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Sharma V, Ali MF, Kawashima T. Insights into dynamic coenocytic endosperm development: Unraveling molecular, cellular, and growth complexity. CURRENT OPINION IN PLANT BIOLOGY 2024; 81:102566. [PMID: 38830335 DOI: 10.1016/j.pbi.2024.102566] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 05/02/2024] [Accepted: 05/13/2024] [Indexed: 06/05/2024]
Abstract
The endosperm, a product of double fertilization, is one of the keys to the evolution and success of angiosperms in conquering the land. While there are differences in endosperm development among flowering plants, the most common form is coenocytic growth, where the endosperm initially undergoes nuclear division without cytokinesis and eventually becomes cellularized. This complex process requires interplay among networks of transcription factors such as MADS-box, auxin response factors (ARFs), and phytohormones. The role of cytoskeletal elements in shaping the coenocytic endosperm and influencing seed growth also becomes evident. This review offers a recent understanding of the molecular and cellular dynamics in coenocytic endosperm development and their contributions to the final seed size.
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Affiliation(s)
- Vijyesh Sharma
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
| | - Mohammad Foteh Ali
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
| | - Tomokazu Kawashima
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA.
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2
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Butel N, Qiu Y, Xu W, Santos-González J, Köhler C. Parental conflict driven regulation of endosperm cellularization by a family of Auxin Response Factors. NATURE PLANTS 2024:10.1038/s41477-024-01706-y. [PMID: 38806655 DOI: 10.1038/s41477-024-01706-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 04/19/2024] [Indexed: 05/30/2024]
Abstract
The endosperm is a reproductive tissue supporting embryo development. In most flowering plants, the initial divisions of endosperm nuclei are not succeeded by cellularization; this process occurs only after a specific number of mitotic cycles have taken place. The timing of cellularization significantly influences seed viability and size. Previous research implicated auxin as a key factor in initiating nuclear divisions and determining the timing of cellularization. Here we uncover the involvement of a family of clustered auxin response factors (cARFs) as dosage-sensitive regulators of endosperm cellularization. cARFs, maternally expressed and paternally silenced, are shown to induce cellularization, thereby restricting seed growth. Our findings align with the predictions of the parental conflict theory, suggesting that cARFs represent major molecular targets in this conflict. We further demonstrate a recurring amplification of cARFs in the Brassicaceae, suggesting an evolutionary response to parental conflict by reinforcing maternal control over endosperm cellularization. Our study highlights that antagonistic parental control on endosperm cellularization converges on auxin biosynthesis and signalling.
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Affiliation(s)
- N Butel
- Department of Plant Reproductive Biology and Epigenetics, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Y Qiu
- Department of Plant Reproductive Biology and Epigenetics, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - W Xu
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Centre for Plant Biology, Uppsala, Sweden
- INRAE Centre Ile-de-France - Versailles-Saclay, France, Versailles-Sacley, France
| | - J Santos-González
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Centre for Plant Biology, Uppsala, Sweden
| | - C Köhler
- Department of Plant Reproductive Biology and Epigenetics, Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany.
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Centre for Plant Biology, Uppsala, Sweden.
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3
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Bente H, Köhler C. Molecular basis and evolutionary drivers of endosperm-based hybridization barriers. PLANT PHYSIOLOGY 2024; 195:155-169. [PMID: 38298124 PMCID: PMC11060687 DOI: 10.1093/plphys/kiae050] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 01/05/2024] [Accepted: 01/06/2024] [Indexed: 02/02/2024]
Abstract
The endosperm, a transient seed tissue, plays a pivotal role in supporting embryo growth and germination. This unique feature sets flowering plants apart from gymnosperms, marking an evolutionary innovation in the world of seed-bearing plants. Nevertheless, the importance of the endosperm extends beyond its role in providing nutrients to the developing embryo by acting as a versatile protector, preventing hybridization events between distinct species and between individuals with different ploidy. This phenomenon centers on growth and differentiation of the endosperm and the speed at which both processes unfold. Emerging studies underscore the important role played by type I MADS-box transcription factors, including the paternally expressed gene PHERES1. These factors, along with downstream signaling pathways involving auxin and abscisic acid, are instrumental in regulating endosperm development and, consequently, the establishment of hybridization barriers. Moreover, mutations in various epigenetic regulators mitigate these barriers, unveiling a complex interplay of pathways involved in their formation. In this review, we discuss the molecular underpinnings of endosperm-based hybridization barriers and their evolutionary drivers.
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Affiliation(s)
- Heinrich Bente
- Department of Plant Reproductive Biology and Epigenetics, Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Claudia Köhler
- Department of Plant Reproductive Biology and Epigenetics, Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
- Department of Plant Biology, Swedish University of Agricultural Sciences and Linnean Center for Plant Biology, Uppsala 75007, Sweden
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4
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Yang K, Tang Y, Li Y, Guo W, Hu Z, Wang X, Berger F, Li J. Two imprinted genes primed by DEMETER in the central cell and activated by WRKY10 in the endosperm. J Genet Genomics 2024:S1673-8527(24)00072-9. [PMID: 38599515 DOI: 10.1016/j.jgg.2024.04.003] [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: 03/28/2024] [Revised: 04/02/2024] [Accepted: 04/02/2024] [Indexed: 04/12/2024]
Abstract
The early development of the endosperm is crucial for balancing the allocation of maternal nutrients to offspring. This process is believed to be evolutionarily associated with genomic imprinting, resulting in parentally biased allelic gene expression. Beyond FertilizationIndependentSeed (FIS) genes, the number of imprinted genes involved in early endosperm development and seed size determination remains limited. This study introduces two early endosperm-expressed HAIKU (IKU) downstream Candidate F-box 1 (ICF1) and ICF2, as maternally expressed imprinted genes (MEGs). Although these genes are also demethylated by DEMETER (DME) in the central cell, their activation differs from the direct DME-mediated activation seen in classical MEGs such as the FIS genes. Instead, ICF maternal alleles carry pre-established hypomethylation in their promoters, priming them for activation by the WRKY10 transcription factor in the endosperm. On the contrary, paternal alleles are predominantly suppressed by CG methylation. Furthermore, we find that ICF genes partially contribute to the small seed size observed in iku mutants. Our discovery reveals a two-step regulatory mechanism that highlights the important role of conventional transcription factors in the activation of imprinted genes, which was previously not fully recognized. Therefore, the mechanism provides a new dimension to understand the transcriptional regulation of imprinting in plant reproduction and development.
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Affiliation(s)
- Ke Yang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Sanya Institute of Breeding and Multiplication, Hainan University, Sanya, Hainan 572025, China; School of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China; Hainan Yazhou Bay Seed Laboratory, Sanya, Hainan 572025, China
| | - Yuling Tang
- Sanya Institute of Breeding and Multiplication, Hainan University, Sanya, Hainan 572025, China; School of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China; Hainan Yazhou Bay Seed Laboratory, Sanya, Hainan 572025, China
| | - Yue Li
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Wenbin Guo
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Zhengdao Hu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Xuanpeng Wang
- Sanya Institute of Breeding and Multiplication, Hainan University, Sanya, Hainan 572025, China; School of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China; Hainan Yazhou Bay Seed Laboratory, Sanya, Hainan 572025, China
| | - Frédéric Berger
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, 1030 Vienna, Austria
| | - Jing Li
- Sanya Institute of Breeding and Multiplication, Hainan University, Sanya, Hainan 572025, China; School of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China; Hainan Yazhou Bay Seed Laboratory, Sanya, Hainan 572025, China.
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5
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Dew-Budd KJ, Chow HT, Kendall T, David BC, Rozelle JA, Mosher RA, Beilstein MA. Mating system is associated with seed phenotypes upon loss of RNA-directed DNA methylation in Brassicaceae. PLANT PHYSIOLOGY 2024; 194:2136-2148. [PMID: 37987565 DOI: 10.1093/plphys/kiad622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 10/03/2023] [Accepted: 10/23/2023] [Indexed: 11/22/2023]
Abstract
In plants, de novo DNA methylation is guided by 24-nt short interfering (si)RNAs in a process called RNA-directed DNA methylation (RdDM). Primarily targeted at transposons, RdDM causes transcriptional silencing and can indirectly influence expression of neighboring genes. During reproduction, a small number of siRNA loci are dramatically upregulated in the maternally derived seed coat, suggesting that RdDM might have a special function during reproduction. However, the developmental consequence of RdDM has been difficult to dissect because disruption of RdDM does not result in overt phenotypes in Arabidopsis (Arabidopsis thaliana), where the pathway has been most thoroughly studied. In contrast, Brassica rapa mutants lacking RdDM have a severe seed production defect, which is determined by the maternal sporophytic genotype. To explore the factors that underlie the different phenotypes of these species, we produced RdDM mutations in 3 additional members of the Brassicaceae family: Camelina sativa, Capsella rubella, and Capsella grandiflora. Among these 3 species, only mutations in the obligate outcrosser, C. grandiflora, displayed a seed production defect similar to Brassica rapa mutants, suggesting that mating system is a key determinant for reproductive phenotypes in RdDM mutants.
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Affiliation(s)
- Kelly J Dew-Budd
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Hiu Tung Chow
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Timmy Kendall
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Brandon C David
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - James A Rozelle
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Rebecca A Mosher
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Mark A Beilstein
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
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6
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Soliman HK, Coughlan JM. United by Conflict: Convergent Signatures of Parental Conflict in Angiosperms and Placental Mammals. J Hered 2024:esae009. [PMID: 38366852 DOI: 10.1093/jhered/esae009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Indexed: 02/18/2024] Open
Abstract
Endosperm in angiosperms and placenta in eutherians are convergent innovations for efficient embryonic nutrient transfer. Despite advantages, this reproductive strategy incurs metabolic costs that maternal parents disproportionately shoulder, leading to potential inter-parental conflict over optimal offspring investment. Genomic imprinting-parent-of-origin-biased gene expression-is fundamental for endosperm and placenta development and has convergently evolved in angiosperms and mammals, in part, to resolve parental conflict. Here, we review the mechanisms of genomic imprinting in these taxa. Despite differences in the timing and spatial extent of imprinting, these taxa exhibit remarkable convergence in the molecular machinery and genes governing imprinting. We then assess the role of parental conflict in shaping evolution within angiosperms and eutherians using four criteria: (1) Do differences in the extent of sibling relatedness cause differences in the inferred strength of parental conflict? (2) Do reciprocal crosses between taxa with different inferred histories of parental conflict exhibit parent-of-origin growth effects? (3) Are these parent-of-origin growth effects caused by dosage-sensitive mechanisms and do these loci exhibit signals of positive selection? (4) Can normal development be restored by genomic perturbations that restore stoichiometric balance in the endosperm/placenta? Although we find evidence for all criteria in angiosperms and eutherians, suggesting that parental conflict may help shape their evolution, many questions remain. Additionally, myriad differences between the two taxa suggest that their respective biologies may shape how/when/where/to what extent parental conflict manifests. Lastly, we discuss outstanding questions, highlighting the power of comparative work in quantifying the role of parental conflict in evolution.
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Affiliation(s)
- Hagar K Soliman
- Department of Ecology & Evolutionary Biology, Yale University, New Haven, CT, 06511, United States
- Department of Biotechnology, Faculty of Science, Cairo University, Giza, 12613, Egypt
| | - Jenn M Coughlan
- Department of Ecology & Evolutionary Biology, Yale University, New Haven, CT, 06511, United States
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7
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Montgomery SA, Berger F. Paternal imprinting in Marchantia polymorpha. THE NEW PHYTOLOGIST 2024; 241:1000-1006. [PMID: 37936346 DOI: 10.1111/nph.19377] [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: 06/22/2023] [Accepted: 10/09/2023] [Indexed: 11/09/2023]
Abstract
We are becoming aware of a growing number of organisms that do not express genetic information equally from both parents as a result of an epigenetic phenomenon called genomic imprinting. Recently, it was shown that the entire paternal genome is repressed during the diploid phase of the life cycle of the liverwort Marchantia polymorpha. The deposition of the repressive epigenetic mark H3K27me3 on the male pronucleus is responsible for the imprinted state, which is reset by the end of meiosis. Here, we put these recent reports in perspective of other forms of imprinting and discuss the potential mechanisms of imprinting in bryophytes and the causes of its evolution.
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Affiliation(s)
- Sean A Montgomery
- Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), C/ del Dr Aiguader, 88, 08003, Barcelona, Spain
| | - Frédéric Berger
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Dr Bohr-Gasse 3, 1030, Vienna, Austria
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8
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Yang G, Feng M, Yu K, Cui G, Zhou Y, Sun L, Gao L, Zhang Y, Peng H, Yao Y, Hu Z, Rossi V, De Smet I, Ni Z, Sun Q, Xin M. Paternally imprinted LATE-FLOWERING2 transcription factor contributes to paternal-excess interploidy hybridization barriers in wheat. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2023; 65:2587-2603. [PMID: 37846823 DOI: 10.1111/jipb.13574] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 10/16/2023] [Indexed: 10/18/2023]
Abstract
Interploidy hybridization between hexaploid and tetraploid genotypes occurred repeatedly during genomic introgression events throughout wheat evolution, and is commonly employed in wheat breeding programs. Hexaploid wheat usually serves as maternal parent because the reciprocal cross generates progeny with severe defects and poor seed germination, but the underlying mechanism is poorly understood. Here, we performed detailed analysis of phenotypic variation in endosperm between two interploidy reciprocal crosses arising from tetraploid (Triticum durum, AABB) and hexaploid wheat (Triticum aestivum, AABBDD). In the paternal- versus the maternal-excess cross, the timing of endosperm cellularization was delayed and starch granule accumulation in the endosperm was repressed, causing reduced germination percentage. The expression profiles of genes involved in nutrient metabolism differed strongly between these endosperm types. Furthermore, expression patterns of parental alleles were dramatically disturbed in interploidy versus intraploidy crosses, leading to increased number of imprinted genes. The endosperm-specific TaLFL2 showed a paternally imprinted expression pattern in interploidy crosses partially due to allele-specific DNA methylation. Paternal TaLFL2 binds to and represses a nutrient accumulation regulator TaNAC019, leading to reduced storage protein and starch accumulation during endosperm development in paternal-excess cross, as confirmed by interploidy crosses between tetraploid wild-type and clustered regularly interspaced palindromic repeats (CRISPR) - CRISPR-associated protein 9 generated hexaploid mutants. These findings reveal a contribution of genomic imprinting to paternal-excess interploidy hybridization barriers during wheat evolution history and explains why experienced breeders preferentially exploit maternal-excess interploidy crosses in wheat breeding programs.
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Affiliation(s)
- Guanghui Yang
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Man Feng
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Kuohai Yu
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Guangxian Cui
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Yan Zhou
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Lv Sun
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Lulu Gao
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Yumei Zhang
- Qingdao Agricultural University, Qingdao, 266109, China
| | - Huiru Peng
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Yingyin Yao
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Zhaorong Hu
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Vincenzo Rossi
- Council for Agricultural Research and Economics, Research Centre for Cereal and Industrial Crops, Bergamo, 24126, Italy
| | - Ive De Smet
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, B-9052, Belgium
- VIB Center for Plant Systems Biology, Ghent, B-9052, Belgium
| | - Zhongfu Ni
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Qixin Sun
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
| | - Mingming Xin
- State Key Laboratory for Agrobiotechnology, Key Laboratory of Crop Heterosis Utilization (MOE), Beijing Key Laboratory of Crop Genetic Improvement, China Agricultural University, Beijing, 100193, China
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Zumajo-Cardona C, Gabrieli F, Anire J, Albertini E, Ezquer I, Colombo L. Evolutionary studies of the bHLH transcription factors belonging to MBW complex: their role in seed development. ANNALS OF BOTANY 2023; 132:383-400. [PMID: 37467144 PMCID: PMC10667011 DOI: 10.1093/aob/mcad097] [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: 06/19/2023] [Accepted: 07/17/2023] [Indexed: 07/21/2023]
Abstract
BACKGROUND AND AIMS The MBW complex consist of proteins belonging to three major families (MYB, bHLH and WDR) involved in various processes throughout plant development: epidermal cell development, mucilage secretory cells and flavonoid biosynthesis. Recently, it has been reported that TT8, encoding a bHLH transcription factor, is involved in the biosynthesis of flavonoids in the seed coat and it also plays a role in bypassing the postzygotic barrier resulting from an unbalance in genetic loads of the parental lines. Here, we focus on the functional evolution, in seed development, of the bHLH proteins that are part of the MBW complex, complemented with a literature review. METHODS Phylogenetic analyses performed across seed plants and expression analyses in the reproductive tissues of four selected angiosperms (Arabidopsis thaliana, Brassica napus, Capsella rubella and Solanum lycopersicum) allow us to hypothesize on the evolution of its functions. KEY RESULTS TT8 expression in the innermost layer of the seed coat is conserved in the selected angiosperms. However, except for Arabidopsis, TT8 is also expressed in ovules, carpels and fruits. The homologues belonging to the sister clade of TT8, EGL3/GL3, involved in trichome development, are expressed in the outermost layer of the seed coat, suggesting potential roles in mucilage. CONCLUSIONS The ancestral function of these genes appears to be flavonoid biosynthesis, and the conservation of TT8 expression patterns in the innermost layer of the seed coat in angiosperms suggests that their function in postzygotic barriers might also be conserved. Moreover, the literature review and the results of the present study suggest a sophisticated association, linking the mechanisms of action of these genes to the cross-communication activity between the different tissues of the seed. Thus, it provides avenues to study the mechanisms of action of TT8 in the postzygotic triploid block, which is crucial because it impacts seed development in unbalanced crosses.
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Affiliation(s)
- Cecilia Zumajo-Cardona
- Department of BioScience, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
| | - Flavio Gabrieli
- Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno 74, Perugia, Italy
- Dipartimento di Ingegneria Industriale DII, University of Padua, via Gradenigo, 6/a, Padova, Italy
| | - Jovannemar Anire
- Department of BioScience, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
- Wageningen UR Plant Breeding, Droevendaalsesteeg 1, NL-6708 PB Wageningen, The Netherlands
- National Coconut Research Center – Visayas, Visayas State University, Baybay City, Leyte, Philippines
| | - Emidio Albertini
- Agricultural, Food and Environmental Sciences, University of Perugia, Borgo XX Giugno 74, Perugia, Italy
| | - Ignacio Ezquer
- Department of BioScience, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
| | - Lucia Colombo
- Department of BioScience, Università degli Studi di Milano, Via Celoria 26, 20133 Milano, Italy
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10
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Rojek J, Ohad N. The phenomenon of autonomous endosperm in sexual and apomictic plants. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4324-4348. [PMID: 37155961 PMCID: PMC10433939 DOI: 10.1093/jxb/erad168] [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: 01/18/2023] [Accepted: 05/04/2023] [Indexed: 05/10/2023]
Abstract
Endosperm is a key nutritive tissue that supports the developing embryo or seedling, and serves as a major nutritional source for human and livestock feed. In sexually-reproducing flowering plants, it generally develops after fertilization. However, autonomous endosperm (AE) formation (i.e. independent of fertilization) is also possible. Recent findings of AE loci/ genes and aberrant imprinting in native apomicts, together with a successful initiation of parthenogenesis in rice and lettuce, have enhanced our understanding of the mechanisms bridging sexual and apomictic seed formation. However, the mechanisms driving AE development are not well understood. This review presents novel aspects related to AE development in sexual and asexual plants underlying stress conditions as the primary trigger for AE. Both application of hormones to unfertilized ovules and mutations that impair epigenetic regulation lead to AE development in sexual Arabidopsis thaliana, which may point to a common pathway for both phenomena. Apomictic-like AE development under experimental conditions can take place due to auxin-dependent gene expression and/or DNA methylation.
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Affiliation(s)
- Joanna Rojek
- Department of Plant Cytology and Embryology, Faculty of Biology, University of Gdansk, Gdansk, Poland
| | - Nir Ohad
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel
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11
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Bjerkan KN, Alling RM, Myking IV, Brysting AK, Grini PE. Genetic and environmental manipulation of Arabidopsis hybridization barriers uncovers antagonistic functions in endosperm cellularization. FRONTIERS IN PLANT SCIENCE 2023; 14:1229060. [PMID: 37600172 PMCID: PMC10433385 DOI: 10.3389/fpls.2023.1229060] [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: 05/26/2023] [Accepted: 07/12/2023] [Indexed: 08/22/2023]
Abstract
Speciation involves reproductive isolation, which can occur by hybridization barriers acting in the endosperm of the developing seed. The nuclear endosperm is a nutrient sink, accumulating sugars from surrounding tissues, and undergoes coordinated cellularization, switching to serve as a nutrient source for the developing embryo. Tight regulation of cellularization is therefore vital for seed and embryonic development. Here we show that hybrid seeds from crosses between Arabidopsis thaliana as maternal contributor and A. arenosa or A. lyrata as pollen donors result in an endosperm based post-zygotic hybridization barrier that gives rise to a reduced seed germination rate. Hybrid seeds display opposite endosperm cellularization phenotypes, with late cellularization in crosses with A. arenosa and early cellularization in crosses with A. lyrata. Stage specific endosperm reporters display temporally ectopic expression in developing hybrid endosperm, in accordance with the early and late cellularization phenotypes, confirming a disturbance of the source-sink endosperm phase change. We demonstrate that the hybrid barrier is under the influence of abiotic factors, and show that a temperature gradient leads to diametrically opposed cellularization phenotype responses in hybrid endosperm with A. arenosa or A. lyrata as pollen donors. Furthermore, different A. thaliana accession genotypes also enhance or diminish seed viability in the two hybrid cross-types, emphasizing that both genetic and environmental cues control the hybridization barrier. We have identified an A. thaliana MADS-BOX type I family single locus that is required for diametrically opposed cellularization phenotype responses in hybrid endosperm. Loss of AGAMOUS-LIKE 35 significantly affects the germination rate of hybrid seeds in opposite directions when transmitted through the A. thaliana endosperm, and is suggested to be a locus that promotes cellularization as part of an endosperm based mechanism involved in post-zygotic hybrid barriers. The role of temperature in hybrid speciation and the identification of distinct loci in control of hybrid failure have great potential to aid the introduction of advantageous traits in breeding research and to support models to predict hybrid admixture in a changing global climate.
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Affiliation(s)
- Katrine N. Bjerkan
- Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Renate M. Alling
- Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Ida V. Myking
- Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Anne K. Brysting
- Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, Oslo, Norway
- Centre for Ecological and Evolutionary Synthesis (CEES), Department of Biosciences, University of Oslo, Oslo, Norway
| | - Paul E. Grini
- Section for Genetics and Evolutionary Biology (EVOGENE), Department of Biosciences, University of Oslo, Oslo, Norway
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12
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He H, Shiragaki K, Tezuka T. Understanding and overcoming hybrid lethality in seed and seedling stages as barriers to hybridization and gene flow. FRONTIERS IN PLANT SCIENCE 2023; 14:1219417. [PMID: 37476165 PMCID: PMC10354522 DOI: 10.3389/fpls.2023.1219417] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 06/20/2023] [Indexed: 07/22/2023]
Abstract
Hybrid lethality is a type of reproductive isolation barrier observed in two developmental stages, hybrid embryos (hybrid seeds) and hybrid seedlings. Hybrid lethality has been reported in many plant species and limits distant hybridization breeding including interspecific and intergeneric hybridization, which increases genetic diversity and contributes to produce new germplasm for agricultural purposes. Recent studies have provided molecular and genetic evidence suggesting that underlying causes of hybrid lethality involve epistatic interaction of one or more loci, as hypothesized by the Bateson-Dobzhansky-Muller model, and effective ploidy or endosperm balance number. In this review, we focus on the similarities and differences between hybrid seed lethality and hybrid seedling lethality, as well as methods of recovering seed/seedling activity to circumvent hybrid lethality. Current knowledge summarized in our article will provides new insights into the mechanisms of hybrid lethality and effective methods for circumventing hybrid lethality.
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Affiliation(s)
- Hai He
- School of Agriculture, Sun Yat-sen University, Shenzhen, China
| | - Kumpei Shiragaki
- Laboratory of Plant Breeding and Genetics, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
| | - Takahiro Tezuka
- Laboratory of Breeding and Genetics, Graduate School of Agriculture, Osaka Metropolitan University, Sakai, Osaka, Japan
- Education and Research Field, School of Agriculture, Osaka Metropolitan University, Sakai, Osaka, Japan
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13
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Dong J, Tu W, Wang H, Zuo Y, Liu T, Zhao Q, Ying J, Wu J, Liu Y, Cai X, Song B. Genome sequence analysis provides insights into the mode of 2n egg formation in Solanum malmeanum. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2023; 136:157. [PMID: 37340281 DOI: 10.1007/s00122-023-04406-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2023] [Accepted: 06/13/2023] [Indexed: 06/22/2023]
Abstract
KEY MESSAGE Our genomic investigation confirms the mechanism of 2n eggs formation in S. malmeanum and aid in optimizing the use of wild germplasm. Wild potatoes are a valuable source of agronomic traits. However, substantial reproductive barriers limit gene flow into cultivated species. 2n gametes are instrumental in preventing endosperm abortion caused by genetic imbalances in the endosperm. However, little is known about the molecular mechanisms underlying the formation of 2n gametes. Here, the wild species Solanum malmeanum Bitter (2x, 1EBN, endosperm balance number) was used in inter- and intrapoloid crosses with other Solanum species, with viable seeds being produced only when S. malmeanum was used as the female parent to cross the 2EBN Solanum genus and with the likely involvement of 2n gametes. Subsequently, we substantiated the formation of 2n eggs in S. malmeanum using fluorescence in situ hybridization (FISH) and genomic sequencing technology. Additionally, the transmission rate of maternal heterozygous polymorphism sites was assessed from a genomic perspective to analyze the mode of 2n egg formation in S. malmeanum × S. tuberosum and S. malmeanum × S. chacoense crosses; each cross acquired an average of 31.12% and 22.79% maternal sites, respectively. This confirmed that 2n egg formation in S. malmeanum attributed to second-division restitution (SDR) coupled with the occurrence of exchange events. The high-throughput sequencing technology used in this study has strong advantages over traditional cytological analyses. Furthermore, S. malmeanum, which has a variety of excellent traits not available from present cultivated potato genepool, has received little research attention and has successfully achieved gene flow in cultivated species in the current study. These findings will facilitate the understanding and optimization of wild germplasm utilization in potatoes.
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Affiliation(s)
- Jianke Dong
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Wei Tu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
- College of Biology and Agricultural Resources, Huanggang Normal University, Huanggang, 438000, China
| | - Haibo Wang
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
- College of Biological and Food Engineering, Hubei Minzu University, Enshi, 445000, China
| | - Yingtao Zuo
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Tengfei Liu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Qinghao Zhao
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jingwen Ying
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Jianghai Wu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Yuanyuan Liu
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Xingkui Cai
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China
| | - Botao Song
- National Key Laboratory for Germplasm Innovation and Utilization of Horticultural Crops, Key Laboratory of Horticultural Plant Biology, Ministry of Education, Key Laboratory of Potato Biology and Biotechnology, Ministry of Agriculture and Rural Affairs, Huazhong Agricultural University, Wuhan, 430070, China.
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14
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Jin C, Sun L, Trinh HK, Danny G. Heat stress promotes haploid formation during CENH3-mediated genome elimination in Arabidopsis. PLANT REPRODUCTION 2023; 36:147-155. [PMID: 36692584 DOI: 10.1007/s00497-023-00457-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Accepted: 01/09/2023] [Indexed: 06/09/2023]
Abstract
Impaired activity of centromeric histone CENH3 causes inaccurate chromosome segregation and in crosses between the Arabidopsis recombinant CENH3 mutant GFP-tailswap and CENH3G83E with wild-type pollen it results in chromosome loss with the formation of haploids. This genome elimination in the zygote and embryo is not absolute as also aneuploid and diploid progeny is formed. Here, we report that a temporal and moderate heat stress during fertilization and early embryogenesis shifts the ratio in favour of haploid progeny in CENH3 mutant lines. Micronuclei formation, a proxy for genome elimination, was similar in control and heat-treated flowers, indicating that heat-induced seed abortion occurred at a late stage during the development of the seed. In the seeds derived from heat-treated crosses, the endosperm did not cellularize and many seeds aborted. Haploid seeds were formed, however, resulting in increased frequencies of haploids in CENH3-mediated genome elimination crosses performed under heat stress. Therefore, heat stress application is a selective force during genome elimination that promotes haploid formation and may be used to improve the development and efficacy of in vivo haploid induction systems.
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Affiliation(s)
- Chunlian Jin
- Faculty of Bioscience Engineering, HortiCell, Ghent University, Coupure Links, 9000, Ghent, Belgium
- Floricultural Research Institute, Yunnan Academy of Agricultural Sciences, National Engineering Research Center for Ornamental Horticulture, Key Laboratory for Flower Breeding of Yunnan Province, Kunming, China
| | - Limin Sun
- Faculty of Bioscience Engineering, HortiCell, Ghent University, Coupure Links, 9000, Ghent, Belgium
| | - Hoang Khai Trinh
- Faculty of Bioscience Engineering, HortiCell, Ghent University, Coupure Links, 9000, Ghent, Belgium
- Biotechnology Research and Development Institute, Can Tho University, Can Tho City, 900000, Vietnam
| | - Geelen Danny
- Faculty of Bioscience Engineering, HortiCell, Ghent University, Coupure Links, 9000, Ghent, Belgium.
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15
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Chow HT, Mosher RA. Small RNA-mediated DNA methylation during plant reproduction. THE PLANT CELL 2023; 35:1787-1800. [PMID: 36651080 DOI: 10.1093/plcell/koad010] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 01/11/2023] [Accepted: 01/11/2023] [Indexed: 05/30/2023]
Abstract
Reproductive tissues are a rich source of small RNAs, including several classes of short interfering (si)RNAs that are restricted to this stage of development. In addition to RNA polymerase IV-dependent 24-nt siRNAs that trigger canonical RNA-directed DNA methylation, abundant reproductive-specific siRNAs are produced from companion cells adjacent to the developing germ line or zygote and may move intercellularly before inducing methylation. In some cases, these siRNAs are produced via non-canonical biosynthesis mechanisms or from sequences with little similarity to transposons. While the precise role of these siRNAs and the methylation they trigger is unclear, they have been implicated in specifying a single megaspore mother cell, silencing transposons in the male germ line, mediating parental dosage conflict to ensure proper endosperm development, hypermethylation of mature embryos, and trans-chromosomal methylation in hybrids. In this review, we summarize the current knowledge of reproductive siRNAs, including their biosynthesis, transport, and function.
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Affiliation(s)
- Hiu Tung Chow
- The School of Plant Sciences, The University of Arizona, Tucson, Arizona 85721-0036, USA
| | - Rebecca A Mosher
- The School of Plant Sciences, The University of Arizona, Tucson, Arizona 85721-0036, USA
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16
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Bellucci M, Caceres ME, Paolocci F, Vega JM, Ortiz JPA, Ceccarelli M, De Marchis F, Pupilli F. ORIGIN OF RECOGNITION COMPLEX 3 controls the development of maternal excess endosperm in the Paspalum simplex agamic complex (Poaceae). JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:3074-3093. [PMID: 36812152 DOI: 10.1093/jxb/erad069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/21/2023] [Indexed: 05/21/2023]
Abstract
Pseudogamous apomixis in Paspalum simplex generates seeds with embryos genetically identical to the mother plant and endosperms deviating from the canonical 2(maternal):1(paternal) parental genome contribution into a maternal excess 4m:1p genome ratio. In P. simplex, the gene homologous to that coding for subunit 3 of the ORIGIN OF RECOGNITION COMPLEX (PsORC3) exists in three isogenic forms: PsORC3a is apomixis specific and constitutively expressed in developing endosperm whereas PsORCb and PsORCc are up-regulated in sexual endosperms and silenced in apomictic ones. This raises the question of how the different arrangement and expression profiles of these three ORC3 isogenes are linked to seed development in interploidy crosses generating maternal excess endosperms. We demonstrate that down-regulation of PsORC3b in sexual tetraploid plants is sufficient to restore seed fertility in interploidy 4n×2n crosses and, in turn, its expression level at the transition from proliferating to endoreduplication endosperm developmental stages dictates the fate of these seeds. Furthermore, we show that only when being maternally inherited can PsORC3c up-regulate PsORC3b. Our findings lay the basis for an innovative route-based on ORC3 manipulation-to introgress the apomictic trait into sexual crops and overcome the fertilization barriers in interploidy crosses.
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Affiliation(s)
- Michele Bellucci
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
| | - Maria Eugenia Caceres
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
| | - Francesco Paolocci
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
| | - Juan Manuel Vega
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET-UNR and Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | - Juan Pablo Amelio Ortiz
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET-UNR and Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | - Marilena Ceccarelli
- Department of Chemistry, Biology and Biotechnology, University of Perugia, 06123, Perugia, Italy
| | - Francesca De Marchis
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
| | - Fulvio Pupilli
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
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17
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Coughlan JM. The role of hybrid seed inviability in angiosperm speciation. AMERICAN JOURNAL OF BOTANY 2023; 110:1-14. [PMID: 36801827 DOI: 10.1002/ajb2.16135] [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: 08/27/2022] [Revised: 01/05/2023] [Accepted: 01/05/2023] [Indexed: 05/11/2023]
Abstract
Understanding which reproductive barriers contribute to speciation is essential to understanding the diversity of life on earth. Several contemporary examples of strong hybrid seed inviability (HSI) between recently diverged species suggest that HSI may play a fundamental role in plant speciation. Yet, a broader synthesis of HSI is needed to clarify its role in diversification. Here, I review the incidence and evolution of HSI. Hybrid seed inviability is common and evolves rapidly, suggesting that it may play an important role early in speciation. The developmental mechanisms that underlie HSI involve similar developmental trajectories in endosperm, even between evolutionarily deeply diverged incidents of HSI. In hybrid endosperm, HSI is often accompanied by whole-scale gene misexpression, including misexpression of imprinted genes which have a key role in endosperm development. I explore how an evolutionary perspective can clarify the repeated and rapid evolution of HSI. In particular, I evaluate the evidence for conflict between maternal and paternal interests in resource allocation to offspring (i.e., parental conflict). I highlight that parental conflict theory generates explicit predictions regarding the expected hybrid phenotypes and genes responsible for HSI. While much phenotypic evidence supports a role of parental conflict in the evolution of HSI, an understanding of the underlying molecular mechanisms of this barrier is essential to test parental conflict theory. Lastly, I explore what factors may influence the strength of parental conflict in natural plant populations as an explanation for why rates of HSI may differ between plant groups and the consequences of strong HSI in secondary contact.
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Affiliation(s)
- Jenn M Coughlan
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06511, USA
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18
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Xu W, Sato H, Bente H, Santos-González J, Köhler C. Endosperm cellularization failure induces a dehydration-stress response leading to embryo arrest. THE PLANT CELL 2023; 35:874-888. [PMID: 36427255 PMCID: PMC9940880 DOI: 10.1093/plcell/koac337] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2022] [Accepted: 11/22/2022] [Indexed: 06/16/2023]
Abstract
The endosperm is a nutritive tissue supporting embryo growth in flowering plants. Most commonly, the endosperm initially develops as a coenocyte (multinucleate cell) and then cellularizes. This process of cellularization is frequently disrupted in hybrid seeds generated by crosses between different flowering plant species or plants that differ in ploidy, resulting in embryo arrest and seed lethality. The reason for embryo arrest upon cellularization failure remains unclear. In this study, we show that triploid Arabidopsis thaliana embryos surrounded by uncellularized endosperm mount an osmotic stress response that is connected to increased levels of abscisic acid (ABA) and enhanced ABA responses. Impairing ABA biosynthesis and signaling aggravated triploid seed abortion, while increasing endogenous ABA levels as well as the exogenous application of ABA-induced endosperm cellularization and suppressed embryo growth arrest. Taking these results together, we propose that endosperm cellularization is required to establish dehydration tolerance in the developing embryo, ensuring its survival during seed maturation.
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Affiliation(s)
- Wenjia Xu
- Swedish University of Agricultural Sciences & Linnean Center for Plant Biology, Uppsala BioCenter, Almas Allé 5, SE-750 07 Uppsala, Sweden
| | - Hikaru Sato
- Swedish University of Agricultural Sciences & Linnean Center for Plant Biology, Uppsala BioCenter, Almas Allé 5, SE-750 07 Uppsala, Sweden
| | - Heinrich Bente
- Swedish University of Agricultural Sciences & Linnean Center for Plant Biology, Uppsala BioCenter, Almas Allé 5, SE-750 07 Uppsala, Sweden
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Juan Santos-González
- Swedish University of Agricultural Sciences & Linnean Center for Plant Biology, Uppsala BioCenter, Almas Allé 5, SE-750 07 Uppsala, Sweden
| | - Claudia Köhler
- Swedish University of Agricultural Sciences & Linnean Center for Plant Biology, Uppsala BioCenter, Almas Allé 5, SE-750 07 Uppsala, Sweden
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
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19
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van Ekelenburg YS, Hornslien KS, Van Hautegem T, Fendrych M, Van Isterdael G, Bjerkan KN, Miller JR, Nowack MK, Grini PE. Spatial and temporal regulation of parent-of-origin allelic expression in the endosperm. PLANT PHYSIOLOGY 2023; 191:986-1001. [PMID: 36437711 PMCID: PMC9922421 DOI: 10.1093/plphys/kiac520] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Accepted: 10/17/2022] [Indexed: 06/16/2023]
Abstract
Genomic imprinting promotes differential expression of parental alleles in the endosperm of flowering plants and is regulated by epigenetic modification such as DNA methylation and histone tail modifications in chromatin. After fertilization, the endosperm develops through a syncytial stage before it cellularizes and becomes a nutrient source for the growing embryo. Regional compartmentalization has been shown both in early and late endosperm development, and different transcriptional domains suggest divergent spatial and temporal regional functions. The analysis of the role of parent-of-origin allelic expression in the endosperm as a whole and the investigation of domain-specific functions have been hampered by the inaccessibility of the tissue for high-throughput transcriptome analyses and contamination from surrounding tissue. Here, we used fluorescence-activated nuclear sorting (FANS) of nuclear targeted GFP fluorescent genetic markers to capture parental-specific allelic expression from different developmental stages and specific endosperm domains. This approach allowed us to successfully identify differential genomic imprinting with temporal and spatial resolution. We used a systematic approach to report temporal regulation of imprinted genes in the endosperm, as well as region-specific imprinting in endosperm domains. Analysis of our data identified loci that are spatially differentially imprinted in one domain of the endosperm, while biparentally expressed in other domains. These findings suggest that the regulation of genomic imprinting is dynamic and challenge the canonical mechanisms for genomic imprinting.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Paul E Grini
- Authors for correspondence: E-mail: (P.E.G.), (K.S.H.)
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20
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Ando A, Kirkbride RC, Qiao H, Chen ZJ. Endosperm and Maternal-specific expression of EIN2 in the endosperm affects endosperm cellularization and seed size in Arabidopsis. Genetics 2023; 223:iyac161. [PMID: 36282525 PMCID: PMC9910398 DOI: 10.1093/genetics/iyac161] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 10/05/2022] [Indexed: 11/13/2022] Open
Abstract
Seed size is related to plant evolution and crop yield and is affected by genetic mutations, imprinting, and genome dosage. Imprinting is a widespread epigenetic phenomenon in mammals and flowering plants. ETHYLENE INSENSITIVE2 (EIN2) encodes a membrane protein that links the ethylene perception to transcriptional regulation. Interestingly, during seed development EIN2 is maternally expressed in Arabidopsis and maize, but the role of EIN2 in seed development is unknown. Here, we show that EIN2 is expressed specifically in the endosperm, and the maternal-specific EIN2 expression affects temporal regulation of endosperm cellularization. As a result, seed size increases in the genetic cross using the ein2 mutant as the maternal parent or in the ein2 mutant. The maternal-specific expression of EIN2 in the endosperm is controlled by DNA methylation but not by H3K27me3 or by ethylene and several ethylene pathway genes tested. RNA-seq analysis in the endosperm isolated by laser-capture microdissection show upregulation of many endosperm-expressed genes such as AGAMOUS-LIKEs (AGLs) in the ein2 mutant or when the maternal EIN2 allele is not expressed. EIN2 does not interact with DNA and may act through ETHYLENE INSENSITIVE3 (EIN3), a DNA-binding protein present in sporophytic tissues, to activate target genes like AGLs, which in turn mediate temporal regulation of endosperm cellularization and seed size. These results provide mechanistic insights into endosperm and maternal-specific expression of EIN2 on endosperm cellularization and seed development, which could help improve seed production in plants and crops.
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Affiliation(s)
- Atsumi Ando
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Ryan C Kirkbride
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Hong Qiao
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Z Jeffrey Chen
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
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21
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Šemberová K, Svitok M, Marhold K, Suda J, Schmickl RE. Morphological and environmental differentiation as prezygotic reproductive barriers between parapatric and allopatric Campanula rotundifolia agg. cytotypes. ANNALS OF BOTANY 2023; 131:71-86. [PMID: 34559179 PMCID: PMC9904352 DOI: 10.1093/aob/mcab123] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 09/21/2021] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIMS Reproductive isolation and local establishment are necessary for plant speciation. Polyploidy, the possession of more than two complete chromosome sets, creates a strong postzygotic reproductive barrier between diploid and tetraploid cytotypes. However, this barrier weakens between polyploids (e.g. tetraploids and hexaploids). Reproductive isolation may be enhanced by cytotype morphological and environmental differentiation. Moreover, morphological adaptations to local conditions contribute to plant establishment. However, the relative contributions of ploidy level and the environment to morphology have generally been neglected. Thus, the extent of morphological variation driven by ploidy level and the environment was modelled for diploid, tetraploid and hexaploid cytotypes of Campanula rotundifolia agg. Cytotype distribution was updated, and morphological and environmental differentiation was tested in the presence and absence of natural contact zones. METHODS Cytotype distribution was assessed from 231 localities in Central Europe, including 48 localities with known chromosome counts, using flow cytometry. Differentiation in environmental niche and morphology was tested for cytotype pairs using discriminant analyses. A structural equation model was used to explore the synergies between cytotype, environment and morphology. KEY RESULTS Tremendous discrepancies were revealed between the reported and detected cytotype distribution. Neither mixed-ploidy populations nor interploidy hybrids were detected in the contact zones. Diploids had the broadest environmental niche, while hexaploids had the smallest and specialized niche. Hexaploids and spatially isolated cytotype pairs differed morphologically, including allopatric tetraploids. While leaf and shoot morphology were influenced by environmental conditions and polyploidy, flower morphology depended exclusively on the cytotype. CONCLUSIONS Reproductive isolation mechanisms vary between cytotypes. While diploids and polyploids are isolated postzygotically, the environmental niche shift is essential between higher polyploids. The impact of polyploidy and the environment on plant morphology implies the adaptive potential of polyploids, while the exclusive relationship between flower morphology and cytotype highlights the role of polyploidy in reproductive isolation.
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Affiliation(s)
| | - Marek Svitok
- Faculty of Ecology and Environmental Sciences, Technical University in Zvolen, T. G. Masaryka, Zvolen, Slovakia
- Faculty of Science, Department of Ecosystem Biology, University of South Bohemia, Branišovská, České Budějovice, Czech Republic
| | - Karol Marhold
- Faculty of Science, Department of Botany, Charles University, Benátská, Prague, Czech Republic
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta, Bratislava, Slovakia
| | | | - Roswitha E Schmickl
- Faculty of Science, Department of Botany, Charles University, Benátská, Prague, Czech Republic
- Czech Academy of Sciences, Institute of Botany, Department of Evolutionary Plant Biology, Zámek, Průhonice, Czech Republic
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22
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Schneider DJ, Levin RA, Miller JS. Reproductive isolation between diploid and tetraploid individuals in mixed-cytotype populations of Lycium australe. AMERICAN JOURNAL OF BOTANY 2023; 110:e16133. [PMID: 36706341 DOI: 10.1002/ajb2.16133] [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: 05/28/2022] [Revised: 12/28/2022] [Accepted: 12/29/2022] [Indexed: 06/18/2023]
Abstract
PREMISE Whole-genome duplication is considered a major mechanism of sympatric speciation due to the creation of strong and instantaneous reproductive barriers. Although postzygotic reproductive isolation between diploids and polyploids is often expected, the extent of reproductive incompatibility must be empirically determined and compared to patterns of genetic isolation to fully characterize the reproductive dynamics between cytotypes. METHODS We investigated reproductive compatibility between diploid and tetraploid Lycium australe in two mixed-cytotype populations using (1) controlled crossing experiments to evaluate fruit and seed production and (2) germination trials to test seed viability following homoploid and heteroploid crosses. We contrast these experiments with a single-nucleotide polymorphism (SNP) data set to measure genetic isolation between cytotypes and explore whether cytotype or population origin better explains patterns of genetic variation. Finally, we explore mating patterns using the observed germination rates of naturally produced seeds in each population. RESULTS Although homoploid and heteroploid crosses resulted in similar fruit and seed production, reproductive isolation between co-occurring diploids and tetraploids was nearly complete, due to low seed viability following heteroploid crosses. Of 191,182 total SNPs, 21,679 were present in ≥90% of individuals and replicate runs using unlinked SNPs revealed strong clustering by cytotype and differentiation of tetraploids based on population origin. CONCLUSIONS As often reported, diploid and tetraploid L. australe experience strong postzygotic isolation via hybrid seed inviability. Consistent with this result, cytotype explained a greater amount of variation in the SNP data set than population origin, despite some evidence of historical introgression.
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Affiliation(s)
- Derek J Schneider
- Department of Biology, Amherst College, Amherst, Massachusetts, 01002, USA
| | - Rachel A Levin
- Department of Biology, Amherst College, Amherst, Massachusetts, 01002, USA
| | - Jill S Miller
- Department of Biology, Amherst College, Amherst, Massachusetts, 01002, USA
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McCartney B, Dudin O. Cellularization across eukaryotes: Conserved mechanisms and novel strategies. Curr Opin Cell Biol 2023; 80:102157. [PMID: 36857882 DOI: 10.1016/j.ceb.2023.102157] [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: 07/15/2022] [Revised: 01/27/2023] [Accepted: 01/31/2023] [Indexed: 03/02/2023]
Abstract
Many eukaryotes form multinucleated cells during their development. Some cells persist as such during their lifetime, others choose to cleave each nucleus individually using a specialized cytokinetic process known as cellularization. What is cellularization and how is it achieved across the eukaryotic tree of life? Are there common pathways among all species supporting a shared ancestry, or are there key differences, suggesting independent evolutionary paths? In this review, we discuss common strategies and key mechanistic differences in how cellularization is executed across vastly divergent eukaryotic species. We present a number of novel methods and non-model organisms that may provide important insight into the evolutionary origins of cellularization.
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Affiliation(s)
- Brooke McCartney
- Department of Biological Sciences, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
| | - Omaya Dudin
- Swiss Institute for Experimental Cancer Research, School of Life Sciences, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland.
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24
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Ali MF, Shin JM, Fatema U, Kurihara D, Berger F, Yuan L, Kawashima T. Cellular dynamics of coenocytic endosperm development in Arabidopsis thaliana. NATURE PLANTS 2023; 9:330-342. [PMID: 36646830 DOI: 10.1038/s41477-022-01331-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
After double fertilization, the endosperm in the seeds of many flowering plants undergoes repeated mitotic nuclear divisions without cytokinesis, resulting in a large coenocytic endosperm that then cellularizes. Growth during the coenocytic phase is strongly associated with the final seed size; however, a detailed description of the cellular dynamics controlling the unique coenocytic development in flowering plants has remained elusive. By integrating confocal microscopy live-cell imaging and genetics, we have characterized the entire development of the coenocytic endosperm of Arabidopsis thaliana including nuclear divisions, their timing intervals, nuclear movement and cytoskeleton dynamics. Around each nucleus, microtubules organize into aster-shaped structures that drive actin filament (F-actin) organization. Microtubules promote nuclear movement after division, while F-actin restricts it. F-actin is also involved in controlling the size of both the coenocytic endosperm and the mature seed. The characterization of cytoskeleton dynamics in real time throughout the entire coenocyte endosperm period provides foundational knowledge of plant coenocytic development, insights into the coordination of F-actin and microtubules in nuclear dynamics, and new opportunities to increase seed size and our food security.
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Affiliation(s)
- Mohammad Foteh Ali
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
| | - Ji Min Shin
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
- Kentucky Tobacco Research and Development Center, University of Kentucky, Lexington, KY, USA
| | - Umma Fatema
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
| | - Daisuke Kurihara
- Institute of Transformative Bio-Molecules (ITbM), Nagoya University, Nagoya, Japan
- Institute for Advanced Research (IAR), Nagoya University, Nagoya, Japan
| | - Frédéric Berger
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, Vienna, Austria
| | - Ling Yuan
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA
- Kentucky Tobacco Research and Development Center, University of Kentucky, Lexington, KY, USA
- Key Laboratory of South China Agricultural Plant Molecular Analysis and Genetic Improvement & Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China
| | - Tomokazu Kawashima
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, USA.
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Zumajo-Cardona C, Aguirre M, Castillo-Bravo R, Mizzotti C, Di Marzo M, Banfi C, Mendes MA, Spillane C, Colombo L, Ezquer I. Maternal control of triploid seed development by the TRANSPARENT TESTA 8 (TT8) transcription factor in Arabidopsis thaliana. Sci Rep 2023; 13:1316. [PMID: 36693864 PMCID: PMC9873634 DOI: 10.1038/s41598-023-28252-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2022] [Accepted: 01/16/2023] [Indexed: 01/25/2023] Open
Abstract
The balance between parental genome dosage is critical to offspring development in both animals and plants. In some angiosperm species, despite the imbalance between maternally and paternally inherited chromosome sets, crosses between parental lines of different ploidy may result in viable offspring. However, many plant species, like Arabidopsis thaliana, present a post-zygotic reproductive barrier, known as triploid block which results in the inability of crosses between individuals of different ploidy to generate viable seeds but also, in defective development of the seed. Several paternal regulators have been proposed as active players in establishing the triploid block. Maternal regulators known to be involved in this process are some flavonoid biosynthetic (FB) genes, expressed in the innermost layer of the seed coat. Here we explore the role of selected flavonoid pathway genes in triploid block, including TRANSPARENT TESTA 4 (TT4), TRANSPARENT TESTA 7 (TT7), SEEDSTICK (STK), TRANSPARENT TESTA 16 (TT16), TT8 and TRANSPARENT TESTA 13 (TT13). This approach allowed us to detect that TT8, a bHLH transcription factor, member of this FB pathway is required for the paternal genome dosage, as loss of function tt8, leads to complete rescue of the triploid block to seed development.
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Affiliation(s)
- Cecilia Zumajo-Cardona
- Dipartimento Di BioScienze, Università Degli Studi Di Milano, Via Celoria 26, 20133, Milano, Italy
| | - Manuel Aguirre
- Dipartimento Di BioScienze, Università Degli Studi Di Milano, Via Celoria 26, 20133, Milano, Italy.,Translational Plant & Microbial Biology, Institute of Environmental Biology, Utrecht University, Padualaan 8, 3584CH, Utrecht, The Netherlands
| | - Rosa Castillo-Bravo
- Genetics and Biotechnology Laboratory, Plant and AgriBioscience Research Centre (PABC), Ryan Institute, National University of Ireland Galway, University Road, Galway, H91 REW4, Ireland
| | - Chiara Mizzotti
- Dipartimento Di BioScienze, Università Degli Studi Di Milano, Via Celoria 26, 20133, Milano, Italy
| | - Maurizio Di Marzo
- Dipartimento Di BioScienze, Università Degli Studi Di Milano, Via Celoria 26, 20133, Milano, Italy
| | - Camilla Banfi
- Dipartimento Di BioScienze, Università Degli Studi Di Milano, Via Celoria 26, 20133, Milano, Italy
| | - Marta A Mendes
- Dipartimento Di BioScienze, Università Degli Studi Di Milano, Via Celoria 26, 20133, Milano, Italy
| | - Charles Spillane
- Genetics and Biotechnology Laboratory, Plant and AgriBioscience Research Centre (PABC), Ryan Institute, National University of Ireland Galway, University Road, Galway, H91 REW4, Ireland
| | - Lucia Colombo
- Dipartimento Di BioScienze, Università Degli Studi Di Milano, Via Celoria 26, 20133, Milano, Italy
| | - Ignacio Ezquer
- Dipartimento Di BioScienze, Università Degli Studi Di Milano, Via Celoria 26, 20133, Milano, Italy.
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26
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Akinmusola RY, Wilkins CA, Doughty J. DDM1-Mediated TE Silencing in Plants. PLANTS (BASEL, SWITZERLAND) 2023; 12:437. [PMID: 36771522 PMCID: PMC9919755 DOI: 10.3390/plants12030437] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 01/05/2023] [Accepted: 01/09/2023] [Indexed: 06/18/2023]
Abstract
Epigenetic modifications are indispensable for regulating gene bodies and TE silencing. DECREASE IN DNA METHYLATION 1 (DDM1) is a chromatin remodeller involved in histone modifications and DNA methylation. Apart from maintaining the epigenome, DDM1 also maintains key plant traits such as flowering time and heterosis. The role of DDM1 in epigenetic regulation is best characterised in plants, especially arabidopsis, rice, maize and tomato. The epigenetic changes induced by DDM1 establish the stable inheritance of many plant traits for at least eight generations, yet DDM1 does not methylate protein-coding genes. The DDM1 TE silencing mechanism is distinct and has evolved independently of other silencing pathways. Unlike the RNA-directed DNA Methylation (RdDM) pathway, DDM1 does not depend on siRNAs to enforce the heterochromatic state of TEs. Here, we review DDM1 TE silencing activity in the RdDM and non-RdDM contexts. The DDM1 TE silencing machinery is strongly associated with the histone linker H1 and histone H2A.W. While the linker histone H1 excludes the RdDM factors from methylating the heterochromatin, the histone H2A.W variant prevents TE mobility. The DDM1-H2A.W strategy alone silences nearly all the mobile TEs in the arabidopsis genome. Thus, the DDM1-directed TE silencing essentially preserves heterochromatic features and abolishes mobile threats to genome stability.
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Coughlan JM. Indirect Effects of Parental Conflict on Conspecific Offspring Development. Am Nat 2023; 201:154-162. [PMID: 36524928 DOI: 10.1086/721919] [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] [Indexed: 11/03/2022]
Abstract
AbstractHybrid seed inviability is a common reproductive barrier in angiosperms. Recent work suggests that the rapid evolution of hybrid seed inviability may, in part, be due to conflict between maternal and paternal optima for resource allocation to developing offspring (i.e., parental conflict). However, parental conflict requires that paternally derived resource-acquiring alleles impose a maternal cost. I test this requirement using three closely related species in the Mimulus guttatus species complex that exhibit significant hybrid seed inviability and differ in their inferred histories of parental conflict. I show that the presence of hybrid seeds significantly affects conspecific seed size for almost all crosses, such that conspecific seeds are smaller after developing with hybrids sired by fathers with a stronger history of conflict and are larger after developing with hybrids sired by fathers with a weaker history of conflict. This work demonstrates a potential maternal cost of paternally derived alleles and also has implications for species fitness in secondary contact.
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Kolarčik V, Kocová V, Mikoláš V, Mártonfiová L, Hajdučeková N, Mártonfi P. Variability of Reproduction Pathways in the Central-European Populations of Hawthorns with Emphasis on Triploids. PLANTS (BASEL, SWITZERLAND) 2022; 11:3497. [PMID: 36559608 PMCID: PMC9786806 DOI: 10.3390/plants11243497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/21/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
The role of apomeiosis, parthenogenesis, and pseudogamy in the asexual reproduction of some plant groups has not been fully elucidated in relation to species diversification. Quantitative analyses of seed origin may help in gaining better understanding of intercytotypic interactions. Asexual reproduction associated with polyploidy and frequent hybridization plays a crucial role in the evolutionary history of the genus Crataegus in North America. In Europe, the genus represents a taxonomically complex and very difficult species group not often studied using a modern biosystematic approach. We investigated the reproduction pathways in mixed-cytotype populations of selected taxa of Crataegus in eastern Slovakia, Central Europe. The investigated accessions were characterized by seed production data and the ploidy level of mature plants as well as the embryo and endosperm tissues of their seeds determined via flow cytometry. Diploid and polyploid hawthorns reproduce successfully; they also produce high numbers of seeds. An exception is represented by an almost sterile triploid. Diploids reproduce sexually. Polyploids shift to asexual reproduction, but pseudogamy seems to be essential for regular seed development. In rare cases, fertilization of unreduced gametes occurs, which offers opportunity for the establishment of new polyploid cytotypes between diploid sexuals and polyploid asexuals. Opposite to sexual diploids, triploids are obligate, and tetraploids almost obligate apomicts. Apomixis is considered to help stabilize individual weakly differentiated polyploid microspecies. Pseudogamy is a common feature and usually leads to unbalanced maternal to paternal contribution in the endosperm of triploid accessions. Parental contribution to endosperm gene dosage is somehow relaxed in triploids. Our Crataegus plant system resembles reproduction in the diploids and polyploids of North American hawthorns. Our data provide support for the hypothesis that polyploidization, shifts in reproduction modes, and hybridization shape the genus diversity also in Central Europe.
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Affiliation(s)
- Vladislav Kolarčik
- Institute of Biology and Ecology, Faculty of Science, Pavol Jozef Šafárik University, Mánesova 23, SK-041 54 Košice, Slovakia
| | - Valéria Kocová
- Botanical Garden, Pavol Jozef Šafárik University, Mánesova 23, SK-043 52 Košice, Slovakia
| | | | - Lenka Mártonfiová
- Botanical Garden, Pavol Jozef Šafárik University, Mánesova 23, SK-043 52 Košice, Slovakia
| | | | - Pavol Mártonfi
- Institute of Biology and Ecology, Faculty of Science, Pavol Jozef Šafárik University, Mánesova 23, SK-041 54 Košice, Slovakia
- Botanical Garden, Pavol Jozef Šafárik University, Mánesova 23, SK-043 52 Košice, Slovakia
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29
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Paczesniak D, Pellino M, Goertzen R, Guenter D, Jahnke S, Fischbach A, Lovell JT, Sharbel TF. Seed size, endosperm and germination variation in sexual and apomictic Boechera. FRONTIERS IN PLANT SCIENCE 2022; 13:991531. [PMID: 36466233 PMCID: PMC9716183 DOI: 10.3389/fpls.2022.991531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/26/2022] [Indexed: 06/17/2023]
Abstract
Asexual reproduction results in offspring that are genetically identical to the mother. Among apomictic plants (reproducing asexually through seeds) many require paternal genetic contribution for proper endosperm development (pseudogamous endosperm). We examined phenotypic diversity in seed traits using a diverse panel of sexual and apomictic accessions from the genus Boechera. While genetic uniformity resulting from asexual reproduction is expected to reduce phenotypic diversity in seeds produced by apomictic individuals, pseudogamous endosperm, variable endosperm ploidy, and the deviations from 2:1 maternal:paternal genome ratio in endosperm can all contribute to increased phenotypic diversity among apomictic offspring. We characterized seed size variation in 64 diploid sexual and apomictic (diploid and triploid) Boechera lineages. In order to find out whether individual seed size was related to endosperm ploidy we performed individual seed measurements (projected area and mass) using the phenoSeeder robot system and flow cytometric seed screen. In order to test whether individual seed size had an effect on resulting fitness we performed a controlled growth experiment and recorded seedling life history traits (germination success, germination timing, and root growth rate). Seeds with triploid embryos were 33% larger than those with diploid embryos, but no average size difference was found between sexual and apomictic groups. We identified a maternal effect whereby chloroplast lineage 2 had 30% larger seeds than lineage 3, despite having broad and mostly overlapping geographic ranges. Apomictic seeds were not more uniform in size than sexual seeds, despite genetic uniformity of the maternal gametophyte in the former. Among specific embryo/endosperm ploidy combinations, seeds with tetraploid (automomous) endosperm were on average smaller, and the proportion of such seeds was highest in apomicts. Larger seeds germinated more quickly than small seeds, and lead to higher rates of root growth in young seedlings. Seed mass is under balancing selection in Boechera, and it is an important predictor of several traits, including germination probability and timing, root growth rates, and developmental abnormalities in apomictic accessions.
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Affiliation(s)
- Dorota Paczesniak
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Marco Pellino
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Richard Goertzen
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
| | - Devan Guenter
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
| | - Siegfried Jahnke
- Forschungszentrum Jülich, Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Jülich, Germany
| | - Andreas Fischbach
- Forschungszentrum Jülich, Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Jülich, Germany
| | - John T. Lovell
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Timothy F. Sharbel
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
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30
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Larios E, Mazer SJ. Genotype × environment interaction obscures genetic sources of variation in seed size in Dithyrea californica but provides the opportunity for selection on phenotypic plasticity. AMERICAN JOURNAL OF BOTANY 2022; 109:1847-1860. [PMID: 36350645 DOI: 10.1002/ajb2.16091] [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: 02/09/2022] [Revised: 07/25/2022] [Accepted: 07/26/2022] [Indexed: 06/16/2023]
Abstract
PREMISE In many species, seed size influences individual fitness, but its heritability is low, impeding its evolution. In heterogeneous environments, even if heritability of seed size is low, genetic variation in phenotypic plasticity for seed size may provide the opportunity for selection, but this possibility has rarely been investigated in wild species. The evolutionary trajectory of seed size depends on whether additive, maternal, or non-additive genetic variance dominates; moreover, the expression of any of these sources of variance may be environment-dependent, reflecting genetic variation in plasticity. In this study, we examined these sources of variation in seed size and their response to drought in Dithyrea californica. METHODS We used a diallel design to estimate variance components for seed size in three greenhouse-raised populations sampled from California and northern Mexico. We replicated diallels in two watering treatments to examine genetic parameters and genotype × environment interactions affecting seed size. We estimated general (GCA) and specific (SCA) combining ability, reciprocal effects (RGCA and RSCA), and their interactions with water availability, and we sought evidence that sexual conflict influences seed size. RESULTS Norms of reaction revealed genetic variation in plasticity for seed size in each population. Seed size in D. californica is determined by the combination of watering treatment, GCA and RGCA; parental identity and water availability do not consistently affect seed size, and we detected no evidence for sexual conflict. CONCLUSIONS Multiple sources of genetic variation in phenotypic plasticity for seed size have the potential to influence its evolutionary trajectory in heterogenous environments.
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Affiliation(s)
- Eugenio Larios
- Department of Ecology Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
| | - Susan J Mazer
- Department of Ecology Evolution and Marine Biology, University of California Santa Barbara, Santa Barbara, CA, 93106, USA
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Sandstedt GD, Sweigart AL. Developmental evidence for parental conflict in driving Mimulus species barriers. THE NEW PHYTOLOGIST 2022; 236:1545-1557. [PMID: 35999713 PMCID: PMC9826125 DOI: 10.1111/nph.18438] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 08/08/2022] [Indexed: 05/25/2023]
Abstract
The endosperm, a tissue that nourishes the embryo in the seeds of flowering plants, is often disrupted in inviable hybrid seeds of closely related species. A key question is whether parental conflict is a major driver of this common form of reproductive isolation. Here, we performed reciprocal crosses between pairs of three monkeyflower species (Mimulus caespitosa, Mimulus tilingii, and Mimulus guttatus). The severity of hybrid seed inviability varies among these crosses, which we inferred to be due to species divergence in effective ploidy. By performing a time series experiment of seed development, we discovered parent-of-origin phenotypes that provide strong evidence for parental conflict in shaping endosperm evolution. We found that the chalazal haustorium, a tissue within the endosperm that is found at the maternal-filial boundary, shows pronounced differences between reciprocal hybrid seeds formed from Mimulus species that differ in effective ploidy. These parent-of-origin effects suggest that the chalazal haustorium might act as a mediator of parental conflict, potentially by controlling sucrose movement from the maternal parent into the endosperm. Our study suggests that parental conflict in the endosperm may function as a driver of speciation by targeting regions and developmental stages critical for resource allocation and thus proper seed development.
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Developing Genetic Engineering Techniques for Control of Seed Size and Yield. Int J Mol Sci 2022; 23:ijms232113256. [PMID: 36362043 PMCID: PMC9655546 DOI: 10.3390/ijms232113256] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/15/2022] [Accepted: 10/15/2022] [Indexed: 11/06/2022] Open
Abstract
Many signaling pathways regulate seed size through the development of endosperm and maternal tissues, which ultimately results in a range of variations in seed size or weight. Seed size can be determined through the development of zygotic tissues (endosperm and embryo) and maternal ovules. In addition, in some species such as rice, seed size is largely determined by husk growth. Transcription regulator factors are responsible for enhancing cell growth in the maternal ovule, resulting in seed growth. Phytohormones induce significant effects on entire features of growth and development of plants and also regulate seed size. Moreover, the vegetative parts are the major source of nutrients, including the majority of carbon and nitrogen-containing molecules for the reproductive part to control seed size. There is a need to increase the size of seeds without affecting the number of seeds in plants through conventional breeding programs to improve grain yield. In the past decades, many important genetic factors affecting seed size and yield have been identified and studied. These important factors constitute dynamic regulatory networks governing the seed size in response to environmental stimuli. In this review, we summarized recent advances regarding the molecular factors regulating seed size in Arabidopsis and other crops, followed by discussions on strategies to comprehend crops' genetic and molecular aspects in balancing seed size and yield.
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Li MM, Su QL, Zu JR, Xie L, Wei Q, Guo HR, Chen J, Zeng RZ, Zhang ZS. Triploid cultivars of Cymbidium act as a bridge in the formation of polyploid plants. FRONTIERS IN PLANT SCIENCE 2022; 13:1029915. [PMID: 36684754 PMCID: PMC9853991 DOI: 10.3389/fpls.2022.1029915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 09/23/2022] [Indexed: 06/17/2023]
Abstract
Triploid is considered a reproductive barrier and also a bridge in the formation of polyploids. However, few reports are available in Cymbidium. In this study, diploid 'Xiaofeng', sexual triploid 'Yuchan' and 'Huanghe' of Cymbidium were used to evaluate hybridization compatibility of the triploids. Results showed that the sexual triploids were fertile whether they were used as male or female parents. 'Yuchan' produced male gametes of 1x, 1x~2x, 2x, 2x~3x, and 3x at frequencies of 8.89%, 77.78%, 6.67%, 3.33%, and 3.33%, respectively; while 'Huanghe' produced 3.33% 1x, 80.00% 1x~2x, 8.89% 2x, 5.56% 2x~3x, and 2.22% 3x male gametes. The cross of 'Xiaofeng' with 'Yuchan' produced progenies with a wide range of ploidy levels, including one diploid, 34 2×~3× aneuploids, 12 triploids, and one tetraploid, indicating that male gametes produced by sexual triploid were fertile and could be transmitted and fused with egg cells. On the other hand, 10 progenies obtained from the cross of 'Yuchan' × 'Xiaofeng' were all aneuploids. The cross of 'Yuchan' with 'Huanghe' produced 40 progenies including three 2×~3× aneuploids, nine 3×~4× aneuploids, 21 tetraploids, six 4×~5× aneuploids, and one pentaploid, suggesting that 2x gametes, instead of the unreduced ones played a more important role in the formation of tetraploids. The survival rates of the hybrids were all above 80.00%, with the tetraploids at 96.67%. Cytological analysis revealed that during meiosis of sexual polyploids, two chromosome sets of the 2n gamete were inclined to enter into the same daughter cell, resulting in the production of 2x gametes. Our results indicate that the triploid cymbidiums are not reproductive barrier but serve as a bridge in the formation of polyploid plants.
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Affiliation(s)
- Man-Man Li
- Guangdong Province Key Laboratory of Plant Molecular Breeding, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Qing-Lian Su
- Guangzhou Flower Research Center, Guangzhou, China
| | - Jun-Rui Zu
- Guangdong Province Key Laboratory of Plant Molecular Breeding, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Li Xie
- Guangdong Province Key Laboratory of Plant Molecular Breeding, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Qian Wei
- Guangdong Province Key Laboratory of Plant Molecular Breeding, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - He-Rong Guo
- Guangdong Province Key Laboratory of Plant Molecular Breeding, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Jianjun Chen
- Mid-Florida Research and Education Center, Environmental Horticulture Department, Institute of Food and Agricultural Sciences, University of Florida, Apopka, FL, United States
| | - Rui-Zhen Zeng
- Guangdong Province Key Laboratory of Plant Molecular Breeding, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Zhi-Sheng Zhang
- Guangdong Province Key Laboratory of Plant Molecular Breeding, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
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Ali MF, Brown P, Thomas J, Salmerόn M, Kawashima T. Effect of assimilate competition during early seed development on the pod and seed growth traits in soybean. PLANT REPRODUCTION 2022; 35:179-188. [PMID: 35235027 DOI: 10.1007/s00497-022-00439-2] [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: 07/08/2021] [Accepted: 02/10/2022] [Indexed: 06/14/2023]
Abstract
Although the seed remains small in size during the initial stage of seed development (the lag phase), several studies indicate that environment and assimilate supply level manipulations during the lag phase affect the final seed size. However, the manipulations were not only at the lag phase, making it difficult to understand the specific role of the lag phase in final seed size determination. It also remained unclear whether environmental cues are sensed by plants and regulate seed development or if it is simply the assimilate supply level, changed by the environment, that affects the subsequent seed development. We investigated soybean (Glycine max L. Merr.) seed phenotypes grown in a greenhouse using different source-sink manipulations (shading and removal of flowers and pods) during the lag phase. We show that assimilate supply is the key factor controlling flower and pod abortion and that the assimilate supply during the lag phase affects the subsequent potential seed growth rate during the seed filling phase. In response to low assimilate supply, plants adjust flower/pod abortion and lag phase duration to supply the minimum assimilate per pod/seed. Our results provide insight into the mechanisms whereby the lag phase is crucial for seed development and final seed size potential, essential parameters that determine yield.
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Affiliation(s)
- Mohammad Foteh Ali
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, 40546, USA
| | - Paige Brown
- Medical Laboratory Science Program, University of Kentucky, Lexington, KY, 40526, USA
| | - John Thomas
- Agricultural and Medical Biotechnology Program, University of Kentucky, Lexington, KY, 40546, USA
| | - Montserrat Salmerόn
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, 40546, USA.
| | - Tomokazu Kawashima
- Department of Plant and Soil Sciences, University of Kentucky, Lexington, KY, 40546, USA.
- Agricultural and Medical Biotechnology Program, University of Kentucky, Lexington, KY, 40546, USA.
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Plant DNA Methylation: An Epigenetic Mark in Development, Environmental Interactions, and Evolution. Int J Mol Sci 2022; 23:ijms23158299. [PMID: 35955429 PMCID: PMC9368846 DOI: 10.3390/ijms23158299] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Revised: 07/21/2022] [Accepted: 07/24/2022] [Indexed: 01/06/2023] Open
Abstract
DNA methylation is an epigenetic modification of the genome involved in the regulation of gene expression and modulation of chromatin structure. Plant genomes are widely methylated, and the methylation generally occurs on the cytosine bases through the activity of specific enzymes called DNA methyltransferases. On the other hand, methylated DNA can also undergo demethylation through the action of demethylases. The methylation landscape is finely tuned and assumes a pivotal role in plant development and evolution. This review illustrates different molecular aspects of DNA methylation and some plant physiological processes influenced by this epigenetic modification in model species, crops, and ornamental plants such as orchids. In addition, this review aims to describe the relationship between the changes in plant DNA methylation levels and the response to biotic and abiotic stress. Finally, we discuss the possible evolutionary implications and biotechnological applications of DNA methylation.
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RNA Pol IV induces antagonistic parent-of-origin effects on Arabidopsis endosperm. PLoS Biol 2022; 20:e3001602. [PMID: 35389984 PMCID: PMC9017945 DOI: 10.1371/journal.pbio.3001602] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 04/19/2022] [Accepted: 03/11/2022] [Indexed: 12/14/2022] Open
Abstract
Gene expression in endosperm-a seed tissue that mediates transfer of maternal resources to offspring-is under complex epigenetic control. We show here that plant-specific RNA polymerase IV (Pol IV) mediates parental control of endosperm gene expression. Pol IV is required for the production of small interfering RNAs that typically direct DNA methylation. We compared small RNAs (sRNAs), DNA methylation, and mRNAs in Arabidopsis thaliana endosperm from heterozygotes produced by reciprocally crossing wild-type (WT) plants to Pol IV mutants. We find that maternally and paternally acting Pol IV induce distinct effects on endosperm. Loss of maternal or paternal Pol IV impacts sRNAs and DNA methylation at different genomic sites. Strikingly, maternally and paternally acting Pol IV have antagonistic impacts on gene expression at some loci, divergently promoting or repressing endosperm gene expression. Antagonistic parent-of-origin effects have only rarely been described and are consistent with a gene regulatory system evolving under parental conflict.
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Castillo-Bravo R, Fort A, Cashell R, Brychkova G, McKeown PC, Spillane C. Parent-of-Origin Effects on Seed Size Modify Heterosis Responses in Arabidopsis thaliana. FRONTIERS IN PLANT SCIENCE 2022; 13:835219. [PMID: 35330872 PMCID: PMC8940307 DOI: 10.3389/fpls.2022.835219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 01/19/2022] [Indexed: 05/05/2023]
Abstract
Parent-of-origin effects arise when a phenotype depends on whether it is inherited maternally or paternally. Parent-of-origin effects can exert a strong influence on F1 seed size in flowering plants, an important agronomic and life-history trait that can contribute to biomass heterosis. Here we investigate the natural variation in the relative contributions of the maternal and paternal genomes to F1 seed size across 71 reciprocal pairs of F1 hybrid diploids and the parental effect on F1 seed size heterosis. We demonstrate that the paternally derived genome influences F1 seed size more significantly than previously appreciated. We further demonstrate (by disruption of parental genome dosage balance in F1 triploid seeds) that hybridity acts as an enhancer of genome dosage effects on F1 seed size, beyond that observed from hybridity or genome dosage effects on their own. Our findings indicate that interactions between genetic hybridity and parental genome dosage can enhance heterosis effects in plants, opening new avenues for boosting heterosis breeding in crop plants.
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Heydlauff J, Erbasol Serbes I, Vo D, Mao Y, Gieseking S, Nakel T, Harten T, Völz R, Hoffmann A, Groß-Hardt R. Dual and opposing roles of EIN3 reveal a generation conflict during seed growth. MOLECULAR PLANT 2022; 15:363-371. [PMID: 34848348 PMCID: PMC8837274 DOI: 10.1016/j.molp.2021.11.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 11/12/2021] [Accepted: 11/26/2021] [Indexed: 05/28/2023]
Abstract
Seed size critically affects grain yield of crops and hence represents a key breeding target. The development of embryo-nourishing endosperm is a key driver of seed expansion. We here report unexpected dual roles of the transcription factor EIN3 in regulating seed size. These EIN3 functions have remained largely undiscovered because they oppose each other. Capitalizing on the analysis of multiple ethylene biosynthesis mutants, we demonstrate that EIN3 represses endosperm and seed development in a pathway regulated by ethylene. We, in addition, provide evidence that EIN3-mediated synergid nucleus disintegration promotes endosperm expansion. Interestingly, synergid nucleus disintegration is not affected in various ethylene biosynthesis mutants, suggesting that this promoting function of EIN3 is independent of ethylene. Whereas the growth-inhibitory ethylene-dependent EIN3 action appears to be encoded by sporophytic tissue, the growth-promoting role of EIN3 is induced by fertilization, revealing a generation conflict that converges toward the key signaling component EIN3.
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Affiliation(s)
- Juliane Heydlauff
- University of Bremen, Centre for Biomolecular Interactions Bremen (CBIB), Leobenerstrasse 5, 28359 Bremen, Germany
| | - Isil Erbasol Serbes
- University of Bremen, Centre for Biomolecular Interactions Bremen (CBIB), Leobenerstrasse 5, 28359 Bremen, Germany
| | - Dieu Vo
- University of Bremen, Centre for Biomolecular Interactions Bremen (CBIB), Leobenerstrasse 5, 28359 Bremen, Germany
| | - Yanbo Mao
- University of Bremen, Centre for Biomolecular Interactions Bremen (CBIB), Leobenerstrasse 5, 28359 Bremen, Germany
| | - Sonja Gieseking
- ZMBP, University of Tübingen, Auf der Morgenstelle 32 72076 Tübingen, Germany
| | - Thomas Nakel
- University of Bremen, Centre for Biomolecular Interactions Bremen (CBIB), Leobenerstrasse 5, 28359 Bremen, Germany
| | - Theresa Harten
- University of Bremen, Centre for Biomolecular Interactions Bremen (CBIB), Leobenerstrasse 5, 28359 Bremen, Germany
| | - Ronny Völz
- ZMBP, University of Tübingen, Auf der Morgenstelle 32 72076 Tübingen, Germany
| | - Anja Hoffmann
- University of Bremen, Centre for Biomolecular Interactions Bremen (CBIB), Leobenerstrasse 5, 28359 Bremen, Germany
| | - Rita Groß-Hardt
- University of Bremen, Centre for Biomolecular Interactions Bremen (CBIB), Leobenerstrasse 5, 28359 Bremen, Germany.
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Wang W, Xiong H, Sun K, Zhang B, Sun MX. New insights into cell-cell communications during seed development in flowering plants. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2022; 64:215-229. [PMID: 34473416 DOI: 10.1111/jipb.13170] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Accepted: 09/01/2021] [Indexed: 06/13/2023]
Abstract
The evolution of seeds is a major reason why flowering plants are a dominant life form on Earth. The developing seed is composed of two fertilization products, the embryo and endosperm, which are surrounded by a maternally derived seed coat. Accumulating evidence indicates that efficient communication among all three seed components is required to ensure coordinated seed development. Cell communication within plant seeds has drawn much attention in recent years. In this study, we review current knowledge of cross-talk among the endosperm, embryo, and seed coat during seed development, and highlight recent advances in this field.
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Affiliation(s)
- Wei Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Hanxian Xiong
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Kaiting Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Bo Zhang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
| | - Meng-Xiang Sun
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan, 430072, China
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Hoffmann T, Shi X, Hsu CY, Brown A, Knight Q, Courtney LS, Mukarram RJ, Wang D. The identification of type I MADS box genes as the upstream activators of an endosperm-specific invertase inhibitor in Arabidopsis. BMC PLANT BIOLOGY 2022; 22:18. [PMID: 34991468 PMCID: PMC8734259 DOI: 10.1186/s12870-021-03399-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 12/15/2021] [Indexed: 05/24/2023]
Abstract
BACKGROUND Nuclear endosperm development is a common mechanism among Angiosperms, including Arabidopsis. During nuclear development, the endosperm nuclei divide rapidly after fertilization without cytokinesis to enter the syncytial phase, which is then followed by the cellularized phase. The endosperm can be divided into three spatial domains with distinct functions: the micropylar, peripheral, and chalazal domains. Previously, we identified two putative small invertase inhibitors, InvINH1 and InvINH2, that are specifically expressed in the micropylar region of the syncytial endosperm. In addition, ectopically expressing InvINH1 in the cellularized endosperm led to a reduction in embryo growth rate. However, it is not clear what are the upstream regulators responsible for the specific expression of InvINHs in the syncytial endosperm. RESULTS Using protoplast transient expression system, we discovered that a group of type I MADS box transcription factors can form dimers to activate InvINH1 promoter. Promoter deletion assays carried out in the protoplast system revealed the presence of an enhancer region in InvINH1 promoter, which contains several consensus cis-elements for the MADS box proteins. Using promoter deletion assay in planta, we further demonstrated that this enhancer region is required for InvINH1 expression in the syncytial endosperm. One of the MADS box genes, AGL62, is a key transcription factor required for syncytial endosperm development. Using promoter-GFP reporter assay, we demonstrated that InvINH1 and InvINH2 are not expressed in agl62 mutant seeds. Collectively, our data supports the role of AGL62 and other type I MADS box genes as the upstream activators of InvINHs expression in the syncytial endosperm. CONCLUSIONS Our findings revealed several type I MADS box genes that are responsible for activating InvINH1 in the syncytial endosperm, which in turn regulates embryo growth rate during early stage of seed development.
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Affiliation(s)
| | - Xiuling Shi
- Biology Department, Spelman College, Atlanta, GA, USA
| | - Chuan-Yu Hsu
- Institute for Genomics, Biocomputing and Biotechnology, Mississippi State University, Mississippi State, MS, USA
| | - Aakilah Brown
- Biology Department, Spelman College, Atlanta, GA, USA
| | | | | | | | - Dongfang Wang
- Biology Department, Spelman College, Atlanta, GA, USA.
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Genome Size, Cytotype Diversity and Reproductive Mode Variation of Cotoneaster integerrimus (Rosaceae) from the Balkans. PLANTS 2021; 10:plants10122798. [PMID: 34961270 PMCID: PMC8708406 DOI: 10.3390/plants10122798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 12/28/2022]
Abstract
Cotoneaster integerrimus represents a multiploid and facultative apomictic system of widely distributed mountain populations. We used flow cytometry to determine genome size, ploidy level, and reproduction mode variation of the Balkan populations, supplemented by analysis of nuclear microsatellites in order to address: (i) geographic distribution and variation of cytotypes among the populations; (ii) variation of reproduction mode and the frequency of sexuality; (iii) pathways of endosperm formation among the sampled polyploids and their endosperm balance requirements; (iv) genotypic diversity and geographic distribution of clonal lineages of polyploids. The prevalence of apomictic tetraploid cytotype followed by sexual diploids and extremely rare triploids was demonstrated. This prevalence of tetraploids affected the populations’ structure composed from clonal genotypes with varying proportions. The co-occurrence of diploids and tetraploids generated higher cytotype, reproductive mode, and genotypic diversity, but mixed-ploidy sites were extremely rare. The endosperm imbalance facilitates the development and the occurrence of intermediate triploids in mixed-ploidy populations, but also different tetraploid lineages elsewhere with unbalanced endosperm. All these results showed that the South European populations of C. integerrimus have higher levels of cytotype and reproductive diversity compared to the Central European ones. Therefore, the South European populations can be considered as a potential reservoir of regional and global diversity for this species.
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Birchler JA, Veitia RA. One Hundred Years of Gene Balance: How Stoichiometric Issues Affect Gene Expression, Genome Evolution, and Quantitative Traits. Cytogenet Genome Res 2021; 161:529-550. [PMID: 34814143 DOI: 10.1159/000519592] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 09/13/2021] [Indexed: 11/19/2022] Open
Abstract
A century ago experiments with the flowering plant Datura stramonium and the fruit fly Drosophila melanogaster revealed that adding an extra chromosome to a karyotype was much more detrimental than adding a whole set of chromosomes. This phenomenon was referred to as gene balance and has been recapitulated across eukaryotic species. Here, we retrace some developments in this field. Molecular studies suggest that the basis of balance involves stoichiometric relationships of multi-component interactions. This concept has implication for the mechanisms controlling gene expression, genome evolution, sex chromosome evolution/dosage compensation, speciation mechanisms, and the underlying genetics of quantitative traits.
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Affiliation(s)
- James A Birchler
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, USA
| | - Reiner A Veitia
- Université de Paris, Paris, France.,Institut Jacques Monod, Université de Paris/CNRS, Paris, France.,Institut de Biologie F. Jacob, Commissariat à l'Energie Atomique, Université Paris-Saclay, Fontenay aux Roses, France
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43
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Marimuthu MPA, Maruthachalam R, Bondada R, Kuppu S, Tan EH, Britt A, Chan SWL, Comai L. Epigenetically mismatched parental centromeres trigger genome elimination in hybrids. SCIENCE ADVANCES 2021; 7:eabk1151. [PMID: 34797718 PMCID: PMC8604413 DOI: 10.1126/sciadv.abk1151] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Wide crosses result in postzygotic elimination of one parental chromosome set, but the mechanisms that result in such differential fate are poorly understood. Here, we show that alterations of centromeric histone H3 (CENH3) lead to its selective removal from centromeres of mature Arabidopsis eggs and early zygotes, while wild-type CENH3 persists. In the hybrid zygotes and embryos, CENH3 and essential centromere proteins load preferentially on the CENH3-rich centromeres of the wild-type parent, while CENH3-depleted centromeres fail to reconstitute new CENH3-chromatin and the kinetochore and are frequently lost. Genome elimination is opposed by E3 ubiquitin ligase VIM1. We propose a model based on cooperative binding of CENH3 to chromatin to explain the differential CENH3 loading rates. Thus, parental CENH3 polymorphisms result in epigenetically distinct centromeres that instantiate a strong mating barrier and produce haploids.
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Affiliation(s)
- Mohan P. A. Marimuthu
- UC Davis Genome Center, UC Davis, Davis, CA, USA
- Department of Plant Biology, UC Davis, Davis, CA, USA
| | - Ravi Maruthachalam
- School of Biology, Indian Institute of Science Education and Research (IISER), Thiruvananthapuram, Vithura, Kerala 695551, India
| | - Ramesh Bondada
- School of Biology, Indian Institute of Science Education and Research (IISER), Thiruvananthapuram, Vithura, Kerala 695551, India
| | | | | | - Anne Britt
- Department of Plant Biology, UC Davis, Davis, CA, USA
| | | | - Luca Comai
- UC Davis Genome Center, UC Davis, Davis, CA, USA
- Department of Plant Biology, UC Davis, Davis, CA, USA
- Corresponding author.
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Morgan EJ, Čertner M, Lučanová M, Deniz U, Kubíková K, Venon A, Kovářík O, Lafon Placette C, Kolář F. Disentangling the components of triploid block and its fitness consequences in natural diploid-tetraploid contact zones of Arabidopsis arenosa. THE NEW PHYTOLOGIST 2021; 232:1449-1462. [PMID: 33768528 DOI: 10.1111/nph.17357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 03/15/2021] [Indexed: 06/12/2023]
Abstract
Hybrid seed inviability (HSI) is an important mechanism of reproductive isolation and speciation. HSI varies in strength among populations of diploid species but it remains to be tested whether similar processes affect natural variation in HSI within ploidy-variable species (triploid block). Here we used extensive endosperm, seed and F1 -hybrid phenotyping to explore HSI variation within a diploid-autotetraploid species. By leveraging 12 population pairs from three ploidy contact zones, we tested for the effect of interploidy crossing direction (parent of origin), ploidy divergence and spatial arrangement in shaping reproductive barriers in a naturally relevant context. We detected strong parent-of-origin effects on endosperm development, F1 germination and survival, which was also reflected in the rates of triploid formation in the field. Endosperm cellularization failure was least severe and F1 -hybrid performance was slightly better in the primary contact zone, with genetically closest diploid and tetraploid lineages. We demonstrated overall strong parent-of-origin effects on HSI in a ploidy variable species, which translate to fitness effects and contribute to interploidy reproductive isolation in a natural context. Subtle intraspecific variation in these traits suggests the fitness consequences of HSI are predominantly a constitutive property of the species regardless of the evolutionary background of its populations.
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Affiliation(s)
- Emma J Morgan
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01, Czech Republic
| | - Martin Čertner
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01, Czech Republic
- Institute of Botany of the Czech Academy of Sciences, Zámek 1, Průhonice, CZ-252 43, Czech Republic
| | - Magdalena Lučanová
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01, Czech Republic
- Institute of Botany of the Czech Academy of Sciences, Zámek 1, Průhonice, CZ-252 43, Czech Republic
- Department of Botany, Faculty of Science, University of South Bohemia, Branišovská 31, České Budějovice, CZ-370 05, Czech Republic
| | - Utku Deniz
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01, Czech Republic
| | - Kateřina Kubíková
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01, Czech Republic
| | - Anthony Venon
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01, Czech Republic
| | - Oleg Kovářík
- Datamole Inc., Vítězné Náměstí 2, Prague, CZ-160 00, Czech Republic
| | - Clément Lafon Placette
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01, Czech Republic
| | - Filip Kolář
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01, Czech Republic
- Institute of Botany of the Czech Academy of Sciences, Zámek 1, Průhonice, CZ-252 43, Czech Republic
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Yang F, Fernández-Jiménez N, Tučková M, Vrána J, Cápal P, Díaz M, Pradillo M, Pecinka A. Defects in meiotic chromosome segregation lead to unreduced male gametes in Arabidopsis SMC5/6 complex mutants. THE PLANT CELL 2021; 33:3104-3119. [PMID: 34240187 PMCID: PMC8462810 DOI: 10.1093/plcell/koab178] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Accepted: 06/27/2021] [Indexed: 05/21/2023]
Abstract
Structural maintenance of chromosome 5/6 (SMC5/6) complex is a crucial factor for preserving genome stability. Here, we show that mutants for several Arabidopsis (Arabidopsis thaliana) SMC5/6 complex subunits produce triploid offspring. This phenotype is caused by a meiotic defect leading to the production of unreduced male gametes. The SMC5/6 complex mutants show an absence of chromosome segregation during the first and/or the second meiotic division, as well as a partially disorganized microtubule network. Importantly, although the SMC5/6 complex is partly required for the repair of SPO11-induced DNA double-strand breaks, the nonreduction described here is SPO11-independent. The measured high rate of ovule abortion suggests that, if produced, such defects are maternally lethal. Upon fertilization with an unreduced pollen, the unbalanced maternal and paternal genome dosage in the endosperm most likely causes seed abortion observed in several SMC5/6 complex mutants. In conclusion, we describe the function of the SMC5/6 complex in the maintenance of gametophytic ploidy in Arabidopsis.
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Affiliation(s)
- Fen Yang
- Institute of Experimental Botany, Czech Academy of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Olomouc, Czech Republic
- Department of Cell Biology and Genetics, Faculty of Science, Palacký University, Olomouc, Czech Republic
- Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Nadia Fernández-Jiménez
- Department of Genetics, Physiology and Microbiology, Faculty of Biology, Complutense University of Madrid, Madrid, Spain
| | - Martina Tučková
- Institute of Experimental Botany, Czech Academy of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Olomouc, Czech Republic
| | - Jan Vrána
- Institute of Experimental Botany, Czech Academy of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Olomouc, Czech Republic
| | - Petr Cápal
- Institute of Experimental Botany, Czech Academy of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Olomouc, Czech Republic
| | - Mariana Díaz
- Max Planck Institute for Plant Breeding Research, Cologne, Germany
| | - Mónica Pradillo
- Department of Genetics, Physiology and Microbiology, Faculty of Biology, Complutense University of Madrid, Madrid, Spain
| | - Ales Pecinka
- Institute of Experimental Botany, Czech Academy of Science, Centre of the Region Haná for Biotechnological and Agricultural Research, Olomouc, Czech Republic
- Max Planck Institute for Plant Breeding Research, Cologne, Germany
- Author for correspondence:
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Jiang H, Guo D, Ye J, Gao Y, Liu H, Wang Y, Xue M, Yan Q, Chen J, Duan L, Li G, Li X, Xie L. Genome-wide analysis of genomic imprinting in the endosperm and allelic variation in flax. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2021; 107:1697-1710. [PMID: 34228847 DOI: 10.1111/tpj.15411] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 06/30/2021] [Indexed: 06/13/2023]
Abstract
Genomic imprinting is an epigenetic phenomenon that causes biased expression of maternally and paternally inherited alleles. In flowering plants, genomic imprinting predominantly occurs in the triploid endosperm and plays a vital role in seed development. In this study, we identified 248 candidate imprinted genes including 114 maternally expressed imprinted genes (MEGs) and 134 paternally expressed imprinted genes (PEGs) in flax (Linum usitatissimum L.) endosperm using deep RNA sequencing. These imprinted genes were neither clustered in specific chromosomal regions nor well conserved among flax and other plant species. MEGs tended to be expressed specifically in the endosperm, whereas the expression of PEGs was not tissue-specific. Imprinted single nucleotide polymorphisms differentiated 200 flax cultivars into the oil flax, oil-fiber dual purpose flax and fiber flax subgroups, suggesting that genomic imprinting contributed to intraspecific variation in flax. The nucleotide diversity of imprinted genes in the oil flax subgroup was significantly higher than that in the fiber flax subgroup, indicating that some imprinted genes underwent positive selection during flax domestication from oil flax to fiber flax. Moreover, imprinted genes that underwent positive selection were related to flax functions. Thirteen imprinted genes related to flax seed size and weight were identified using a candidate gene-based association study. Therefore, our study provides information for further exploration of the function and genomic variation of imprinted genes in the flax population.
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Affiliation(s)
- Haixia Jiang
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, Xinjiang, China
| | - Dongliang Guo
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, Xinjiang, China
| | - Jiali Ye
- State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, China
| | - Yanfang Gao
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, Xinjiang, China
| | - Huiqing Liu
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, Xinjiang, China
| | - Yue Wang
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, Xinjiang, China
| | - Min Xue
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, Xinjiang, China
| | - Qingcheng Yan
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, Xinjiang, China
| | - Jiaxun Chen
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, Xinjiang, China
| | - Lepeng Duan
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, Xinjiang, China
| | - Gongze Li
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, Xinjiang, China
| | - Xiao Li
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, Xinjiang, China
| | - Liqiong Xie
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, College of Life Science and Technology, Xinjiang University, Urumqi, Xinjiang, China
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47
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Kinser TJ, Smith RD, Lawrence AH, Cooley AM, Vallejo-Marín M, Conradi Smith GD, Puzey JR. Endosperm-based incompatibilities in hybrid monkeyflowers. THE PLANT CELL 2021; 33:2235-2257. [PMID: 33895820 PMCID: PMC8364248 DOI: 10.1093/plcell/koab117] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 04/15/2021] [Indexed: 05/31/2023]
Abstract
Endosperm is an angiosperm innovation central to their reproduction whose development, and thus seed viability, is controlled by genomic imprinting, where expression from certain genes is parent-specific. Unsuccessful imprinting has been linked to failed inter-specific and inter-ploidy hybridization. Despite their importance in plant speciation, the underlying mechanisms behind these endosperm-based barriers remain poorly understood. Here, we describe one such barrier between diploid Mimulus guttatus and tetraploid Mimulus luteus. The two parents differ in endosperm DNA methylation, expression dynamics, and imprinted genes. Hybrid seeds suffer from underdeveloped endosperm, reducing viability, or arrested endosperm and seed abortion when M. guttatus or M. luteus is seed parent, respectively, and transgressive methylation and expression patterns emerge. The two inherited M. luteus subgenomes, genetically distinct but epigenetically similar, are expressionally dominant over the M. guttatus genome in hybrid embryos and especially their endosperm, where paternal imprints are perturbed. In aborted seeds, de novo methylation is inhibited, potentially owing to incompatible paternal instructions of imbalanced dosage from M. guttatus imprints. We suggest that diverged epigenetic/regulatory landscapes between parental genomes induce epigenetic repatterning and global shifts in expression, which, in endosperm, may uniquely facilitate incompatible interactions between divergent imprinting schemes, potentially driving rapid barriers.
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Affiliation(s)
- Taliesin J. Kinser
- Biology Department, College of William and Mary, Williamsburg, Virginia 23185
| | - Ronald D. Smith
- Department of Applied Science, College of William and Mary, Williamsburg, Virginia 23185
| | - Amelia H. Lawrence
- Biology Department, College of William and Mary, Williamsburg, Virginia 23185
| | | | - Mario Vallejo-Marín
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland FK9 4LA, UK
| | | | - Joshua R. Puzey
- Biology Department, College of William and Mary, Williamsburg, Virginia 23185
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48
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Sutherland BL, Galloway LF. Variation in heteroploid reproduction and gene flow across a polyploid complex: One size does not fit all. Ecol Evol 2021; 11:9676-9688. [PMID: 34306653 PMCID: PMC8293777 DOI: 10.1002/ece3.7791] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 03/18/2021] [Accepted: 03/18/2021] [Indexed: 11/17/2022] Open
Abstract
Whole-genome duplication is considered an important speciation mechanism in plants. However, its effect on reproductive isolation between higher cytotypes is not well understood. We used backcrosses between different ploidy levels and surveys of mixed-ploidy contact zones to determine how reproductive barriers differed with cytotype across a polyploid complex. We backcrossed F1 hybrids derived from 2X-4X and 4X-6X crosses in the Campanula rotundifolia autopolyploid complex, measured backcross fitness, and estimated backcross DNA cytotype. We then sampled four natural mixed-ploidy contact zones (two 2X-4X and two 4X-6X), estimated ploidy, and genotyped individuals across each contact zone. Reproductive success and capacity for gene flow was markedly lower for 2X-4X than 4X-6X hybrids. In fact, 3X hybrids could not backcross; all 2X-4X backcross progeny resulted from neotetraploid F1 hybrids. Further, no 3X individuals were found in 2X-4X contact zones, and 2X and 4X individuals were genetically distinct. By contrast, backcrosses of 5X hybrids were relatively successful, particularly when crossed to 6X individuals. In 4X-6X contact zones, 5X individuals and aneuploids were common and all cytotypes were largely genetically similar and spatially intermixed. Taken together, these results provide strong evidence that reproduction is low between 2X and 4X cytotypes, primarily occurring via unreduced gamete production, but that reproduction and gene flow are ongoing between 4X and 6X cytotypes. Further, it suggests whole-genome duplication can result in speciation between diploids and polyploids, but is less likely to create reproductive barriers between different polyploid cytotypes, resulting in two fundamentally different potentials for speciation across polyploid complexes.
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Affiliation(s)
- Brittany L. Sutherland
- Department of BiologyUniversity of VirginiaCharlottesvilleVAUSA
- Department of BiologyUniversity of Louisiana at LafayetteLafayetteLAUSA
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49
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Städler T, Florez-Rueda AM, Roth M. A revival of effective ploidy: the asymmetry of parental roles in endosperm-based hybridization barriers. CURRENT OPINION IN PLANT BIOLOGY 2021; 61:102015. [PMID: 33639340 DOI: 10.1016/j.pbi.2021.102015] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Revised: 01/15/2021] [Accepted: 01/25/2021] [Indexed: 05/15/2023]
Abstract
Interest in understanding hybrid seed failure (HSF) has mushroomed, both in terms of identifying underlying molecular processes and their evolutionary drivers. We review phenotypic and molecular advances with a focus on the 'effective ploidy' concept, witnessing a recent revival after long obscurity. Endosperm misdevelopment has now been shown to underlie HSF in many inter-specific, homoploid crosses. The consistent asymmetries in seed size and developmental trajectories likely reflect parental divergence in key, dosage-sensitive processes. Transcriptomic and epigenomic studies reveal genome-wide, polarized expression perturbations and shifts in parental expression proportions, consistent with small-RNA imbalances between parental roles. Among-species differences in levels of parental conflict over resource allocation enjoy strong support in explaining why differences in effective ploidy may evolve.
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Affiliation(s)
- Thomas Städler
- Institute of Integrative Biology, ETH Zurich & Zurich-Basel Plant Science Center, Universitätstrasse 16, 8092 Zurich, Switzerland.
| | - Ana M Florez-Rueda
- Department of Plant and Microbial Biology, University of Zurich and Zurich-Basel Plant Science Center, Zollikerstrasse 107, 8008 Zurich, Switzerland
| | - Morgane Roth
- GAFL INRAE, Allée des Chênes 67, 84140 Montfavet, France
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50
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Florez-Rueda AM, Fiscalini F, Roth M, Grossniklaus U, Städler T. Endosperm and Seed Transcriptomes Reveal Possible Roles for Small RNA Pathways in Wild Tomato Hybrid Seed Failure. Genome Biol Evol 2021; 13:6278300. [PMID: 34009298 PMCID: PMC8358227 DOI: 10.1093/gbe/evab107] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2021] [Indexed: 01/10/2023] Open
Abstract
Crosses between the wild tomato species Solanum peruvianum and Solanum chilense result in hybrid seed failure (HSF), characterized by endosperm misdevelopment and embryo arrest. We previously showed that genomic imprinting, the parent-of-origin–dependent expression of alleles, is perturbed in the hybrid endosperm, with many of the normally paternally expressed genes losing their imprinted status. Here, we report transcriptome-based analyses of gene and small RNA (sRNA) expression levels. We identified 2,295 genes and 387 sRNA clusters as differentially expressed when comparing reciprocal hybrid seed to seeds and endosperms from the two within-species crosses. Our analyses uncovered a pattern of overdominance in endosperm gene expression in both hybrid cross directions, in marked contrast to the patterns of sRNA expression in whole seeds. Intriguingly, patterns of increased gene expression resemble the previously reported increased maternal expression proportions in hybrid endosperms. We identified physical clusters of sRNAs; differentially expressed sRNAs exhibit reduced transcript abundance in hybrid seeds of both cross directions. Moreover, sRNAs map to genes coding for key proteins involved in epigenetic regulation of gene expression, suggesting a regulatory feedback mechanism. We describe examples of genes that appear to be targets of sRNA-mediated gene silencing; in these cases, reduced sRNA abundance is concomitant with increased gene expression in hybrid seeds. Our analyses also show that S. peruvianum dominance impacts gene and sRNA expression in hybrid seeds. Overall, our study indicates roles for sRNA-mediated epigenetic regulation in HSF between closely related wild tomato species.
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Affiliation(s)
- Ana Marcela Florez-Rueda
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland.,Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, 8092 Zurich, Switzerland
| | - Flurin Fiscalini
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland
| | - Morgane Roth
- Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, 8092 Zurich, Switzerland
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland
| | - Thomas Städler
- Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, 8092 Zurich, Switzerland
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