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Bente H, Köhler C. Molecular basis and evolutionary drivers of endosperm-based hybridization barriers. PLANT PHYSIOLOGY 2024; 195:155-169. [PMID: 38298124 PMCID: PMC11060687 DOI: 10.1093/plphys/kiae050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 01/05/2024] [Accepted: 01/06/2024] [Indexed: 02/02/2024]
Abstract
The endosperm, a transient seed tissue, plays a pivotal role in supporting embryo growth and germination. This unique feature sets flowering plants apart from gymnosperms, marking an evolutionary innovation in the world of seed-bearing plants. Nevertheless, the importance of the endosperm extends beyond its role in providing nutrients to the developing embryo by acting as a versatile protector, preventing hybridization events between distinct species and between individuals with different ploidy. This phenomenon centers on growth and differentiation of the endosperm and the speed at which both processes unfold. Emerging studies underscore the important role played by type I MADS-box transcription factors, including the paternally expressed gene PHERES1. These factors, along with downstream signaling pathways involving auxin and abscisic acid, are instrumental in regulating endosperm development and, consequently, the establishment of hybridization barriers. Moreover, mutations in various epigenetic regulators mitigate these barriers, unveiling a complex interplay of pathways involved in their formation. In this review, we discuss the molecular underpinnings of endosperm-based hybridization barriers and their evolutionary drivers.
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Affiliation(s)
- Heinrich Bente
- Department of Plant Reproductive Biology and Epigenetics, Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Claudia Köhler
- Department of Plant Reproductive Biology and Epigenetics, Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala 75007, Sweden
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2
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Yang G, Feng M, Yu K, Cui G, Zhou Y, Sun L, Gao L, Zhang Y, Peng H, Yao Y, Hu Z, Rossi V, De Smet I, Ni Z, Sun Q, Xin M. Paternally imprinted LATE-FLOWERING2 transcription factor contributes to paternal-excess interploidy hybridization barriers in wheat. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2023; 65:2587-2603. [PMID: 37846823 DOI: 10.1111/jipb.13574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 10/16/2023] [Indexed: 10/18/2023]
Abstract
Interploidy hybridization between hexaploid and tetraploid genotypes occurred repeatedly during genomic introgression events throughout wheat evolution, and is commonly employed in wheat breeding programs. Hexaploid wheat usually serves as maternal parent because the reciprocal cross generates progeny with severe defects and poor seed germination, but the underlying mechanism is poorly understood. Here, we performed detailed analysis of phenotypic variation in endosperm between two interploidy reciprocal crosses arising from tetraploid (Triticum durum, AABB) and hexaploid wheat (Triticum aestivum, AABBDD). In the paternal- versus the maternal-excess cross, the timing of endosperm cellularization was delayed and starch granule accumulation in the endosperm was repressed, causing reduced germination percentage. The expression profiles of genes involved in nutrient metabolism differed strongly between these endosperm types. Furthermore, expression patterns of parental alleles were dramatically disturbed in interploidy versus intraploidy crosses, leading to increased number of imprinted genes. The endosperm-specific TaLFL2 showed a paternally imprinted expression pattern in interploidy crosses partially due to allele-specific DNA methylation. Paternal TaLFL2 binds to and represses a nutrient accumulation regulator TaNAC019, leading to reduced storage protein and starch accumulation during endosperm development in paternal-excess cross, as confirmed by interploidy crosses between tetraploid wild-type and clustered regularly interspaced palindromic repeats (CRISPR) - CRISPR-associated protein 9 generated hexaploid mutants. These findings reveal a contribution of genomic imprinting to paternal-excess interploidy hybridization barriers during wheat evolution history and explains why experienced breeders preferentially exploit maternal-excess interploidy crosses in wheat breeding programs.
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Affiliation(s)
- Guanghui Yang
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Man Feng
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Kuohai Yu
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Guangxian Cui
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Yan Zhou
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Lv Sun
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Lulu Gao
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Yumei Zhang
- Qingdao Agricultural University, Qingdao, 266109, China
| | - Huiru Peng
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Yingyin Yao
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Zhaorong Hu
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Vincenzo Rossi
- Council for Agricultural Research and Economics, Research Centre for Cereal and Industrial Crops, Bergamo, 24126, Italy
| | - Ive De Smet
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, B-9052, Belgium
- VIB Center for Plant Systems Biology, Ghent, B-9052, Belgium
| | - Zhongfu Ni
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Qixin Sun
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Mingming Xin
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
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3
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Dong J, Tu W, Wang H, Zuo Y, Liu T, Zhao Q, Ying J, Wu J, Liu Y, Cai X, Song B. Genome sequence analysis provides insights into the mode of 2n egg formation in Solanum malmeanum. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2023; 136:157. [PMID: 37340281 DOI: 10.1007/s00122-023-04406-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 06/13/2023] [Indexed: 06/22/2023]
Abstract
KEY MESSAGE Our genomic investigation confirms the mechanism of 2n eggs formation in S. malmeanum and aid in optimizing the use of wild germplasm. Wild potatoes are a valuable source of agronomic traits. However, substantial reproductive barriers limit gene flow into cultivated species. 2n gametes are instrumental in preventing endosperm abortion caused by genetic imbalances in the endosperm. However, little is known about the molecular mechanisms underlying the formation of 2n gametes. Here, the wild species Solanum malmeanum Bitter (2x, 1EBN, endosperm balance number) was used in inter- and intrapoloid crosses with other Solanum species, with viable seeds being produced only when S. malmeanum was used as the female parent to cross the 2EBN Solanum genus and with the likely involvement of 2n gametes. Subsequently, we substantiated the formation of 2n eggs in S. malmeanum using fluorescence in situ hybridization (FISH) and genomic sequencing technology. Additionally, the transmission rate of maternal heterozygous polymorphism sites was assessed from a genomic perspective to analyze the mode of 2n egg formation in S. malmeanum × S. tuberosum and S. malmeanum × S. chacoense crosses; each cross acquired an average of 31.12% and 22.79% maternal sites, respectively. This confirmed that 2n egg formation in S. malmeanum attributed to second-division restitution (SDR) coupled with the occurrence of exchange events. The high-throughput sequencing technology used in this study has strong advantages over traditional cytological analyses. Furthermore, S. malmeanum, which has a variety of excellent traits not available from present cultivated potato genepool, has received little research attention and has successfully achieved gene flow in cultivated species in the current study. These findings will facilitate the understanding and optimization of wild germplasm utilization in potatoes.
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Affiliation(s)
- Jianke Dong
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Wei Tu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
- College of Biology and Agricultural Resources, Huanggang Normal University, Huanggang, 438000, China
| | - Haibo Wang
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
- College of Biological and Food Engineering, Hubei Minzu University, Enshi, 445000, China
| | - Yingtao Zuo
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Tengfei Liu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Qinghao Zhao
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jingwen Ying
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jianghai Wu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yuanyuan Liu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xingkui Cai
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Botao Song
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China.
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Bellucci M, Caceres ME, Paolocci F, Vega JM, Ortiz JPA, Ceccarelli M, De Marchis F, Pupilli F. ORIGIN OF RECOGNITION COMPLEX 3 controls the development of maternal excess endosperm in the Paspalum simplex agamic complex (Poaceae). JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:3074-3093. [PMID: 36812152 DOI: 10.1093/jxb/erad069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/21/2023] [Indexed: 05/21/2023]
Abstract
Pseudogamous apomixis in Paspalum simplex generates seeds with embryos genetically identical to the mother plant and endosperms deviating from the canonical 2(maternal):1(paternal) parental genome contribution into a maternal excess 4m:1p genome ratio. In P. simplex, the gene homologous to that coding for subunit 3 of the ORIGIN OF RECOGNITION COMPLEX (PsORC3) exists in three isogenic forms: PsORC3a is apomixis specific and constitutively expressed in developing endosperm whereas PsORCb and PsORCc are up-regulated in sexual endosperms and silenced in apomictic ones. This raises the question of how the different arrangement and expression profiles of these three ORC3 isogenes are linked to seed development in interploidy crosses generating maternal excess endosperms. We demonstrate that down-regulation of PsORC3b in sexual tetraploid plants is sufficient to restore seed fertility in interploidy 4n×2n crosses and, in turn, its expression level at the transition from proliferating to endoreduplication endosperm developmental stages dictates the fate of these seeds. Furthermore, we show that only when being maternally inherited can PsORC3c up-regulate PsORC3b. Our findings lay the basis for an innovative route-based on ORC3 manipulation-to introgress the apomictic trait into sexual crops and overcome the fertilization barriers in interploidy crosses.
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Affiliation(s)
- Michele Bellucci
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
| | - Maria Eugenia Caceres
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
| | - Francesco Paolocci
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
| | - Juan Manuel Vega
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET-UNR and Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | - Juan Pablo Amelio Ortiz
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET-UNR and Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | - Marilena Ceccarelli
- Department of Chemistry, Biology and Biotechnology, University of Perugia, 06123, Perugia, Italy
| | - Francesca De Marchis
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
| | - Fulvio Pupilli
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
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5
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Paczesniak D, Pellino M, Goertzen R, Guenter D, Jahnke S, Fischbach A, Lovell JT, Sharbel TF. Seed size, endosperm and germination variation in sexual and apomictic Boechera. FRONTIERS IN PLANT SCIENCE 2022; 13:991531. [PMID: 36466233 PMCID: PMC9716183 DOI: 10.3389/fpls.2022.991531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/26/2022] [Indexed: 06/17/2023]
Abstract
Asexual reproduction results in offspring that are genetically identical to the mother. Among apomictic plants (reproducing asexually through seeds) many require paternal genetic contribution for proper endosperm development (pseudogamous endosperm). We examined phenotypic diversity in seed traits using a diverse panel of sexual and apomictic accessions from the genus Boechera. While genetic uniformity resulting from asexual reproduction is expected to reduce phenotypic diversity in seeds produced by apomictic individuals, pseudogamous endosperm, variable endosperm ploidy, and the deviations from 2:1 maternal:paternal genome ratio in endosperm can all contribute to increased phenotypic diversity among apomictic offspring. We characterized seed size variation in 64 diploid sexual and apomictic (diploid and triploid) Boechera lineages. In order to find out whether individual seed size was related to endosperm ploidy we performed individual seed measurements (projected area and mass) using the phenoSeeder robot system and flow cytometric seed screen. In order to test whether individual seed size had an effect on resulting fitness we performed a controlled growth experiment and recorded seedling life history traits (germination success, germination timing, and root growth rate). Seeds with triploid embryos were 33% larger than those with diploid embryos, but no average size difference was found between sexual and apomictic groups. We identified a maternal effect whereby chloroplast lineage 2 had 30% larger seeds than lineage 3, despite having broad and mostly overlapping geographic ranges. Apomictic seeds were not more uniform in size than sexual seeds, despite genetic uniformity of the maternal gametophyte in the former. Among specific embryo/endosperm ploidy combinations, seeds with tetraploid (automomous) endosperm were on average smaller, and the proportion of such seeds was highest in apomicts. Larger seeds germinated more quickly than small seeds, and lead to higher rates of root growth in young seedlings. Seed mass is under balancing selection in Boechera, and it is an important predictor of several traits, including germination probability and timing, root growth rates, and developmental abnormalities in apomictic accessions.
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Affiliation(s)
- Dorota Paczesniak
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Marco Pellino
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Richard Goertzen
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
| | - Devan Guenter
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
| | - Siegfried Jahnke
- Forschungszentrum Jülich, Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Jülich, Germany
| | - Andreas Fischbach
- Forschungszentrum Jülich, Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Jülich, Germany
| | - John T. Lovell
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Timothy F. Sharbel
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
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6
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Kinser TJ, Smith RD, Lawrence AH, Cooley AM, Vallejo-Marín M, Conradi Smith GD, Puzey JR. Endosperm-based incompatibilities in hybrid monkeyflowers. THE PLANT CELL 2021; 33:2235-2257. [PMID: 33895820 PMCID: PMC8364248 DOI: 10.1093/plcell/koab117] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 04/15/2021] [Indexed: 05/31/2023]
Abstract
Endosperm is an angiosperm innovation central to their reproduction whose development, and thus seed viability, is controlled by genomic imprinting, where expression from certain genes is parent-specific. Unsuccessful imprinting has been linked to failed inter-specific and inter-ploidy hybridization. Despite their importance in plant speciation, the underlying mechanisms behind these endosperm-based barriers remain poorly understood. Here, we describe one such barrier between diploid Mimulus guttatus and tetraploid Mimulus luteus. The two parents differ in endosperm DNA methylation, expression dynamics, and imprinted genes. Hybrid seeds suffer from underdeveloped endosperm, reducing viability, or arrested endosperm and seed abortion when M. guttatus or M. luteus is seed parent, respectively, and transgressive methylation and expression patterns emerge. The two inherited M. luteus subgenomes, genetically distinct but epigenetically similar, are expressionally dominant over the M. guttatus genome in hybrid embryos and especially their endosperm, where paternal imprints are perturbed. In aborted seeds, de novo methylation is inhibited, potentially owing to incompatible paternal instructions of imbalanced dosage from M. guttatus imprints. We suggest that diverged epigenetic/regulatory landscapes between parental genomes induce epigenetic repatterning and global shifts in expression, which, in endosperm, may uniquely facilitate incompatible interactions between divergent imprinting schemes, potentially driving rapid barriers.
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Affiliation(s)
- Taliesin J. Kinser
- Biology Department, College of William and Mary, Williamsburg, Virginia 23185
| | - Ronald D. Smith
- Department of Applied Science, College of William and Mary, Williamsburg, Virginia 23185
| | - Amelia H. Lawrence
- Biology Department, College of William and Mary, Williamsburg, Virginia 23185
| | | | - Mario Vallejo-Marín
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland FK9 4LA, UK
| | | | - Joshua R. Puzey
- Biology Department, College of William and Mary, Williamsburg, Virginia 23185
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7
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Städler T, Florez-Rueda AM, Roth M. A revival of effective ploidy: the asymmetry of parental roles in endosperm-based hybridization barriers. CURRENT OPINION IN PLANT BIOLOGY 2021; 61:102015. [PMID: 33639340 DOI: 10.1016/j.pbi.2021.102015] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/15/2021] [Accepted: 01/25/2021] [Indexed: 05/15/2023]
Abstract
Interest in understanding hybrid seed failure (HSF) has mushroomed, both in terms of identifying underlying molecular processes and their evolutionary drivers. We review phenotypic and molecular advances with a focus on the 'effective ploidy' concept, witnessing a recent revival after long obscurity. Endosperm misdevelopment has now been shown to underlie HSF in many inter-specific, homoploid crosses. The consistent asymmetries in seed size and developmental trajectories likely reflect parental divergence in key, dosage-sensitive processes. Transcriptomic and epigenomic studies reveal genome-wide, polarized expression perturbations and shifts in parental expression proportions, consistent with small-RNA imbalances between parental roles. Among-species differences in levels of parental conflict over resource allocation enjoy strong support in explaining why differences in effective ploidy may evolve.
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Affiliation(s)
- Thomas Städler
- Institute of Integrative Biology, ETH Zurich & Zurich-Basel Plant Science Center, Universitätstrasse 16, 8092 Zurich, Switzerland.
| | - Ana M Florez-Rueda
- Department of Plant and Microbial Biology, University of Zurich and Zurich-Basel Plant Science Center, Zollikerstrasse 107, 8008 Zurich, Switzerland
| | - Morgane Roth
- GAFL INRAE, Allée des Chênes 67, 84140 Montfavet, France
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8
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Volokhina I, Gusev Y, Moiseeva Y, Gutorova O, Fadeev V, Chumakov M. Gene Expression in Parthenogenic Maize Proembryos. PLANTS (BASEL, SWITZERLAND) 2021; 10:964. [PMID: 34066123 PMCID: PMC8151209 DOI: 10.3390/plants10050964] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/06/2021] [Accepted: 05/07/2021] [Indexed: 12/19/2022]
Abstract
Angiosperm plants reproduce both sexually and asexually (by apomixis). In apomictic plants, the embryo and endosperm develop without fertilization. Modern maize seems to have a broken apomixis-triggering mechanism, which still works in Tripsacum and in Tripsacum-maize hybrids. For the first time, maize lines characterized by pronounced and inheritable high-frequency maternal parthenogenesis were generated 40 years ago, but there are no data on gene expression in parthenogenic maize proembryos. Here we examined for the first time gene expression in parthenogenic proembryos isolated from unpollinated embryo sacs (ESs) of a parthenogenic maize line (AT-4). The DNA-methylation genes (dmt103, dmt105) and the genes coding for the chromatin-modifying enzymes (chr106, hdt104, hon101) were expressed much higher in parthenogenic proembryos than in unpollinated ESs. The expression of the fertilization-independent endosperm (fie1) genes was found for the first time in parthenogenic proembryos and unpollinated ESs. In parthenogenic proembryos, the Zm_fie2 gene was expressed up to two times higher than it was expressed in unpollinated ESs.
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Affiliation(s)
- Irina Volokhina
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, 13 Prospekt Entuziastov, 410049 Saratov, Russia; (I.V.); (Y.G.); (Y.M.); (V.F.)
| | - Yury Gusev
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, 13 Prospekt Entuziastov, 410049 Saratov, Russia; (I.V.); (Y.G.); (Y.M.); (V.F.)
| | - Yelizaveta Moiseeva
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, 13 Prospekt Entuziastov, 410049 Saratov, Russia; (I.V.); (Y.G.); (Y.M.); (V.F.)
| | - Olga Gutorova
- Genetics Department, Saratov State University, 83 Ulitsa Astrakhanskaya, 410012 Saratov, Russia;
| | - Vladimir Fadeev
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, 13 Prospekt Entuziastov, 410049 Saratov, Russia; (I.V.); (Y.G.); (Y.M.); (V.F.)
| | - Mikhail Chumakov
- Institute of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, 13 Prospekt Entuziastov, 410049 Saratov, Russia; (I.V.); (Y.G.); (Y.M.); (V.F.)
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9
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Köhler C, Dziasek K, Del Toro-De León G. Postzygotic reproductive isolation established in the endosperm: mechanisms, drivers and relevance. Philos Trans R Soc Lond B Biol Sci 2021; 376:20200118. [PMID: 33866810 DOI: 10.1098/rstb.2020.0118] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The endosperm is a developmental innovation of angiosperms that supports embryo growth and germination. Aside from this essential reproductive function, the endosperm fuels angiosperm evolution by rapidly establishing reproductive barriers between incipient species. Specifically, the endosperm prevents hybridization of newly formed polyploids with their non-polyploid progenitors, a phenomenon termed the triploid block. Furthermore, recently diverged diploid species are frequently reproductively isolated by endosperm-based hybridization barriers. Current genetic approaches have revealed a prominent role for epigenetic processes establishing these barriers. In particular, imprinted genes, which are expressed in a parent-of-origin-specific manner, underpin the interploidy barrier in the model species Arabidopsis. We will discuss the mechanisms establishing hybridization barriers in the endosperm, the driving forces for these barriers and their impact for angiosperm evolution. This article is part of the theme issue 'How does epigenetics influence the course of evolution?'
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Affiliation(s)
- Claudia Köhler
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala 75007, Sweden
| | - Katarzyna Dziasek
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala 75007, Sweden
| | - Gerardo Del Toro-De León
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala 75007, Sweden
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10
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Dziasek K, Simon L, Lafon-Placette C, Laenen B, Wärdig C, Santos-González J, Slotte T, Köhler C. Hybrid seed incompatibility in Capsella is connected to chromatin condensation defects in the endosperm. PLoS Genet 2021; 17:e1009370. [PMID: 33571184 PMCID: PMC7904229 DOI: 10.1371/journal.pgen.1009370] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 02/24/2021] [Accepted: 01/15/2021] [Indexed: 11/18/2022] Open
Abstract
Hybridization of closely related plant species is frequently connected to endosperm arrest and seed failure, for reasons that remain to be identified. In this study, we investigated the molecular events accompanying seed failure in hybrids of the closely related species pair Capsella rubella and C. grandiflora. Mapping of QTL for the underlying cause of hybrid incompatibility in Capsella identified three QTL that were close to pericentromeric regions. We investigated whether there are specific changes in heterochromatin associated with interspecific hybridizations and found a strong reduction of chromatin condensation in the endosperm, connected with a strong loss of CHG and CHH methylation and random loss of a single chromosome. Consistent with reduced DNA methylation in the hybrid endosperm, we found a disproportionate deregulation of genes located close to pericentromeric regions, suggesting that reduced DNA methylation allows access of transcription factors to targets located in heterochromatic regions. Since the identified QTL were also associated with pericentromeric regions, we propose that relaxation of heterochromatin in response to interspecies hybridization exposes and activates loci leading to hybrid seed failure.
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Affiliation(s)
- Katarzyna Dziasek
- Department of Plant Biology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala, Sweden
| | - Lauriane Simon
- Department of Plant Biology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala, Sweden
| | - Clément Lafon-Placette
- Department of Plant Biology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala, Sweden
- Present address: Department of Botany, Faculty of Science, Charles University, Prague, Czech Republic
| | - Benjamin Laenen
- Department of Ecology, Environment and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Cecilia Wärdig
- Department of Plant Biology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala, Sweden
| | - Juan Santos-González
- Department of Plant Biology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala, Sweden
| | - Tanja Slotte
- Department of Ecology, Environment and Plant Sciences, Science for Life Laboratory, Stockholm University, Stockholm, Sweden
| | - Claudia Köhler
- Department of Plant Biology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala, Sweden
- * E-mail:
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11
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He H, Yokoi S, Tezuka T. A high maternal genome excess causes severe seed abortion leading to ovary abscission in Nicotiana interploidy-interspecific crosses. PLANT DIRECT 2020; 4:e00257. [PMID: 32821875 PMCID: PMC7430375 DOI: 10.1002/pld3.257] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 07/21/2020] [Accepted: 07/23/2020] [Indexed: 05/05/2023]
Abstract
Seed abortion and ovary abscission, two types of postzygotic reproductive barriers, are often observed in interspecific and/or interploidy crosses in plants. However, the mechanisms underlying these reproductive barriers remain unclear. Here, we show that the distinct types of seed developmental abnormalities (type I and type II seed abortion) occur in a phased manner as maternal to paternal genome dosage increases and that type II seed abortion is followed by ovary abscission. We revealed that these two types of seed developmental abnormalities are observed during seed development in the interploidy-interspecific crosses of Nicotiana suaveolens and N. tabacum. Moreover, in the cross showing type II seed abortion, several events, such as changes in abscission-related gene expression and lignin deposition, occurred in the ovary abscission zone, eventually leading to ovary abscission. Notably, successive increases in maternal ploidy using ploidy manipulated lines resulted in successive type I and type II seed abortions, and the latter was accompanied by ovary abscission. Conversely, both types of seed abortion and ovary abscission could be overcome with a ploidy manipulation technique that balances parental ploidy levels. We thus concluded that a high maternal genome excess cross may cause severe seed developmental defects and ovary abscission. Based on our findings, we propose a model explaining the abortion phenomena, where an interaction between the promotive and inhibitive effects of the parental genomes determines the developmental destiny of seeds. SIGNIFICANCE STATEMENT We demonstrate that a stepwise increase in maternal ploidy results in a stepwise increase in seed abortion severity, leading to ovary abscission in plants. We propose a model explaining the abortion phenomena, where an interaction between the promotive and inhibitive effects of the parental genomes determines the developmental destiny of seeds.
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Affiliation(s)
- Hai He
- Graduate School of Life and Environmental SciencesOsaka Prefecture UniversitySakaiJapan
| | - Shuji Yokoi
- Graduate School of Life and Environmental SciencesOsaka Prefecture UniversitySakaiJapan
- Education and Research FieldCollege of Life, Environment, and Advanced SciencesOsaka Prefecture UniversitySakaiJapan
- Bioeconomy Research InstituteResearch Center for the 21st CenturyOsaka Prefecture UniversitySakaiJapan
| | - Takahiro Tezuka
- Graduate School of Life and Environmental SciencesOsaka Prefecture UniversitySakaiJapan
- Education and Research FieldCollege of Life, Environment, and Advanced SciencesOsaka Prefecture UniversitySakaiJapan
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12
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Differences in Effective Ploidy Drive Genome-Wide Endosperm Expression Polarization and Seed Failure in Wild Tomato Hybrids. Genetics 2019; 212:141-152. [PMID: 30902809 DOI: 10.1534/genetics.119.302056] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Accepted: 03/18/2019] [Indexed: 01/24/2023] Open
Abstract
Parental imbalances in the endosperm leading to impaired development and eventual hybrid seed failure are common causes of postzygotic isolation in flowering plants. Endosperm sensitivity to parental dosage is reflected by canonical phenotypes of "parental excess" in reciprocal interploid crosses. Moreover, parental-excess traits are also evident in many homoploid interspecific crosses, potentially reflecting among-lineage variation in "effective ploidy" driven by endosperm properties. However, the genetic basis of effective ploidy is unknown and genome-wide expression perturbations in parental-excess endosperms from homoploid crosses have yet to be reported. The tomato clade (Solanum section Lycopersicon), encompassing closely related diploids with partial-to-complete hybrid seed failure, provides outstanding opportunities to study these issues. Here, we compared replicated endosperm transcriptomes from six crosses within and among three wild tomato lineages. Strikingly, strongly inviable hybrid crosses displayed conspicuous, asymmetric expression perturbations that mirror previously characterized parental-excess phenotypes. Solanum peruvianum, the species inferred to have evolved higher effective ploidy than the other two, drove expression landscape polarization between maternal and paternal roles. This global expression divergence was mirrored in functionally important gene families such as MADS-box transcription factors and E3 ubiquitin ligases, and revealed differences in cell cycle tuning that match phenotypic differences in developing endosperm and mature seed size between reciprocal crosses. Our work starts to uncover the complex interactions between expression divergence, parental conflict, and hybrid seed failure that likely contributed to plant diversity.
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13
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Batista RA, Figueiredo DD, Santos-González J, Köhler C. Auxin regulates endosperm cellularization in Arabidopsis. Genes Dev 2019; 33:466-476. [PMID: 30819818 PMCID: PMC6446538 DOI: 10.1101/gad.316554.118] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 01/24/2019] [Indexed: 12/25/2022]
Abstract
Batista et al. show that increased auxin biosynthesis in the endosperm prevents its cellularization, leading to seed arrest. The endosperm is an ephemeral tissue that nourishes the developing embryo, similar to the placenta in mammals. In most angiosperms, endosperm development starts as a syncytium, in which nuclear divisions are not followed by cytokinesis. The timing of endosperm cellularization largely varies between species, and the event triggering this transition remains unknown. Here we show that increased auxin biosynthesis in the endosperm prevents its cellularization, leading to seed arrest. Auxin-overproducing seeds phenocopy paternal-excess triploid seeds derived from hybridizations of diploid maternal plants with tetraploid fathers. Concurrently, auxin-related genes are strongly overexpressed in triploid seeds, correlating with increased auxin activity. Reducing auxin biosynthesis and signaling reestablishes endosperm cellularization in triploid seeds and restores their viability, highlighting a causal role of increased auxin in preventing endosperm cellularization. We propose that auxin determines the time of endosperm cellularization, and thereby uncovered a central role of auxin in establishing hybridization barriers in plants.
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Affiliation(s)
- Rita A Batista
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 7080 Uppsala, Sweden
| | - Duarte D Figueiredo
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 7080 Uppsala, Sweden
| | - Juan Santos-González
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 7080 Uppsala, Sweden
| | - Claudia Köhler
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 7080 Uppsala, Sweden
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14
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Cailleau A, Grimanelli D, Blanchet E, Cheptou PO, Lenormand T. Dividing a Maternal Pie among Half-Sibs: Genetic Conflicts and the Control of Resource Allocation to Seeds in Maize. Am Nat 2018; 192:577-592. [PMID: 30332585 DOI: 10.1086/699653] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Resource allocation to offspring is the battleground for various intrafamilial conflicts. Understanding these conflicts requires knowledge of how the different actors (mother, siblings with different paternal genotypes) influence resource allocation. In angiosperms, allocation of resources to seeds happens postfertilization, and the paternally inherited genome in offspring can therefore influence resource allocation. However, the precise mode of resource allocation-and, in particular, the occurrence of sibling rivalry-has rarely been investigated in plants. In this article, we develop a new method for analyzing the resource-allocation traits of the different actors (maternal sporophyte and half-sibs) using data obtained from a large-scale diallel cross experiment in maize involving mixed hand pollination and color markers to assess seed weight of known paternity. We found strong evidence for the occurrence of sibling rivalry: resources invested in an ear were allocated competitively, and offspring with different paternal genotypes aggressively competed for these resources, entailing a measurable direct cost to the mother. We also show how resource allocation can be described for each genotype by two maternal traits (source effect, average sink responsiveness) and two offspring traits (ability to attract maternal resources, competitive ability toward siblings). We will discuss how these findings help to understand how genetic conflicts shape resource-allocation traits in angiosperms.
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15
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Roth M, Florez-Rueda AM, Paris M, Städler T. Wild tomato endosperm transcriptomes reveal common roles of genomic imprinting in both nuclear and cellular endosperm. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 95:1084-1101. [PMID: 29953688 DOI: 10.1111/tpj.14012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 06/01/2018] [Accepted: 06/20/2018] [Indexed: 05/06/2023]
Abstract
Genomic imprinting is a conspicuous feature of the endosperm, a triploid tissue nurturing the embryo and synchronizing angiosperm seed development. An unknown subset of imprinted genes (IGs) is critical for successful seed development and should have highly conserved functions. Recent genome-wide studies have found limited conservation of IGs among distantly related species, but there is a paucity of data from closely related lineages. Moreover, most studies focused on model plants with nuclear endosperm development, and comparisons with properties of IGs in cellular-type endosperm development are lacking. Using laser-assisted microdissection, we characterized parent-specific expression in the cellular endosperm of three wild tomato lineages (Solanum section Lycopersicon). We identified 1025 candidate IGs and 167 with putative homologs previously identified as imprinted in distantly related taxa with nuclear-type endosperm. Forty-two maternally expressed genes (MEGs) and 17 paternally expressed genes (PEGs) exhibited conserved imprinting status across all three lineages, but differences in power to assess imprinted expression imply that the actual degree of conservation might be higher than that directly estimated (20.7% for PEGs and 10.4% for MEGs). Regardless, the level of shared imprinting status was higher for PEGs than for MEGs, indicating dissimilar evolutionary trajectories. Expression-level data suggest distinct epigenetic modulation of MEGs and PEGs, and gene ontology analyses revealed MEGs and PEGs to be enriched for different functions. Importantly, our data provide evidence that MEGs and PEGs interact in modulating both gene expression and the endosperm cell cycle, and uncovered conserved cellular functions of IGs uniting taxa with cellular- and nuclear-type endosperm.
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Affiliation(s)
- Morgane Roth
- Plant Ecological Genetics, Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, 8092, Zurich, Switzerland
| | - Ana M Florez-Rueda
- Plant Ecological Genetics, Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, 8092, Zurich, Switzerland
| | - Margot Paris
- Plant Ecological Genetics, Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, 8092, Zurich, Switzerland
| | - Thomas Städler
- Plant Ecological Genetics, Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, 8092, Zurich, Switzerland
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16
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Tonosaki K, Sekine D, Ohnishi T, Ono A, Furuumi H, Kurata N, Kinoshita T. Overcoming the species hybridization barrier by ploidy manipulation in the genus Oryza. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 93:534-544. [PMID: 29271099 DOI: 10.1111/tpj.13803] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2017] [Revised: 11/16/2017] [Accepted: 11/27/2017] [Indexed: 05/21/2023]
Abstract
In most eudicot and monocot species, interspecific and interploidy crosses generally display abnormalities in the endosperm that are the major cause of a post-zygotic hybridization barrier. In some eudicot species, however, this type of hybridization barrier can be overcome by the manipulation of ploidy levels of one parental species, suggesting that the molecular mechanisms underlying the species hybridization barrier can be circumvented by genome dosage. We previously demonstrated that endosperm barriers in interspecific and interploidy crosses in the genus Oryza involve overlapping but different mechanisms. This result contrasts with those in the genus Arabidopsis, which shows similar outcomes in both interploidy and interspecific crosses. Therefore, we postulated that an exploration of pathways for overcoming the species hybridization barrier in Oryza endosperm, by manipulating the ploidy levels in one parental species, might provide novel insights into molecular mechanisms. We showed that fertile hybrid seeds could be produced by an interspecific cross of female tetraploid Oryza sativa and male diploid Oryza longistaminata. Although the rate of nuclear divisions did not return to normal levels in the hybrid endosperm, the timing of cellularization, nucellus degeneration and the accumulation of storage products were close to normal levels. In addition, the expression patterns of the imprinted gene MADS87 and YUCCA11 were changed when the species barrier was overcome. These results suggest that the regulatory machinery for developmental transitions and imprinted gene expression are likely to play a central role in overcoming species hybridization barriers by genome dosage in the genus Oryza.
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Affiliation(s)
- Kaoru Tonosaki
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka Totsuka, Yokohama, Kanagawa, 244-0813, Japan
| | - Daisuke Sekine
- Institute of Crop Science, National Agriculture and Food Research Organization (NARO), 2-1-18 Kannondai, Tsukuba, Ibaraki, 305-8602, Japan
| | - Takayuki Ohnishi
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka Totsuka, Yokohama, Kanagawa, 244-0813, Japan
- Center for Education and Research of Community Collaboration, Utsunomiya University, 350 Mine, Utsunomiya, Tochigi, 321-8505, Japan
| | - Akemi Ono
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka Totsuka, Yokohama, Kanagawa, 244-0813, Japan
| | - Hiroyasu Furuumi
- Genetic Strains Research Center, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Nori Kurata
- Genetic Strains Research Center, National Institute of Genetics, Mishima, Shizuoka, 411-8540, Japan
| | - Tetsu Kinoshita
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka Totsuka, Yokohama, Kanagawa, 244-0813, Japan
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17
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Endosperm-based hybridization barriers explain the pattern of gene flow between Arabidopsis lyrata and Arabidopsis arenosa in Central Europe. Proc Natl Acad Sci U S A 2017; 114:E1027-E1035. [PMID: 28115687 DOI: 10.1073/pnas.1615123114] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Based on the biological species concept, two species are considered distinct if reproductive barriers prevent gene flow between them. In Central Europe, the diploid species Arabidopsis lyrata and Arabidopsis arenosa are genetically isolated, thus fitting this concept as "good species." Nonetheless, interspecific gene flow involving their tetraploid forms has been described. The reasons for this ploidy-dependent reproductive isolation remain unknown. Here, we show that hybridization between diploid A. lyrata and A. arenosa causes mainly inviable seed formation, revealing a strong postzygotic reproductive barrier separating these two species. Although viability of hybrid seeds was impaired in both directions of hybridization, the cause for seed arrest differed. Hybridization of A. lyrata seed parents with A. arenosa pollen donors resulted in failure of endosperm cellularization, whereas the endosperm of reciprocal hybrids cellularized precociously. Endosperm cellularization failure in both hybridization directions is likely causal for the embryo arrest. Importantly, natural tetraploid A. lyrata was able to form viable hybrid seeds with diploid and tetraploid A. arenosa, associated with the reestablishment of normal endosperm cellularization. Conversely, the defects of hybrid seeds between tetraploid A. arenosa and diploid A. lyrata were aggravated. According to these results, we hypothesize that a tetraploidization event in A. lyrata allowed the production of viable hybrid seeds with A. arenosa, enabling gene flow between the two species.
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18
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Lafon-Placette C, Köhler C. Endosperm-based postzygotic hybridization barriers: developmental mechanisms and evolutionary drivers. Mol Ecol 2016; 25:2620-9. [PMID: 26818717 DOI: 10.1111/mec.13552] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 12/28/2015] [Indexed: 01/06/2023]
Abstract
The endosperm is a nourishing tissue that serves to support embryo growth. Failure of endosperm development will ultimately cause embryo arrest and seed lethality, a phenomenon that is frequently observed upon hybridization of related plant species or species that differ in ploidy. Endosperm-based interspecies or interploidy hybridization barriers depend on the direction of the hybridization, causing nonreciprocal seed defects. This reveals that the parental genomes are not equivalent, implicating parent-of-origin specific genes generating this type of hybridization barrier. Recent work revealed that endosperm-based hybridization barriers are rapidly evolving. In this review, we discuss the developmental mechanisms causing hybrid seed lethality in angiosperms as well as the evolutionary forces establishing endosperm-based postzygotic hybridization barriers.
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Affiliation(s)
- Clément Lafon-Placette
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 750 07, Uppsala, Sweden
| | - Claudia Köhler
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, 750 07, Uppsala, Sweden
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19
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Siena LA, Ortiz JPA, Calderini O, Paolocci F, Cáceres ME, Kaushal P, Grisan S, Pessino SC, Pupilli F. An apomixis-linked ORC3-like pseudogene is associated with silencing of its functional homolog in apomictic Paspalum simplex. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:1965-78. [PMID: 26842983 DOI: 10.1093/jxb/erw018] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Apomixis in plants consists of asexual reproduction by seeds. Here we characterized at structural and functional levels an apomixis-linked sequence of Paspalum simplex homologous to subunit 3 of the ORIGIN RECOGNITION COMPLEX (ORC3). ORC is a multiprotein complex which controls DNA replication and cell differentiation in eukaryotes. Three PsORC3 copies were identified, each one characterized by a specific expression profile. Of these, PsORC3a, specific for apomictic genotypes, is a pseudogene that was poorly and constitutively expressed in all developmental stages of apomictic flowers, whereas PsORC3b, the putative functional gene in sexual flowers, showed a precise time-related regulation. Sense transcripts of PsORC3 were expressed in the female cell lineage of both apomictic and sexual reproductive phenotypes, and in aposporous initials. Although strong expression was detected in sexual early endosperm, no expression was present in the apomictic endosperm. Antisense PsORC3 transcripts were revealed exclusively in apomictic germ cell lineages. Defective orc3 mutants of rice and Arabidopsis showed normal female gametophytes although the embryo and endosperm were arrested at early phases of development. We hypothesize that PsORC3a is associated with the down-regulation of its functional homolog and with the development of apomictic endosperm which deviates from the canonical 2(maternal):1(paternal) genome ratio.
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Affiliation(s)
- Lorena A Siena
- Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, (S2125ZAA) Zavalla, Argentina Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR-CONICET-UNR), Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, (S2125ZAA) Zavalla, Argentina
| | - Juan Pablo A Ortiz
- Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, (S2125ZAA) Zavalla, Argentina Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR-CONICET-UNR), Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, (S2125ZAA) Zavalla, Argentina
| | - Ornella Calderini
- Istituto di Bioscienze e Biorisorse (IBBR-CNR), via della Madonna alta 130, I-06128 Perugia, Italy
| | - Francesco Paolocci
- Istituto di Bioscienze e Biorisorse (IBBR-CNR), via della Madonna alta 130, I-06128 Perugia, Italy
| | - Maria E Cáceres
- Istituto di Bioscienze e Biorisorse (IBBR-CNR), via della Madonna alta 130, I-06128 Perugia, Italy
| | - Pankaj Kaushal
- Istituto di Bioscienze e Biorisorse (IBBR-CNR), via della Madonna alta 130, I-06128 Perugia, Italy
| | - Simone Grisan
- Istituto di Bioscienze e Biorisorse (IBBR-CNR), via della Madonna alta 130, I-06128 Perugia, Italy
| | - Silvina C Pessino
- Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, (S2125ZAA) Zavalla, Argentina Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR-CONICET-UNR), Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, (S2125ZAA) Zavalla, Argentina
| | - Fulvio Pupilli
- Istituto di Bioscienze e Biorisorse (IBBR-CNR), via della Madonna alta 130, I-06128 Perugia, Italy
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20
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Pires ND. Seed evolution: parental conflicts in a multi-generational household. Biomol Concepts 2015; 5:71-86. [PMID: 25372743 DOI: 10.1515/bmc-2013-0034] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2013] [Accepted: 12/17/2013] [Indexed: 12/12/2022] Open
Abstract
Seeds are multi-generational structures containing a small embryonic plant enclosed in layers of diverse parental origins. The evolution of seeds was a pinnacle in an evolutionary trend towards a progressive retention of embryos and gametes within parental tissue. This strategy, which dates back to the first land plants, allowed an increased protection and nourishing of the developing embryo. Flowering plants took parental control one step further with the evolution of a biparental endosperm that derives from a second parallel fertilization event. The endosperm directly nourishes the developing embryo and allows not only the maternal genes, but also paternal genes, to play an active role during seed development. The appearance of an endosperm set the conditions for the manifestation of conflicts of interest between maternal and paternal genomes over the allocation of resources to the developing embryos. As a consequence, a dynamic balance was established between maternal and paternal gene dosage in the endosperm, and maintaining a correct balance became essential to ensure a correct seed development. This balance was achieved in part by changes in the genetic constitution of the endosperm and through epigenetic mechanisms that allow a differential expression of alleles depending on their parental origin. This review discusses the evolutionary steps that resulted in the appearance of seeds and endosperm, and the epigenetic and genetic mechanisms that allow a harmonious coinhabitance of multiple generations within a single seed.
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21
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Zheng Y, Wang Z. The cereal starch endosperm development and its relationship with other endosperm tissues and embryo. PROTOPLASMA 2015; 252:33-40. [PMID: 25123370 DOI: 10.1007/s00709-014-0687-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2014] [Accepted: 08/01/2014] [Indexed: 05/28/2023]
Abstract
The cereal starch endosperm is the central part of endosperm, and it is rich in starch and protein which are the important resources for human food. The starch and protein are separately accumulated in starch granules and protein bodies. Content and configuration of starch granules and protein bodies affect the quality of the starch endosperm. The development of starch endosperm is mediated by genes, enzymes, and hormones, and it also has a close relationship with other endosperm tissues and embryo. This paper reviews the latest investigations on the starch endosperm and will provide some useful information for the future researches on the development of cereal endosperm.
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Affiliation(s)
- Yankun Zheng
- College of Agriculture, Yangzhou University, Yangzhou, 225009, Jiangsu, China
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22
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Buzgariu W, Crescenzi M, Galliot B. Robust G2 pausing of adult stem cells in Hydra. Differentiation 2014; 87:83-99. [PMID: 24703763 DOI: 10.1016/j.diff.2014.03.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2013] [Revised: 03/10/2014] [Accepted: 03/13/2014] [Indexed: 12/18/2022]
Abstract
Hydra is a freshwater hydrozoan polyp that constantly renews its two tissue layers thanks to three distinct stem cell populations that cannot replace each other, epithelial ectodermal, epithelial endodermal, and multipotent interstitial. These adult stem cells, located in the central body column, exhibit different cycling paces, slow for the epithelial, fast for the interstitial. To monitor the changes in cell cycling in Hydra, we established a fast and efficient flow cytometry procedure, which we validated by confirming previous findings, as the Nocodazole-induced reversible arrest of cell cycling in G2/M, and the mitogenic signal provided by feeding. Then to dissect the cycling and differentiation behaviors of the interstitial stem cells, we used the AEP_cnnos1 and AEP_Icy1 transgenic lines that constitutively express GFP in this lineage. For the epithelial lineages we used the sf-1 strain that rapidly eliminates the fast cycling cells upon heat-shock and progressively becomes epithelial. This study evidences similar cycling patterns for the interstitial and epithelial stem cells, which all alternate between the G2 and S-phases traversing a minimal G1-phase. We also found interstitial progenitors with a shorter G2 that pause in G1/G0. At the animal extremities, most cells no longer cycle, the epithelial cells terminally differentiate in G2 and the interstitial progenitors in G1/G0. At the apical pole ~80% cells are post-mitotic differentiated cells, reflecting the higher density of neurons and nematocytes in this region. We discuss how the robust G2 pausing of stem cells, maintained over weeks of starvation, may contribute to regeneration.
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Affiliation(s)
- Wanda Buzgariu
- Department of Genetics and Evolution, University of Geneva, Sciences III, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland
| | | | - Brigitte Galliot
- Department of Genetics and Evolution, University of Geneva, Sciences III, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland.
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Sekine D, Ohnishi T, Furuumi H, Ono A, Yamada T, Kurata N, Kinoshita T. Dissection of two major components of the post-zygotic hybridization barrier in rice endosperm. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2013; 76:792-9. [PMID: 24286595 DOI: 10.1111/tpj.12333] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 09/07/2013] [Accepted: 09/10/2013] [Indexed: 05/13/2023]
Abstract
A post-zygotic hybridization barrier is often observed in the endosperm of seeds produced by interspecific or interploidy crosses. In Arabidopsis thaliana, for example, hybrid endosperm from both types of cross shows altered timing of cellularization and an altered rate of nuclear divisions. Therefore, it has been proposed that interspecific and interploidy crosses share common molecular mechanisms for establishment of an effective species barrier. However, these two types of hybridization barrier may be initiated by different intrinsic cues: the interspecific cross barrier arises after hybridization of genomes with differences in DNA sequences, while the interploidy cross barrier arises after hybridization of genomes with the same DNA sequences but differences in ploidy levels. In this study, we performed interploidy crosses to identify components of the post-hybridization barrier in the endosperm of rice. We performed an intra-cultivar cross of autotetraploid (4n) × diploid (2n) rice, and found precocious cellularization and a decreased rate of nuclear division in the syncytial endosperm. By contrast, seeds from the reciprocal cross showed delayed cellularization and an increased rate of nuclear division. This differential effect on nuclear division rates contrasts with the outcome of rice interspecific crosses, which were previously shown to have altered timing of cellularization without any change in nuclear division rates. Thus, we propose that the post-zygotic hybridization barrier in rice endosperm has two separable components, namely control of the timing of cellularization and control of the nuclear division rates in the syncytial stage of endosperm development.
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Affiliation(s)
- Daisuke Sekine
- Graduate School of Biological Science, Nara Institute of Science and Technology, Nara, 630-0192, Japan; Division of Life Sciences, Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, 920-1192, Japan
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Abstract
Seeds are complex structures that unite diploid maternal tissues with filial tissues that may be haploid (gametophyte), diploid (embryo), or triploid (endosperm). Maternal tissues are predicted to favor smaller seeds than are favored by filial tissues, and filial genes of maternal origin are predicted to favor smaller seeds than are favored by filial genes of paternal origin. Consistent with these predictions, seed size is determined by an interplay between growth of maternal integuments, which limits seed size, and of filial endosperm, which promotes larger seeds. Within endosperm, genes of paternal origin favor delayed cellularization of endosperm and larger seeds, whereas genes of maternal origin favor early cellularization and smaller seeds. The ratio of maternal and paternal gene products in endosperm contributes to the failure of crosses between different ploidy levels of the same species and crosses between species. Maternally expressed small-interfering RNAs (siRNAs) are predicted to associate with growth-enhancing genes.
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Affiliation(s)
- David Haig
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138;
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Sabelli PA. Replicate and die for your own good: Endoreduplication and cell death in the cereal endosperm. J Cereal Sci 2012. [DOI: 10.1016/j.jcs.2011.09.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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26
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The politics of emergence: Public–private partnerships and the conflictive timescapes of apomixis technology development. BIOSOCIETIES 2012. [DOI: 10.1057/biosoc.2011.30] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Ishikawa R, Ohnishi T, Kinoshita Y, Eiguchi M, Kurata N, Kinoshita T. Rice interspecies hybrids show precocious or delayed developmental transitions in the endosperm without change to the rate of syncytial nuclear division. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2011; 65:798-806. [PMID: 21251103 DOI: 10.1111/j.1365-313x.2010.04466.x] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In angiosperms, interspecific crosses often display hybrid incompatibilities that are manifested as under-proliferation or over-proliferation of endosperm. Recent analyses using crosses between Arabidopsis thaliana and its related species with different ploidy levels have shown that interspecific hybridization causes delayed developmental transition and increased mitotic activity in the endosperm. In this study, we investigated endosperm development in interspecific crosses between diploid Oryza species. In a cross between female O. sativa and male O. punctata, we found that the hybrid endosperm was reduced in size and this cross was associated with precocious developmental transition. By contrast, the cross between O. sativa and O. longistaminata generated enlarged hybrid endosperm at the mid-point of seed development and this cross was associated with delayed developmental transition. Subsequently, the hybrid endosperm displayed a shriveled appearance at the seed maturation stage. We found that the accumulation of storage products and the expression patterns of several marker genes were also altered in the hybrid endosperm. By contrast, the rate of syncytial mitotic nuclear divisions was not significantly affected. The gene OsMADS87 showed a maternal origin-specific expression pattern in rice endosperm, in contrast to its Arabidopsis homologue PHERES1, which shows paternal origin-specific expression. OsMADS87 expression was decreased or increased depending on the type of developmental transition change in the hybrid rice endosperm. Our results indicate that one of the interspecies hybridization barriers in Oryza endosperm is mediated by precocious or delayed developmental alterations and de-regulation of OsMADS87, without change to the rate of syncytial mitotic nuclear division in the hybrid endosperm.
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Affiliation(s)
- Ryo Ishikawa
- Plant Reproductive Genetics, GCOE Research Group, Graduate School of Biological Science, Nara Institute of Science and Technology, Nara 630-0192, Japan
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Tiwari S, Spielman M, Schulz R, Oakey RJ, Kelsey G, Salazar A, Zhang K, Pennell R, Scott RJ. Transcriptional profiles underlying parent-of-origin effects in seeds of Arabidopsis thaliana. BMC PLANT BIOLOGY 2010; 10:72. [PMID: 20406451 PMCID: PMC3095346 DOI: 10.1186/1471-2229-10-72] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2009] [Accepted: 04/20/2010] [Indexed: 05/21/2023]
Abstract
BACKGROUND Crossing plants of the same species but different ploidies can have dramatic effects on seed growth, but little is known about the alterations to transcriptional programmes responsible for this. Parental genomic imbalance particularly affects proliferation of the endosperm, with an increased ratio of paternally to maternally contributed genomes ('paternal excess') associated with overproliferation, while maternal excess inhibits endosperm growth. One interpretation is that interploidy crosses disrupt the balance in the seed of active copies of parentally imprinted genes. This is supported by the observation that mutations in imprinted FIS-class genes of Arabidopsis thaliana share many features of the paternal excess phenotype. Here we investigated gene expression underlying parent-of-origin effects in Arabidopsis through transcriptional profiling of siliques generated by interploidy crosses and FIS-class mutants. RESULTS We found that fertilized fis1 mutant seeds have similar profiles to seeds with paternal excess, showing that the shared phenotypes are underpinned by similar patterns of gene expression. We identified genes strongly associated with enhanced or inhibited seed growth; this provided many candidates for further investigation including MADS-box transcription factors, cell cycle genes, and genes involved in hormone pathways. CONCLUSIONS The work presented here is a step towards understanding the effects on seed development of the related phenomena of parental genome balance and imprinting.
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Affiliation(s)
- Sushma Tiwari
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Melissa Spielman
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Reiner Schulz
- Department of Medical and Molecular Genetics, King's College London School of Medicine at Guy's, King's College and St Thomas' Hospitals, 8th Floor Guy's Tower, London SE1 9RT, UK
| | - Rebecca J Oakey
- Department of Medical and Molecular Genetics, King's College London School of Medicine at Guy's, King's College and St Thomas' Hospitals, 8th Floor Guy's Tower, London SE1 9RT, UK
| | - Gavin Kelsey
- Laboratory of Developmental Genetics and Imprinting, The Babraham Institute, Babraham Research Campus, Cambridge CB2 4AT, UK
| | - Andres Salazar
- Ceres Inc., 1535 Rancho Conejo Boulevard, Thousand Oaks, CA 91320, USA
| | - Ke Zhang
- Ceres Inc., 1535 Rancho Conejo Boulevard, Thousand Oaks, CA 91320, USA
| | - Roger Pennell
- Ceres Inc., 1535 Rancho Conejo Boulevard, Thousand Oaks, CA 91320, USA
| | - Rod J Scott
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
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Jullien PE, Berger F. Parental genome dosage imbalance deregulates imprinting in Arabidopsis. PLoS Genet 2010; 6:e1000885. [PMID: 20333248 PMCID: PMC2841625 DOI: 10.1371/journal.pgen.1000885] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2009] [Accepted: 02/22/2010] [Indexed: 11/19/2022] Open
Abstract
In mammals and in plants, parental genome dosage imbalance deregulates embryo growth and might be involved in reproductive isolation between emerging new species. Increased dosage of maternal genomes represses growth while an increased dosage of paternal genomes has the opposite effect. These observations led to the discovery of imprinted genes, which are expressed by a single parental allele. It was further proposed in the frame of the parental conflict theory that parental genome imbalances are directly mirrored by antagonistic regulations of imprinted genes encoding maternal growth inhibitors and paternal growth enhancers. However these hypotheses were never tested directly. Here, we investigated the effect of parental genome imbalance on the expression of Arabidopsis imprinted genes FERTILIZATION INDEPENDENT SEED2 (FIS2) and FLOWERING WAGENINGEN (FWA) controlled by DNA methylation, and MEDEA (MEA) and PHERES1 (PHE1) controlled by histone methylation. Genome dosage imbalance deregulated the expression of FIS2 and PHE1 in an antagonistic manner. In addition increased dosage of inactive alleles caused a loss of imprinting of FIS2 and MEA. Although FIS2 controls histone methylation, which represses MEA and PHE1 expression, the changes of PHE1 and MEA expression could not be fully accounted for by the corresponding fluctuations of FIS2 expression. Our results show that parental genome dosage imbalance deregulates imprinting using mechanisms, which are independent from known regulators of imprinting. The complexity of the network of regulations between expressed and silenced alleles of imprinted genes activated in response to parental dosage imbalance does not support simple models derived from the parental conflict hypothesis.
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Affiliation(s)
- Pauline E. Jullien
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore
- Zentrum für Molekularbiologie der Pflanzen, Entwicklungsgenetik, Universität Tübingen, Tübingen, Germany
| | - Frédéric Berger
- Temasek Life Sciences Laboratory, National University of Singapore, Singapore
- Department of Biological Sciences, National University of Singapore, Singapore
- * E-mail:
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30
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Li N, Dickinson HG. Balance between maternal and paternal alleles sets the timing of resource accumulation in the maize endosperm. Proc Biol Sci 2009; 277:3-10. [PMID: 19793746 DOI: 10.1098/rspb.2009.1209] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Key aspects of seed development in flowering plants are held to be under epigenetic control and to have evolved as a result of conflict between the interests of the male and female gametes (kinship theory). Attempts to identify the genes involved have focused on imprinted sequences, although imprinting is only one mechanism by which male or female parental alleles may be exclusively expressed immediately post-fertilization. We have studied the expression of a subset of endosperm gene classes immediately following interploidy crosses in maize and show that departure from the normal 2 : 1 ratio between female and male genomes exerts a dramatic effect on the timing of expression of some, but not all, genes investigated. Paternal genomic excess prolongs the expression of early genes and delays accumulation of reserves, while maternal genomic excess foreshortens the expression period of early genes and dramatically brings forward endosperm maturation. Our data point to a striking interdependence between the phases of endosperm development, and are consonant with previous work from maize showing progression from cell proliferation to endoreduplication is regulated by the balance between maternal and paternal genomes, and from Arabidopsis suggesting that this 'phasing' is regulated by maternally expressed imprinted genes. Our findings are discussed in context of the kinship theory.
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Affiliation(s)
- Na Li
- Department of Plant Sciences, South Parks Road, Oxford OX1 3RB, UK
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31
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The contribution of cell cycle regulation to endosperm development. ACTA ACUST UNITED AC 2009; 22:207-19. [DOI: 10.1007/s00497-009-0105-4] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Accepted: 07/05/2009] [Indexed: 01/08/2023]
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32
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Sabelli PA, Larkins BA. The development of endosperm in grasses. PLANT PHYSIOLOGY 2009; 149:14-26. [PMID: 19126691 PMCID: PMC2613697 DOI: 10.1104/pp.108.129437] [Citation(s) in RCA: 264] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Accepted: 10/18/2008] [Indexed: 05/18/2023]
Affiliation(s)
- Paolo A Sabelli
- Department of Plant Sciences, University of Arizona, Tucson, Arizona 85721, USA
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Dilkes BP, Spielman M, Weizbauer R, Watson B, Burkart-Waco D, Scott RJ, Comai L. The maternally expressed WRKY transcription factor TTG2 controls lethality in interploidy crosses of Arabidopsis. PLoS Biol 2008; 6:2707-20. [PMID: 19071961 PMCID: PMC2596861 DOI: 10.1371/journal.pbio.0060308] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2008] [Accepted: 10/29/2008] [Indexed: 11/18/2022] Open
Abstract
The molecular mechanisms underlying lethality of F1 hybrids between diverged parents are one target of speciation research. Crosses between diploid and tetraploid individuals of the same genotype can result in F1 lethality, and this dosage-sensitive incompatibility plays a role in polyploid speciation. We have identified variation in F1 lethality in interploidy crosses of Arabidopsis thaliana and determined the genetic architecture of the maternally expressed variation via QTL mapping. A single large-effect QTL, DR. STRANGELOVE 1 (DSL1), was identified as well as two QTL with epistatic relationships to DSL1. DSL1 affects the rate of postzygotic lethality via expression in the maternal sporophyte. Fine mapping placed DSL1 in an interval encoding the maternal effect transcription factor TTG2. Maternal parents carrying loss-of-function mutations in TTG2 suppressed the F1 lethality caused by paternal excess interploidy crosses. The frequency of cellularization in the endosperm was similarly affected by both natural variation and ttg2 loss-of-function mutants. The simple genetic basis of the natural variation and effects of single-gene mutations suggests that F1 lethality in polyploids could evolve rapidly. Furthermore, the role of the sporophytically active TTG2 gene in interploidy crosses indicates that the developmental programming of the mother regulates the viability of interploidy hybrid offspring.
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Affiliation(s)
- Brian P Dilkes
- Section of Plant Biology and Genome Center, University of California Davis, Davis, California, United States of America
- Department of Biology, University of Washington, Seattle, Washington, United States of America
| | - Melissa Spielman
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Renate Weizbauer
- Department of Biology, University of Washington, Seattle, Washington, United States of America
| | - Brian Watson
- Department of Biology, University of Washington, Seattle, Washington, United States of America
| | - Diana Burkart-Waco
- Section of Plant Biology and Genome Center, University of California Davis, Davis, California, United States of America
| | - Rod J Scott
- Department of Biology and Biochemistry, University of Bath, Bath, United Kingdom
| | - Luca Comai
- Section of Plant Biology and Genome Center, University of California Davis, Davis, California, United States of America
- Department of Biology, University of Washington, Seattle, Washington, United States of America
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Coelho CM, Wu S, Li Y, Hunter B, Dante RA, Cui Y, Wu R, Larkins BA. Identification of quantitative trait loci that affect endoreduplication in maize endosperm. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2007; 115:1147-62. [PMID: 17912496 DOI: 10.1007/s00122-007-0640-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2006] [Accepted: 08/28/2007] [Indexed: 05/17/2023]
Abstract
Endoreduplication in maize endosperm precedes the onset of starch and storage protein synthesis, and it is generally thought to influence grain filling. We created four backcross populations by reciprocally crossing the F(1) progeny of a cross between Sg18 and Mo17 to the parental inbreds, which differ in endoreduplication by two parameters--mean ploidy and percentage of endoreduplicated nuclei. This four-backcross design allowed us to estimate and test the additive and dominant genetic effects of quantitative trait loci (QTLs) affecting endoreduplication. An analysis of endosperm from the four backcross populations at 16 days after pollination using a modified triploid mapping approach identified three endosperm QTLs influencing mean ploidy and two endosperm QTLs affecting the percentage of endoreduplicated nuclei. Some of these QTLs may manifest their effects on endoreduplication via expression in the embryo. The QTLs detected display strong dominance or over-dominance and interacted epistatically with an embryo-expressed QTL. This helps to explain the genetic basis for transgressive segregation in the backcross progeny. Although the favorable alleles that increase mean ploidy and percentage of endoreduplicated nuclei can be contributed by both parents, the Mo17-derived alleles for endoreduplication were often dominant or over-dominant to the Sg18-derived allele. One QTL on chromosome 7 that may be expressed in both the embryo and endosperm exerted a pleiotropic effect on two different parameters of endoreduplication. The results from this study shed light on the regulation of endoreduplication in maize endosperm and provide a marker-assisted selection strategy for potentially improving grain yield.
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Affiliation(s)
- Cintia M Coelho
- Department of Plant Sciences, Forbes Hall 303, University of Arizona, Tucson, AZ 85721, USA
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Hermon P, Srilunchang KO, Zou J, Dresselhaus T, Danilevskaya ON. Activation of the imprinted Polycomb Group Fie1 gene in maize endosperm requires demethylation of the maternal allele. PLANT MOLECULAR BIOLOGY 2007; 64:387-95. [PMID: 17437065 DOI: 10.1007/s11103-007-9160-0] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2006] [Accepted: 03/01/2007] [Indexed: 05/06/2023]
Abstract
Imprinting refers to the epigenetic regulation of gene expression that is dependent upon gene inheritance from the maternal or paternal parent. Previously, we have identified two maize homologs of the single Arabidopsis Polycomb Group gene FIE. Here, we report on the expression pattern of these genes in individual gametes before and after fertilization, and on the role of DNA methylation in determining the maternal expression of the Fie1 gene. We found that Fie1 is neither expressed in the sperm, egg cell nor central cell before fertilization. Activation of the Fie1 maternal allele occurs around two days after pollination (DAP) in the primary endosperm and peaks at 10-11 DAP coinciding with endosperm transition from mitotic division to endoreduplication. In contrast, Fie2 is expressed in the egg cell and more intensively in the central cell similar to Arabidopsis FIE, which strongly supports the hypothesis that it functions as a repressor of endosperm development before fertilization. Using MSRE-PCR and bisulfite sequencing, we could show that the methylated inactive state is the default status of Fie1 in most tissues. In the endosperm the paternal Fie1 allele remains methylated and silent, but the maternal allele appears hypomethylated and active, explaining mono-allelic expression of Fie1 in the endosperm. Taking together, these data demonstrate that the regulation of Fie1 imprinting in maize is different from Arabidopsis and that Fie1 is likely to have acquired important novel functions for endosperm development.
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Affiliation(s)
- Pedro Hermon
- Pioneer Hi-Bred International Inc, 7250 NW 62nd Ave, Johnston, IA, USA
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Bauer MJ, Birchler JA. Organization of endoreduplicated chromosomes in the endosperm of Zea mays L. Chromosoma 2006; 115:383-94. [PMID: 16741707 DOI: 10.1007/s00412-006-0068-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2005] [Revised: 04/10/2006] [Accepted: 04/12/2006] [Indexed: 10/24/2022]
Abstract
The chromosomes of the maize endosperm proceed through an endoreduplication phase in later stages of development. Endoreduplication is a process in which the cell cycle continues DNA synthesis but does not proceed through cytokinesis. When this occurs, the normally triploid endosperm cell can reach ploidy levels greater than 200x in some lines of maize. In this work, we examined the structure of the endoreduplicated chromosomes. Previous cytological work has indicated that, although the DNA content per cell increases, the number of nucleoli and knobs remains the same. Using fluorescence in situ hybridization and slot blot techniques, we show that the highly repetitive heterochromatic areas both on the A and B chromosomes, as well as several actively transcribed genes, are endoreduplicated. This result suggests that the entire genome follows that same trend. Further evidence shows that the various chromatin strands stay associated throughout the length of the chromosomes after they have been replicated, and that the DNA at the centromeric and knob regions is more tightly associated than the other regions of the chromosomes. Interploidy crosses between diploid and tetraploid derivatives of the same inbred exhibit changes in the chromatin organization of centromeres and heterochromatic knobs.
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Affiliation(s)
- Matthew J Bauer
- Division of Biological Sciences, University of Missouri, Columbia, MO 65211, USA
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Scott RJ, Spielman M. Genomic imprinting in plants and mammals: how life history constrains convergence. Cytogenet Genome Res 2006; 113:53-67. [PMID: 16575163 DOI: 10.1159/000090815] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2005] [Accepted: 08/02/2005] [Indexed: 12/25/2022] Open
Abstract
In both flowering plants and mammals, DNA methylation is involved in silencing alleles of imprinted genes, but surprising differences in imprinting control are emerging between the two taxa which may be traced to differences in their life cycles. Imprinted gene expression in plants occurs in the endosperm, a separate fertilisation product which transmits nutrients to the embryo and does not contribute a genome to the next generation. Regulation of expression of the known imprinted genes in Arabidopsis involves a cascade of gene expression beginning in the gametophyte, a haploid life phase interposed between the meiotic products and the gametes, which evolved from free-living organisms that constitute the dominant life phase of lower plants. Although the gametophytes of flowering plants are highly reduced they still express large numbers of genes, perhaps reflecting their evolutionary legacy, and which may now be recruited for control of imprinting. Strikingly, the genes at the top of the expression cascade appear to be specifically activated by demethylation, rather than targeted for silencing. Unlike in mammals, there is no evidence for global resetting of methylation in plants, and although imprinting involves the activity of a maintenance methyltransferase, de novo methyltransferases do not appear to be required. Plants do not set aside a germline; instead the cells that undergo meiosis to produce gametophytes differentiate in the adult plant during flower development. Both the late differentiation of the lineage producing germ cells, and the extent of gene expression during the haploid phase, may be incompatible with global resetting of methylation. Resetting may be unnecessary in any case because the adult plant expresses imprinted loci either biallelically or not at all, suggesting there is no chromosomal memory of parent-of-origin in the lineage that produces the gametophytes. Thus several features of the plant life cycle may account for the different strategies used by plants and animals to regulate parent-specific gene expression.
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Affiliation(s)
- R J Scott
- Department of Biology and Biochemistry, University of Bath, Bath, UK.
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40
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Autran D, Huanca-Mamani W, Vielle-Calzada JP. Genomic imprinting in plants: the epigenetic version of an Oedipus complex. CURRENT OPINION IN PLANT BIOLOGY 2005; 8:19-25. [PMID: 15653395 DOI: 10.1016/j.pbi.2004.11.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Genomic imprinting is a mitotically stable epigenetic modification that results in the functional non-equivalency of both parental genomes following fertilization. In flowering plants, studies of parent-of-origin effects have mostly identified genes that are only transcribed from a maternally inherited allele. In Arabidopsis, the Polycomb group protein MEDEA regulates seed development through the expression of the MADS-box gene PHERES1. Activation of the maternal MEDEA allele requires the function of DEMETER, a plant DNA glycosylase that also controls the transcriptional activity of the maternally inherited allele of the late-flowering gene FWA. Current studies of parent-of-origin effects have mostly identified genes that are only transcribed from a maternally inherited allele. Our current understanding of parent-of-origin effects could represent a new form of an Oedipus complex in which flowering plants prefer to rely transcriptionally on their maternal rather than their paternal chromosomes to ensure normal initiation of seed development.
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Affiliation(s)
- Daphné Autran
- Laboratory of Reproductive Development and Apomixis, Department of Genetic Engineering, CINVESTAV--Unidad Irapuato, Apartado Postal 629, CP 36 500, Irapuato, Gto. México.
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von Wangenheim KH, Peterson HP. Aberrant endosperm development in interploidy crosses reveals a timer of differentiation. Dev Biol 2004; 270:277-89. [PMID: 15183714 DOI: 10.1016/j.ydbio.2004.03.014] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2003] [Revised: 12/19/2003] [Accepted: 03/03/2004] [Indexed: 01/09/2023]
Abstract
The common assumption that the seed failure in interploidy crosses of flowering plants is due to parental genomic imprinting is based on vague interpretations and needs reevaluation since the general question is involved, how differentiation is timed so that cell progenies, while specializing, pass through proper numbers of amplification divisions before proliferation ceases. As recently confirmed, endosperm differentiation is accelerated or de-accelerated, depending upon whether polyploid females are crossed with diploid males, or vice-versa. Unlike the zygote, the first cell of the endosperm is determined to produce a tissue that successively induces growth of maternal tissues, stimulates and nourishes the embryo, and finally ceases cell cycling. Altered timing of endosperm differentiation, thus, perturbs seed development. During fertilization, only the female genomes contribute cytoplasmic equivalents to endosperm development so that in interploidy crosses, the initial amount of cytoplasm per chromosome set is altered, and due to semi-autonomy of cytoplasmic growth, altered numbers of division cycles are needed to provide the amount of cytoplasmic organelles required for differentiation. Cytoplasmic semi-autonomy and dependence of differentiation on an increase in cytoplasm has been shown in other tissues of plants and animals, thus, revealing a common mechanism for intracellular timing of differentiation. As demonstrated, imprinted genes can alter the extent of cell proliferation by interfering with this mechanism.
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