1
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Jo L, Nodine MD. "To remember or forget: Insights into the mechanisms of epigenetic reprogramming and priming in early plant embryos". CURRENT OPINION IN PLANT BIOLOGY 2024; 81:102612. [PMID: 39098309 DOI: 10.1016/j.pbi.2024.102612] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2024] [Revised: 07/14/2024] [Accepted: 07/16/2024] [Indexed: 08/06/2024]
Abstract
Chromatin is dynamically modified throughout the plant life cycle to regulate gene expression in response to environmental and developmental cues. Although such epigenetic information can be inherited across generations in plants, chromatin features that regulate gene expression are typically reprogrammed during plant gametogenesis and directly after fertilization. Nevertheless, environmentally induced epigenetic marks on genes can be transmitted across generations. Moreover, epigenetic information installed on early embryonic chromatin can be stably inherited during subsequent growth and influence how plants respond to environmental conditions much later in development. Here, we review recent breakthroughs towards deciphering mechanisms underlying epigenetic reprogramming and transcriptional priming during early plant embryogenesis.
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Affiliation(s)
- Leonardo Jo
- Experimental and Computational Plant Development, Institute of Environment Biology, Utrecht University, Padualaan 8, 3584 CH, Utrecht, the Netherlands
| | - Michael D Nodine
- Laboratory of Molecular Biology, Cluster of Plant Developmental Biology, Wageningen University & Research, Droevendaalsesteeg 1, 6708 PB, Wageningen, the Netherlands.
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2
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Cheng T, Liu Z, Li H, Huang X, Wang W, Shi C, Zhang X, Chen H, Yao Z, Zhao P, Peng X, Sun MX. Sperm-origin paternal effects on root stem cell niche differentiation. Nature 2024; 634:220-227. [PMID: 39198649 DOI: 10.1038/s41586-024-07885-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 07/30/2024] [Indexed: 09/01/2024]
Abstract
Fertilization introduces parental genetic information into the zygote to guide embryogenesis. Parental contributions to postfertilization development have been discussed for decades, and the data available show that both parents contribute to the zygotic transcriptome, suggesting a paternal role in early embryogenesis1-6. However, because the specific paternal effects on postfertilization development and the molecular pathways underpinning these effects remain poorly understood, paternal contribution to early embryogenesis and plant development has not yet been adequately demonstrated7. Here our research shows that TREE1 and its homologue DAZ3 are expressed exclusively in Arabidopsis sperm. Despite presenting no evident defects in sperm development and fertilization, tree1 daz3 unexpectedly led to aberrant differentiation of the embryo root stem cell niche. This defect persisted in seedlings and disrupted root tip regeneration, comparable to congenital defects in animals. TREE1 and DAZ3 function by suppression of maternal RKD2 transcription, thus mitigating the detrimental maternal effects from RKD2 on root stem cell niche. Therefore, our findings illuminate how genetic deficiencies in sperm can exert enduring paternal effects on specific plant organ differentiation and how parental-of-origin genes interact to ensure normal embryogenesis. This work also provides a new concept of how gamete quality or genetic deficiency can affect specific plant organ formation.
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Affiliation(s)
- Tianhe Cheng
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhenzhen Liu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Haiming Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiaorong Huang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
- State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Wei Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Ce Shi
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xuecheng Zhang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Hong Chen
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Zhuang Yao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Xiongbo Peng
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China.
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3
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Tang J, Huang X, Sun M, Liang W. DWARF TILLER1 regulates apical-basal pattern formation and proper orientation of rice embryos. PLANT PHYSIOLOGY 2024; 196:309-322. [PMID: 38905146 DOI: 10.1093/plphys/kiae318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2024] [Accepted: 05/10/2024] [Indexed: 06/23/2024]
Abstract
Body axis establishment is one of the earliest patterning events in plant embryogenesis. Asymmetric zygote division is critical for apical-basal axis formation in Arabidopsis (Arabidopsis thaliana). However, how the orientation of the cell division plane is regulated and its relation to apical-basal axis establishment and proper position of embryos in grasses remain poorly understood. By characterizing mutants of 3 rice (Oryza sativa) WUSCHEL HOMEOBOX9 (WOX9) genes, whose paralogs in Arabidopsis play essential roles in zygotic asymmetric cell division and cell fate determination, we found 2 kinds of independent embryonic defects: topsy-turvy embryos, in which apical-basal axis twists from being parallel to the longitudinal axis of the seed to being perpendicular; and organ-less embryos. In contrast to their Arabidopsis orthologs, OsWOX9s displayed dynamic distribution during embryo development. Both DWT1/OsWOX9A and DWL2/WOX9C play major roles in the apical-basal axis formation and initiation of stem cells. In addition, DWT1 has a distinct function in regulating the first few embryonic cell divisions to ensure the correct orientation of the embryo in the ovary. In summary, DWT1 acts in 2 steps during rice embryo pattern formation: the initial zygotic division, and with DWL2 to establish the main body axes and stem cell fate 2 to 3 d after pollination.
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Affiliation(s)
- Jingyao Tang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiaorong Huang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Mengxiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Wanqi Liang
- Joint International Research Laboratory of Metabolic and Developmental Sciences, State Key Laboratory of Hybrid Rice, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
- Yazhou Bay Institute of Deepsea Sci-Tech, Shanghai Jiao Tong University, Sanya 572024, China
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4
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Zhang H, Zhu JK. Epigenetic gene regulation in plants and its potential applications in crop improvement. Nat Rev Mol Cell Biol 2024:10.1038/s41580-024-00769-1. [PMID: 39192154 DOI: 10.1038/s41580-024-00769-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/18/2024] [Indexed: 08/29/2024]
Abstract
DNA methylation, also known as 5-methylcytosine, is an epigenetic modification that has crucial functions in plant growth, development and adaptation. The cellular DNA methylation level is tightly regulated by the combined action of DNA methyltransferases and demethylases. Protein complexes involved in the targeting and interpretation of DNA methylation have been identified, revealing intriguing roles of methyl-DNA binding proteins and molecular chaperones. Structural studies and in vitro reconstituted enzymatic systems have provided mechanistic insights into RNA-directed DNA methylation, the main pathway catalysing de novo methylation in plants. A better understanding of the regulatory mechanisms will enable locus-specific manipulation of the DNA methylation status. CRISPR-dCas9-based epigenome editing tools are being developed for this goal. Given that DNA methylation patterns can be stably transmitted through meiosis, and that large phenotypic variations can be contributed by epimutations, epigenome editing holds great promise in crop breeding by creating additional phenotypic variability on the same genetic material.
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Affiliation(s)
- Heng Zhang
- Department of Genetics and Developmental Science, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China.
| | - Jian-Kang Zhu
- Institute of Advanced Biotechnology and School of Medicine, Southern University of Science and Technology, Shenzhen, China.
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5
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Tonosaki K, Susaki D, Morinaka H, Ono A, Nagata H, Furuumi H, Nonomura KI, Sato Y, Sugimoto K, Comai L, Hatakeyama K, Kawakatsu T, Kinoshita T. Multilayered epigenetic control of persistent and stage-specific imprinted genes in rice endosperm. NATURE PLANTS 2024; 10:1231-1245. [PMID: 39080502 DOI: 10.1038/s41477-024-01754-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 07/01/2024] [Indexed: 08/22/2024]
Abstract
In angiosperms, epigenetic profiles for genomic imprinting are established before fertilization. However, the causal relationships between epigenetic modifications and imprinted expression are not fully understood. In this study, we classified 'persistent' and 'stage-specific' imprinted genes on the basis of time-course transcriptome analysis in rice (Oryza sativa) endosperm and compared them to epigenetic modifications at a single time point. While the levels of epigenetic modifications are relatively low in stage-specific imprinted genes, they are considerably higher in persistent imprinted genes. Overall trends revealed that the maternal alleles of maternally expressed imprinted genes are activated by DNA demethylation, while the maternal alleles of paternally expressed imprinted genes with gene body methylation (gbM) are silenced by DNA demethylation and H3K27me3 deposition, and these regions are associated with an enriched motif related to Tc/Mar-Stowaway. Our findings provide insight into the stability of genomic imprinting and the potential variations associated with endosperm development, different cell types and parental genotypes.
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Grants
- 20K15504 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- 22K15145 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- 23H04749 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- 23H04756 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- 23K23585 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- 22H05175 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- 21H02170 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
- 22H02320 Ministry of Education, Culture, Sports, Science and Technology (MEXT)
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Affiliation(s)
- Kaoru Tonosaki
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Kanagawa, Japan.
- Faculty of Agriculture, Iwate University, Morioka, Iwate, Japan.
| | - Daichi Susaki
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Kanagawa, Japan
| | - Hatsune Morinaka
- RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan
| | - Akemi Ono
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Kanagawa, Japan
| | - Hiroki Nagata
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Kanagawa, Japan
| | - Hiroyasu Furuumi
- Genetic Strains Research Center, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Ken-Ichi Nonomura
- Plant Cytogenetics, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Yutaka Sato
- Genetic Strains Research Center, National Institute of Genetics, Mishima, Shizuoka, Japan
| | - Keiko Sugimoto
- RIKEN Center for Sustainable Resource Science, Yokohama, Kanagawa, Japan
| | - Luca Comai
- Department of Plant Biology and Genome Center, University of California, Davis, CA, USA
| | | | - Taiji Kawakatsu
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Ibaraki, Japan.
| | - Tetsu Kinoshita
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Kanagawa, Japan.
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6
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Maupilé L, Chaib J, Boualem A, Bendahmane A. Parthenocarpy, a pollination-independent fruit set mechanism to ensure yield stability. TRENDS IN PLANT SCIENCE 2024:S1360-1385(24)00151-1. [PMID: 39034223 DOI: 10.1016/j.tplants.2024.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 06/11/2024] [Accepted: 06/17/2024] [Indexed: 07/23/2024]
Abstract
Fruit development is essential for flowering plants' reproduction and a significant food source. Climate change threatens fruit yields due to its impact on pollination and fertilization processes, especially vulnerable to extreme temperatures, insufficient light, and pollinator decline. Parthenocarpy, the development of fruit without fertilization, offers a solution, ensuring yield stability in adverse conditions and enhancing fruit quality. Parthenocarpic fruits not only secure agricultural production but also exhibit improved texture, appearance, and shelf life, making them desirable for food processing and other applications. Recent research unveils the molecular mechanisms behind parthenocarpy, implicating transcription factors (TFs), noncoding RNAs, and phytohormones such as auxin, gibberellin (GA), and cytokinin (CK). Here we review recent findings, construct regulatory models, and identify areas for further research.
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Affiliation(s)
- Lea Maupilé
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190 Gif sur Yvette, France; Vilmorin & Cie, Route d'Ennezat, 63720 Chappes, France
| | - Jamila Chaib
- Vilmorin & Cie, Paraje La Reserva, 04725 La Mojonera, Spain
| | - Adnane Boualem
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190 Gif sur Yvette, France; Université de Paris, Institute of Plant Sciences Paris-Saclay (IPS2), 91190 Gif sur Yvette, France.
| | - Abdelhafid Bendahmane
- Université Paris-Saclay, CNRS, INRAE, Université Evry, Institute of Plant Sciences Paris-Saclay (IPS2), 91190 Gif sur Yvette, France; Université de Paris, Institute of Plant Sciences Paris-Saclay (IPS2), 91190 Gif sur Yvette, France.
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7
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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 PHYSIOLOGY 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] [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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8
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Li X, Zhu B, Lu Y, Zhao F, Liu Q, Wang J, Ye M, Chen S, Nie J, Xiong L, Zhao Y, Wu C, Zhou DX. DNA methylation remodeling and the functional implication during male gametogenesis in rice. Genome Biol 2024; 25:84. [PMID: 38566207 PMCID: PMC10985897 DOI: 10.1186/s13059-024-03222-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 03/25/2024] [Indexed: 04/04/2024] Open
Abstract
BACKGROUND Epigenetic marks are reprogrammed during sexual reproduction. In flowering plants, DNA methylation is only partially remodeled in the gametes and the zygote. However, the timing and functional significance of the remodeling during plant gametogenesis remain obscure. RESULTS Here we show that DNA methylation remodeling starts after male meiosis in rice, with non-CG methylation, particularly at CHG sites, being first enhanced in the microspore and subsequently decreased in sperm. Functional analysis of rice CHG methyltransferase genes CMT3a and CMT3b indicates that CMT3a functions as the major CHG methyltransferase in rice meiocyte, while CMT3b is responsible for the increase of CHG methylation in microspore. The function of the two histone demethylases JMJ706 and JMJ707 that remove H3K9me2 may contribute to the decreased CHG methylation in sperm. During male gametogenesis CMT3a mainly silences TE and TE-related genes while CMT3b is required for repression of genes encoding factors involved in transcriptional and translational activities. In addition, CMT3b functions to repress zygotic gene expression in egg and participates in establishing the zygotic epigenome upon fertilization. CONCLUSION Collectively, the results indicate that DNA methylation is dynamically remodeled during male gametogenesis, distinguish the function of CMT3a and CMT3b in sex cells, and underpin the functional significance of DNA methylation remodeling during rice reproduction.
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Affiliation(s)
- Xue Li
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Bo Zhu
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yue Lu
- Key Laboratory of Plant Functional Genomics of the Ministry of Education/Jiangsu Key Laboratory of Crop Genomics and Molecular Breeding, College of Agriculture, Yangzhou University, Yangzhou, 225009, China
| | - Feng Zhao
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Qian Liu
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jiahao Wang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Miaomiao Ye
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Siyuan Chen
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Junwei Nie
- Vazyme Biotech Co., Ltd, Nanjing, 210000, China
| | - Lizhong Xiong
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yu Zhao
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Changyin Wu
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Dao-Xiu Zhou
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China.
- Institute of Plant Science Paris-Saclay (IPS2), CNRS, INRAE, Université Paris-Saclay, 91405, Orsay, France.
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9
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Vernet A, Meynard D, Guiderdoni E. Clonal reproduction by seed of a cultivated hybrid plant: a new perspective for small-scale rice growers. C R Biol 2024; 346:107-116. [PMID: 38206040 DOI: 10.5802/crbiol.125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2023] [Revised: 10/04/2023] [Accepted: 10/05/2023] [Indexed: 01/12/2024]
Abstract
Transferring an asexual mode of reproduction by seeds (apomixis) to cultivated plants would enable clonal reproduction of heterozygous genotypes such as F1 hybrids with hybrid vigor (heterosis), facilitating their access and multiplication by small-scale growers. Although sources of apomixis and the genetic loci controlling its constituent elements have been identified in wild species, their transfer by crossing to cultivated species has so far been unsuccessful. Here, we have introduced synthetic apomixis in hybrid rice to produce a high (95-100%) frequency of clonal seeds, via the inactivation of three meiotic genes-resulting in unreduced, non-recombined gametes-and the addition of an egg cell parthenogenesis trigger. The genotype and phenotype, including grain quality, of the F1 hybrid are reproduced identically in the clonal apomictic progenies. These results make synthetic apomixis compatible with future use in agriculture.
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10
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Yuan HY, Kagale S, Ferrie AMR. Multifaceted roles of transcription factors during plant embryogenesis. FRONTIERS IN PLANT SCIENCE 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] [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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11
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Xu H, Bartley L, Libault M, Sundaresan V, Fu H, Russell S. The roles of a novel CDKB/KRP/FB3 cell cycle core complex in rice gametes and initiation of embryogenesis. PLANT REPRODUCTION 2023; 36:301-320. [PMID: 37491485 DOI: 10.1007/s00497-023-00474-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Accepted: 06/29/2023] [Indexed: 07/27/2023]
Abstract
The cell cycle controls division and proliferation of all eukaryotic cells and is tightly regulated at multiple checkpoints by complexes of core cell cycle proteins. Due to the difficulty in accessing female gametes and zygotes of flowering plants, little is known about the molecular mechanisms underlying embryogenesis initiation despite the crucial importance of this process for seed crops. In this study, we reveal three levels of factors involved in rice zygotic cell cycle control and characterize their functions and regulation. Protein-protein interaction studies, including within zygote cells, and in vitro biochemical analyses delineate a model of the zygotic cell cycle core complex for rice. In this model, CDKB1, a major regulator of plant mitosis, is a cyclin (CYCD5)-dependent kinase; its activity is coordinately inhibited by two cell cycle inhibitors, KRP4 and KRP5; and both KRPs are regulated via F-box protein 3 (FB3)-mediated proteolysis. Supporting their critical roles in controlling the rice zygotic cell cycle, mutations in KRP4, KRP5 and FB3 result in the compromised function of sperm cells and abnormal organization of female germ units, embryo and endosperm, thus significantly reducing seed-set rate. This work helps reveal regulatory mechanisms controlling the zygotic cell cycle toward seed formation in angiosperms.
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Affiliation(s)
- Hengping Xu
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, 73019, USA.
| | - Laura Bartley
- Institute of Biological Chemistry, Washington State University, Pullman, WA, 99164, USA
| | - Marc Libault
- Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE, 68503, USA
| | | | - Hong Fu
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, 73019, USA
| | - Scott Russell
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, 73019, USA
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12
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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 PHYSIOLOGY 2023; 193:2278-2281. [PMID: 37610248 DOI: 10.1093/plphys/kiad461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [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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13
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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. NATURE 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] [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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14
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Liu Q, Ma X, Li X, Zhang X, Zhou S, Xiong L, Zhao Y, Zhou DX. Paternal DNA methylation is remodeled to maternal levels in rice zygote. Nat Commun 2023; 14:6571. [PMID: 37852973 PMCID: PMC10584822 DOI: 10.1038/s41467-023-42394-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Accepted: 10/09/2023] [Indexed: 10/20/2023] Open
Abstract
Epigenetic reprogramming occurs during reproduction to reset the genome for early development. In flowering plants, mechanistic details of parental methylation remodeling in zygote remain elusive. Here we analyze allele-specific DNA methylation in rice hybrid zygotes and during early embryo development and show that paternal DNA methylation is predominantly remodeled to match maternal allelic levels upon fertilization, which persists after the first zygotic division. The DNA methylation remodeling pattern supports the predominantly maternal-biased gene expression during zygotic genome activation (ZGA) in rice. However, parental allelic-specific methylations are reestablished at the globular embryo stage and associate with allelic-specific histone modification patterns in hybrids. These results reveal that paternal DNA methylation is remodeled to match the maternal pattern during zygotic genome reprogramming and suggest existence of a chromatin memory allowing parental allelic-specific methylation to be maintained in the hybrid.
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Affiliation(s)
- Qian Liu
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xuan Ma
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xue Li
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xinran Zhang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Shaoli Zhou
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Lizhong Xiong
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yu Zhao
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China.
| | - Dao-Xiu Zhou
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan, 430070, China.
- Institute of Plant Science Paris-Saclay (IPS2), CNRS, INRAE, University Paris-Saclay, 91405, Orsay, France.
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15
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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] [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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16
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Li C, Deans NC, Buell CR. "Simple Tidy GeneCoEx": A gene co-expression analysis workflow powered by tidyverse and graph-based clustering in R. THE PLANT GENOME 2023:e20323. [PMID: 37063055 DOI: 10.1002/tpg2.20323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 01/31/2023] [Accepted: 02/15/2023] [Indexed: 06/19/2023]
Abstract
Gene co-expression analysis is an effective method to detect groups (or modules) of co-expressed genes that display similar expression patterns, which may function in the same biological processes. Here, we present "Simple Tidy GeneCoEx", a gene co-expression analysis workflow written in the R programming language. The workflow is highly customizable across multiple stages of the pipeline including gene selection, edge selection, clustering resolution, and data visualization. Powered by the tidyverse package ecosystem and network analysis functions provided by the igraph package, the workflow detects gene co-expression modules whose members are highly interconnected. Step-by-step instructions with two use case examples as well as source code are available at https://github.com/cxli233/SimpleTidy_GeneCoEx.
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Affiliation(s)
- Chenxin Li
- Center for Applied Genetic Technologies, University of Georgia, Athens, Georgia, USA
| | - Natalie C Deans
- Center for Applied Genetic Technologies, University of Georgia, Athens, Georgia, USA
| | - C Robin Buell
- Center for Applied Genetic Technologies, University of Georgia, Athens, Georgia, USA
- Department of Crop and Soil Sciences, University of Georgia, Athens, Georgia, USA
- Institute of Plant Breeding, Genetics, and Genomics, University of Georgia, Athens, Georgia, USA
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17
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Khanday I, Santos-Medellín C, Sundaresan V. Somatic embryo initiation by rice BABY BOOM1 involves activation of zygote-expressed auxin biosynthesis genes. THE NEW PHYTOLOGIST 2023; 238:673-687. [PMID: 36707918 DOI: 10.1111/nph.18774] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2022] [Accepted: 01/12/2023] [Indexed: 05/02/2023]
Abstract
Plant embryogenesis results from the fusion of male and female gametes but can also be induced in somatic cells. The molecular pathways for embryo initiation are poorly understood, especially in monocots. In rice, the male gamete expressed BABY BOOM1 (OsBBM1) transcription factor functions as an embryogenic trigger in the zygote and can also promote somatic embryogenesis when ectopically expressed in somatic tissues. We used gene editing, transcriptome profiling, and chromatin immunoprecipitation to determine the molecular players involved in embryo initiation downstream of OsBBM1. We identify OsYUCCA (OsYUC) auxin biosynthesis genes as direct targets of OsBBM1. Unexpectedly, these OsYUC targets in zygotes are expressed only from the maternal genome, whereas the paternal genome exclusively provides functional OsBBM1 to initiate embryogenesis. Induction of somatic embryogenesis by exogenous auxin requires OsBBM genes and downstream OsYUC targets. Ectopic OsBBM1 initiates somatic embryogenesis without exogenous auxins but requires functional OsYUC genes. Thus, an OsBBM-OsYUC module is a key player for both somatic and zygotic embryogenesis in rice. Zygotic embryo initiation involves a partnership of male and female genomes, through which paternal OsBBM1 activates maternal OsYUC genes. In somatic embryogenesis, exogenous auxin triggers OsBBM1 expression, which then activates endogenous auxin biosynthesis OsYUC genes.
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Affiliation(s)
- Imtiyaz Khanday
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA
- Innovative Genomics Institute, University of California, Berkeley, CA, 94720, USA
| | | | - Venkatesan Sundaresan
- Department of Plant Sciences, University of California, Davis, CA, 95616, USA
- Innovative Genomics Institute, University of California, Berkeley, CA, 94720, USA
- Department of Plant Biology, University of California, Davis, CA, 95616, USA
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18
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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. MOLECULAR PLANT 2023; 16:489-492. [PMID: 36609144 DOI: 10.1016/j.molp.2023.01.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [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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19
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Li X, Wu J, Yi F, Lai J, Chen J. High temporal-resolution transcriptome landscapes of maize embryo sac and ovule during early seed development. PLANT MOLECULAR BIOLOGY 2023; 111:233-248. [PMID: 36508138 DOI: 10.1007/s11103-022-01318-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 10/07/2022] [Indexed: 06/18/2023]
Abstract
Here we provided a high temporal-resolution transcriptome atlas of maize embryo sac and ovule to reveal the gene activity dynamic during early seed development. The early maize (Zea mays) seed development is initiated from double fertilization in the embryo sac and needs to undergo a highly dynamic and complex development process to form the differentiated embryo and endosperm. Despite the importance of maize seed for food, feed, and biofuel, many regulators responsible for controlling its early development are not known yet. Here, we reported a high temporal-resolution transcriptome atlas of embryo sac and ovule based on 44 time point samples collected within the first four days of seed development. A total of 25,187 genes including 1598 transcription factors (TFs) involved in early seed development were detected. Global comparisons of the expressions of these genes revealed five distinct development stages of early seed, which are mainly related to double fertilization, asymmetric cell division of the zygote, as well as coenocyte formation, cellularization and differentiation in endosperm. We identified 3327 seed-specific genes, which more than one thousand seed-specific genes with main expressions during early seed development were newly identified here, including 859 and 186 genes predominantly expressed in the embryo sac and ovule, respectively. Combined with the published transcriptome data of seed, we uncovered the dominant auxin biosynthesis, transport and signaling related genes at different development stages and subregions of seed. These results are helpful for understanding the genetic control of early seed development.
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Affiliation(s)
- Xinchen Li
- State Key Laboratory of Plant Physiology and Biochemistry, China Agricultural University, Beijing, People's Republic of China
- Department of Plant Genetics and Breeding, National Maize Improvement Center, China Agricultural University, Beijing, People's Republic of China
| | - Jian Wu
- CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, People's Republic of China
| | - Fei Yi
- State Key Laboratory of Plant Physiology and Biochemistry, China Agricultural University, Beijing, People's Republic of China
- Engineering Research Center of Plant Growth Regulator, Ministry of Education & College of Agronomy and Biotechnology, China Agricultural University, Beijing, People's Republic of China
| | - Jinsheng Lai
- State Key Laboratory of Plant Physiology and Biochemistry, China Agricultural University, Beijing, People's Republic of China
- Department of Plant Genetics and Breeding, National Maize Improvement Center, China Agricultural University, Beijing, People's Republic of China
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing, People's Republic of China
| | - Jian Chen
- State Key Laboratory of Plant Physiology and Biochemistry, China Agricultural University, Beijing, People's Republic of China.
- Department of Plant Genetics and Breeding, National Maize Improvement Center, China Agricultural University, Beijing, People's Republic of China.
- Center for Crop Functional Genomics and Molecular Breeding, China Agricultural University, Beijing, People's Republic of China.
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20
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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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21
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Jia Z, Gao P, Yin F, Quilichini TD, Sheng H, Song J, Yang H, Gao J, Chen T, Yang B, Kochian LV, Zou J, Patterson N, Yang Q, Gillmor CS, Datla R, Li Q, Xiang D. Asymmetric gene expression in grain development of reciprocal crosses between tetraploid and hexaploid wheats. Commun Biol 2022; 5:1412. [PMID: 36564439 PMCID: PMC9789062 DOI: 10.1038/s42003-022-04374-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
Production of viable progeny from interploid crosses requires precise regulation of gene expression from maternal and paternal chromosomes, yet the transcripts contributed to hybrid seeds from polyploid parent species have rarely been explored. To investigate the genome-wide maternal and paternal contributions to polyploid grain development, we analyzed the transcriptomes of developing embryos, from zygote to maturity, alongside endosperm in two stages of development, using reciprocal crosses between tetraploid and hexaploid wheats. Reciprocal crosses between species with varied levels of ploidy displayed broad impacts on gene expression, including shifts in alternative splicing events in select crosses, as illustrated by active splicing events, enhanced protein synthesis and chromatin remodeling. Homoeologous gene expression was repressed on the univalent D genome in pentaploids, but this suppression was attenuated in crosses with a higher ploidy maternal parent. Imprinted genes were identified in endosperm and early embryo tissues, supporting predominant maternal effects on early embryogenesis. By systematically investigating the complex transcriptional networks in reciprocal-cross hybrids, this study presents a framework for understanding the genomic incompatibility and transcriptome shock that results from interspecific hybridization and uncovers the transcriptional impacts on hybrid seeds created from agriculturally-relevant polyploid species.
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Affiliation(s)
- Zhen Jia
- grid.35155.370000 0004 1790 4137National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Peng Gao
- grid.25152.310000 0001 2154 235XGlobal Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 4J8 Canada
| | - Feifan Yin
- grid.35155.370000 0004 1790 4137National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China ,grid.35155.370000 0004 1790 4137Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, 430070 Wuhan, China
| | - Teagen D. Quilichini
- grid.24433.320000 0004 0449 7958Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
| | - Huajin Sheng
- grid.25152.310000 0001 2154 235XGlobal Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 4J8 Canada
| | - Jingpu Song
- grid.24433.320000 0004 0449 7958Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
| | - Hui Yang
- grid.24433.320000 0004 0449 7958Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
| | - Jie Gao
- grid.35155.370000 0004 1790 4137National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Ting Chen
- grid.35155.370000 0004 1790 4137National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Bo Yang
- grid.35155.370000 0004 1790 4137National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Leon V. Kochian
- grid.25152.310000 0001 2154 235XGlobal Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 4J8 Canada
| | - Jitao Zou
- grid.24433.320000 0004 0449 7958Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
| | - Nii Patterson
- grid.24433.320000 0004 0449 7958Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
| | - Qingyong Yang
- grid.35155.370000 0004 1790 4137National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China ,grid.35155.370000 0004 1790 4137Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, 430070 Wuhan, China
| | - C. Stewart Gillmor
- grid.512574.0Langebio, Unidad de Genómica Avanzada, Centro de Investigación y Estudios Avanzados del IPN (CINVESTAV-IPN), Irapuato, Guanajuato, 36821 México
| | - Raju Datla
- grid.25152.310000 0001 2154 235XGlobal Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 4J8 Canada
| | - Qiang Li
- grid.35155.370000 0004 1790 4137National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Daoquan Xiang
- grid.24433.320000 0004 0449 7958Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
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22
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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; 23:15950. [PMID: 36555594 PMCID: PMC9781121 DOI: 10.3390/ijms232415950] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [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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Affiliation(s)
| | | | - Claudio Pugliesi
- Department of Agriculture Food and Environment, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
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23
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Alaniz-Fabián J, Orozco-Nieto A, Abreu-Goodger C, Gillmor CS. Hybridization alters maternal and paternal genome contributions to early plant embryogenesis. Development 2022; 149:281772. [PMID: 36314727 DOI: 10.1242/dev.201025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2022] [Accepted: 10/17/2022] [Indexed: 11/06/2022]
Abstract
After fertilization, zygotic genome activation results in a transcriptionally competent embryo. Hybrid transcriptome experiments in Arabidopsis have concluded that the maternal and paternal genomes make equal contributions to zygotes and embryos, yet embryo defective (emb) mutants in the Columbia (Col) ecotype display early maternal effects. Here, we show that hybridization of Col with Landsberg erecta (Ler) or Cape Verde Islands (Cvi) ecotypes decreases the maternal effects of emb mutants. Reanalysis of Col/Ler and Col/Cvi transcriptomes confirmed equal parental contributions in Col/Cvi early embryos. By contrast, thousands of genes in Col/Ler zygotes and one-cell embryos were biallelic in one cross and monoallelic in the reciprocal cross, with analysis of intron reads pointing to active transcription as responsible for this parent-of-origin bias. Our analysis shows that, contrary to previous conclusions, the maternal and paternal genomes in Col/Ler zygotes are activated in an asymmetric manner. The decrease in maternal effects in hybrid embryos compared with those in isogenic Col along with differences in genome activation between Col/Cvi and Col/Ler suggest that neither of these hybrids accurately reflects the general trends of parent-of-origin regulation in Arabidopsis embryogenesis.
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Affiliation(s)
- Jaime Alaniz-Fabián
- Langebio, Unidad de Genómica Avanzada, CINVESTAV-IPN, Irapuato 36824, México
| | - Axel Orozco-Nieto
- Langebio, Unidad de Genómica Avanzada, CINVESTAV-IPN, Irapuato 36824, México
| | - Cei Abreu-Goodger
- Institute of Ecology and Evolution, School of Biological Sciences, University of Edinburgh, Edinburgh EH9 3FL, UK
| | - C Stewart Gillmor
- Langebio, Unidad de Genómica Avanzada, CINVESTAV-IPN, Irapuato 36824, México
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24
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Xia Y, Wang Y, Hu Y, Zhan Y, Dan J, Tang N, Tian J, Cao M. Double-seedlings and embryo-free seeds generated by genetic engineering. FRONTIERS IN PLANT SCIENCE 2022; 13:999031. [PMID: 36262658 PMCID: PMC9576183 DOI: 10.3389/fpls.2022.999031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 09/16/2022] [Indexed: 06/16/2023]
Abstract
Apomixis can fix the heterosis of Hybrid F1, by maintaining its heterozygous genotype, and is an ideal way for the development of hybrid rice. In this paper, we designed an engineering strategy for realizing apomictic reproduction of hybrid rice in the way of induce adventitious embryos. An embryogenesis gene, AtWUS, controlled by the ovule-specific promoter, a ribonuclease gene Barnase driven by the egg cell-specific promoter pDD45, and an inactivation gene ZmAA1 driven by the pollen-specific promoter pG47 were simultaneously integrated into one T-DNA, and co-transformed with the second T-DNA carrying a Barstar gene. Double-seedlings were observed in transgenic line. Whole-genome sequencing and ploidy levels confirmed by flow cytometry showed that one of the double-seedlings was heterozygous diploid and the other seedling was homozygous haploid, which confirmed that embryogenesis in one of the double-seedlings arises from the zygote after fertilization and the other derived from an unfertilized gamete. Meanwhile we obtained embryo-free seeds at frequencies of 2.6% to 3.8% in T1 generation, and 0.75% to 3% in T2 generation. Though we did not obtained adventitious embryos in hybrid rice in this study, the phenomenon of double-seedlings and embryo-free seeds in transgenic line was informative and strongly suggested that endosperm development is an autonomously organized process in rice, independent of egg cell fertilization and embryo-endosperm communication. This provides novel insights into the induction of haploid embryos and lends theoretical support to successful clonal propagation using synthetic apomixis.
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Affiliation(s)
- Yumei Xia
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, China
- National Center of Technology Innovation for Saline-Alkali Tolerant Rice in Sanya, Sanya, China
| | - Yao Wang
- Long Ping Branch, Graduate School of Hunan University, Changsha, China
| | - Yuanyi Hu
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, China
- National Center of Technology Innovation for Saline-Alkali Tolerant Rice in Sanya, Sanya, China
| | - Yijie Zhan
- Long Ping Branch, Graduate School of Hunan University, Changsha, China
| | - Junhao Dan
- Long Ping Branch, Graduate School of Hunan University, Changsha, China
| | - Ning Tang
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, China
| | - Junyou Tian
- Long Ping Branch, Graduate School of Hunan University, Changsha, China
| | - Mengliang Cao
- State Key Laboratory of Hybrid Rice, Hunan Hybrid Rice Research Center, Changsha, China
- National Center of Technology Innovation for Saline-Alkali Tolerant Rice in Sanya, Sanya, China
- Long Ping Branch, Graduate School of Hunan University, Changsha, China
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25
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Huang Y, Zhou L, Hou C, Guo D. The dynamic proteome in Arabidopsis thaliana early embryogenesis. Development 2022; 149:276287. [DOI: 10.1242/dev.200715] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Accepted: 07/26/2022] [Indexed: 11/20/2022]
Abstract
ABSTRACT
The morphology of the flowering plant is established during early embryogenesis. In recent years, many studies have focused on transcriptional profiling in plant embryogenesis, but the dynamic landscape of the Arabidopsis thaliana proteome remains elusive. In this study, Arabidopsis embryos at 2/4-cell, 8-cell, 16-cell, 32-cell, globular and heart stages were collected for nanoproteomic analysis. In total, 5386 proteins were identified. Of these, 1051 proteins were universally identified in all developmental stages and a range of 27 to 2154 proteins was found to be stage specific. These proteins could be grouped into eight clusters according to their expression levels. Gene Ontology enrichment analysis showed that genes involved in ribosome biogenesis and auxin-activated signalling were enriched during early embryogenesis, indicating that active translation and auxin signalling are important events in Arabidopsis embryo development. Combining RNA-sequencing data with the proteomics analysis, the correlation between mRNA and protein was evaluated. An overall positive correlation was found between mRNA and protein. This work provides a comprehensive landscape of the Arabidopsis proteome in early embryogenesis. Some important proteins/transcription factors identified through network analysis may serve as potential targets for future investigation.
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Affiliation(s)
- Yingzhang Huang
- State Key Laboratory of Agrobiotechnology and School of Life Science, The Chinese University of Hong Kong 1 , 999077 Hong Kong , China
| | - Limeng Zhou
- State Key Laboratory of Agrobiotechnology and School of Life Science, The Chinese University of Hong Kong 1 , 999077 Hong Kong , China
| | - Chunhui Hou
- Southern University of Science and Technology 2 Department of Biology , , Shenzhen 518055 , China
| | - Dianjing Guo
- State Key Laboratory of Agrobiotechnology and School of Life Science, The Chinese University of Hong Kong 1 , 999077 Hong Kong , China
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26
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Montgomery SA, Hisanaga T, Wang N, Axelsson E, Akimcheva S, Sramek M, Liu C, Berger F. Polycomb-mediated repression of paternal chromosomes maintains haploid dosage in diploid embryos of Marchantia. eLife 2022; 11:79258. [PMID: 35996955 PMCID: PMC9402228 DOI: 10.7554/elife.79258] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Accepted: 07/18/2022] [Indexed: 02/06/2023] Open
Abstract
Complex mechanisms regulate gene dosage throughout eukaryotic life cycles. Mechanisms controlling gene dosage have been extensively studied in animals, however it is unknown how generalizable these mechanisms are to diverse eukaryotes. Here, we use the haploid plant Marchantia polymorpha to assess gene dosage control in its short-lived diploid embryo. We show that throughout embryogenesis, paternal chromosomes are repressed resulting in functional haploidy. The paternal genome is targeted for genomic imprinting by the Polycomb mark H3K27me3 starting at fertilization, rendering the maternal genome in control of embryogenesis. Maintaining haploid gene dosage by this new form of imprinting is essential for embryonic development. Our findings illustrate how haploid-dominant species can regulate gene dosage through paternal chromosome inactivation and initiates the exploration of the link between life cycle history and gene dosage in a broader range of organisms.
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Affiliation(s)
- Sean Akira Montgomery
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria.,Vienna BioCenter PhD Program, Doctoral School of the University of Vienna and Medical University of Vienna, Vienna, Austria
| | - Tetsuya Hisanaga
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Nan Wang
- Institute of Biology, University of Hohenheim, Stuttgart, Germany
| | - Elin Axelsson
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Svetlana Akimcheva
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Milos Sramek
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Chang Liu
- Institute of Biology, University of Hohenheim, Stuttgart, Germany
| | - Frédéric Berger
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
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27
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Toda E, Kiba T, Kato N, Okamoto T. Isolation of gametes and zygotes from Setaria viridis. JOURNAL OF PLANT RESEARCH 2022; 135:627-633. [PMID: 35534650 DOI: 10.1007/s10265-022-01393-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/25/2022] [Indexed: 06/14/2023]
Abstract
Setaria viridis, the wild ancestor of foxtail millet (Setaria italica), is an effective model plant for larger C4 crops because S. viridis has several desirable traits, such as short generation time, prolific seed production and a small genome size. These advantages are well suited for investigating molecular mechanisms in angiosperms, especially C4 crop species. Here, we report a procedure for isolating gametes and zygotes from S. viridis flowers. To isolate egg cells, ovaries were harvested from unpollinated mature flowers and cut transversely, which allowed direct access to the embryo sac. Thereafter, an egg cell was released from the cut end of the basal portion of the dissected ovary. To isolate sperm cells, pollen grains released from anthers were immersed in a mannitol solution, resulting in pollen-grain bursting, which released sperm cells. Additionally, S. viridis zygotes were successfully isolated from freshly pollinated flowers. Isolated zygotes cultured in a liquid medium developed into globular-like embryos and cell masses. Thus, isolated S. viridis gametes, zygotes and embryos are attainable for detailed observations and investigations of fertilization and developmental events in angiosperms.
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Affiliation(s)
- Erika Toda
- Plant Breeding Innovation Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan.
- Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, 192-0392, Japan.
- Department of Biological Sciences, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
| | - Takatoshi Kiba
- Plant Breeding Innovation Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
- Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8601, Japan
| | - Norio Kato
- Plant Breeding Innovation Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
- Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, 192-0392, Japan
| | - Takashi Okamoto
- Plant Breeding Innovation Laboratory, RIKEN Cluster for Science, Technology and Innovation Hub, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
- Department of Biological Sciences, Tokyo Metropolitan University, 1-1 Minami-osawa, Hachioji, Tokyo, 192-0392, Japan
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28
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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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29
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Zhong Y, Wang Y, Chen B, Liu J, Wang D, Li M, Qi X, Liu C, Boutilier K, Chen S. Establishment of a dmp based maternal haploid induction system for polyploid Brassica napus and Nicotiana tabacum. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:1281-1294. [PMID: 35249255 DOI: 10.1111/jipb.13244] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 03/02/2022] [Indexed: 06/14/2023]
Abstract
Doubled haploid (DH) technology is used to obtain homozygous lines in a single generation, a technique that significantly accelerates the crop breeding trajectory. Traditionally, in vitro culture is used to generate DHs, but this technique is limited by species and genotype recalcitrance. In vivo haploid induction (HI) through seed is widely and efficiently used in maize and was recently extended to several other crops. Here we show that in vivo HI can be triggered by mutation of DMP maternal haploid inducer genes in allopolyploid (allotetraploid) Brassica napus and Nicotiana tabacum. We developed a pipeline for selection of DMP orthologs for clustered regularly interspaced palindromic repeats mutagenesis and demonstrated average amphihaploid induction rates of 2.4% and 1.2% in multiple B. napus and N. tabacum genotypes, respectively. These results further confirmed the HI ability of DMP gene in polyploid dicot crops. The DMP-HI system offers a novel DH technology to facilitate breeding in these crops. The success of this approach and the conservation of DMP genes in dicots suggest the broad applicability of this technique in other dicot crops.
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Affiliation(s)
- Yu Zhong
- National Maize Improvement Center of China, Key Laboratory of Crop Heterosis and Utilization/Engineering Research Center for Maize Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Yuwen Wang
- National Maize Improvement Center of China, Key Laboratory of Crop Heterosis and Utilization/Engineering Research Center for Maize Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Baojian Chen
- Bioscience, Wageningen University and Research, 6700 AA, Wageningen, The Netherlands
| | - Jinchu Liu
- National Maize Improvement Center of China, Key Laboratory of Crop Heterosis and Utilization/Engineering Research Center for Maize Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Dong Wang
- National Maize Improvement Center of China, Key Laboratory of Crop Heterosis and Utilization/Engineering Research Center for Maize Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Mengran Li
- National Maize Improvement Center of China, Key Laboratory of Crop Heterosis and Utilization/Engineering Research Center for Maize Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Xiaolong Qi
- National Maize Improvement Center of China, Key Laboratory of Crop Heterosis and Utilization/Engineering Research Center for Maize Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Chenxu Liu
- National Maize Improvement Center of China, Key Laboratory of Crop Heterosis and Utilization/Engineering Research Center for Maize Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China
| | - Kim Boutilier
- Bioscience, Wageningen University and Research, 6700 AA, Wageningen, The Netherlands
| | - Shaojiang Chen
- National Maize Improvement Center of China, Key Laboratory of Crop Heterosis and Utilization/Engineering Research Center for Maize Breeding, Ministry of Education, College of Agronomy and Biotechnology, China Agricultural University, Beijing, 100193, China
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30
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Underwood CJ, Mercier R. Engineering Apomixis: Clonal Seeds Approaching the Fields. ANNUAL REVIEW OF PLANT BIOLOGY 2022; 73:201-225. [PMID: 35138881 DOI: 10.1146/annurev-arplant-102720-013958] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
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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31
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Khurana R, Bhimrajka S, Sivakrishna Rao G, Verma V, Boora N, Gawande G, Kapoor M, Rao KV, Kapoor S. Characterization of Transcription Regulatory Domains of OsMADS29: Identification of Proximal Auxin-Responsive Domains and a Strong Distal Negative Element. FRONTIERS IN PLANT SCIENCE 2022; 13:850956. [PMID: 35557721 PMCID: PMC9085466 DOI: 10.3389/fpls.2022.850956] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Accepted: 03/02/2022] [Indexed: 06/15/2023]
Abstract
OsMADS29 (M29) is a seed-specific MADS-box transcription factor involved in programmed cell death of nucellar tissue and maintaining auxin:cytokinin homeostasis. It affects embryo and endosperm development and starch filling during seed development in rice. Its expression seems to be tightly regulated by developmental, spatial, and temporal cues; however, cis- and trans-regulatory factors that affect its expression are largely unknown. In silico analysis of the 1.7 kb upstream regulatory region (URR) consisting of 1,290 bp promoter and 425 bp 5'-UTR regions revealed several auxin-responsive and seed-specific cis-regulatory elements distributed across the URR. In this study, the analysis of four URR deletions fused to a downstream β-glucuronidase (GUS) reporter in transgenic rice has revealed the presence of several proximal positive elements and a strong distal negative element (NE). The promoter regions containing auxin-responsive elements responded positively to the exogenous application of auxins to transgenic seedlings. The proximal positive elements are capable of driving reporter expression in both vegetative and reproductive tissues. In contrast, the NE strongly suppresses reporter gene expression in both vegetative and reproductive tissues. In a transient onion peel assay system, the NE could reduce the efficacy of a 2x CaMV 35S promoter by ∼90%. Our results indicate the existence of a complex array of positive and negative regulatory regions along with auxin-responsive elements guiding the development-dependent and spatial expression of M29.
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Affiliation(s)
- Ridhi Khurana
- Interdisciplinary Centre for Plant Genomics and Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Sanchi Bhimrajka
- Interdisciplinary Centre for Plant Genomics and Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | | | - Vibha Verma
- Interdisciplinary Centre for Plant Genomics and Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Neelima Boora
- Interdisciplinary Centre for Plant Genomics and Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Gautam Gawande
- Interdisciplinary Centre for Plant Genomics and Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
| | - Meenu Kapoor
- University School of Biotechnology, Guru Gobind Singh Indraprastha University, New Delhi, India
| | | | - Sanjay Kapoor
- Interdisciplinary Centre for Plant Genomics and Department of Plant Molecular Biology, University of Delhi South Campus, New Delhi, India
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32
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Aini H, Sato Y, Uno K, Higashiyama T, Okamoto T. Dynamics of mitochondrial distribution during development and asymmetric division of rice zygotes. PLANT REPRODUCTION 2022; 35:47-60. [PMID: 34633536 DOI: 10.1007/s00497-021-00430-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2021] [Accepted: 10/01/2021] [Indexed: 06/13/2023]
Abstract
Mitochondria change their distribution from nuclear peripheral to uniformly distributed in cytoplasm during zygotic development of rice, and the mitochondria re-distribute around nucleus for even segregation into daughter cells. Mitochondria are highly dynamic organelles that actively move and change their localization along with actin filaments during the cell cycle. Studies of mitochondrial dynamics and distribution in plant cells have mainly been conducted on somatic cells, and our understanding about these aspects during the formation and development of zygotes remains limited. In this study, mitochondrial nucleoids of rice egg cells and zygotes were successfully stained by using N-aryl pyrido cyanine 3 (PC3), and their intracellular localization and distribution were demonstrated. Mitochondria in rice egg cells were small and coccoid in shape and were primarily distributed around the nucleus. Upon gamete fusion, the resulting zygotes showed mitochondrial dispersion and accumulation equivalent to those in rice egg cells until 8 h after fusion (HAF). Around 12 HAF, the mitochondria started to disperse throughout the cytoplasm of the zygotes, and this dispersive distribution pattern continued until the zygotes entered the mitotic phase. At early prophase, the mitochondria redistributed from dispersive to densely accumulated around the nucleus, and during the metaphase and anaphase, the mitochondria were depleted from possible mitotic spindle region. Thereafter, during cell plate formation between daughter nuclei, the mitochondria distributed along the phragmoplast, where the new cell wall was formed. Finally, relatively equivalent amounts of mitochondria were detected in the apical and basal cells which were produced through asymmetric division of the zygotes. Further observation by treating the egg cell with latrunculin B revealed that the accumulation of mitochondria around the nuclear periphery in egg cells and early zygotes depended on the actin meshwork converging toward the egg or zygote nucleus.
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Affiliation(s)
- Hanifah Aini
- Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa, Hachioji, Tokyo, 192-0397, Japan
| | - Yoshikatsu Sato
- Graduate School of Science, Nagoya University, Chikusa, Nagoya, 464-8601, Japan
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya, 464-8601, Japan
| | - Kakishi Uno
- Graduate School of Science, Nagoya University, Chikusa, Nagoya, 464-8601, Japan
- Department of NanoBiophotonics, Max Planck Institute for Biophysical Chemistry, Göttingen, Germany
| | - Tetsuya Higashiyama
- Graduate School of Science, Nagoya University, Chikusa, Nagoya, 464-8601, Japan
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Chikusa, Nagoya, 464-8601, Japan
- Department of Biological Sciences, Graduate School of Science, The University of Tokyo, Bunkyo, Tokyo, 113-0033, Japan
| | - Takashi Okamoto
- Department of Biological Sciences, Tokyo Metropolitan University, Minami-osawa, Hachioji, Tokyo, 192-0397, Japan.
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33
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Zhao P, Shi C, Wang L, Sun MX. The parental contributions to early plant embryogenesis and the concept of maternal-to-zygotic transition in plants. CURRENT OPINION IN PLANT BIOLOGY 2022; 65:102144. [PMID: 34823206 DOI: 10.1016/j.pbi.2021.102144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Revised: 10/20/2021] [Accepted: 10/21/2021] [Indexed: 06/13/2023]
Abstract
The maternal-to-zygotic transition (MZT) is a major developmental transition in the life cycles of animals. It consists of two associated processes: maternal transcript clearance and zygotic genome activation (ZGA). The concept of MZT has been controversially discussed in plants. In this short review, we summarize recent advances in understanding the timing of ZGA and the similarities and differences between ZGA in eudicots and monocots. We discuss the parental contributions to the transcriptome of the proembryo and parental control of early embryogenesis, and we examine distinct differences in the ZGA between animals and plants, update relevant concepts on MZT, and highlight outstanding questions in this field.
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Affiliation(s)
- Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China; Hubei Hongshan Laboratory, Wuhan, 430070, China
| | - Ce Shi
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Ling Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China.
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34
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Li C, Gent JI, Xu H, Fu H, Russell SD, Sundaresan V. Resetting of the 24-nt siRNA landscape in rice zygotes. Genome Res 2022; 32:309-323. [PMID: 34949668 PMCID: PMC8805726 DOI: 10.1101/gr.275981.121] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Accepted: 12/19/2021] [Indexed: 11/24/2022]
Abstract
The zygote, a totipotent stem cell, is crucial to the life cycle of sexually reproducing organisms. It is produced by the fusion of two differentiated cells-the egg and sperm, which in plants have radically different siRNA transcriptomes from each other and from multicellular embryos. Owing to technical challenges, the epigenetic changes that accompany the transition from differentiated gametes to totipotent zygote are poorly understood. Because siRNAs serve as both regulators and outputs of the epigenome, we characterized small RNA transcriptomes of zygotes from rice. Zygote small RNAs exhibit extensive maternal carryover and an apparent lack of paternal contribution, indicated by absence of sperm signature siRNAs. Zygote formation is accompanied by widespread redistribution of 24-nt siRNAs relative to gametes, such that ∼70% of the zygote siRNA loci do not overlap any egg cell siRNA loci. Newly detected siRNA loci in zygote are gene-proximal and not associated with centromeric heterochromatin, similar to canonical siRNAs, in sharp contrast to gametic siRNA loci that are gene-distal and heterochromatic. In addition, zygote but not egg siRNA loci are associated with high DNA methylation in the mature embryo. Thus, the zygote begins transitioning before the first embryonic division to an siRNA profile that is associated with future RdDM in embryogenesis. These findings indicate that, in addition to changes in gene expression, the transition to totipotency in the plant zygote is accompanied by resetting of the epigenetic reprogramming that occurred during gamete formation.
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Affiliation(s)
- Chenxin Li
- Department of Plant Biology, University of California, Davis, California 95616, USA
| | - Jonathan I Gent
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602, USA
| | - Hengping Xu
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Hong Fu
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Scott D Russell
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Venkatesan Sundaresan
- Department of Plant Biology, University of California, Davis, California 95616, USA
- Department of Plant Sciences, University of California, Davis, California 95616, USA
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35
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Gao P, Quilichini TD, Yang H, Li Q, Nilsen KT, Qin L, Babic V, Liu L, Cram D, Pasha A, Esteban E, Condie J, Sidebottom C, Zhang Y, Huang Y, Zhang W, Bhowmik P, Kochian LV, Konkin D, Wei Y, Provart NJ, Kagale S, Smith M, Patterson N, Gillmor CS, Datla R, Xiang D. Evolutionary divergence in embryo and seed coat development of U's Triangle Brassica species illustrated by a spatiotemporal transcriptome atlas. THE NEW PHYTOLOGIST 2022; 233:30-51. [PMID: 34687557 DOI: 10.1111/nph.17759] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
The economically valuable Brassica species include the six related members of U's Triangle. Despite the agronomic and economic importance of these Brassicas, the impacts of evolution and relatively recent domestication events on the genetic landscape of seed development have not been comprehensively examined in these species. Here we present a 3D transcriptome atlas for the six species of U's Triangle, producing a unique resource that captures gene expression data for the major subcompartments of the seed, from the unfertilized ovule to the mature embryo and seed coat. This comprehensive dataset for seed development in tetraploid and ancestral diploid Brassicas provides new insights into evolutionary divergence and expression bias at the gene and subgenome levels during the domestication of these valued crop species. Comparisons of gene expression associated with regulatory networks and metabolic pathways operating in the embryo and seed coat during seed development reveal differences in storage reserve accumulation and fatty acid metabolism among the six Brassica species. This study illustrates the genetic underpinnings of seed traits and the selective pressures placed on seed production, providing an immense resource for continued investigation of Brassica polyploid biology, genomics and evolution.
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Affiliation(s)
- Peng Gao
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, SK, S7N 4L8, Canada
| | - Teagen D Quilichini
- Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Hui Yang
- Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Qiang Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Kirby T Nilsen
- Brandon Research and Development Centre, Agriculture and Agri-Food Canada, 2701 Grand Valley Road, Brandon, MB, R7C 1A1, Canada
| | - Li Qin
- College of Art & Science, University of Saskatchewan, 9 Campus Dr, Saskatoon, SK, S7N 5A5, Canada
| | - Vivijan Babic
- Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Li Liu
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, SK, S7N 4L8, Canada
| | - Dustin Cram
- Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Asher Pasha
- Department of Cell & Systems Biology, University of Toronto, 25 Willcocks St., Toronto, ON, M5S 3B2, Canada
| | - Eddi Esteban
- Department of Cell & Systems Biology, University of Toronto, 25 Willcocks St., Toronto, ON, M5S 3B2, Canada
| | - Janet Condie
- Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Christine Sidebottom
- Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Yan Zhang
- Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK, S7N 0X2, Canada
| | - Yi Huang
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture and Rural Affairs, Oil Crops Research Institute, Chinese Academy of Agricultural Sciences, Wuhan, 430062, China
| | - Wentao Zhang
- Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Pankaj Bhowmik
- Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Leon V Kochian
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, SK, S7N 4L8, Canada
| | - David Konkin
- Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Yangdou Wei
- College of Art & Science, University of Saskatchewan, 9 Campus Dr, Saskatoon, SK, S7N 5A5, Canada
| | - Nicholas J Provart
- Department of Cell & Systems Biology, University of Toronto, 25 Willcocks St., Toronto, ON, M5S 3B2, Canada
| | - Sateesh Kagale
- Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - Mark Smith
- Saskatoon Research and Development Centre, Agriculture and Agri-Food Canada, 107 Science Place, Saskatoon, SK, S7N 0X2, Canada
| | - Nii Patterson
- Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
| | - C Stewart Gillmor
- Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Unidad de Genómica Avanzada, Centro de Investigación y Estudios Avanzados del IPN (CINVESTAV-IPN), Irapuato, Guanajuato, 36821, México
| | - Raju Datla
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, SK, S7N 4L8, Canada
| | - Daoquan Xiang
- Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK, S7N 0W9, Canada
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Zhou S, Li X, Liu Q, Zhao Y, Jiang W, Wu A, Zhou DX. DNA demethylases remodel DNA methylation in rice gametes and zygote and are required for reproduction. MOLECULAR PLANT 2021; 14:1569-1583. [PMID: 34116223 DOI: 10.1016/j.molp.2021.06.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/07/2021] [Accepted: 06/06/2021] [Indexed: 05/24/2023]
Abstract
Fertilization constitutes a critical step in the plant life cycle during which the gamete genomes undergo chromatin dynamics in preparation for embryogenesis. In mammals, parental chromatin is extensively reprogrammed through the global erasure of DNA methylation. However, in flowering plants it remains unclear whether and how DNA methylation is remodeled in gametes and after fertilization in the zygote. In this study, we characterize DNA methylation patterns and investigate the function of DNA glycosylases in rice eggs, sperm, and unicellular zygotes and during embryogenesis. We found that DNA methylation is locally reconfigured after fertilization and is intensified during embryogenesis. Genetic, epigenomic, and transcriptomic analysis revealed that three rice DNA glycosylases, DNG702, DNG701, and DNG704, demethylate DNA at distinct genomic regions in the gametes and the zygote, and are required for zygotic gene expression and development. Collectively, these results indicate that active DNA demethylation takes place in the gametes and the zygote to locally remodel DNA methylation, which is critical for egg and zygote gene expression and reproduction in rice.
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Affiliation(s)
- Shaoli Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Xue Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Qian Liu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Yu Zhao
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Wei Jiang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Anqi Wu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Dao-Xiu Zhou
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China; Institute of Plant Science Paris-Saclay (IPS2), CNRS, INRAE, University Paris-Saclay, 91405 Orsay, France.
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37
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Dresselhaus T, Jürgens G. Comparative Embryogenesis in Angiosperms: Activation and Patterning of Embryonic Cell Lineages. ANNUAL REVIEW OF PLANT BIOLOGY 2021; 72:641-676. [PMID: 33606951 DOI: 10.1146/annurev-arplant-082520-094112] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
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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38
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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] [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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Liu XQ, Shi JJ, Fan H, Jiao J, Gao L, Tan L, Nagawa S, Wang DY. Nuclear DNA replicates during zygote development in Arabidopsis and Torenia fournieri. PLANT PHYSIOLOGY 2021; 185:137-145. [PMID: 33631800 PMCID: PMC8133679 DOI: 10.1093/plphys/kiaa014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 10/23/2020] [Indexed: 06/02/2023]
Abstract
The progression of the cell cycle is continuous in most cells, but gametes (sperm and egg cells) exhibit an arrest of the cell cycle to await fertilization to form a zygote, which then continues through the subsequent phases to complete cell division. The phase in which gametes of flowering plants arrest has been a matter of debate, since different phases have been reported for the gametes of different species. In this study, we reassessed the phase of cell-cycle arrest in the gametes of two species, Arabidopsis (Arabidopsis thaliana) and Torenia fournieri. We first showed that 4', 6-diamidino-2-phenylindole staining was not feasible to detect changes in gametic nuclear DNA in T. fournieri. Next, using 5-ethynyl-2'-deoxyuridine (EdU) staining that detects DNA replication by labeling the EdU absorbed by deoxyribonucleic acid, we found that the replication of nuclear DNA did not occur during gamete development but during zygote development, revealing that the gametes of these species have a haploid nuclear DNA content before fertilization. We thus propose that gametes in the G1 phase participate in the fertilization event in Arabidopsis and T. fournieri.
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Affiliation(s)
- Xue-Qiong Liu
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi’an 710069, China
| | - Jiao-Jiao Shi
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi’an 710069, China
| | - Hua Fan
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi’an 710069, China
| | - Jiao Jiao
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi’an 710069, China
| | - Long Gao
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi’an 710069, China
| | - Li Tan
- Plant Stress Center, CAS Center for Excellence in Molecular Plant Sciences, Shanghai 201602, China
| | - Shingo Nagawa
- Plant Stress Center, CAS Center for Excellence in Molecular Plant Sciences, Shanghai 201602, China
- FAFU-UCR Joint Center Horticulture, Plant Biology and Metabolomics Center, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Dan-Yang Wang
- Key Laboratory of Resource Biology and Biotechnology in Western China (Ministry of Education), College of Life Science, Northwest University, Xi’an 710069, China
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40
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Khanday I, Sundaresan V. Plant zygote development: recent insights and applications to clonal seeds. CURRENT OPINION IN PLANT BIOLOGY 2021; 59:101993. [PMID: 33422964 DOI: 10.1016/j.pbi.2020.101993] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 12/11/2020] [Accepted: 12/15/2020] [Indexed: 05/22/2023]
Abstract
In flowering plants, haploid gametes - an egg cell and a sperm cell fuse to form the first diploid cell - the zygote. The zygote is the progenitor stem cell that gives rise to all the embryonic and post embryonic tissues and organs. Unlike animals, both maternal and paternal gene products participate in the initial development of zygotes in plants. Here, we discuss recent advances in understanding of the zygotic transition and embryo initiation in angiosperms, including the role of parental contributions to gene expression in the zygote. We further discuss utilization of this knowledge in agricultural biotechnology through synthetic apomixis. Parthenogenesis obtained by manipulation of embryogenic factors, combined with mutations that bypass meiosis, enables clonal propagation of hybrid crops through seeds.
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Affiliation(s)
- Imtiyaz Khanday
- Department of Plant Biology, University of California, Davis, CA, USA; Innovative Genomics Institute, University of California, Berkeley, CA, USA
| | - Venkatesan Sundaresan
- Department of Plant Biology, University of California, Davis, CA, USA; Innovative Genomics Institute, University of California, Berkeley, CA, USA; Department of Plant Sciences, University of California, Davis, CA, USA.
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41
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Deushi R, Toda E, Koshimizu S, Yano K, Okamoto T. Effect of Paternal Genome Excess on the Developmental and Gene Expression Profiles of Polyspermic Zygotes in Rice. PLANTS (BASEL, SWITZERLAND) 2021; 10:255. [PMID: 33525652 PMCID: PMC7911625 DOI: 10.3390/plants10020255] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/22/2021] [Accepted: 01/26/2021] [Indexed: 11/17/2022]
Abstract
Polyploid zygotes with a paternal gamete/genome excess exhibit arrested development, whereas polyploid zygotes with a maternal excess develop normally. These observations indicate that paternal and maternal genomes synergistically influence zygote development via distinct functions. In this study, to clarify how paternal genome excess affects zygotic development, the developmental and gene expression profiles of polyspermic rice zygotes were analyzed. The results indicated that polyspermic zygotes were mostly arrested at the one-cell stage after karyogamy had completed. Through comparison of transcriptomes between polyspermic zygotes and diploid zygotes, 36 and 43 genes with up-regulated and down-regulated expression levels, respectively, were identified in the polyspermic zygotes relative to the corresponding expression in the diploid zygotes. Notably, OsASGR-BBML1, which encodes an AP2 transcription factor possibly involved in initiating rice zygote development, was expressed at a much lower level in the polyspermic zygotes than in the diploid zygotes.
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Affiliation(s)
- Ryouya Deushi
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0392, Japan; (R.D.); (E.T.)
| | - Erika Toda
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0392, Japan; (R.D.); (E.T.)
| | - Shizuka Koshimizu
- Department of Life Sciences, Meiji University, Kanagawa 214-8571, Japan; (S.K.); (K.Y.)
| | - Kentaro Yano
- Department of Life Sciences, Meiji University, Kanagawa 214-8571, Japan; (S.K.); (K.Y.)
| | - Takashi Okamoto
- Department of Biological Sciences, Tokyo Metropolitan University, Tokyo 192-0392, Japan; (R.D.); (E.T.)
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42
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Armenta-Medina A, Gillmor CS, Gao P, Mora-Macias J, Kochian LV, Xiang D, Datla R. Developmental and genomic architecture of plant embryogenesis: from model plant to crops. PLANT COMMUNICATIONS 2021; 2:100136. [PMID: 33511346 PMCID: PMC7816075 DOI: 10.1016/j.xplc.2020.100136] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2020] [Revised: 12/05/2020] [Accepted: 12/11/2020] [Indexed: 05/08/2023]
Abstract
Embryonic development represents an important reproductive phase of sexually reproducing plant species. The fusion of egg and sperm produces the plant zygote, a totipotent cell that, through cell division and cell identity specification in early embryogenesis, establishes the major cell lineages and tissues of the adult plant. The subsequent morphogenesis phase produces the full-sized embryo, while the late embryogenesis maturation process prepares the seed for dormancy and subsequent germination, ensuring continuation of the plant life cycle. In this review on embryogenesis, we compare the model eudicot Arabidopsis thaliana with monocot crops, focusing on genome activation, paternal and maternal regulation of early zygote development, and key organizers of patterning, such as auxin and WOX transcription factors. While the early stages of embryo development are apparently conserved among plant species, embryo maturation programs have diversified between eudicots and monocots. This diversification in crop species reflects the likely effects of domestication on seed quality traits that are determined during embryo maturation, and also assures seed germination in different environmental conditions. This review describes the most important features of embryonic development in plants, and the scope and applications of genomics in plant embryo studies.
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Affiliation(s)
- Alma Armenta-Medina
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 4J8, Canada
- Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Unidad de Genómica Avanzada, Centro de Investigación y Estudios Avanzados del IPN (CINVESTAV-IPN), Irapuato, Guanajuato, México
| | - C. Stewart Gillmor
- Laboratorio Nacional de Genómica para la Biodiversidad (Langebio), Unidad de Genómica Avanzada, Centro de Investigación y Estudios Avanzados del IPN (CINVESTAV-IPN), Irapuato, Guanajuato, México
| | - Peng Gao
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 4J8, Canada
| | - Javier Mora-Macias
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 4J8, Canada
| | - Leon V. Kochian
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 4J8, Canada
| | - Daoquan Xiang
- National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9, Canada
| | - Raju Datla
- Global Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 4J8, Canada
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43
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Zhao P, Zhou X, Zheng Y, Ren Y, Sun MX. Equal parental contribution to the transcriptome is not equal control of embryogenesis. NATURE PLANTS 2020; 6:1354-1364. [PMID: 33106635 DOI: 10.1038/s41477-020-00793-x] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2020] [Accepted: 09/16/2020] [Indexed: 05/06/2023]
Abstract
In animals, early embryogenesis is maternally controlled, whereas in plants, parents contribute equally to the proembryo transcriptome. Thus, the question remains whether equivalent parental contribution to the transcriptome of the early proembryo means equal control of early embryogenesis. Here, on the basis of cell-lineage-specific and allele-specific transcriptome analysis, we reveal that paternal and maternal genomes contribute equally to the transcriptomes of both the apical cell lineage and the basal cell lineage of early proembryos. However, a strong maternal effect on basal cell lineage development was found, indicating that equal parental contribution to the transcriptome is not necessarily coupled with equivalent parental control of proembryonic development. Parental contributions to embryogenesis therefore cannot be concluded solely on the basis of the ratio of paternal/maternal transcripts. Furthermore, we demonstrate that parent-of-origin genes display developmental-stage-dependent and cell-lineage-dependent allelic expression patterns. These findings will facilitate the investigation of specific parental roles in specific processes of early embryogenesis.
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Affiliation(s)
- Peng Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China.
| | - Xuemei Zhou
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
- College of Life Sciences, South-Central University for Nationalities, Wuhan, China
| | - Yifan Zheng
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Yanru Ren
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, China.
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Abstract
In higher plants, fertilization induces many structural and physiological changes in the fertilized egg that reflect the transition from the haploid female gamete to the diploid zygote - the first cell of the sporophyte. After fusion of the egg nucleus with the sperm nucleus, many molecular changes occur in the zygote during the process of zygote activation during embryogenesis. The zygote originates from the egg, from which some pre-stored translation initiation factors transfer into the zygote and function during zygote activation. This indicates that the control of zygote activation is pre-set in the egg. After the egg and sperm nuclei fuse, gene expression is activated in the zygote, and paternal and maternal gene expression patterns are displayed. This highlights the diversity of zygotic genome activation in higher plants. In addition to new gene expression in the zygote, some genes show quantitative changes in expression. The asymmetrical division of the zygote produces an apical cell and a basal cell that have different destinies during plant reconstruction; these destinies are determined in the zygote. This review describes significant advances in research on the mechanisms controlling zygote activation in higher plants.
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45
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Scheben A, Hojsgaard D. Can We Use Gene-Editing to Induce Apomixis in Sexual Plants? Genes (Basel) 2020; 11:E781. [PMID: 32664641 PMCID: PMC7397034 DOI: 10.3390/genes11070781] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 12/12/2022] Open
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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46
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Shin JM, Yuan L, Ohme-Takagi M, Kawashima T. Cellular dynamics of double fertilization and early embryogenesis in flowering plants. JOURNAL OF EXPERIMENTAL ZOOLOGY PART B-MOLECULAR AND DEVELOPMENTAL EVOLUTION 2020; 336:642-651. [PMID: 32638525 DOI: 10.1002/jez.b.22981] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 06/12/2020] [Accepted: 06/18/2020] [Indexed: 12/12/2022]
Abstract
Flowering plants (angiosperms) perform a unique double fertilization in which two sperm cells fuse with two female gamete cells in the embryo sac to develop a seed. Furthermore, during land plant evolution, the mode of sexual reproduction has been modified dramatically from motile sperm in the early-diverging land plants, such as mosses and ferns as well as some gymnosperms (Ginkgo and cycads) to nonmotile sperm that are delivered to female gametes by the pollen tube in flowering plants. Recent studies have revealed the cellular dynamics and molecular mechanisms for the complex series of double fertilization processes and elucidated differences and similarities between animals and plants. Here, together with a brief comparison with animals, we review the current understanding of flowering plant zygote dynamics, covering from gamete nuclear migration, karyogamy, and polyspermy block, to zygotic genome activation as well as asymmetrical division of the zygote. Further analyses of the detailed molecular and cellular mechanisms of flowering plant fertilization should shed light on the evolution of the unique sexual reproduction of flowering plants.
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Affiliation(s)
- Ji Min Shin
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky.,Kentucky Tobacco Research and Development Center, University of Kentucky, Lexington, Kentucky.,Graduate School of Science and Engineering, Saitama University, Saitama, Saitama, Japan
| | - Ling Yuan
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky.,Kentucky Tobacco Research and Development Center, University of Kentucky, Lexington, Kentucky
| | - Masaru Ohme-Takagi
- Graduate School of Science and Engineering, Saitama University, Saitama, Saitama, Japan.,Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Ibaraki, Japan
| | - Tomokazu Kawashima
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky
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Ohnishi Y, Kawashima T. Plasmogamic Paternal Contributions to Early Zygotic Development in Flowering Plants. FRONTIERS IN PLANT SCIENCE 2020; 11:871. [PMID: 32636867 PMCID: PMC7317025 DOI: 10.3389/fpls.2020.00871] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 05/28/2020] [Indexed: 06/01/2023]
Abstract
Flowering plant zygotes possess complete developmental potency, and the mixture of male and female genetic and cytosolic materials in the zygote is a trigger to initiate embryo development. Plasmogamy, the fusion of the gamete cytoplasms, facilitates the cellular dynamics of the zygote. In the last decade, mutant analyses, live cell imaging-based observations, and direct observations of fertilized egg cells by in vitro fusion of isolated gametes have accelerated our understanding of the post-plasmogamic events in flowering plants including cell wall formation, gamete nuclear migration and fusion, and zygotic cell elongation and asymmetric division. Especially, it has become more evident that paternal parent-of-origin effects, via sperm cytoplasm contents, not only control canonical early zygotic development, but also activate a biparental signaling pathway critical for cell fate determination after the first cell division. Here, we summarize the plasmogamic paternal contributions via the entry of sperm contents during/after fertilization in flowering plants.
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Affiliation(s)
- Yukinosuke Ohnishi
- Kihara Institute for Biological Research, Yokohama City University, Yokohama, Japan
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, United States
| | - Tomokazu Kawashima
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, United States
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48
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Abstract
Transcriptomic studies have proven powerful and effective as a tool to study the molecular underpinnings of plant development. Still, it remains challenging to disentangle cell- or tissue-specific transcriptomes in complex structures like the plant seed. In particular, the embryo of flowering plants is embedded in the endosperm, a nurturing tissue, which, in turn, is enclosed by the maternal seed coat. Here, we describe laser-assisted microdissection (LAM) to isolate highly pure embryo tissue from whole seeds. This technique is applicable to virtually any plant seed, and we illustrate the use of LAM to isolate embryos from species of the Boechera and Solanum genera. LAM is a tool that will greatly help to increase the repertoires of tissue-specific transcriptomes, including those of embryos and parts thereof, in nonmodel plants.
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49
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Li C, Xu H, Fu FF, Russell SD, Sundaresan V, Gent JI. Genome-wide redistribution of 24-nt siRNAs in rice gametes. Genome Res 2020; 30:173-184. [PMID: 31896557 PMCID: PMC7050532 DOI: 10.1101/gr.253674.119] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 12/23/2019] [Indexed: 12/13/2022]
Abstract
Gametes constitute a critical stage of the plant life cycle during which the genome undergoes reprogramming in preparation for embryogenesis. Here, we examined genome-wide distributions of small RNAs in the sperm and egg cells of rice. We found that 24-nt siRNAs, which are a hallmark of RNA-directed DNA methylation (RdDM) in plants, were depleted from heterochromatin boundaries in both gametes relative to vegetative tissues, reminiscent of siRNA patterns in DDM1-type nucleosome remodeler mutants. In sperm cells, 24-nt siRNAs were spread across heterochromatic regions, while in egg cells, 24-nt siRNAs were concentrated at a smaller number of heterochromatic loci throughout the genome, especially at loci which also produced siRNAs in other tissues. In both gametes, patterns of CHH methylation, typically a strong indicator of RdDM, were similar to vegetative tissues, although lower in magnitude. These findings indicate that the small RNA transcriptome undergoes large-scale redistribution in both male and female gametes, which is not correlated with recruitment of DNA methyltransferases in gametes and suggestive of unexplored regulatory activities of gamete small RNAs.
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Affiliation(s)
- Chenxin Li
- Department of Plant Biology, University of California, Davis, California 95616, USA
| | - Hengping Xu
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Fang-Fang Fu
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602, USA
| | - Scott D Russell
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, Oklahoma 73019, USA
| | - Venkatesan Sundaresan
- Department of Plant Biology, University of California, Davis, California 95616, USA.,Department of Plant Sciences, University of California, Davis, California 95616, USA
| | - Jonathan I Gent
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602, USA
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Kao P, Nodine MD. Transcriptional Activation of Arabidopsis Zygotes Is Required for Initial Cell Divisions. Sci Rep 2019; 9:17159. [PMID: 31748673 PMCID: PMC6868190 DOI: 10.1038/s41598-019-53704-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Accepted: 11/04/2019] [Indexed: 11/10/2022] Open
Abstract
Commonly referred to as the maternal-to-zygotic transition, the shift of developmental control from maternal-to-zygotic genomes is a key event during animal and plant embryogenesis. Together with the degradation of parental gene products, the increased transcriptional activities of the zygotic genome remodels the early embryonic transcriptome during this transition. Although evidence from multiple flowering plants suggests that zygotes become transcriptionally active soon after fertilization, the timing and developmental requirements of zygotic genome activation in Arabidopsis thaliana (Arabidopsis) remained a matter of debate until recently. In this report, we optimized an expansion microscopy technique for robust immunostaining of Arabidopsis ovules and seeds. This enabled the detection of marks indicative of active transcription in zygotes before the first cell division. Moreover, we employed a live-imaging culture system together with transcriptional inhibitors to demonstrate that such active transcription is physiologically required in zygotes and early embryos. Our results indicate that zygotic genome activation occurs soon after fertilization and is required for the initial zygotic divisions in Arabidopsis.
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Affiliation(s)
- Ping Kao
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030, Vienna, Austria
| | - Michael D Nodine
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna Biocenter (VBC), Dr. Bohr-Gasse 3, 1030, Vienna, Austria.
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