1
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Zhong S, Zhao P, Peng X, Li HJ, Duan Q, Cheung AY. From gametes to zygote: Mechanistic advances and emerging possibilities in plant reproduction. Plant Physiol 2024; 195:4-35. [PMID: 38431529 PMCID: PMC11060694 DOI: 10.1093/plphys/kiae125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 02/13/2024] [Accepted: 02/13/2024] [Indexed: 03/05/2024]
Affiliation(s)
- Sheng Zhong
- State Key Laboratory for Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, New Cornerstone Science Laboratory, College of Life Sciences, Peking University, Beijing 100871, China
| | - Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Xiongbo Peng
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Hong-Ju Li
- Key Laboratory of Seed Innovation, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Center for Molecular Agrobiology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Qiaohong Duan
- College of Horticulture Science and Engineering, Shandong Agricultural University, Tai’an, Shandong 271018, China
| | - Alice Y Cheung
- Department of Biochemistry and Molecular Biology, Molecular and Cellular Biology Program, Plant Biology Graduate Program, University of Massachusetts, Amherst, MA 01003, USA
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2
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Quiroz LF, Gondalia N, Brychkova G, McKeown PC, Spillane C. Haploid rhapsody: the molecular and cellular orchestra of in vivo haploid induction in plants. New Phytol 2024; 241:1936-1949. [PMID: 38180262 DOI: 10.1111/nph.19523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2023] [Accepted: 12/11/2023] [Indexed: 01/06/2024]
Abstract
In planta haploid induction (HI), which reduces the chromosome number in the progeny after fertilization, has garnered increasing attention for its significant potential in crop breeding and genetic research. Despite the identification of several natural and synthetic HI systems in different plant species, the molecular and cellular mechanisms underlying these HI systems remain largely unknown. This review synthesizes the current understanding of HI systems in plants (with a focus on genes and molecular mechanisms involved), including the molecular and cellular interactions which orchestrate the HI process. As most HI systems can function across taxonomic boundaries, we particularly discuss the evidence for conserved mechanisms underlying the process. These include mechanisms involved in preserving chromosomal integrity, centromere function, gamete communication and/or fusion, and maintenance of karyogamy. While significant discoveries and advances on haploid inducer systems have arisen over the past decades, we underscore gaps in understanding and deliberate on directions for further research for a more comprehensive understanding of in vivo HI processes in plants.
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Affiliation(s)
- Luis Felipe Quiroz
- Agriculture and Bioeconomy Research Centre, Ryan Institute, University of Galway, University Road, Galway, H91 REW4, Ireland
| | - Nikita Gondalia
- Agriculture and Bioeconomy Research Centre, Ryan Institute, University of Galway, University Road, Galway, H91 REW4, Ireland
| | - Galina Brychkova
- Agriculture and Bioeconomy Research Centre, Ryan Institute, University of Galway, University Road, Galway, H91 REW4, Ireland
| | - Peter C McKeown
- Agriculture and Bioeconomy Research Centre, Ryan Institute, University of Galway, University Road, Galway, H91 REW4, Ireland
| | - Charles Spillane
- Agriculture and Bioeconomy Research Centre, Ryan Institute, University of Galway, University Road, Galway, H91 REW4, Ireland
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3
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Yuan HY, Kagale S, Ferrie AMR. Multifaceted roles of transcription factors during plant embryogenesis. Front Plant Sci 2024; 14:1322728. [PMID: 38235196 PMCID: PMC10791896 DOI: 10.3389/fpls.2023.1322728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/16/2023] [Accepted: 12/11/2023] [Indexed: 01/19/2024]
Abstract
Transcription factors (TFs) are diverse groups of regulatory proteins. Through their specific binding domains, TFs bind to their target genes and regulate their expression, therefore TFs play important roles in various growth and developmental processes. Plant embryogenesis is a highly regulated and intricate process during which embryos arise from various sources and undergo development; it can be further divided into zygotic embryogenesis (ZE) and somatic embryogenesis (SE). TFs play a crucial role in the process of plant embryogenesis with a number of them acting as master regulators in both ZE and SE. In this review, we focus on the master TFs involved in embryogenesis such as BABY BOOM (BBM) from the APETALA2/Ethylene-Responsive Factor (AP2/ERF) family, WUSCHEL and WUSCHEL-related homeobox (WOX) from the homeobox family, LEAFY COTYLEDON 2 (LEC2) from the B3 family, AGAMOUS-Like 15 (AGL15) from the MADS family and LEAFY COTYLEDON 1 (LEC1) from the Nuclear Factor Y (NF-Y) family. We aim to present the recent progress pertaining to the diverse roles these master TFs play in both ZE and SE in Arabidopsis, as well as other plant species including crops. We also discuss future perspectives in this context.
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Affiliation(s)
| | | | - Alison M. R. Ferrie
- Aquatic and Crop Resource Development Research Center, National Research Council Canada, Saskatoon, SK, Canada
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4
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Skinner DJ, Mallari MD, Zafar K, Cho MJ, Sundaresan V. Efficient parthenogenesis via egg cell expression of maize BABY BOOM 1: a step toward synthetic apomixis. Plant Physiol 2023; 193:2278-2281. [PMID: 37610248 DOI: 10.1093/plphys/kiad461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2023] [Revised: 08/01/2023] [Accepted: 08/21/2023] [Indexed: 08/24/2023]
Abstract
The maize BABY BOOM 1 gene, when ectopically expressed in egg cells, induces parthenogenetic haploid progeny at high frequency, suggesting a promising route for producing clonal hybrid seeds in maize.
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Affiliation(s)
- Debra J Skinner
- Department of Plant Biology, University of California, Davis, CA 95616, USA
| | - Michelle D Mallari
- Department of Plant Biology, University of California, Davis, CA 95616, USA
| | - Kashaf Zafar
- Department of Plant Sciences, University of California, Davis, CA 95616, USA
| | - Myeong-Je Cho
- Plant Genomics and Transformation Facility, Innovative Genomics Institute, University of California, Berkeley 94704, USA
| | - Venkatesan Sundaresan
- Department of Plant Biology, University of California, Davis, CA 95616, USA
- Department of Plant Sciences, University of California, Davis, CA 95616, USA
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5
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Wu X, Xie L, Sun X, Wang N, Finnegan EJ, Helliwell C, Yao J, Zhang H, Wu X, Hands P, Lu F, Ma L, Zhou B, Chaudhury A, Cao X, Luo M. Mutation in Polycomb repressive complex 2 gene OsFIE2 promotes asexual embryo formation in rice. Nat Plants 2023; 9:1848-1861. [PMID: 37814022 PMCID: PMC10654051 DOI: 10.1038/s41477-023-01536-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 09/06/2023] [Indexed: 10/11/2023]
Abstract
Prevention of autonomous division of the egg apparatus and central cell in a female gametophyte before fertilization ensures successful reproduction in flowering plants. Here we show that rice ovules of Polycomb repressive complex 2 (PRC2) Osfie1 and Osfie2 double mutants exhibit asexual embryo and autonomous endosperm formation at a high frequency, while ovules of single Osfie2 mutants display asexual pre-embryo-like structures at a lower frequency without fertilization. Earlier onset, higher penetrance and better development of asexual embryos in the double mutants compared with those in Osfie2 suggest that the autonomous endosperm facilitated asexual embryo development. Transcriptomic analysis showed that male genome-expressed OsBBM1 and OsWOX8/9 were activated in the asexual embryos. Similarly, the maternal alleles of the paternally expressed imprinted genes were activated in the autonomous endosperm, suggesting that the egg apparatus and central cell convergently adopt PRC2 to maintain the non-dividing state before fertilization, possibly through silencing of the maternal alleles of male genome-expressed genes.
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Affiliation(s)
- Xiaoba Wu
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, Australia.
| | - Liqiong Xie
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, School of Life Science and Technology, Xinjiang University, Urumqi, P. R. China
| | - Xizhe Sun
- The State Key Laboratory of North China Crop Improvement and Regulation, College of Horticulture, Hebei Agricultural University, Baoding, P. R. China
- Division of Plant Science, Research School of Biology, the Australian National University, Canberra, Australian Capital Territory, Australia
| | - Ningning Wang
- Faculty of Agronomy, Jilin Agricultural University, Changchun, P. R. China
| | - E Jean Finnegan
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, Australia
| | - Chris Helliwell
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, Australia
| | - Jialing Yao
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, P. R. China
| | - Hongyu Zhang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Rice Research Institute, Sichuan Agricultural University, Chengdu, P. R. China
| | - Xianjun Wu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Rice Research Institute, Sichuan Agricultural University, Chengdu, P. R. China
| | - Phil Hands
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, Australia
| | - Falong Lu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, P. R. China
- University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Lisong Ma
- The State Key Laboratory of North China Crop Improvement and Regulation, College of Horticulture, Hebei Agricultural University, Baoding, P. R. China
- Division of Plant Science, Research School of Biology, the Australian National University, Canberra, Australian Capital Territory, Australia
| | - Bing Zhou
- Institute of Zoology, Chinese Academy of Sciences, Beijing, P. R. China
| | - Abed Chaudhury
- Krishan Foundation Pty Ltd, Canberra, Australian Capital Territory, Australia
| | - Xiaofeng Cao
- University of Chinese Academy of Sciences, Beijing, P. R. China
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, P. R. China
| | - Ming Luo
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, Australia.
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6
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Siena LA, Michaud C, Selles B, Vega JM, Pessino SC, Ingouff M, Ortiz JPA, Leblanc O. TRIMETHYLGUANOSINE SYNTHASE1 mutations decanalize female germline development in Arabidopsis. New Phytol 2023; 240:597-612. [PMID: 37548040 DOI: 10.1111/nph.19179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 07/14/2023] [Indexed: 08/08/2023]
Abstract
Here, we report the characterization of a plant RNA methyltransferase, orthologous to yeast trimethylguanosine synthase1 (Tgs1p) and whose downregulation was associated with apomixis in Paspalum grasses. Using phylogenetic analyses and yeast complementation, we determined that land plant genomes all encode a conserved, specific TGS1 protein. Next, we studied the role of TGS1 in female reproduction using reporter lines and loss-of-function mutants in Arabidopsis thaliana. pAtTGS1:AtTGS1 reporters showed a dynamic expression pattern. They were highly active in the placenta and ovule primordia at emergence but, subsequently, showed weak signals in the nucellus. Although expressed throughout gametophyte development, activity became restricted to the female gamete and was also detected after fertilization during embryogenesis. TGS1 depletion altered the specification of the precursor cells that give rise to the female gametophytic generation and to the sporophyte, resulting in the formation of a functional aposporous-like lineage. Our results indicate that TGS1 participates in the mechanisms restricting cell fate acquisition to a single cell at critical transitions throughout the female reproductive lineage and, thus, expand our current knowledge of the mechanisms governing female reproductive fate in plants.
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Affiliation(s)
- Lorena A Siena
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | | | - Benjamin Selles
- DIADE, Univ Montpellier, IRD, CIRAD, 34394, Montpellier, France
| | - Juan Manuel Vega
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | - Silvina C Pessino
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | - Mathieu Ingouff
- DIADE, Univ Montpellier, IRD, CIRAD, 34394, Montpellier, France
| | - Juan Pablo A Ortiz
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | - Olivier Leblanc
- DIADE, Univ Montpellier, IRD, CIRAD, 34394, Montpellier, France
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7
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Rogo U, Fambrini M, Pugliesi C. Embryo Rescue in Plant Breeding. Plants (Basel) 2023; 12:3106. [PMID: 37687352 PMCID: PMC10489947 DOI: 10.3390/plants12173106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 08/14/2023] [Accepted: 08/19/2023] [Indexed: 09/10/2023]
Abstract
Embryo rescue (ER) techniques are among the oldest and most successful in vitro tissue culture protocols used with plant species. ER refers to a series of methods that promote the development of an immature or lethal embryo into a viable plant. Intraspecific, interspecific, or intergeneric crosses allow the introgression of important alleles of agricultural interest from wild species, such as resistance or tolerance to abiotic and biotic stresses or morphological traits in crops. However, pre-zygotic and post-zygotic reproductive barriers often present challenges in achieving successful hybridization. Pre-zygotic barriers manifest as incompatibility reactions that hinder pollen germination, pollen tube growth, or penetration into the ovule occurring in various tissues, such as the stigma, style, or ovary. To overcome these barriers, several strategies are employed, including cut-style or graft-on-style techniques, the utilization of mixed pollen from distinct species, placenta pollination, and in vitro ovule pollination. On the other hand, post-zygotic barriers act at different tissues and stages ranging from early embryo development to the subsequent growth and reproduction of the offspring. Many crosses among different genera result in embryo abortion due to the failure of endosperm development. In such cases, ER techniques are needed to rescue these hybrids. ER holds great promise for not only facilitating successful crosses but also for obtaining haploids, doubled haploids, and manipulating the ploidy levels for chromosome engineering by monosomic and disomic addition as well substitution lines. Furthermore, ER can be used to shorten the reproductive cycle and for the propagation of rare plants. Additionally, it has been repeatedly used to study the stages of embryonic development, especially in embryo-lethal mutants. The most widely used ER procedure is the culture of immature embryos taken and placed directly on culture media. In certain cases, the in vitro culture of ovule, ovaries or placentas enables the successful development of young embryos from the zygote stage to maturity.
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Affiliation(s)
| | | | - Claudio Pugliesi
- Department of Agriculture Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy; (U.R.); (M.F.)
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8
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Chen X, Li Y, Ai G, Chen J, Guo D, Zhu Z, Zhu X, Tian S, Wang J, Liu M, Yuan L. Creation of a watermelon haploid inducer line via ClDMP3-mediated single fertilization of the central cell. Hortic Res 2023; 10:uhad081. [PMID: 37323231 PMCID: PMC10261877 DOI: 10.1093/hr/uhad081] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2023] [Accepted: 04/18/2023] [Indexed: 06/17/2023]
Abstract
The use of doubled haploids is one of the most efficient breeding methods in modern agriculture. Irradiation of pollen grains has been shown to induce haploids in cucurbit crops, possibly because it causes preferential fertilization of the central cell over the egg cell. Disruption of the DMP gene is known to induce single fertilization of the central cell, which can lead to the formation of haploids. In the present study, a detailed method of creating a watermelon haploid inducer line via ClDMP3 mutation is described. The cldmp3 mutant induced haploids in multiple watermelon genotypes at rates of up to 1.12%. These haploids were confirmed via fluorescent markers, flow cytometry, molecular markers, and immuno-staining. The haploid inducer created by this method has the potential to greatly advance watermelon breeding in the future.
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Affiliation(s)
- Xiner Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling, 712100, Shanxi, China
| | - Yuxiu Li
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling, 712100, Shanxi, China
| | - Gongli Ai
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling, 712100, Shanxi, China
| | - Jinfan Chen
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling, 712100, Shanxi, China
| | - Dalong Guo
- College of Horticulture and Plant Protection Henan University of Science and Technology, 471000, Luoyang, China
| | - Zhonghou Zhu
- Luoyang Nongfa Agricultural Technology Co., LTD, 471100, Luoyang, China
| | - Xuejie Zhu
- Luoyang Nongfa Agricultural Technology Co., LTD, 471100, Luoyang, China
| | - Shujuan Tian
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling, 712100, Shanxi, China
- Shenzhen Research Institute, Northwest A&F University, Shenzhen, 518000, Guangdong, China
| | - Jiafa Wang
- State Key Laboratory of Crop Stress Biology for Arid Areas, College of Horticulture, Northwest A&F University, Yangling, 712100, Shanxi, China
- Shenzhen Research Institute, Northwest A&F University, Shenzhen, 518000, Guangdong, China
| | - Man Liu
- Corresponding author. E-mail: ,
| | - Li Yuan
- Corresponding author. E-mail: ,
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9
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Mahlandt A, Singh DK, Mercier R. Engineering apomixis in crops. Theor Appl Genet 2023; 136:131. [PMID: 37199785 DOI: 10.1007/s00122-023-04357-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 04/04/2023] [Indexed: 05/19/2023]
Abstract
Apomixis is an asexual mode of reproduction through seeds where progeny are clones of the mother plants. Naturally apomictic modes of reproduction are found in hundreds of plant genera distributed across more than 30 plant families, but are absent in major crop plants. Apomixis has the potential to be a breakthrough technology by allowing the propagation through seed of any genotype, including F1 hybrids. Here, we have summarized the recent progress toward synthetic apomixis, where combining targeted modifications of both the meiosis and fertilization processes leads to the production of clonal seeds at high frequencies. Despite some remaining challenges, the technology has approached a level of maturity that allows its consideration for application in the field.
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Affiliation(s)
- Alexander Mahlandt
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, Cologne, Germany
| | - Dipesh Kumar Singh
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, Cologne, Germany
| | - Raphael Mercier
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Carl-von-Linné-Weg 10, Cologne, Germany.
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10
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Luo M, Wu X, Xie L, Sun X, Wang N, Finnegan J, Helliwell C, Yao J, Zhang H, Wu X, Lu F, Ma L, Zhou B, Chaudhury A, Cao X, Hands P. Polycomb Repressive Complex 2 (PRC2) suppresses asexual embryo and autonomous endosperm formation in rice.. [DOI: 10.21203/rs.3.rs-1087314/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
Abstract
Abstract
Prevention of autonomous division of the egg apparatus and central cell in a female gametophyte before fertilization ensures successful reproduction in flowering plants. Here we show that rice ovules with PRC2 Osfie1 and Osfie2 double mutations exhibit asexual embryo and autonomous endosperm formation at a high frequency, while ovules with a single Osfie2 mutation display asexual pre-embryo-like structures at a lower frequency without fertilization. Confocal microscopy images indicate that the asexual embryos were mainly derived from eggs in the double mutants, while the asexual pre-embryos likely originated from eggs or synergids. Early onsetting, higher penetrance and better development of asexual embryos in the double mutants compared with those in Osfie2 suggest that autonomous endosperm facilitated the asexual embryo development. Transcriptomic analysis showed pluripotency factors such as male genome expressed OsBBM1 and OsWOX8/9 were activated in the asexual embryos. Similarly, the maternal alleles of the paternally expressed imprinted genes were activated in the autonomous endosperm. Our results suggest that the egg apparatus and central cell convergently adopt PRC2 to suppresses asexual embryo and autonomous endosperm formation possibly through silencing male genome-expressed genes.
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Affiliation(s)
- Ming Luo
- CSIRO Agriculture and Food, Box 1700, ACT 2601, Australia
| | - Xiaoba Wu
- Institute of Botany, Chinese Academy of Sciences
| | - Liqiong Xie
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, School of Life Science and Technology, Xinjiang University, Urumqi 830046, P. R. China
| | - Xizhe Sun
- Division of Plant Science, Research School of Biology, the Australian National University, ACT 2601, Australia
| | - Ningning Wang
- Faculty of agronomy, Jilin Agricultural University, Changchun, 130118, P.R. China
| | - Jean Finnegan
- CSIRO Agriculture and Food, Box 1700, ACT 2601, Australia
| | | | | | - Hongyu Zhang
- Sate Key Laboratory of Gene Discovery and Utilization, Rice Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu 611130, P. R. China
| | | | - Falong Lu
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences
| | - Lisong Ma
- Division of Plant Science, Research School of Biology, the Australian National University, ACT 2601, Australia
| | - Bing Zhou
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences; Beijing
| | | | - Xiaofeng Cao
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences
| | - Phil Hands
- CSIRO Agriculture and Food, Box 1700, ACT 2601, Australia
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11
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Liu C, He Z, Zhang Y, Hu F, Li M, Liu Q, Huang Y, Wang J, Zhang W, Wang C, Wang K. Synthetic apomixis enables stable transgenerational transmission of heterotic phenotypes in hybrid rice. Plant Commun 2023; 4:100470. [PMID: 36325606 PMCID: PMC10030361 DOI: 10.1016/j.xplc.2022.100470] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Revised: 09/28/2022] [Accepted: 10/29/2022] [Indexed: 05/04/2023]
Abstract
In hybrid plants, heterosis often produces large, vigorous plants with high yields; however, hybrid seeds are generated by costly and laborious crosses of inbred parents. Apomixis, in which a plant produces a clone of itself via asexual reproduction through seeds, may produce another revolution in plant biology. Recently, synthetic apomixis enabled clonal reproduction of F1 hybrids through seeds in rice (Oryza sativa), but the inheritance of the synthetic apomixis trait and superior heterotic phenotypes across generations remained unclear. Here, we propagated clonal plants to the T4 generation and investigated their genetic and molecular stability at each generation. By analyzing agronomic traits, as well as the genome, methylome, transcriptome, and allele-specific transcriptome, we showed that the descendant clonal plants remained stable. Unexpectedly, in addition to normal clonal seeds, the plants also produced a few aneuploids that had eliminated large genomic segments in each generation. Despite the identification of rare aneuploids, the observation that the synthetic apomixis trait is stably transmitted through multiple generations helps confirm the feasibility of using apomixis in the future.
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Affiliation(s)
- Chaolei Liu
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
| | - Zexue He
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, CIC-MCP, Nanjing Agriculture University, Nanjing, Jiangsu 210095, China
| | - Yan Zhang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
| | - Fengyue Hu
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
| | - Mengqi Li
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, CIC-MCP, Nanjing Agriculture University, Nanjing, Jiangsu 210095, China
| | - Qing Liu
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
| | - Yong Huang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
| | - Jian Wang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
| | - Wenli Zhang
- State Key Laboratory for Crop Genetics and Germplasm Enhancement, CIC-MCP, Nanjing Agriculture University, Nanjing, Jiangsu 210095, China.
| | - Chun Wang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China.
| | - Kejian Wang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China; Hainan Yazhou Bay Seed Lab, Sanya, Hainan 572025, China.
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12
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Wei X, Liu C, Chen X, Lu H, Wang J, Yang S, Wang K. Synthetic apomixis with normal hybrid rice seed production. Mol Plant 2023; 16:489-492. [PMID: 36609144 DOI: 10.1016/j.molp.2023.01.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/03/2023] [Accepted: 01/04/2023] [Indexed: 06/17/2023]
Affiliation(s)
- Xin Wei
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
| | - Chaolei Liu
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
| | - Xi Chen
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
| | - Hongwei Lu
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
| | - Jian Wang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China
| | - Shenlin Yang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China; Hainan Yazhou Bay Seed Laboratory, Sanya 572025, China
| | - Kejian Wang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Hangzhou 310006, China; Hainan Yazhou Bay Seed Laboratory, Sanya 572025, China.
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13
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Zhang X, Shi C, Li S, Zhang B, Luo P, Peng X, Zhao P, Dresselhaus T, Sun MX. A female in vivo haploid-induction system via mutagenesis of egg cell-specific peptidases. Mol Plant 2023; 16:471-480. [PMID: 36600599 DOI: 10.1016/j.molp.2023.01.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 12/08/2022] [Accepted: 01/03/2023] [Indexed: 06/17/2023]
Abstract
Crop breeding schemes can be significantly accelerated by using (doubled) haploid plants. In vivo haploid induction has been applied in plant breeding for decades but is still not available for all crops and genotypes, and haploidization rates are generally very low. Therefore, methodological improvements to and new concepts for haploidization are required. Here, we report a novel system for the induction of haploid plants by mutating genes encoding egg cell-specific aspartic endopeptidases (ECSs). We show that after successful sperm-egg cell fusion, ECSs play a critical role to ensure male and female nucleus fusion after fertilization. The ecs1 ecs2 double mutant can induce haploids by both selfing and hybridization in Arabidopsis and ECS mutation is also capable of producing haploids in rice. In summary, our study develops a novel approach for maternal haploidization and provides new insights into the molecular basis of fertilization.
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Affiliation(s)
- Xuecheng Zhang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Ce Shi
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Siling Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Bo Zhang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Pan Luo
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xiongbo Peng
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China; Hubei Hongshan Laboratory, Wuhan 430070, China
| | - Thomas Dresselhaus
- Cell Biology and Plant Biochemistry, University of Regensburg, Regensburg, Germany
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China.
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14
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Xiong J, Hu F, Ren J, Huang Y, Liu C, Wang K. Synthetic apomixis: the beginning of a new era. Curr Opin Biotechnol 2023; 79:102877. [PMID: 36628906 DOI: 10.1016/j.copbio.2022.102877] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 11/24/2022] [Accepted: 12/05/2022] [Indexed: 01/11/2023]
Abstract
Apomixis is a process of asexual reproduction that enables plants to bypass meiosis and fertilization to generate clonal seeds that are identical to the maternal genotype. Apomixis has tremendous potential for breeding plants with desired characteristics, given its ability to fix any elite genotype. However, little is known about the origin and dynamics of natural apomictic plant systems. The introgression of apomixis-related genes from natural apomicts has achieved limited success. Therefore, synthetic apomixis, engineered to include apomeiosis, autonomous embryo formation, and autonomous endosperm development, has been proposed as a promising platform to effectuate apomixis in any crop. In this study, we have summarized recent advances in the understanding of synthetic apomixis and discussed the limitations of current synthetic apomixis systems and ways to overcome them.
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15
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Shen K, Qu M, Zhao P. The Roads to Haploid Embryogenesis. Plants (Basel) 2023; 12:plants12020243. [PMID: 36678955 PMCID: PMC9865920 DOI: 10.3390/plants12020243] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 12/19/2022] [Accepted: 12/30/2022] [Indexed: 05/31/2023]
Abstract
Although zygotic embryogenesis is usually studied in the field of seed biology, great attention has been paid to the methods used to generate haploid embryos due to their applications in crop breeding. These mainly include two methods for haploid embryogenesis: in vitro microspore embryogenesis and in vivo haploid embryogenesis. Although microspore culture systems and maize haploid induction systems were discovered in the 1960s, little is known about the molecular mechanisms underlying haploid formation. In recent years, major breakthroughs have been made in in vivo haploid induction systems, and several key factors, such as the matrilineal (MTL), baby boom (BBM), domain of unknown function 679 membrane protein (DMP), and egg cell-specific (ECS) that trigger in vivo haploid embryo production in both the crops and Arabidopsis models have been identified. The discovery of these haploid inducers indicates that haploid embryogenesis is highly related to gamete development, fertilization, and genome stability in ealry embryos. Here, based on recent efforts to identify key players in haploid embryogenesis and to understand its molecular mechanisms, we summarize the different paths to haploid embryogenesis, and we discuss the mechanisms of haploid generation and its potential applications in crop breeding. Although these haploid-inducing factors could assist egg cells in bypassing fertilization to initiate embryogenesis or trigger genome elimination in zygotes after fertilization to form haploid embryos, the fertilization of central cells to form endosperms is a prerequisite step for haploid formation. Deciphering the molecular and cellular mechanisms for haploid embryogenesis, increasing the haploid induction efficiency, and establishing haploid induction systems in other crops are critical for promoting the application of haploid technology in crop breeding, and these should be addressed in further studies.
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Affiliation(s)
- Kun Shen
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Mengxue Qu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
- Hubei Hongshan Laboratory, Wuhan 430070, China
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16
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Vernet A, Meynard D, Lian Q, Mieulet D, Gibert O, Bissah M, Rivallan R, Autran D, Leblanc O, Meunier AC, Frouin J, Taillebois J, Shankle K, Khanday I, Mercier R, Sundaresan V, Guiderdoni E. High-frequency synthetic apomixis in hybrid rice. Nat Commun 2022; 13:7963. [PMID: 36575169 DOI: 10.1038/s41467-022-35679-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 12/18/2022] [Indexed: 12/28/2022] Open
Abstract
Introducing asexual reproduction through seeds - apomixis - into crop species could revolutionize agriculture by allowing F1 hybrids with enhanced yield and stability to be clonally propagated. Engineering synthetic apomixis has proven feasible in inbred rice through the inactivation of three genes (MiMe), which results in the conversion of meiosis into mitosis in a line ectopically expressing the BABYBOOM1 (BBM1) parthenogenetic trigger in egg cells. However, only 10-30% of the seeds are clonal. Here, we show that synthetic apomixis can be achieved in an F1 hybrid of rice by inducing MiMe mutations and egg cell expression of BBM1 in a single step. We generate hybrid plants that produce more than 95% of clonal seeds across multiple generations. Clonal apomictic plants maintain the phenotype of the F1 hybrid along successive generations. Our results demonstrate that there is no barrier to almost fully penetrant synthetic apomixis in an important crop species, rendering it compatible with use in agriculture.
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17
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Fambrini M, Usai G, Pugliesi C. Induction of Somatic Embryogenesis in Plants: Different Players and Focus on WUSCHEL and WUS-RELATED HOMEOBOX (WOX) Transcription Factors. Int J Mol Sci 2022; 23. [PMID: 36555594 DOI: 10.3390/ijms232415950] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/06/2022] [Accepted: 12/08/2022] [Indexed: 12/23/2022] Open
Abstract
In plants, other cells can express totipotency in addition to the zygote, thus resulting in embryo differentiation; this appears evident in apomictic and epiphyllous plants. According to Haberlandt's theory, all plant cells can regenerate a complete plant if the nucleus and the membrane system are intact. In fact, under in vitro conditions, ectopic embryos and adventitious shoots can develop from many organs of the mature plant body. We are beginning to understand how determination processes are regulated and how cell specialization occurs. However, we still need to unravel the mechanisms whereby a cell interprets its position, decides its fate, and communicates it to others. The induction of somatic embryogenesis might be based on a plant growth regulator signal (auxin) to determine an appropriate cellular environment and other factors, including stress and ectopic expression of embryo or meristem identity transcription factors (TFs). Still, we are far from having a complete view of the regulatory genes, their target genes, and their action hierarchy. As in animals, epigenetic reprogramming also plays an essential role in re-establishing the competence of differentiated cells to undergo somatic embryogenesis. Herein, we describe the functions of WUSCHEL-RELATED HOMEOBOX (WOX) transcription factors in regulating the differentiation-dedifferentiation cell process and in the developmental phase of in vitro regenerated adventitious structures.
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18
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Noyes RD. Mendelian segregation for parthenogenetic embryo development at the diploid level in the flowering plant Erigeron. Am J Bot 2022; 109:1641-1651. [PMID: 36112611 DOI: 10.1002/ajb2.16071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 06/15/2023]
Abstract
PREMISE Parthenogenesis is the capacity of organisms to develop embryos from unfertilized eggs. When parthenogenesis is coupled with unreduced gamete formation (apomeiosis), genetically maternal progeny result. Genetic elucidation of this form of reproduction in plants, apomixis, has important agronomic implications. However, genetic characterization of apomeiosis and parthenogenesis has been problematic in part because the traits usually co-occur and are restricted to polyploids. In this work, the inheritance of parthenogenetic embryo development, by itself, was studied at the diploid level. METHODS Progeny resulting from a cross between a diploid (2n = 18), heterozygous, parthenogenetic pollen donor, and a diploid, wildtype, sexual seed parent were evaluated. Paternity was tested with conserved orthologous sequence (COS) markers, reproductive development of F1s was evaluated with microscopy of cleared ovules, and an amplified fragment length polymorphism (AFLP) marker (Eagc × Macg.615) co-segregating with parthenogenesis was characterized at the sequence level. RESULTS Of 102 diploid biparental progeny, 47 exhibited parthenogenetic embryo and endosperm development, and 55 lacked development of the egg and central cell. This result is consistent with Mendelian inheritance for a single locus (P = 0.43). Isolation and sequencing of the AFLP marker indicates that it is likely a portion of a Ty-Gypsy retrotransposon. Attempts to develop a sequence-characterized amplified region marker from the AFLP were unsuccessful. CONCLUSIONS This work shows that parthenogenesis can be transmitted simply at the diploid level. This advance is key in the development of a tractable system in Erigeron aimed at the identification of the parthenogenesis locus using genetic mapping strategies.
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Affiliation(s)
- Richard D Noyes
- Department of Biology, University of Central Arkansas, Conway, AR, US 72035
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19
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Chahal LS, Conner JA, Ozias-Akins P. Phylogenetically Distant BABY BOOM Genes From Setaria italica Induce Parthenogenesis in Rice. Front Plant Sci 2022; 13:863908. [PMID: 35909735 PMCID: PMC9329937 DOI: 10.3389/fpls.2022.863908] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 06/13/2022] [Indexed: 06/02/2023]
Abstract
The combination of apomixis and hybrid production is hailed as the holy grail of agriculture for the ability of apomixis to fix heterosis of F1 hybrids in succeeding generations, thereby eliminating the need for repeated crosses to produce F1 hybrids. Apomixis, asexual reproduction through seed, achieves this feat by circumventing two processes that are fundamental to sexual reproduction (meiosis and fertilization) and replacing them with apomeiosis and parthenogenesis, resulting in seeds that are clonal to the maternal parent. Parthenogenesis, embryo development without fertilization, has been genetically engineered in rice, maize, and pearl millet using PsASGR-BABY BOOM-like (PsASGR-BBML) transgenes and in rice using the OsBABY BOOM1 (OsBBM1) cDNA sequence when expressed under the control of egg cell-specific promoters. A phylogenetic analysis revealed that BABY BOOM (BBM)/BBML genes from monocots cluster within three different clades. The BBM/BBML genes shown to induce parthenogenesis cluster within clade 1 (the ASGR-BBML clade) along with orthologs from other monocot species, such as Setaria italica. For this study, we tested the parthenogenetic potential of three BBM transgenes from S. italica, each a member of a different phylogenetic BBM clade. All transgenes were genomic constructs under the control of the AtDD45 egg cell-specific promoter. All SiBBM transgenes induced various levels of parthenogenetic embryo development, resulting in viable haploid T1 seedlings. Poor seed set and lower haploid seed production were characteristics of multiple transgenic lines. The results presented in this study illustrate that further functional characterization of BBMs in zygote/embryo development is warranted.
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Affiliation(s)
- Lovepreet Singh Chahal
- Institute of Plant Breeding, Genetics, and Genomics, University of Georgia, Tifton, GA, United States
| | - Joann A. Conner
- Institute of Plant Breeding, Genetics, and Genomics, University of Georgia, Tifton, GA, United States
- Department of Horticulture, University of Georgia, Tifton, GA, United States
| | - Peggy Ozias-Akins
- Institute of Plant Breeding, Genetics, and Genomics, University of Georgia, Tifton, GA, United States
- Department of Horticulture, University of Georgia, Tifton, GA, United States
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20
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Sidhu GS, Conner JA, Ozias-Akins P. Controlled Induction of Parthenogenesis in Transgenic Rice via Post-translational Activation of PsASGR-BBML. Front Plant Sci 2022; 13:925467. [PMID: 35873991 PMCID: PMC9305695 DOI: 10.3389/fpls.2022.925467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Accepted: 05/25/2022] [Indexed: 06/15/2023]
Abstract
Modern plant breeding programs rely heavily on the generation of homozygous lines, with the traditional process requiring the inbreeding of a heterozygous cross for five to six generations. Doubled haploid (DH) technology, a process of generating haploid plants from an initial heterozygote, followed by chromosome doubling, reduces the process to two generations. Currently established in vitro methods of haploid induction include androgenesis and gynogenesis, while in vivo methods are based on uni-parental genome elimination. Parthenogenesis, embryogenesis from unfertilized egg cells, presents another potential method of haploid induction. PsASGR-BABY BOOM-like, an AP2 transcription factor, induces parthenogenesis in a natural apomictic species, Pennisetum squamulatum (Cenchrus squamulatus) and PsASGR-BBML transgenes promote parthenogenesis in several crop plants, including rice, maize, and pearl millet. The dominant nature of PsASGR-BBML transgenes impedes their use in DH technology. Using a glucocorticoid-based post-translational regulation system and watering with a 100 μM DEX solution before anthesis, PsASGR-BBML can be regulated at the flowering stage to promote parthenogenesis. Conditional expression presents a novel opportunity to use parthenogenetic genes in DH production technology and to elucidate the molecular mechanism underlying parthenogenetic embryogenesis.
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Affiliation(s)
- Gurjot Singh Sidhu
- Institute of Plant Breeding, Genetics, and Genomics, University of Georgia, Tifton, GA, United States
| | - Joann A. Conner
- Institute of Plant Breeding, Genetics, and Genomics, University of Georgia, Tifton, GA, United States
- Department of Horticulture, University of Georgia, Tifton, GA, United States
| | - Peggy Ozias-Akins
- Institute of Plant Breeding, Genetics, and Genomics, University of Georgia, Tifton, GA, United States
- Department of Horticulture, University of Georgia, Tifton, GA, United States
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21
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Chen B, Maas L, Figueiredo D, Zhong Y, Reis R, Li M, Horstman A, Riksen T, Weemen M, Liu H, Siemons C, Chen S, Angenent GC, Boutilier K. BABY BOOM regulates early embryo and endosperm development. Proc Natl Acad Sci U S A 2022; 119:e2201761119. [PMID: 35709319 DOI: 10.1073/pnas.2201761119] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The zygote is a totipotent structure that develops into an embryo with all of the cells needed to produce an entire plant. The BABY BOOM (BBM) transcription factor induces spontaneous asexual embryo development on plant organs when ectopically expressed. Although BBM is at the top of a transcriptional network that promotes asexual embryo development, little is known about its expression and role during zygotic embryogenesis. Here we show in Arabidopsis that BBM regulates the progression of zygotic embryo development and embryo patterning, and division and cellularization of the filial endosperm. In line with its role as a totipotency factor, ectopic BBM expression in the egg cell is also sufficient to induce haploid embryo development in Arabidopsis and dicot crops. The BABY BOOM (BBM) AINTEGUMENTA-LIKE (AIL) AP2/ERF domain transcription factor is a major regulator of plant cell totipotency, as it induces asexual embryo formation when ectopically expressed. Surprisingly, only limited information is available on the role of BBM during zygotic embryogenesis. Here we reexamined BBM expression and function in the model plant Arabidopsis thaliana (Arabidopsis) using reporter analysis and newly developed CRISPR mutants. BBM was expressed in the embryo from the zygote stage and also in the maternal (nucellus) and filial (endosperm) seed tissues. Analysis of CRISPR mutant alleles for BBM (bbm-cr) and the redundantly acting AIL gene PLETHORA2 (PLT2) (plt2-cr) uncovered individual roles for these genes in the timing of embryo progression. We also identified redundant roles for BBM and PLT2 in endosperm proliferation and cellularization and the maintenance of zygotic embryo development. Finally, we show that ectopic BBM expression in the egg cell of Arabidopsis and the dicot crops Brassica napus and Solanum lycopersicon is sufficient to bypass the fertilization requirement for embryo development. Together these results highlight roles for BBM and PLT2 in seed development and demonstrate the utility of BBM genes for engineering asexual embryo development in dicot species.
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22
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Eliby S, Bekkuzhina S, Kishchenko O, Iskakova G, Kylyshbayeva G, Jatayev S, Soole K, Langridge P, Borisjuk N, Shavrukov Y. Developments and prospects for doubled haploid wheat. Biotechnol Adv 2022; 60:108007. [PMID: 35732257 DOI: 10.1016/j.biotechadv.2022.108007] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 05/28/2022] [Accepted: 06/15/2022] [Indexed: 11/02/2022]
Abstract
Doubled haploid production is a valuable biotechnology that can accelerate the breeding of new wheat varieties by several years through the one-step creation of 100% homozygous plants. The technology also plays important role in studying the genetic control of traits in wheat, in marker-assisted selection, in genomics and in genetic engineering. In this paper, recent advances in androgenesis and gynogenesis techniques, emphasizing predominantly the in vitro culture phase, as well as the emerging innovative approaches in researching and producing wheat doubled haploids are reviewed. Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)-based genome editing, that allows targeted mutagenesis and gene targeting, is being tested extensively as a powerful and precise tool to induce doubled haploids in wheat. The review provides the reader with recent examples of gene modifications in wheat to induce haploidy.
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Affiliation(s)
- Serik Eliby
- University of Adelaide, Urrbrae, SA, Australia
| | - Sara Bekkuzhina
- Faculty of Agronomy, S.Seifullin Kazakh AgroTechnical University, Nur-Sultan, Kazakhstan
| | - Olena Kishchenko
- Jiangsu Key Laboratory for Eco-Agricultural Biotechnology around Hongze Lake, School of Life Sciences, Huaiyin Normal University, Huai'an, China; Institute of Cell Biology and Genetic Engineering, National Academy of Science of Ukraine, Kyiv, Ukraine
| | - Gulnur Iskakova
- Kazakh Agrarian National University, Almaty, Kazakhstan; Institute of Molecular Biology and Biochemistry, Almaty, Kazakhstan
| | | | - Satyvaldy Jatayev
- Faculty of Agronomy, S.Seifullin Kazakh AgroTechnical University, Nur-Sultan, Kazakhstan
| | - Kathleen Soole
- College of Science and Engineering, Biological Sciences, Flinders University, SA, Australia
| | - Peter Langridge
- University of Adelaide, Urrbrae, SA, Australia; Wheat Initiative, Julius-Kühn-Institute, Berlin, Germany
| | - Nikolai Borisjuk
- Jiangsu Key Laboratory for Eco-Agricultural Biotechnology around Hongze Lake, School of Life Sciences, Huaiyin Normal University, Huai'an, China
| | - Yuri Shavrukov
- College of Science and Engineering, Biological Sciences, Flinders University, SA, Australia.
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23
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Abstract
Apomixis is a form of reproduction leading to clonal seeds and offspring that are genetically identical to the maternal plant. While apomixis naturally occurs in hundreds of plant species distributed across diverse plant families, it is absent in major crop species. Apomixis has a revolutionary potential in plant breeding, as it could allow the instant fixation and propagation though seeds of any plant genotype, most notably F1 hybrids. Mastering and implementing apomixis would reduce the cost of hybrid seed production, facilitate new types of hybrid breeding, and make it possible to harness hybrid vigor in crops that are not presently cultivated as hybrids. Synthetic apomixis can be engineered by combining modifications of meiosis and fertilization. Here, we review the current knowledge and recent major achievements toward the development of efficient apomictic systems usable in agriculture.
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Affiliation(s)
- Charles J Underwood
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany; ,
| | - Raphael Mercier
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany; ,
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24
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Chumakov MI, Mazilov SI. Genetic Control of Maize Gynogenesis. RUSS J GENET+ 2022. [DOI: 10.1134/s1022795422040044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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25
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Yin PP, Tang LP, Zhang XS, Su YH. Options for Engineering Apomixis in Plants. Front Plant Sci 2022; 13:864987. [PMID: 35371148 PMCID: PMC8967160 DOI: 10.3389/fpls.2022.864987] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/29/2022] [Accepted: 02/24/2022] [Indexed: 06/14/2023]
Abstract
In plants, embryogenesis and reproduction are not strictly dependent on fertilization. Several species can produce embryos in seeds asexually, a process known as apomixis. Apomixis is defined as clonal asexual reproduction through seeds, whereby the progeny is identical to the maternal genotype, and provides valuable opportunities for developing superior cultivars, as its induction in agricultural crops can facilitate the development and maintenance of elite hybrid genotypes. In this review, we summarize the current understanding of apomixis and highlight the successful introduction of apomixis methods into sexual crops. In addition, we discuss several genes whose overexpression can induce somatic embryogenesis as candidate genes to induce parthenogenesis, a unique reproductive method of gametophytic apomixis. We also summarize three schemes to achieve engineered apomixis, which will offer more opportunities for the realization of apomictic reproduction.
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26
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Underwood CJ, Vijverberg K, Rigola D, Okamoto S, Oplaat C, Camp RHMOD, Radoeva T, Schauer SE, Fierens J, Jansen K, Mansveld S, Busscher M, Xiong W, Datema E, Nijbroek K, Blom EJ, Bicknell R, Catanach A, Erasmuson S, Winefield C, van Tunen AJ, Prins M, Schranz ME, van Dijk PJ. A PARTHENOGENESIS allele from apomictic dandelion can induce egg cell division without fertilization in lettuce. Nat Genet 2022; 54:84-93. [PMID: 34992267 DOI: 10.1038/s41588-021-00984-y] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 11/03/2021] [Indexed: 01/21/2023]
Abstract
Apomixis, the clonal formation of seeds, is a rare yet widely distributed trait in flowering plants. We have isolated the PARTHENOGENESIS (PAR) gene from apomictic dandelion that triggers embryo development in unfertilized egg cells. PAR encodes a K2-2 zinc finger, EAR-domain protein. Unlike the recessive sexual alleles, the dominant PAR allele is expressed in egg cells and has a miniature inverted-repeat transposable element (MITE) transposon insertion in the promoter. The MITE-containing promoter can invoke a homologous gene from sexual lettuce to complement dandelion LOSS OF PARTHENOGENESIS mutants. A similar MITE is also present in the promoter of the PAR gene in apomictic forms of hawkweed, suggesting a case of parallel evolution. Heterologous expression of dandelion PAR in lettuce egg cells induced haploid embryo-like structures in the absence of fertilization. Sexual PAR alleles are expressed in pollen, suggesting that the gene product releases a block on embryogenesis after fertilization in sexual species while in apomictic species PAR expression triggers embryogenesis in the absence of fertilization.
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Affiliation(s)
- Charles J Underwood
- Keygene N.V., Wageningen, the Netherlands
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Kitty Vijverberg
- Biosystematics Group, Wageningen University, Wageningen, the Netherlands
- Naturalis Biodiversity Center, Radboud University, Nijmegen, the Netherlands
| | | | - Shunsuke Okamoto
- Keygene N.V., Wageningen, the Netherlands
- Takii & Co. Ltd, Plant Breeding and Experiment Station, Konan Shiga, Japan
| | - Carla Oplaat
- Biosystematics Group, Wageningen University, Wageningen, the Netherlands
- National Reference Centre of Plant Health, National Plant Protection Organization, Wageningen, the Netherlands
| | | | | | | | | | - Kim Jansen
- Keygene N.V., Wageningen, the Netherlands
| | | | - Marco Busscher
- Biosystematics Group, Wageningen University, Wageningen, the Netherlands
| | - Wei Xiong
- Biosystematics Group, Wageningen University, Wageningen, the Netherlands
| | | | | | | | - Ross Bicknell
- New Zealand Institute for Plant & Food Research, Lincoln, New Zealand
| | - Andrew Catanach
- New Zealand Institute for Plant & Food Research, Lincoln, New Zealand
| | - Sylvia Erasmuson
- New Zealand Institute for Plant & Food Research, Lincoln, New Zealand
| | | | | | | | - M Eric Schranz
- Biosystematics Group, Wageningen University, Wageningen, the Netherlands.
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Soliman M, Bocchini M, Stein J, Ortiz JPA, Albertini E, Delgado L. Environmental and Genetic Factors Affecting Apospory Expressivity in Diploid Paspalum rufum. Plants (Basel) 2021; 10:plants10102100. [PMID: 34685909 PMCID: PMC8537111 DOI: 10.3390/plants10102100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/22/2021] [Accepted: 09/27/2021] [Indexed: 11/30/2022]
Abstract
In angiosperms, gametophytic apomixis (clonal reproduction through seeds) is strongly associated with polyploidy and hybridization. The trait is facultative and its expressivity is highly variable between genotypes. Here, we used an F1 progeny derived from diploid apomictic (aposporic) genotypes of Paspalum rufum and two F2 families, derived from F1 hybrids with different apospory expressivity (%AES), to analyze the influence of the environment and the transgenerational transmission of the trait. In addition, AFLP markers were developed in the F1 population to identify genomic regions associated with the %AES. Cytoembryological analyses showed that the %AES was significantly influenced by different environments, but remained stable across the years. F1 and F2 progenies showed a wide range of %AES variation, but most hybrids were not significantly different from the parental genotypes. Maternal and paternal genetic linkage maps were built covering the ten expected linkage groups (LG). A single-marker analysis detected at least one region of 5.7 cM on LG3 that was significantly associated with apospory expressivity. Our results underline the importance of environmental influence in modulating apospory expressivity and identified a genomic region associated with apospory expressivity at the diploid level.
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Affiliation(s)
- Mariano Soliman
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Rosario S2125ZAA, Zavalla, Argentina; (M.S.); (J.S.); (J.P.A.O.)
| | - Marika Bocchini
- Department Agricultural, Food and Environmental Sciences, University of Perugia, 06121 Perugia, Italy; (M.B.); (E.A.)
| | - Juliana Stein
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Rosario S2125ZAA, Zavalla, Argentina; (M.S.); (J.S.); (J.P.A.O.)
| | - Juan Pablo A. Ortiz
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Rosario S2125ZAA, Zavalla, Argentina; (M.S.); (J.S.); (J.P.A.O.)
| | - Emidio Albertini
- Department Agricultural, Food and Environmental Sciences, University of Perugia, 06121 Perugia, Italy; (M.B.); (E.A.)
| | - Luciana Delgado
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Rosario S2125ZAA, Zavalla, Argentina; (M.S.); (J.S.); (J.P.A.O.)
- Correspondence:
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Dierschke T, Flores-Sandoval E, Rast-Somssich MI, Althoff F, Zachgo S, Bowman JL. Gamete expression of TALE class HD genes activates the diploid sporophyte program in Marchantia polymorpha. eLife 2021; 10:57088. [PMID: 34533136 PMCID: PMC8476127 DOI: 10.7554/elife.57088] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 09/15/2021] [Indexed: 12/16/2022] Open
Abstract
Eukaryotic life cycles alternate between haploid and diploid phases and in phylogenetically diverse unicellular eukaryotes, expression of paralogous homeodomain genes in gametes primes the haploid-to-diploid transition. In the unicellular chlorophyte alga Chlamydomonas, KNOX and BELL TALE-homeodomain genes mediate this transition. We demonstrate that in the liverwort Marchantia polymorpha, paternal (sperm) expression of three of five phylogenetically diverse BELL genes, MpBELL234, and maternal (egg) expression of both MpKNOX1 and MpBELL34 mediate the haploid-to-diploid transition. Loss-of-function alleles of MpKNOX1 result in zygotic arrest, whereas a loss of either maternal or paternal MpBELL234 results in variable zygotic and early embryonic arrest. Expression of MpKNOX1 and MpBELL34 during diploid sporophyte development is consistent with a later role for these genes in patterning the sporophyte. These results indicate that the ancestral mechanism to activate diploid gene expression was retained in early diverging land plants and subsequently co-opted during evolution of the diploid sporophyte body.
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Affiliation(s)
- Tom Dierschke
- School of Biological Sciences, Monash University, Melbourne, Australia.,Botany Department, University of Osnabrück, Osnabrück, Germany
| | | | | | - Felix Althoff
- Botany Department, University of Osnabrück, Osnabrück, Germany
| | - Sabine Zachgo
- Botany Department, University of Osnabrück, Osnabrück, Germany
| | - John L Bowman
- School of Biological Sciences, Monash University, Melbourne, Australia
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29
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Thondehaalmath T, Kulaar DS, Bondada R, Maruthachalam R. Understanding and exploiting uniparental genome elimination in plants: insights from Arabidopsis thaliana. J Exp Bot 2021; 72:4646-4662. [PMID: 33851980 DOI: 10.1093/jxb/erab161] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/06/2020] [Accepted: 04/10/2021] [Indexed: 06/12/2023]
Abstract
Uniparental genome elimination (UGE) refers to the preferential exclusion of one set of the parental chromosome complement during embryogenesis following successful fertilization, giving rise to uniparental haploid progeny. This artificially induced phenomenon was documented as one of the consequences of distant (wide) hybridization in plants. Ten decades since its discovery, attempts to unravel the molecular mechanism behind this process remained elusive due to a lack of genetic tools and genomic resources in the species exhibiting UGE. Hence, its successful adoption in agronomic crops for in planta (in vivo) haploid production remains implausible. Recently, Arabidopsis thaliana has emerged as a model system to unravel the molecular basis of UGE. It is now possible to simulate the genetic consequences of distant crosses in an A. thaliana intraspecific cross by a simple modification of centromeres, via the manipulation of the centromere-specific histone H3 variant gene, CENH3. Thus, the experimental advantages conferred by A. thaliana have been used to elucidate and exploit the benefits of UGE in crop breeding. In this review, we discuss developments and prospects of CENH3 gene-mediated UGE and other in planta haploid induction strategies to illustrate its potential in expediting plant breeding and genetics in A. thaliana and other model plants.
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Affiliation(s)
- Tejas Thondehaalmath
- School of Biology, Indian Institute of Science Education and Research (IISER)- Thiruvananthapuram, Vithura, Kerala, India
| | - Dilsher Singh Kulaar
- School of Biology, Indian Institute of Science Education and Research (IISER)- Thiruvananthapuram, Vithura, Kerala, India
| | - Ramesh Bondada
- School of Biology, Indian Institute of Science Education and Research (IISER)- Thiruvananthapuram, Vithura, Kerala, India
| | - Ravi Maruthachalam
- School of Biology, Indian Institute of Science Education and Research (IISER)- Thiruvananthapuram, Vithura, Kerala, India
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Abstract
Following fertilization in flowering plants (angiosperms), egg and sperm cells unite to form the zygote, which generates an entire new organism through a process called embryogenesis. In this review, we provide a comparative perspective on early zygotic embryogenesis in flowering plants by using the Poaceae maize and rice as monocot grass and crop models as well as Arabidopsis as a eudicot model of the Brassicaceae family. Beginning with the activation of the egg cell, we summarize and discuss the process of maternal-to-zygotic transition in plants, also taking recent work on parthenogenesis and haploid induction into consideration. Aspects like imprinting, which is mainly associated with endosperm development and somatic embryogenesis, are not considered. Controversial findings about the timing of zygotic genome activation as well as maternal versus paternal contribution to zygote and early embryo development are highlighted. The establishment of zygotic polarity, asymmetric division, and apical and basal cell lineages represents another chapter in which we also examine and compare the role of major signaling pathways, cell fate genes, and hormones in early embryogenesis. Except for the model Arabidopsis, little is known about embryopatterning and the establishment of the basic body plan in angiosperms. Using available in situ hybridization, RNA-sequencing, and marker data, we try to compare how and when stem cell niches are established. Finally, evolutionary aspects of plant embryo development are discussed.
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Affiliation(s)
- Thomas Dresselhaus
- Department of Cell Biology and Plant Biochemistry, University of Regensburg, D-93053 Regensburg, Germany;
| | - Gerd Jürgens
- Department of Cell Biology, Max Planck Institute for Developmental Biology, D-72076 Tübingen, Germany
- Center for Plant Molecular Biology, University of Tübingen, D-72076 Tübingen, Germany;
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31
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Ke Y, Podio M, Conner J, Ozias-Akins P. Single-cell transcriptome profiling of buffelgrass (Cenchrus ciliaris) eggs unveils apomictic parthenogenesis signatures. Sci Rep 2021; 11:9880. [PMID: 33972603 PMCID: PMC8110759 DOI: 10.1038/s41598-021-89170-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/15/2021] [Indexed: 12/04/2022] Open
Abstract
Apomixis, a type of asexual reproduction in angiosperms, results in progenies that are genetically identical to the mother plant. It is a highly desirable trait in agriculture due to its potential to preserve heterosis of F1 hybrids through subsequent generations. However, no major crops are apomictic. Deciphering mechanisms underlying apomixis becomes one of the alternatives to engineer self-reproducing capability into major crops. Parthenogenesis, a major component of apomixis, commonly described as the ability to initiate embryo formation from the egg cell without fertilization, also can be valuable in plant breeding for doubled haploid production. A deeper understanding of transcriptional differences between parthenogenetic and sexual or non-parthenogenetic eggs can assist with pathway engineering. By conducting laser capture microdissection-based RNA-seq on sexual and parthenogenetic egg cells on the day of anthesis, a de novo transcriptome for the Cenchrus ciliaris egg cells was created, transcriptional profiles that distinguish the parthenogenetic egg from its sexual counterpart were identified, and functional roles for a few transcription factors in promoting natural parthenogenesis were suggested. These transcriptome data expand upon previous gene expression studies and will be a resource for future research on the transcriptome of egg cells in parthenogenetic and sexual genotypes.
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Affiliation(s)
- Yuji Ke
- Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Tifton, GA, 31793, USA
| | - Maricel Podio
- Department of Horticulture, University of Georgia, Tifton, GA, 31793, USA
| | - Joann Conner
- Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Tifton, GA, 31793, USA.,Department of Horticulture, University of Georgia, Tifton, GA, 31793, USA
| | - Peggy Ozias-Akins
- Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Tifton, GA, 31793, USA. .,Department of Horticulture, University of Georgia, Tifton, GA, 31793, USA.
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Deushi R, Toda E, Koshimizu S, Yano K, Okamoto T. Effect of Paternal Genome Excess on the Developmental and Gene Expression Profiles of Polyspermic Zygotes in Rice. Plants (Basel) 2021; 10:255. [PMID: 33525652 PMCID: PMC7911625 DOI: 10.3390/plants10020255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/22/2021] [Accepted: 01/26/2021] [Indexed: 11/17/2022]
Abstract
Polyploid zygotes with a paternal gamete/genome excess exhibit arrested development, whereas polyploid zygotes with a maternal excess develop normally. These observations indicate that paternal and maternal genomes synergistically influence zygote development via distinct functions. In this study, to clarify how paternal genome excess affects zygotic development, the developmental and gene expression profiles of polyspermic rice zygotes were analyzed. The results indicated that polyspermic zygotes were mostly arrested at the one-cell stage after karyogamy had completed. Through comparison of transcriptomes between polyspermic zygotes and diploid zygotes, 36 and 43 genes with up-regulated and down-regulated expression levels, respectively, were identified in the polyspermic zygotes relative to the corresponding expression in the diploid zygotes. Notably, OsASGR-BBML1, which encodes an AP2 transcription factor possibly involved in initiating rice zygote development, was expressed at a much lower level in the polyspermic zygotes than in the diploid zygotes.
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Affiliation(s)
- Ryouya Deushi
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0392, Japan; (R.D.); (E.T.)
| | - Erika Toda
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0392, Japan; (R.D.); (E.T.)
| | - Shizuka Koshimizu
- Department of Life Sciences, Meiji University, Kanagawa 214-8571, Japan; (S.K.); (K.Y.)
| | - Kentaro Yano
- Department of Life Sciences, Meiji University, Kanagawa 214-8571, Japan; (S.K.); (K.Y.)
| | - Takashi Okamoto
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0392, Japan; (R.D.); (E.T.)
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Abstract
Generation of plant lines with transgene or edited gene variants is the desired outcome of transformation technology. Conventional DNA-based plant transformation methods are the most commonly used technology but these approaches are limited to a small number of plant species with efficient transformation systems. The ideal transformation technologies are those that allow biotechnology applications across wide genetic background, especially within elite germplasm of major crop species. This chapter will briefly review key regulatory genes involved in plant morphogenesis with a focus on in vitro somatic embryogenesis and their application in improving plant transformation.
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Affiliation(s)
- Samson Nalapalli
- Seeds Research, Syngenta Crop Protection LLC, Research Triangle Park, NC, USA.
| | | | - Yuejin Sun
- Seeds Research, Syngenta Crop Protection LLC, Research Triangle Park, NC, USA
| | - Sivamani Elumalai
- Seeds Research, Syngenta Crop Protection LLC, Research Triangle Park, NC, USA
| | - Qiudeng Que
- Seeds Research, Syngenta Crop Protection LLC, Research Triangle Park, NC, USA
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34
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Zhang Z, Conner J, Guo Y, Ozias-Akins P. Haploidy in Tobacco Induced by PsASGR-BBML Transgenes via Parthenogenesis. Genes (Basel) 2020; 11:E1072. [PMID: 32932590 PMCID: PMC7564442 DOI: 10.3390/genes11091072] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/10/2020] [Accepted: 09/10/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Engineering apomixis in sexually reproducing plants has been long desired because of the potential to fix hybrid vigor. Validating the functionality of genes originated from apomictic species that contribute to apomixis upon transfer to sexually reproducing species is an important step. The PsASGR-BABYBOOM-like (PsASGR-BBML) gene from Pennisetum squamulatum confers parthenogenesis in this apomict, and its functionality was demonstrated in several sexually reproducing monocots but not in any dicots. METHODS We introduced the PsASGR-BBML gene regulated by egg cell-specific promoters, either AtDD45 or AtRKD2, into tobacco, and analyzed progeny of the transgenic lines resulting from self-pollination and crossing by flow cytometry. RESULTS We identified haploid progeny at a frequency lower than 1% in the AtDD45pro lines, while at a frequency of 9.3% for an octoploid (2n = 8x) AtRKD2pro line. Haploid production in the T2 generation, derived from the tetraploid T1 offspring of this original octoploid AtRKD2pro line, was also observed. Pollinated by homozygous transgenic tobacco carrying a DsRed marker gene, 4x progeny of the AtRKD2pro line yielded parthenogenetic embryos identified as DsRed negative. We verified that the DsRed negative seedlings recovered were haploid (2x). CONCLUSION The PsASGR-BBML gene regulated by egg cell-specific promoters could enable parthenogenesis in tobacco, a dicotyledon species.
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Affiliation(s)
| | | | | | - Peggy Ozias-Akins
- Department of Horticulture and Institute of Plant Breeding, Genetics & Genomics, University of Georgia, Tifton, GA 31793, USA; (Z.Z.); (J.C.); (Y.G.)
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35
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Abstract
Apomixis, the asexual formation of seeds, is a potentially valuable agricultural trait. Inducing apomixis in sexual crop plants would, for example, allow breeders to fix heterosis in hybrid seeds and rapidly generate doubled haploid crop lines. Molecular models explain the emergence of functional apomixis, i.e., apomeiosis + parthenogenesis + endosperm development, as resulting from a combination of genetic or epigenetic changes that coordinate altered molecular and developmental steps to form clonal seeds. Apomixis-like features and synthetic clonal seeds have been induced with limited success in the sexual plants rice and maize by using gene editing to mutate genes related to meiosis and fertility or via egg-cell specific expression of embryogenesis genes. Inducing functional apomixis and increasing the penetrance of apomictic seed production will be important for commercial deployment of the trait. Optimizing the induction of apomixis with gene editing strategies that use known targets as well as identifying alternative targets will be possible by better understanding natural genetic variation in apomictic species. With the growing availability of genomic data and precise gene editing tools, we are making substantial progress towards engineering apomictic crops.
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Affiliation(s)
- Armin Scheben
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA;
| | - Diego Hojsgaard
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Untere Karspuele 2, 37073 Goettingen, Germany
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36
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Abstract
Projections indicate that current plant breeding approaches will be unable to incorporate the global crop yields needed to deliver global food security. Apomixis is a disruptive innovation by which a plant produces clonal seeds capturing heterosis and gene combinations of elite phenotypes. Introducing apomixis into hybrid cultivars is a game-changing development in the current plant breeding paradigm that will accelerate the generation of high-yield cultivars. However, apomixis is a developmentally complex and genetically multifaceted trait. The central problem behind current constraints to apomixis breeding is that the genomic configuration and molecular mechanism that initiate apomixis and guide the formation of a clonal seed are still unknown. Today, not a single explanation about the origin of apomixis offer full empirical coverage, and synthesizing apomixis by manipulating individual genes has failed or produced little success. Overall evidence suggests apomixis arise from a still unknown single event molecular mechanism with multigenic effects. Disentangling the genomic basis and complex genetics behind the emergence of apomixis in plants will require the use of novel experimental approaches benefiting from Next Generation Sequencing technologies and targeting not only reproductive genes, but also the epigenetic and genomic configurations associated with reproductive phenotypes in homoploid sexual and apomictic carriers. A comprehensive picture of most regulatory changes guiding apomixis emergence will be central for successfully installing apomixis into the target species by exploiting genetic modification techniques.
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Affiliation(s)
- Diego Hojsgaard
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, Georg-August-University of Göttingen, Untere Karspüle 2, D-37073-1 Göttingen, Germany
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37
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Ozias-Akins P, Conner JA. Clonal Reproduction through Seeds in Sight for Crops. Trends Genet 2020; 36:215-226. [PMID: 31973878 DOI: 10.1016/j.tig.2019.12.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 11/27/2019] [Accepted: 12/10/2019] [Indexed: 10/25/2022]
Abstract
Apomixis or asexual reproduction through seeds, enables the preservation of hybrid vigor. Hybrids are heterozygous and segregate for genotype and phenotype upon sexual reproduction. While apomixis, that is, clonal reproduction, is intuitively antithetical to diversity, it is rarely obligate and actually provides a mechanism to recover and maintain superior hybrid gene combinations for which sexual reproduction would reveal deleterious alleles in less fit genotypes. Apomixis, widespread across flowering plant orders, does not occur in major crop species, yet its introduction could add a valuable tool to the breeder's toolbox. In the past decade, discovery of genetic mechanisms regulating meiosis, embryo and endosperm development have facilitated proof-of-concept for the synthesis of apomixis, bringing apomictic crops closer to reality.
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Affiliation(s)
- Peggy Ozias-Akins
- Department of Horticulture and Institute of Plant Breeding and Genomics, University of Georgia, Tifton, GA 31793, USA.
| | - Joann A Conner
- Department of Horticulture and Institute of Plant Breeding and Genomics, University of Georgia, Tifton, GA 31793, USA
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38
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Abstract
Apomixis is an asexual reproduction process in which clonal seeds are formed without meiosis and fertilization. Because of its potential in permanently preserving hybrid vigor, apomixis has attracted a great deal of interests from plant biologists and the seed industry. However, despite of decades of effort, introgression of apomixis traits from wild relatives into major crops has remained unsuccessful. Therefore, synthetic apomixis has been proposed as an alternative to fix hybrid vigor. In this article, I present the development of the MiMe (Mitosis instead of Meiosis), which turns meiosis into mitosis and leads to the production of clonal gametes. Apomixis-like clonal seeds are generated when MiMe plants are crossed to special genome elimination lines, which contain an altered centromere-specific histone 3 (CENH3). Furthermore, induction of haploid plants from egg cells can be achieved by either egg cell-specific expression of BABY BOOM1 (BBM1), or disruption of MATRILINEAL (MTL) using CRISPR/Cas9 gene-editing technology. Synthetic apomixis is established and clonal seeds are produced by simultaneous engineering MiMe with altering BBM1 expression or MTL disruption. Finally, I discuss how to further improve the apomixis strategy and its applications in crop breeding.
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Affiliation(s)
- Kejian Wang
- State Key Laboratory of Rice Biology, China National Rice Research Institute, Chinese Academy of Agricultural Sciences, Hangzhou, 310006 China
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39
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Chaikam V, Molenaar W, Melchinger AE, Boddupalli PM. Doubled haploid technology for line development in maize: technical advances and prospects. Theor Appl Genet 2019; 132:3227-3243. [PMID: 31555890 PMCID: PMC6820599 DOI: 10.1007/s00122-019-03433-x] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 09/17/2019] [Indexed: 05/05/2023]
Abstract
KEY MESSAGE Increased efficiencies achieved in different steps of DH line production offer greater benefits to maize breeding programs. Doubled haploid (DH) technology has become an integral part of many commercial maize breeding programs as DH lines offer several economic, logistic and genetic benefits over conventional inbred lines. Further, new advances in DH technology continue to improve the efficiency of DH line development and fuel its increased adoption in breeding programs worldwide. The established method for maize DH production covered in this review involves in vivo induction of maternal haploids by a male haploid inducer genotype, identification of haploids from diploids at the seed or seedling stage, chromosome doubling of haploid (D0) seedlings and finally, selfing of fertile D0 plants. Development of haploid inducers with high haploid induction rates and adaptation to different target environments have facilitated increased adoption of DH technology in the tropics. New marker systems for haploid identification, such as the red root marker and high oil marker, are being increasingly integrated into new haploid inducers and have the potential to make DH technology accessible in germplasm such as some Flint, landrace, or tropical material, where the standard R1-nj marker is inhibited. Automation holds great promise to further reduce the cost and time in haploid identification. Increasing success rates in chromosome doubling protocols and/or reducing environmental and human toxicity of chromosome doubling protocols, including research on genetic improvement in spontaneous chromosome doubling, have the potential to greatly reduce the production costs per DH line.
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Affiliation(s)
- Vijay Chaikam
- International Maize and Wheat Improvement Center (CIMMYT), ICRAF campus, UN Avenue, Gigiri, P.O. Box 1041, Nairobi, 00621, Kenya
| | - Willem Molenaar
- Institute of Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, 70593, Stuttgart, Germany
| | - Albrecht E Melchinger
- Institute of Plant Breeding, Seed Science and Population Genetics, University of Hohenheim, 70593, Stuttgart, Germany
| | - Prasanna M Boddupalli
- International Maize and Wheat Improvement Center (CIMMYT), ICRAF campus, UN Avenue, Gigiri, P.O. Box 1041, Nairobi, 00621, Kenya.
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Fayos I, Mieulet D, Petit J, Meunier AC, Périn C, Nicolas A, Guiderdoni E. Engineering meiotic recombination pathways in rice. Plant Biotechnol J 2019; 17:2062-2077. [PMID: 31199561 PMCID: PMC6790369 DOI: 10.1111/pbi.13189] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2019] [Revised: 06/01/2019] [Accepted: 06/05/2019] [Indexed: 05/02/2023]
Abstract
In the last 15 years, outstanding progress has been made in understanding the function of meiotic genes in the model dicot and monocot plants Arabidopsis and rice (Oryza sativa L.), respectively. This knowledge allowed to modulate meiotic recombination in Arabidopsis and, more recently, in rice. For instance, the overall frequency of crossovers (COs) has been stimulated 2.3- and 3.2-fold through the inactivation of the rice FANCM and RECQ4 DNA helicases, respectively, two genes involved in the repair of DNA double-strand breaks (DSBs) as noncrossovers (NCOs) of the Class II crossover pathway. Differently, the programmed induction of DSBs and COs at desired sites is currently explored by guiding the SPO11-1 topoisomerase-like transesterase, initiating meiotic recombination in all eukaryotes, to specific target regions of the rice genome. Furthermore, the inactivation of 3 meiosis-specific genes, namely PAIR1, OsREC8 and OsOSD1, in the Mitosis instead of Meiosis (MiMe) mutant turned rice meiosis into mitosis, thereby abolishing recombination and achieving the first component of apomixis, apomeiosis. The successful translation of Arabidopsis results into a crop further allowed the implementation of two breakthrough strategies that triggered parthenogenesis from the MiMe unreduced clonal egg cell and completed the second component of diplosporous apomixis. Here, we review the most recent advances in and future prospects of the manipulation of meiotic recombination in rice and potentially other major crops, all essential for global food security.
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Affiliation(s)
- Ian Fayos
- CiradUMR AGAPMontpellierFrance
- Université de MontpellierCirad-Inra-Montpellier SupAgroMontpellierFrance
| | - Delphine Mieulet
- CiradUMR AGAPMontpellierFrance
- Université de MontpellierCirad-Inra-Montpellier SupAgroMontpellierFrance
| | - Julie Petit
- CiradUMR AGAPMontpellierFrance
- Université de MontpellierCirad-Inra-Montpellier SupAgroMontpellierFrance
| | - Anne Cécile Meunier
- CiradUMR AGAPMontpellierFrance
- Université de MontpellierCirad-Inra-Montpellier SupAgroMontpellierFrance
| | - Christophe Périn
- CiradUMR AGAPMontpellierFrance
- Université de MontpellierCirad-Inra-Montpellier SupAgroMontpellierFrance
| | - Alain Nicolas
- Institut Curie, CNRS UMR 3244University PSLParisFrance
- MeiogenixParisFrance
| | - Emmanuel Guiderdoni
- CiradUMR AGAPMontpellierFrance
- Université de MontpellierCirad-Inra-Montpellier SupAgroMontpellierFrance
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41
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Albertini E, Barcaccia G, Carman JG, Pupilli F. Did apomixis evolve from sex or was it the other way around? J Exp Bot 2019; 70:2951-2964. [PMID: 30854543 DOI: 10.1093/jxb/erz109] [Citation(s) in RCA: 40] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 02/25/2019] [Indexed: 05/20/2023]
Abstract
In angiosperms, there are two pathways of reproduction through seeds: sexual, or amphimictic, and asexual, or apomictic. The essential feature of apomixis is that an embryo in an ovule is formed autonomously. It may form from a cell of the nucellus or integuments in an otherwise sexual ovule, a process referred to as adventitious embryony. Alternatively, the embryo may form by parthenogenesis from an unreduced egg that forms in an unreduced embryo sac. The latter may form from an ameiotic megasporocyte, in which case it is referred to as diplospory, or from a cell of the nucellus or integument, in which case it is referred to as apospory. Progeny of apomictic plants are generally identical to the mother plant. Apomixis has been seen over the years as either a gain- or loss-of-function over sexuality, implying that the latter is the default condition. Here, we consider an additional point of view, that apomixis may be anciently polyphenic with sex and that both reproductive phenisms involve anciently canalized components of complex molecular processes. This polyphenism viewpoint suggests that apomixis fails to occur in obligately sexual eukaryotes because genetic or epigenetic modifications have silenced the primitive sex apomixis switch and/or disrupted molecular capacities for apomixis. In eukaryotes where sex and apomixis are clearly polyphenic, apomixis exponentially drives clonal fecundity during reproductively favorable conditions, while stress induces sex for stress-tolerant spore or egg formation. The latter often guarantees species survival during environmentally harsh seasons.
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Affiliation(s)
- Emidio Albertini
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Perugia, Italy
| | - Gianni Barcaccia
- Laboratory of Genomics, Department of Agronomy, Food, Natural Resources, Animals and the Environment (DAFNAE), University of Padova Legnaro, PD, Italy
| | - John G Carman
- Department of Plants, Soils and Climate, Utah State University, Logan, Utah, USA
| | - Fulvio Pupilli
- Institute of Biosciences and Bioresources, Research Division of Perugia, National Research Council (CNR), Perugia, Italy
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42
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Rahman MH, Toda E, Kobayashi M, Kudo T, Koshimizu S, Takahara M, Iwami M, Watanabe Y, Sekimoto H, Yano K, Okamoto T. Expression of Genes from Paternal Alleles in Rice Zygotes and Involvement of OsASGR-BBML1 in Initiation of Zygotic Development. Plant Cell Physiol 2019; 60:725-737. [PMID: 30801122 DOI: 10.1093/pcp/pcz030] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 02/07/2019] [Indexed: 05/11/2023]
Abstract
Upon fertilization in angiosperms, one sperm cell fuses with the egg cell to produce a zygote, and, via karyogamy, the parental genetic information is combined to form the diploid zygotic genome. Recently, analyses with parentally imbalanced rice zygotes indicated that parental genomes are utilized synergistically in zygotes with different functions, and that genes transcribed from the paternal or maternal allele might play important roles in zygotic development. Herein, we first conducted single nucleotide polymorphism-based mRNA-sequencing using intersubspecific rice zygotes. Twenty-three genes, with paternal allele-specific expression in zygotes, were identified, and, surprisingly, their allele dependencies in the globular-like embryo tended to be biallelic. This suggests that the paternal-dependent expression of these genes is temporary, occurring during the early stages of zygote development. Of the 23 genes, we focused on Oryza sativa Apospory-specific Genome Region (ASGR)-BABY-BOOM LIKE (BBML) 1 (OsASGR-BBML1), presumed to encode an AP2-transcription factor, due to its reported role in zygotic development. Interestingly, ectopic expression of OsASGR-BBML1 in egg cells induced nuclear and cell divisions, indicating that exogenously expressed OsASGR-BBML1 converts the proliferation status of the egg cell from quiescent to active. In addition, the suppression of the function of OsASGR-BBML1 and its homologs in zygotes resulted in the developmental arrest, suggesting that OsASGR-BBML1 possesses an important role in initiating zygotic development. Monoallelic or preferential gene expression from the paternal genome in the zygote might be a safety mechanism allowing egg cells to suppress the gene expression cascade toward early embryogenesis that is normally triggered by fusion with a sperm cell.
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Affiliation(s)
- Md Hassanur Rahman
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, Japan
| | - Erika Toda
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, Japan
| | | | - Toru Kudo
- Department of Life Sciences, Meiji University, Kanagawa, Japan
| | | | - Mirei Takahara
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, Japan
| | - Momoka Iwami
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, Japan
| | - Yoriko Watanabe
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, Japan
| | - Hiroyuki Sekimoto
- Department of Chemical and Biological Sciences, Japan Women's University, Tokyo, Japan
| | - Kentaro Yano
- Department of Life Sciences, Meiji University, Kanagawa, Japan
| | - Takashi Okamoto
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo, Japan
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43
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Kaushal P, Dwivedi KK, Radhakrishna A, Srivastava MK, Kumar V, Roy AK, Malaviya DR. Partitioning Apomixis Components to Understand and Utilize Gametophytic Apomixis. Front Plant Sci 2019; 10:256. [PMID: 30906306 PMCID: PMC6418048 DOI: 10.3389/fpls.2019.00256] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 02/18/2019] [Indexed: 05/07/2023]
Abstract
Apomixis is a method of reproduction to generate clonal seeds and offers tremendous potential to fix heterozygosity and hybrid vigor. The process of apomictic seed development is complex and comprises three distinct components, viz., apomeiosis (leading to formation of unreduced egg cell), parthenogenesis (development of embryo without fertilization) and functional endosperm development. Recently, in many crops, these three components are reported to be uncoupled leading to their partitioning. This review provides insight into the recent status of our understanding surrounding partitioning apomixis components in gametophytic apomictic plants and research avenues that it offers to help understand the biology of apomixis. Possible consequences leading to diversity in seed developmental pathways, resources to understand apomixis, inheritance and identification of candidate gene(s) for partitioned components, as well as contribution towards creation of variability are all discussed. The potential of Panicum maximum, an aposporous crop, is also discussed as a model crop to study partitioning principle and effects. Modifications in cytogenetic status, as well as endosperm imprinting effects arising due to partitioning effects, opens up new opportunities to understand and utilize apomixis components, especially towards synthesizing apomixis in crops.
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Affiliation(s)
- Pankaj Kaushal
- ICAR-National Institute of Biotic Stress Management, Raipur, India
| | | | | | | | - Vinay Kumar
- ICAR-National Institute of Biotic Stress Management, Raipur, India
| | - Ajoy Kumar Roy
- ICAR-Indian Grassland and Fodder Research Institute, Jhansi, India
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44
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Kalinowska K, Chamas S, Unkel K, Demidov D, Lermontova I, Dresselhaus T, Kumlehn J, Dunemann F, Houben A. State-of-the-art and novel developments of in vivo haploid technologies. Theor Appl Genet 2019; 132:593-605. [PMID: 30569366 PMCID: PMC6439148 DOI: 10.1007/s00122-018-3261-9] [Citation(s) in RCA: 59] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 12/05/2018] [Indexed: 05/02/2023]
Abstract
The ability to generate (doubled) haploid plants significantly accelerates the crop breeding process. Haploids have been induced mainly through the generation of plants from cultivated gametophic (haploid) cells and tissues, i.e., in vitro haploid technologies, or through the selective loss of a parental chromosome set upon inter- or intraspecific hybridization. Here, we focus our review on the mechanisms responsible for the in vivo formation of haploids in the context of inter- and intraspecific hybridization. The application of a modified CENH3 for uniparental genome elimination, the IG1 system used for paternal as well as the BBM-like and the patatin-like phospholipase essential for maternal haploidy induction are discussed in detail.
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Affiliation(s)
- Kamila Kalinowska
- Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Sindy Chamas
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstraße 3, 06466, Stadt Seeland, Germany
| | - Katharina Unkel
- Institute for Breeding Research on Horticultural Crops, Federal Research Centre for Cultivated Plants, Julius Kühn-Institute (JKI), Erwin-Baur-Str. 27, 06484, Quedlinburg, Germany
| | - Dmitri Demidov
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstraße 3, 06466, Stadt Seeland, Germany
| | - Inna Lermontova
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstraße 3, 06466, Stadt Seeland, Germany
| | - Thomas Dresselhaus
- Biochemie-Zentrum Regensburg, University of Regensburg, Universitätsstraße 31, 93053, Regensburg, Germany
| | - Jochen Kumlehn
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstraße 3, 06466, Stadt Seeland, Germany
| | - Frank Dunemann
- Institute for Breeding Research on Horticultural Crops, Federal Research Centre for Cultivated Plants, Julius Kühn-Institute (JKI), Erwin-Baur-Str. 27, 06484, Quedlinburg, Germany
| | - Andreas Houben
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK) Gatersleben, Corrensstraße 3, 06466, Stadt Seeland, Germany.
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45
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Affiliation(s)
- Matthew R. Willmann
- Plant Transformation Facility, Cornell University, School of Integrative Plant Science, Ithaca, New York
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46
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47
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Vijverberg K, Ozias-Akins P, Schranz ME. Identifying and Engineering Genes for Parthenogenesis in Plants. Front Plant Sci 2019; 10:128. [PMID: 30838007 PMCID: PMC6389702 DOI: 10.3389/fpls.2019.00128] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 01/24/2019] [Indexed: 05/16/2023]
Abstract
Parthenogenesis is the spontaneous development of an embryo from an unfertilized egg cell. It naturally occurs in a variety of plant and animal species. In plants, parthenogenesis usually is found in combination with apomeiosis (the omission of meiosis) and pseudogamous or autonomous (with or without central cell fertilization) endosperm formation, together known as apomixis (clonal seed production). The initiation of embryogenesis in vivo and in vitro has high potential in plant breeding methods, particularly for the instant production of homozygous lines from haploid gametes [doubled haploids (DHs)], the maintenance of vigorous F1-hybrids through clonal seed production after combining it with apomeiosis, reverse breeding approaches, and for linking diploid and polyploid gene pools. Because of this large interest, efforts to identify gene(s) for parthenogenesis from natural apomicts have been undertaken by using map-based cloning strategies and comparative gene expression studies. In addition, engineering parthenogenesis in sexual model species has been investigated via mutagenesis and gain-of-function strategies. These efforts have started to pay off, particularly by the isolation of the PsASGR-BabyBoom-Like from apomictic Pennisetum, a gene proven to be transferable to and functional in sexual pearl millet, rice, and maize. This review aims to summarize the current knowledge on parthenogenesis, the possible gene candidates also outside the grasses, and the use of these genes in plant breeding protocols. It shows that parthenogenesis is able to inherit and function independently from apomeiosis and endosperm formation, is expressed and active in the egg cell, and can induce embryogenesis in polyploid, diploid as well as haploid egg cells in plants. It also shows the importance of genes involved in the suppression of transcription and modifications thereof at one hand, and in embryogenesis for which transcription is allowed or artificially overexpressed on the other, in parthenogenetic reproduction. Finally, it emphasizes the importance of functional endosperm to allow for successful embryo growth and viable seed production.
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Affiliation(s)
- Kitty Vijverberg
- Biosystematics Group, Experimental Plant Sciences, Wageningen University and Research, Wageningen, Netherlands
- *Correspondence: Kitty Vijverberg,
| | - Peggy Ozias-Akins
- Department of Horticulture, Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Tifton Campus, Tifton, GA, United States
| | - M. Eric Schranz
- Biosystematics Group, Experimental Plant Sciences, Wageningen University and Research, Wageningen, Netherlands
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48
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Khanday I, Skinner D, Yang B, Mercier R, Sundaresan V. A male-expressed rice embryogenic trigger redirected for asexual propagation through seeds. Nature 2018; 565:91-95. [PMID: 30542157 DOI: 10.1038/s41586-018-0785-8] [Citation(s) in RCA: 195] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 10/29/2018] [Indexed: 11/09/2022]
Abstract
The molecular pathways that trigger the initiation of embryogenesis after fertilization in flowering plants, and prevent its occurrence without fertilization, are not well understood1. Here we show in rice (Oryza sativa) that BABY BOOM1 (BBM1), a member of the AP2 family2 of transcription factors that is expressed in sperm cells, has a key role in this process. Ectopic expression of BBM1 in the egg cell is sufficient for parthenogenesis, which indicates that a single wild-type gene can bypass the fertilization checkpoint in the female gamete. Zygotic expression of BBM1 is initially specific to the male allele but is subsequently biparental, and this is consistent with its observed auto-activation. Triple knockout of the genes BBM1, BBM2 and BBM3 causes embryo arrest and abortion, which are fully rescued by male-transmitted BBM1. These findings suggest that the requirement for fertilization in embryogenesis is mediated by male-genome transmission of pluripotency factors. When genome editing to substitute mitosis for meiosis (MiMe)3,4 is combined with the expression of BBM1 in the egg cell, clonal progeny can be obtained that retain genome-wide parental heterozygosity. The synthetic asexual-propagation trait is heritable through multiple generations of clones. Hybrid crops provide increased yields that cannot be maintained by their progeny owing to genetic segregation. This work establishes the feasibility of asexual reproduction in crops, and could enable the maintenance of hybrids clonally through seed propagation5,6.
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Affiliation(s)
- Imtiyaz Khanday
- Department of Plant Biology, University of California, Davis, CA, USA.,Innovative Genomics Institute, Berkeley, CA, USA
| | - Debra Skinner
- Department of Plant Biology, University of California, Davis, CA, USA
| | - Bing Yang
- Department of Genetics, Development and Cell Biology, Iowa State University, Ames, IA, USA
| | - Raphael Mercier
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, Versailles, France
| | - Venkatesan Sundaresan
- Department of Plant Biology, University of California, Davis, CA, USA. .,Innovative Genomics Institute, Berkeley, CA, USA. .,Department of Plant Sciences, University of California, Davis, CA, USA.
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49
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Zhang S, Liang M, Wang N, Xu Q, Deng X, Chai L. Reproduction in woody perennial Citrus: an update on nucellar embryony and self-incompatibility. Plant Reprod 2018; 31:43-57. [PMID: 29457194 DOI: 10.1007/s00497-018-0327-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 02/14/2018] [Indexed: 05/22/2023]
Abstract
Review on citrus reproduction. Citrus is one of the most important and widely grown fruit crops. It possesses several special reproductive characteristics, such as nucellar embryony and self-incompatibility. The special phenomenon of nucellar embryony in citrus, also known as the polyembryony, is a kind of sporophytic apomixis. During the past decade, the emergence of novel technologies and the construction of multiple citrus reference genomes have facilitated rapid advances to our understanding of nucellar embryony. Indeed, several research teams have preliminarily determined the genetic basis of citrus apomixis. On the other hand, the phenomenon of self-incompatibility that promotes genetic diversity by rejecting self-pollen and accepting non-self-pollen is difficult to study in citrus because the long juvenile period of citrus presents challenges to identifying candidate genes that control this phenomenon. In this review, we focus on advances to our understanding of reproduction in citrus from the last decade and discuss priorities for the coming decade.
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Affiliation(s)
- Siqi Zhang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Horticultural Crop Biology and Genetic Improvement (Central Region), MOA, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Mei Liang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Horticultural Crop Biology and Genetic Improvement (Central Region), MOA, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Nan Wang
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Horticultural Crop Biology and Genetic Improvement (Central Region), MOA, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Qiang Xu
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Horticultural Crop Biology and Genetic Improvement (Central Region), MOA, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Xiuxin Deng
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Horticultural Crop Biology and Genetic Improvement (Central Region), MOA, Huazhong Agricultural University, Wuhan, 430070, Hubei, China
| | - Lijun Chai
- Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Horticultural Crop Biology and Genetic Improvement (Central Region), MOA, Huazhong Agricultural University, Wuhan, 430070, Hubei, China.
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50
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Hojsgaard D. Transient Activation of Apomixis in Sexual Neotriploids May Retain Genomically Altered States and Enhance Polyploid Establishment. Front Plant Sci 2018; 9:230. [PMID: 29535745 PMCID: PMC5834478 DOI: 10.3389/fpls.2018.00230] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Accepted: 02/09/2018] [Indexed: 05/19/2023]
Abstract
Polyploid genomes evolve and follow a series of dynamic transfigurations along with adaptation and speciation. The initial formation of a new polyploid individual within a diploid population usually involves a triploid bridge, a two-step mechanism of cell fusions between ubiquitous (reduced) and rare (unreduced) gametes. The primary fusion event creates an intermediate triploid individual with unbalanced genome sets, a situation of genomic-shock characterized by gene expression dysregulation, high dosage sensitivity, disturbed cell divisions, and physiological and reproductive attributes drastically altered. This near-sterile neotriploid must produce (even) eupolyploids through secondary fusion events to restore genome steadiness, meiotic balance, and fertility required for the demographic establishment of a nascent lineage. Natural conditions locate several difficulties to polyploid establishment, including the production of highly unbalanced and rarely unreduced (euploid) gametes, frequency-dependent disadvantages (minority cytotype exclusion), severe fitness loss, and ecological competition with diploid parents. Persistence and adaptation of neopolyploids depend upon genetic and phenotypic novelty coupled to joint selective forces that preserve shock-induced genomic changes (subgenome homeolog partitioning) and drive meiotic (reproductive) stabilization and ecological diversification. Thus, polyploid establishment through the triploid bridge is a feasible but not ubiquitous process that requires a number of low-probability events and singular circumstances. Yet, frequencies of polyploids suggest that polyploid establishment is a pervasive process. To explain this disparity, and supported in experimental evidence, I propose that situations like hybridization and ploidy-state transitions associated to genomic shock and substantial developmental alterations can transiently activate apomixis as a mechanism to halt genomic instability and cancel factors restraining neopolyploid's sexual fertility, particularly in triploids. Apomixis -as a temporal alternative to sex- skip meiosis and syngamy, and thus can freeze genomic attributes, avoid unbalanced chromosomal segregation and increase the formation of unreduced euploid gametes, elude frequency-dependent reproductive disadvantages by parthenogenetic development of the embryo and permissive development of endosperm during seed formation, and increase the effective population size of the neopolyploid lineage favoring the formation rate of eupolyploids compared to aneuploids. The subsequent action of genome resilience mechanisms that alleviate transcriptomic shock and selection upon gene interactions might restore a stable meiosis and sexual fertility within few generations, as observed in synthetic polyploids. Alternatively, provided that resilience mechanisms fail, the neopolyploid might retain apomixis and hold genomically and transcriptionally altered states for many generations.
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Affiliation(s)
- Diego Hojsgaard
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, Georg August University of Göttingen, Göttingen, Germany
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