on postfertilization development and the molecular pathways underpinning these effects remain poorly understood, paternal contribution to early embryogenesis and plant development has not yet been adequately demonstrated7. Here our research shows that TREE1 and its homologue DAZ3 are expressed exclusively in Arabidopsis sperm. Despite presenting no evident defects in sperm development and fertilization, tree1 daz3 unexpectedly led to aberrant differentiation of the embryo root stem cell niche. This defect persisted in seedlings and disrupted root tip regeneration, comparable to congenital defects in animals. TREE1 and DAZ3 function by suppression of maternal RKD2 transcription, thus mitigating the detrimental maternal effects from RKD2 on root stem cell niche. Therefore, our findings illuminate how genetic deficiencies in sperm can exert enduring paternal effects on specific plant organ differentiation and how parental-of-origin genes interact to ensure normal embryogenesis. This work also provides a new concept of how gamete quality or genetic deficiency can affect specific plant organ formation.
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Affiliation(s)
- Tianhe Cheng
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhenzhen Liu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Haiming Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiaorong Huang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Wei Wang
- 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
| | - Xuecheng Zhang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Hong Chen
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhuang Yao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiongbo Peng
- 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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2
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Hisanaga T, Fujimoto S, Cui Y, Sato K, Sano R, Yamaoka S, Kohchi T, Berger F, Nakajima K. Deep evolutionary origin of gamete-directed zygote activation by KNOX/BELL transcription factors in green plants. eLife 2021; 10:57090. [PMID: 34579806 PMCID: PMC8478417 DOI: 10.7554/elife.57090] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 09/02/2021] [Indexed: 02/03/2023] Open
Abstract
KNOX and BELL transcription factors regulate distinct steps of diploid development in plants. In the green alga Chlamydomonas reinhardtii, KNOX and BELL proteins are inherited by gametes of the opposite mating types and heterodimerize in zygotes to activate diploid development. By contrast, in land plants such as Physcomitrium patens and Arabidopsis thaliana, KNOX and BELL proteins function in sporophyte and spore formation, meristem maintenance and organogenesis during the later stages of diploid development. However, whether the contrasting functions of KNOX and BELL were acquired independently in algae and land plants is currently unknown. Here, we show that in the basal land plant species Marchantia polymorpha, gamete-expressed KNOX and BELL are required to initiate zygotic development by promoting nuclear fusion in a manner strikingly similar to that in C. reinhardtii. Our results indicate that zygote activation is the ancestral role of KNOX/BELL transcription factors, which shifted toward meristem maintenance as land plants evolved.
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Affiliation(s)
- Tetsuya Hisanaga
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara, Japan.,Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter, Vienna, Austria
| | - Shota Fujimoto
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara, Japan
| | - Yihui Cui
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara, Japan
| | - Katsutoshi Sato
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara, Japan
| | - Ryosuke Sano
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara, Japan
| | - Shohei Yamaoka
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Takayuki Kohchi
- Graduate School of Biostudies, Kyoto University, Kyoto, Japan
| | - Frédéric Berger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter, Vienna, Austria
| | - Keiji Nakajima
- Graduate School of Science and Technology, Nara Institute of Science and Technology, Nara, Japan
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In Response to Abiotic Stress, DNA Methylation Confers EpiGenetic Changes in Plants. PLANTS 2021; 10:plants10061096. [PMID: 34070712 PMCID: PMC8227271 DOI: 10.3390/plants10061096] [Citation(s) in RCA: 38] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 02/07/2023]
Abstract
Epigenetics involves the heritable changes in patterns of gene expression determined by developmental and abiotic stresses, i.e., drought, cold, salinity, trace metals, and heat. Gene expression is driven by changes in DNA bases, histone proteins, the biogenesis of ncRNA, and changes in the nucleotide sequence. To cope with abiotic stresses, plants adopt certain changes driven by a sophisticated biological system. DNA methylation is a primary mechanism for epigenetic variation, which can induce phenotypic alterations in plants under stress. Some of the stress-driven changes in plants are temporary, while some modifications may be stable and inheritable to the next generations to allow them to cope with such extreme stress challenges in the future. In this review, we discuss the pivotal role of epigenetically developed phenotypic characteristics in plants as an evolutionary process participating in adaptation and tolerance responses to abiotic and biotic stresses that alter their growth and development. We emphasize the molecular process underlying changes in DNA methylation, differential variation for different species, the roles of non-coding RNAs in epigenetic modification, techniques for studying DNA methylation, and its role in crop improvement in tolerance to abiotic stress (drought, salinity, and heat). We summarize DNA methylation as a significant future research priority for tailoring crops according to various challenging environmental issues.
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Deushi R, Toda E, Koshimizu S, Yano K, Okamoto T. Effect of Paternal Genome Excess on the Developmental and Gene Expression Profiles of Polyspermic Zygotes in Rice. PLANTS (BASEL, SWITZERLAND) 2021; 10:255. [PMID: 33525652 PMCID: PMC7911625 DOI: 10.3390/plants10020255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/22/2021] [Accepted: 01/26/2021] [Indexed: 11/17/2022]
Abstract
Polyploid zygotes with a paternal gamete/genome excess exhibit arrested development, whereas polyploid zygotes with a maternal excess develop normally. These observations indicate that paternal and maternal genomes synergistically influence zygote development via distinct functions. In this study, to clarify how paternal genome excess affects zygotic development, the developmental and gene expression profiles of polyspermic rice zygotes were analyzed. The results indicated that polyspermic zygotes were mostly arrested at the one-cell stage after karyogamy had completed. Through comparison of transcriptomes between polyspermic zygotes and diploid zygotes, 36 and 43 genes with up-regulated and down-regulated expression levels, respectively, were identified in the polyspermic zygotes relative to the corresponding expression in the diploid zygotes. Notably, OsASGR-BBML1, which encodes an AP2 transcription factor possibly involved in initiating rice zygote development, was expressed at a much lower level in the polyspermic zygotes than in the diploid zygotes.
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Affiliation(s)
- Ryouya Deushi
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0392, Japan; (R.D.); (E.T.)
| | - Erika Toda
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0392, Japan; (R.D.); (E.T.)
| | - Shizuka Koshimizu
- Department of Life Sciences, Meiji University, Kanagawa 214-8571, Japan; (S.K.); (K.Y.)
| | - Kentaro Yano
- Department of Life Sciences, Meiji University, Kanagawa 214-8571, Japan; (S.K.); (K.Y.)
| | - Takashi Okamoto
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0392, Japan; (R.D.); (E.T.)
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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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Chen H, Li S, Li L, Hu H, Zhao J. Arabidopsis EMB1990 Encoding a Plastid-Targeted YlmG Protein Is Required for Chloroplast Biogenesis and Embryo Development. FRONTIERS IN PLANT SCIENCE 2018; 9:181. [PMID: 29503657 PMCID: PMC5820536 DOI: 10.3389/fpls.2018.00181] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 01/31/2018] [Indexed: 05/24/2023]
Abstract
In higher plants, embryo development originated from fertilized egg cell is the first step of the life cycle. The chloroplast participates in many essential metabolic pathways, and its function is highly associated with embryo development. However, the mechanisms and relevant genetic components by which the chloroplast functions in embryogenesis are largely uncharacterized. In this paper, we describe the Arabidopsis EMB1990 gene, encoding a plastid-targeted YlmG protein which is required for chloroplast biogenesis and embryo development. Loss of the EMB1990/YLMG1-1 resulted in albino seeds containing abortive embryos, and the morphological development of homozygous emb1990 embryos was disrupted after the globular stage. Our results showed that EMB1990/YLMG1-1 was expressed in the primordia and adaxial region of cotyledon during embryogenesis, and the encoded protein was targeted to the chloroplast. TEM observation of cellular ultrastructure showed that chloroplast biogenesis was impaired in emb1990 embryo cells. Expression of certain plastid genes was also affected in the loss-of-function mutants, including genes encoding core protein complex subunits located in the thylakoid membrane. Moreover, the tissue-specific genes of embryo development were misexpressed in emb1990 mutant, including genes known to delineate cell fate decisions in the SAM (shoot apical meristem), cotyledon and hypophysis. Taken together, we propose that the nuclear-encoded YLMG1-1 is targeted to the chloroplast and required for normal plastid gene expression. Hence, YLMG1-1 plays a critical role in Arabidopsis embryogenesis through participating in chloroplast biogenesis.
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Zhao P, Begcy K, Dresselhaus T, Sun MX. Does Early Embryogenesis in Eudicots and Monocots Involve the Same Mechanism and Molecular Players? PLANT PHYSIOLOGY 2017; 173:130-142. [PMID: 27909044 PMCID: PMC5210740 DOI: 10.1104/pp.16.01406] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2016] [Accepted: 11/30/2016] [Indexed: 05/18/2023]
Abstract
A comparison of eudicot and monocot model plants explores recent advances and open questions on gene regulatory networks during zygote development, parental influences on early embryogenesis, zygotic genome activation, and cell fate determination.
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Affiliation(s)
- Peng Zhao
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China (P.Z., M.-X.S.); and
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany (K.B., T.D.)
| | - Kevin Begcy
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China (P.Z., M.-X.S.); and
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany (K.B., T.D.)
| | - Thomas Dresselhaus
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China (P.Z., M.-X.S.); and
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany (K.B., T.D.)
| | - Meng-Xiang Sun
- College of Life Sciences, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China (P.Z., M.-X.S.); and
- Cell Biology and Plant Biochemistry, Biochemie-Zentrum Regensburg, University of Regensburg, 93053 Regensburg, Germany (K.B., T.D.)
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Abstract
Flowering plants, like placental mammals, have an extensive maternal contribution toward progeny development. Plants are distinguished from animals by a genetically active haploid phase of growth and development between meiosis and fertilization, called the gametophyte. Flowering plants are further distinguished by the process of double fertilization that produces sister progeny, the endosperm and the embryo, of the seed. Because of this, there is substantial gene expression in the female gametophyte that contributes to the regulation of growth and development of the seed. A primary function of the endosperm is to provide growth support to its sister embryo. Several mutations in Zea mays subsp. mays have been identified that affect the contribution of the mother gametophyte to the seed. The majority affect both the endosperm and the embryo, although some embryo-specific effects have been observed. Many alter the pattern of expression of a marker for the basal endosperm transfer layer, a tissue that transports nutrients from the mother plant to the developing seed. Many of them cause abnormal development of the female gametophyte prior to fertilization, revealing potential cellular mechanisms of maternal control of seed development. These effects include reduced central cell size, abnormal architecture of the central cell, abnormal numbers and morphology of the antipodal cells, and abnormal egg cell morphology. These mutants provide insight into the logic of seed development, including necessary features of the gametes and supporting cells prior to fertilization, and set up future studies on the mechanisms regulating maternal contributions to the seed.
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Luo A, Zhao P, Zhang LY, Sun MX. Initiation of programmed cell death in the suspensor is predominantly regulated maternally in a tobacco hybrid. Sci Rep 2016; 6:29467. [PMID: 27432530 PMCID: PMC4949469 DOI: 10.1038/srep29467] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Accepted: 06/20/2016] [Indexed: 11/16/2022] Open
Abstract
Maternal gene products deposited in the egg regulate early embryogenesis before activation of the embryonic genome in animals. While in higher plants, it is believed that genes of parental origin contribute to early embryogenesis. However, little is known regarding the particular processes in which genes of parental origin are involved during early embryogenesis. Previously, we found that the initiation of programmed cell death (PCD) in the suspensor of the embryo is regulated by the cystatin, NtCYS. Here, we confirmed that both parental transcripts contribute to PCD, but the relative expression level of the maternal NtCYS allele was much higher than that of the paternal allele in early embryos of tobacco interspecific hybrids. The expression level of the maternal NtCYS allele was decreased markedly, which was necessary for the initiation of PCD, while the paternal allele didn't change. Interestingly, the pattern of PCD in the hybrid suspensor and the morphology of the hybrid suspensor were similar to those of the maternal parent. Our results suggest that NtCYS-mediated PCD initiation in the hybrid suspensor is likely controlled in a maternal dominant manner. This finding represents an example of the involvement of parental transcripts in a specific developmental event during early embryogenesis.
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Affiliation(s)
- An Luo
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
- College of Life Science, Yangtze University, Jingzhou, 434023, China
| | - Peng Zhao
- College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan 430072, China
| | - Li-Yao Zhang
- 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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Rensing SA. (Why) Does Evolution Favour Embryogenesis? TRENDS IN PLANT SCIENCE 2016; 21:562-573. [PMID: 26987708 DOI: 10.1016/j.tplants.2016.02.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 02/14/2016] [Accepted: 02/19/2016] [Indexed: 05/05/2023]
Abstract
Complex multicellular organisms typically possess life cycles in which zygotes (formed by gamete fusion) and meiosis occur. Canonical animal embryogenesis describes development from zygote to birth. It involves polarisation of the egg/zygote, asymmetric cell divisions, establishment of axes, symmetry breaking, formation of organs, and parental nutrition (at least in early stages). Similar developmental patterns have independently evolved in other eukaryotic lineages, including land plants and brown algae. The question arises whether embryo-like structures and associated developmental processes recurrently emerge because they are local optima of the evolutionary landscape. To understand which evolutionary principles govern complex multicellularity, we need to analyse why and how similar processes evolve convergently - von Baer's and Haeckel's phylotypic stage revisited in other phyla.
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Affiliation(s)
- Stefan A Rensing
- Plant Cell Biology, Faculty of Biology, University of Marburg, Karl-von-Frisch-Str. 8, D-35043 Marburg, Germany; BIOSS Centre for Biological Signalling Studies, University of Freiburg, Freiburg, Germany.
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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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12
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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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