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Khouider S, Gehring M. Parental dialectic: Epigenetic conversations in endosperm. CURRENT OPINION IN PLANT BIOLOGY 2024; 81:102591. [PMID: 38944896 PMCID: PMC11392645 DOI: 10.1016/j.pbi.2024.102591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2024] [Revised: 05/21/2024] [Accepted: 06/07/2024] [Indexed: 07/02/2024]
Abstract
Endosperm is a major evolutionary innovation of flowering plants, and its proper development critically impacts seed growth and viability. Epigenetic regulators have a key function in parental control of endosperm development. Notably, epigenetic regulation of parental genome dosage is a major determinant of seed development success, and disruption of this balance can produce inviable seed, as observed in some interploidy and interspecific crosses. These postzygotic reproduction barriers are also a potent driver of speciation. The molecular machinery and regulatory architecture governing endosperm development is proposed to have evolved under parental conflict. In this review, we emphasize parental conflict as a dialectic conflict and discuss recent findings about the epigenetic molecular machinery that mediates parental conflict in the endosperm.
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Affiliation(s)
- Souraya Khouider
- Whitehead Institute for Biomedical Research, Cambridge MA 02142, USA
| | - Mary Gehring
- Whitehead Institute for Biomedical Research, Cambridge MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge MA 02139, USA.
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2
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Frost JM, Rhee JH, Choi Y. Dynamics of DNA methylation and its impact on plant embryogenesis. CURRENT OPINION IN PLANT BIOLOGY 2024; 81:102593. [PMID: 38941722 DOI: 10.1016/j.pbi.2024.102593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2024] [Revised: 06/08/2024] [Accepted: 06/09/2024] [Indexed: 06/30/2024]
Abstract
Flowering plants exhibit unique DNA methylation dynamics during development. Particular attention can be focused on seed development and the embryo, which represents the starting point of the sporophytic life cycle. A build-up of CHH methylation is now recognized as highly characteristic of embryo development. This process is thought to occur in order to silence potentially harmful transposable element expression, though roles in promoting seed dormancy and dessication tolerance have also been revealed. Recent studies show that increased CHH methylation in embryos inhabits both novel loci, unmethylated elsewhere in the plant, as well as shared loci, exhibiting more dense methylation. The role of DNA methylation in cis-regulatory gene regulation in plants is less well established compared to mammals, and here we discuss both transposable element regulation and the potential role of DNA methylation in dynamic gene expression.
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Affiliation(s)
- Jennifer M Frost
- Medical and Molecular Genetics, King's College London, St Thomas' Street, London SE1 9RT, UK.
| | - Ji Hoon Rhee
- Department of Biological Sciences, Seoul National University, Seoul, South Korea; Research Center for Plant Plasticity, Seoul National University, Seoul, South Korea
| | - Yeonhee Choi
- Department of Biological Sciences, Seoul National University, Seoul, South Korea; Research Center for Plant Plasticity, Seoul National University, Seoul, South Korea.
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3
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Pal AK, Gandhivel VHS, Nambiar AB, Shivaprasad PV. Upstream regulator of genomic imprinting in rice endosperm is a small RNA-associated chromatin remodeler. Nat Commun 2024; 15:7807. [PMID: 39242590 PMCID: PMC11379814 DOI: 10.1038/s41467-024-52239-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 08/29/2024] [Indexed: 09/09/2024] Open
Abstract
Genomic imprinting is observed in endosperm, a placenta-like seed tissue, where transposable elements (TEs) and repeat-derived small RNAs (sRNAs) mediate epigenetic changes in plants. In imprinting, uniparental gene expression arises due to parent-specific epigenetic marks on one allele but not on the other. The importance of sRNAs and their regulation in endosperm development or in imprinting is poorly understood in crops. Here we show that a previously uncharacterized CLASSY (CLSY)-family chromatin remodeler named OsCLSY3 is essential for rice endosperm development and imprinting, acting as an upstream player in the sRNA pathway. Comparative transcriptome and genetic analysis indicated its endosperm-preferred expression and its likely paternal imprinted nature. These important features are modulated by RNA-directed DNA methylation (RdDM) of tandemly arranged TEs in its promoter. Upon perturbation of OsCLSY3 in transgenic lines, we observe defects in endosperm development and a loss of around 70% of all sRNAs. Interestingly, well-conserved endosperm-specific sRNAs (siren) that are vital for reproductive fitness in angiosperms are also dependent on OsCLSY3. We observed that many imprinted genes and seed development-associated genes are under the control of OsCLSY3. These results support an essential role of OsCLSY3 in rice endosperm development and imprinting, and propose similar regulatory strategies involving CLSY3 homologs among other cereals.
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Affiliation(s)
- Avik Kumar Pal
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bangalore, India
| | - Vivek Hari-Sundar Gandhivel
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bangalore, India
| | - Amruta B Nambiar
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bangalore, India
| | - P V Shivaprasad
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, GKVK Campus, Bangalore, India.
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Del Toro-De León G, van Boven J, Santos-González J, Jiao WB, Peng H, Schneeberger K, Köhler C. Epigenetic and transcriptional consequences in the endosperm of chemically induced transposon mobilization in Arabidopsis. Nucleic Acids Res 2024; 52:8833-8848. [PMID: 38967011 PMCID: PMC11347142 DOI: 10.1093/nar/gkae572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Revised: 06/13/2024] [Accepted: 06/26/2024] [Indexed: 07/06/2024] Open
Abstract
Genomic imprinting, an epigenetic phenomenon leading to parent-of-origin-specific gene expression, has independently evolved in the endosperm of flowering plants and the placenta of mammals-tissues crucial for nurturing embryos. While transposable elements (TEs) frequently colocalize with imprinted genes and are implicated in imprinting establishment, direct investigations of the impact of de novo TE transposition on genomic imprinting remain scarce. In this study, we explored the effects of chemically induced transposition of the Copia element ONSEN on genomic imprinting in Arabidopsis thaliana. Through the combination of chemical TE mobilization and doubled haploid induction, we generated a line with 40 new ONSEN copies. Our findings reveal a preferential targeting of maternally expressed genes (MEGs) for transposition, aligning with the colocalization of H2A.Z and H3K27me3 in MEGs-both previously identified as promoters of ONSEN insertions. Additionally, we demonstrate that chemically-induced DNA hypomethylation induces global transcriptional deregulation in the endosperm, leading to the breakdown of MEG imprinting. This study provides insights into the consequences of chemically induced TE remobilization in the endosperm, revealing that chemically-induced epigenome changes can have long-term consequences on imprinted gene expression.
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Affiliation(s)
- Gerardo Del Toro-De León
- Department of Plant Reproductive Biology and Epigenetics, Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Joram van Boven
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Centre for Plant Biology, Uppsala 75007, Sweden
| | - Juan Santos-González
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Centre for Plant Biology, Uppsala 75007, Sweden
| | - Wen-Biao Jiao
- National Key Laboratory for Germplasm Innovation & Utilization of Horticultural Crops, Huazhong Agricultural University, Wuhan 430070, China
| | - Haoran Peng
- Department of Plant Reproductive Biology and Epigenetics, Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
| | - Korbinian Schneeberger
- Department of Chromosome Biology, Max Planck Institute for Plant Breeding Research, Cologne 50829, Germany
- Faculty for Biology, LMU Munich, Planegg-Martinsried 82152, Germany
- Cluster of Excellence on Plant Sciences, Heinrich-Heine University, Düsseldorf 40225, Germany
| | - Claudia Köhler
- Department of Plant Reproductive Biology and Epigenetics, Max Planck Institute of Molecular Plant Physiology, Potsdam 14476, Germany
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Centre for Plant Biology, Uppsala 75007, Sweden
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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; 51:855-865. [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] [MESH Headings] [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 early endosperm-expressed HAIKU (IKU) downstream Candidate F-box 1 (ICF1) and ICF2 as maternally expressed imprinted genes (MEGs) in Arabidopsis thaliana. 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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June V, Song X, Chen ZJ. Imprinting but not cytonuclear interactions determines seed size heterosis in Arabidopsis hybrids. PLANT PHYSIOLOGY 2024; 195:1214-1228. [PMID: 38319651 PMCID: PMC11142339 DOI: 10.1093/plphys/kiae061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Revised: 12/14/2023] [Accepted: 12/19/2023] [Indexed: 02/07/2024]
Abstract
The parent-of-origin effect on seeds can result from imprinting (unequal expression of paternal and maternal alleles) or combinational effects between cytoplasmic and nuclear genomes, but their relative contributions remain unknown. To discern these confounding factors, we produced cytoplasmic-nuclear substitution (CNS) lines using recurrent backcrossing in Arabidopsis (Arabidopsis thaliana) ecotypes Col-0 and C24. These CNS lines differed only in the nuclear genome (imprinting) or cytoplasm. The CNS reciprocal hybrids with the same cytoplasm displayed ∼20% seed size difference, whereas the seed size was similar between the reciprocal hybrids with fixed imprinting. Transcriptome analyses in the endosperm of CNS hybrids using laser-capture microdissection identified 104 maternally expressed genes (MEGs) and 90 paternally expressed genes (PEGs). These imprinted genes were involved in pectin catabolism and cell wall modification in the endosperm. Homeodomain Glabrous9 (HDG9), an epiallele and one of 11 cross-specific imprinted genes, affected seed size. In the embryo, there were a handful of imprinted genes in the CNS hybrids but only 1 was expressed at higher levels than in the endosperm. AT4G13495 was found to encode a long-noncoding RNA (lncRNA), but no obvious seed phenotype was observed in lncRNA knockout lines. Nuclear RNA Polymerase D1 (NRPD1), encoding the largest subunit of RNA Pol IV, was involved in the biogenesis of small interfering RNAs. Seed size and embryos were larger in the cross using nrpd1 as the maternal parent than in the reciprocal cross, supporting a role of the maternal NRPD1 allele in seed development. Although limited ecotypes were tested, these results suggest that imprinting and the maternal NRPD1-mediated small RNA pathway play roles in seed size heterosis in plant hybrids.
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Affiliation(s)
- Viviana June
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Xiaoya Song
- 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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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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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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Han B, Li Y, Wu D, Li DZ, Liu A, Xu W. Dynamics of imprinted genes and their epigenetic mechanisms in castor bean seed with persistent endosperm. THE NEW PHYTOLOGIST 2023; 240:1868-1882. [PMID: 37717216 DOI: 10.1111/nph.19265] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 08/25/2023] [Indexed: 09/19/2023]
Abstract
Genomic imprinting refers to parent-of-origin-dependent gene expression and primarily occurs in the endosperm of flowering plants, but its functions and epigenetic mechanisms remain to be elucidated in eudicots. Castor bean, a eudicot with large and persistent endosperm, provides an excellent system for studying the imprinting. Here, we identified 131 imprinted genes in developing endosperms and endosperm at seed germination phase of castor bean, involving into the endosperm development, accumulation of storage compounds and specially seed germination. Our results showed that the transcriptional repression of maternal allele of DNA METHYLTRANSFERASE 1 (MET1) may be required for maternal genome demethylation in the endosperm. DNA methylation analysis showed that only a small fraction of imprinted genes was associated with allele-specific DNA methylation, and most of them were closely associated with constitutively unmethylated regions (UMRs), suggesting a limited role for DNA methylation in controlling genomic imprinting. Instead, histone modifications can be asymmetrically deposited in maternal and paternal genomes in a DNA methylation-independent manner to control expression of most imprinted genes. These results expanded our understanding of the occurrence and biological functions of imprinted genes and showed the evolutionary flexibility of the imprinting machinery and mechanisms in plants.
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Affiliation(s)
- Bing Han
- Germplasm Bank of Wild Species, Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
| | - Yelan Li
- Germplasm Bank of Wild Species, Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
| | - Di Wu
- Germplasm Bank of Wild Species, Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
| | - De-Zhu Li
- Germplasm Bank of Wild Species, Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, China
| | - Aizhong Liu
- Key Laboratory for Forest Resources Conservation and Utilization in the Southwest Mountains of China, Ministry of Education, Southwest Forestry University, Kunming, 650224, China
| | - Wei Xu
- Germplasm Bank of Wild Species, Yunnan Key Laboratory of Crop Wild Relatives Omics, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, 650201, Yunnan, 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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11
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Frost JM, Lee J, Hsieh PH, Lin SJH, Min Y, Bauer M, Runkel AM, Cho HT, Hsieh TF, Fischer RL, Choi Y. H2A.X promotes endosperm-specific DNA methylation in Arabidopsis thaliana. BMC PLANT BIOLOGY 2023; 23:585. [PMID: 37993808 PMCID: PMC10664615 DOI: 10.1186/s12870-023-04596-y] [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: 05/24/2023] [Accepted: 11/08/2023] [Indexed: 11/24/2023]
Abstract
BACKGROUND H2A.X is an H2A variant histone in eukaryotes, unique for its ability to respond to DNA damage, initiating the DNA repair pathway. H2A.X replacement within the histone octamer is mediated by the FAcilitates Chromatin Transactions (FACT) complex, a key chromatin remodeler. FACT is required for DEMETER (DME)-mediated DNA demethylation at certain loci in Arabidopsis thaliana female gametophytes during reproduction. Here, we sought to investigate whether H2A.X is involved in DME- and FACT-mediated DNA demethylation during reproduction. RESULTS H2A.X is encoded by two genes in Arabidopsis genome, HTA3 and HTA5. We generated h2a.x double mutants, which displayed a normal growth profile, whereby flowering time, seed development, and root tip organization, S-phase progression and proliferation were all normal. However, h2a.x mutants were more sensitive to genotoxic stress, consistent with previous reports. H2A.X fused to Green Fluorescent Protein (GFP) under the H2A.X promoter was highly expressed especially in newly developing Arabidopsis tissues, including in male and female gametophytes, where DME is also expressed. We examined DNA methylation in h2a.x developing seeds and seedlings using whole genome bisulfite sequencing, and found that CG DNA methylation is decreased genome-wide in h2a.x mutant endosperm. Hypomethylation was most striking in transposon bodies, and occurred on both parental alleles in the developing endosperm, but not the embryo or seedling. h2a.x-mediated hypomethylated sites overlapped DME targets, but also included other loci, predominately located in heterochromatic transposons and intergenic DNA. CONCLUSIONS Our genome-wide methylation analyses suggest that H2A.X could function in preventing access of the DME demethylase to non-canonical sites. Overall, our data suggest that H2A.X is required to maintain DNA methylation homeostasis in the unique chromatin environment of the Arabidopsis endosperm.
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Affiliation(s)
- Jennifer M Frost
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA.
- Present Address: Genomics and Child Health, Queen Mary University of London, London, UK.
| | - Jaehoon Lee
- Department of Biological Sciences, Seoul National University, Seoul, Korea
- Research Center for Plant Plasticity, Seoul National University, Seoul, Korea
| | - Ping-Hung Hsieh
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
- Present Address: DOE Joint Genome Institute, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, USA
| | - Samuel J H Lin
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Yunsook Min
- Department of Biological Sciences, Seoul National University, Seoul, Korea
| | - Matthew Bauer
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Anne M Runkel
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Hyung-Taeg Cho
- Department of Biological Sciences, Seoul National University, Seoul, Korea
| | - Tzung-Fu Hsieh
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, USA
- Plants for Human Health Institute, North Carolina State University, North Carolina Research Campus, Kannapolis, NC, USA
| | - Robert L Fischer
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA.
| | - Yeonhee Choi
- Department of Biological Sciences, Seoul National University, Seoul, Korea.
- Research Center for Plant Plasticity, Seoul National University, Seoul, Korea.
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12
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Wu X, Xie L, Sun X, Wang N, Finnegan EJ, Helliwell C, Yao J, Zhang H, Wu X, Hands P, Lu F, Ma L, Zhou B, Chaudhury A, Cao X, Luo M. Mutation in Polycomb repressive complex 2 gene OsFIE2 promotes asexual embryo formation in rice. NATURE PLANTS 2023; 9:1848-1861. [PMID: 37814022 PMCID: PMC10654051 DOI: 10.1038/s41477-023-01536-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Accepted: 09/06/2023] [Indexed: 10/11/2023]
Abstract
Prevention of autonomous division of the egg apparatus and central cell in a female gametophyte before fertilization ensures successful reproduction in flowering plants. Here we show that rice ovules of Polycomb repressive complex 2 (PRC2) Osfie1 and Osfie2 double mutants exhibit asexual embryo and autonomous endosperm formation at a high frequency, while ovules of single Osfie2 mutants display asexual pre-embryo-like structures at a lower frequency without fertilization. Earlier onset, higher penetrance and better development of asexual embryos in the double mutants compared with those in Osfie2 suggest that the autonomous endosperm facilitated asexual embryo development. Transcriptomic analysis showed that male genome-expressed OsBBM1 and OsWOX8/9 were activated in the asexual embryos. Similarly, the maternal alleles of the paternally expressed imprinted genes were activated in the autonomous endosperm, suggesting that the egg apparatus and central cell convergently adopt PRC2 to maintain the non-dividing state before fertilization, possibly through silencing of the maternal alleles of male genome-expressed genes.
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Affiliation(s)
- Xiaoba Wu
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, Australia.
| | - Liqiong Xie
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, School of Life Science and Technology, Xinjiang University, Urumqi, P. R. China
| | - Xizhe Sun
- The State Key Laboratory of North China Crop Improvement and Regulation, College of Horticulture, Hebei Agricultural University, Baoding, P. R. China
- Division of Plant Science, Research School of Biology, the Australian National University, Canberra, Australian Capital Territory, Australia
| | - Ningning Wang
- Faculty of Agronomy, Jilin Agricultural University, Changchun, P. R. China
| | - E Jean Finnegan
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, Australia
| | - Chris Helliwell
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, Australia
| | - Jialing Yao
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, P. R. China
| | - Hongyu Zhang
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Rice Research Institute, Sichuan Agricultural University, Chengdu, P. R. China
| | - Xianjun Wu
- State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China, Rice Research Institute, Sichuan Agricultural University, Chengdu, P. R. China
| | - Phil Hands
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, Australia
| | - Falong Lu
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, P. R. China
- University of Chinese Academy of Sciences, Beijing, P. R. China
| | - Lisong Ma
- The State Key Laboratory of North China Crop Improvement and Regulation, College of Horticulture, Hebei Agricultural University, Baoding, P. R. China
- Division of Plant Science, Research School of Biology, the Australian National University, Canberra, Australian Capital Territory, Australia
| | - Bing Zhou
- Institute of Zoology, Chinese Academy of Sciences, Beijing, P. R. China
| | - Abed Chaudhury
- Krishan Foundation Pty Ltd, Canberra, Australian Capital Territory, Australia
| | - Xiaofeng Cao
- University of Chinese Academy of Sciences, Beijing, P. R. China
- State Key Laboratory of Plant Genomics and National Center for Plant Gene Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, P. R. China
| | - Ming Luo
- CSIRO Agriculture and Food, Canberra, Australian Capital Territory, Australia.
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13
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Dong X, Luo H, Bi W, Chen H, Yu S, Zhang X, Dai Y, Cheng X, Xing Y, Fan X, Zhu Y, Guo Y, Meng D. Transcriptome-wide identification and characterization of genes exhibit allele-specific imprinting in maize embryo and endosperm. BMC PLANT BIOLOGY 2023; 23:470. [PMID: 37803280 PMCID: PMC10557216 DOI: 10.1186/s12870-023-04473-8] [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: 04/18/2023] [Accepted: 09/18/2023] [Indexed: 10/08/2023]
Abstract
BACKGROUND Genomic imprinting refers to a subset of genes that are expressed from only one parental allele during seed development in plants. Studies on genomic imprinting have revealed that intraspecific variations in genomic imprinting expression exist in naturally genetic varieties. However, there have been few studies on the functional analysis of allele-specific imprinted genes. RESULTS Here, we generated three reciprocal crosses among the B73, Mo17 and CAU5 inbred lines. Based on the transcriptome-wide analysis of allele-specific expression using RNA sequencing technology, 305 allele-specific imprinting genes (ASIGs) were identified in embryos, and 655 ASIGs were identified in endosperms from three maize F1 hybrids. Of these ASIGs, most did not show consistent maternal or paternal bias between the same tissue from different hybrids or different tissues from one hybrid cross. By gene ontology (GO) analysis, five and eight categories of GO exhibited significantly higher functional enrichments for ASIGs identified in embryo and endosperm, respectively. These functional categories indicated that ASIGs are involved in intercellular nutrient transport, signaling pathways, and transcriptional regulation of kernel development. Finally, the mutation and overexpression of one ASIG (Zm305) affected the length and width of the kernel. CONCLUSION In this study, our data will be helpful in gaining further knowledge of genes exhibiting allele-specific imprinting patterns in seeds. The gain- and loss-of-function phenotypes of ASIGs associated with agronomically important seed traits provide compelling evidence for ASIGs as crucial targets to optimize seed traits in crop plants.
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Affiliation(s)
- Xiaomei Dong
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, Liaoning, China
- Shenyang City Key Laboratory of Maize Genomic Selection Breeding, Shenyang, 110866, Liaoning, China
| | - Haishan Luo
- College of Agronomy, Shenyang Agricultural University, Shenyang, 110866, Liaoning, China
| | - Wenjing Bi
- College of Agronomy, Shenyang Agricultural University, Shenyang, 110866, Liaoning, China
| | - Hanyu Chen
- College of Agronomy, Shenyang Agricultural University, Shenyang, 110866, Liaoning, China
| | - Shuai Yu
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, Liaoning, China
- Shenyang City Key Laboratory of Maize Genomic Selection Breeding, Shenyang, 110866, Liaoning, China
| | - Xiaoyu Zhang
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, Liaoning, China
- Shenyang City Key Laboratory of Maize Genomic Selection Breeding, Shenyang, 110866, Liaoning, China
| | - Yuxin Dai
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, Liaoning, China
- Shenyang City Key Laboratory of Maize Genomic Selection Breeding, Shenyang, 110866, Liaoning, China
| | - Xipeng Cheng
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, Liaoning, China
- Shenyang City Key Laboratory of Maize Genomic Selection Breeding, Shenyang, 110866, Liaoning, China
| | - Yupeng Xing
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, 110866, Liaoning, China
- Shenyang City Key Laboratory of Maize Genomic Selection Breeding, Shenyang, 110866, Liaoning, China
| | - Xiaoqin Fan
- Manas Agricultural Experimental Station of Xinjiang Academy of Agricultural Sciences, Changji, 832200, Xinjiang, China
| | - Yanbin Zhu
- National Key Laboratory of Maize Biological Breeding, Key Laboratory of Genetics and Breeding of Main Crops in Northeast Region, Ministry of Agriculture and Rural Affairs, Liaoning Dongya Seed Industry Co., Ltd, Shenyang, Liaoning, 110164, China
| | - Yanling Guo
- National Key Laboratory of Maize Biological Breeding, Key Laboratory of Genetics and Breeding of Main Crops in Northeast Region, Ministry of Agriculture and Rural Affairs, Liaoning Dongya Seed Industry Co., Ltd, Shenyang, Liaoning, 110164, China
| | - Dexuan Meng
- College of Agronomy, Shenyang Agricultural University, Shenyang, 110866, Liaoning, China.
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14
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Grin IR, Petrova DV, Endutkin AV, Ma C, Yu B, Li H, Zharkov DO. Base Excision DNA Repair in Plants: Arabidopsis and Beyond. Int J Mol Sci 2023; 24:14746. [PMID: 37834194 PMCID: PMC10573277 DOI: 10.3390/ijms241914746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Revised: 09/27/2023] [Accepted: 09/27/2023] [Indexed: 10/15/2023] Open
Abstract
Base excision DNA repair (BER) is a key pathway safeguarding the genome of all living organisms from damage caused by both intrinsic and environmental factors. Most present knowledge about BER comes from studies of human cells, E. coli, and yeast. Plants may be under an even heavier DNA damage threat from abiotic stress, reactive oxygen species leaking from the photosynthetic system, and reactive secondary metabolites. In general, BER in plant species is similar to that in humans and model organisms, but several important details are specific to plants. Here, we review the current state of knowledge about BER in plants, with special attention paid to its unique features, such as the existence of active epigenetic demethylation based on the BER machinery, the unexplained diversity of alkylation damage repair enzymes, and the differences in the processing of abasic sites that appear either spontaneously or are generated as BER intermediates. Understanding the biochemistry of plant DNA repair, especially in species other than the Arabidopsis model, is important for future efforts to develop new crop varieties.
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Affiliation(s)
- Inga R. Grin
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia; (D.V.P.); (A.V.E.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia
| | - Daria V. Petrova
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia; (D.V.P.); (A.V.E.)
| | - Anton V. Endutkin
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia; (D.V.P.); (A.V.E.)
| | - Chunquan Ma
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Harbin 150080, China; (C.M.); (B.Y.); (H.L.)
- Heilongjiang Provincial Key Laboratory of Plant Genetic Engineering and Biological Fermentation Engineering for Cold Region, Harbin 150080, China
- School of Life Sciences, Heilongjiang University, Harbin 150080, China
| | - Bing Yu
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Harbin 150080, China; (C.M.); (B.Y.); (H.L.)
- Heilongjiang Provincial Key Laboratory of Plant Genetic Engineering and Biological Fermentation Engineering for Cold Region, Harbin 150080, China
- School of Life Sciences, Heilongjiang University, Harbin 150080, China
| | - Haiying Li
- Engineering Research Center of Agricultural Microbiology Technology, Ministry of Education, Harbin 150080, China; (C.M.); (B.Y.); (H.L.)
- Heilongjiang Provincial Key Laboratory of Plant Genetic Engineering and Biological Fermentation Engineering for Cold Region, Harbin 150080, China
- School of Life Sciences, Heilongjiang University, Harbin 150080, China
| | - Dmitry O. Zharkov
- Siberian Branch of the Russian Academy of Sciences Institute of Chemical Biology and Fundamental Medicine, 8 Lavrentieva Ave., Novosibirsk 630090, Russia; (D.V.P.); (A.V.E.)
- Department of Natural Sciences, Novosibirsk State University, 2 Pirogova St., Novosibirsk 630090, Russia
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15
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June V, Song X, Jeffrey Chen Z. Imprinting but not cytonuclear interactions affects parent-of-origin effect on seed size in Arabidopsis hybrids. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.09.15.557997. [PMID: 37745544 PMCID: PMC10516054 DOI: 10.1101/2023.09.15.557997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The parent-of-origin effect on seed size can result from imprinting or a combinational effect between cytoplasmic and nuclear genomes, but their relative contributions remain unknown. To discern these confounding effects, we generated cytoplasmic-nuclear substitution (CNS) lines using recurrent backcrossing in the Arabidopsis thaliana ecotypes Col-0 and C24. These CNS lines differ only in the nuclear genome (imprinting) or in the cytoplasm. The CNS reciprocal hybrids with the same cytoplasm display a ~20% seed size difference as observed in the conventional hybrids. However, seed size is similar between the reciprocal cybrids with fixed imprinting. Transcriptome analyses in the endosperm of CNS hybrids using laser-capture microdissection have identified 104 maternally expressed genes (MEGs) and 90 paternally-expressed genes (PEGs). These imprinted genes are involved in pectin catabolism and cell wall modification in the endosperm. HDG9, an epiallele and one of 11 cross-specific imprinted genes, controls seed size. In the embryo, a handful of imprinted genes is found in the CNS hybrids but only one is expressed higher in the embryo than endosperm. AT4G13495 encodes a long-noncoding RNA (lncRNA), but no obvious seed phenotype is observed in the lncRNA knockout lines. NRPD1, encoding the largest subunit of RNA Pol IV, is involved in the biogenesis of small interfering RNAs. Seed size and embryo is larger in the cross using nrpd1 as the maternal parent than in the reciprocal cross. In spite of limited ecotypes tested, these results suggest potential roles of imprinting and NRPD1-mediated small RNA pathway in seed size variation in hybrids.
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Affiliation(s)
- Viviana June
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Xiaoya Song
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
| | - Z. Jeffrey Chen
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, Texas 78712, USA
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16
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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: 1] [Impact Index Per Article: 1.0] [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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17
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Zhou H, Deng XW, He H. Gene expression variations and allele-specific expression of two rice and their hybrid in caryopses at single-nucleus resolution. FRONTIERS IN PLANT SCIENCE 2023; 14:1171474. [PMID: 37287712 PMCID: PMC10242081 DOI: 10.3389/fpls.2023.1171474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 04/26/2023] [Indexed: 06/09/2023]
Abstract
Seeds are an indispensable part of the flowering plant life cycle and a critical determinant of agricultural production. Distinct differences in the anatomy and morphology of seeds separate monocots and dicots. Although some progress has been made with respect to understanding seed development in Arabidopsis, the transcriptomic features of monocotyledon seeds at the cellular level are much less understood. Since most important cereal crops, such as rice, maize, and wheat, are monocots, it is essential to study transcriptional differentiation and heterogeneity during seed development at a finer scale. Here, we present single-nucleus RNA sequencing (snRNA-seq) results of over three thousand nuclei from caryopses of the rice cultivars Nipponbare and 9311 and their intersubspecies F1 hybrid. A transcriptomics atlas that covers most of the cell types present during the early developmental stage of rice caryopses was successfully constructed. Additionally, novel specific marker genes were identified for each nuclear cluster in the rice caryopsis. Moreover, with a focus on rice endosperm, the differentiation trajectory of endosperm subclusters was reconstructed to reveal the developmental process. Allele-specific expression (ASE) profiling in endosperm revealed 345 genes with ASE (ASEGs). Further pairwise comparisons of the differentially expressed genes (DEGs) in each endosperm cluster among the three rice samples demonstrated transcriptional divergence. Our research reveals differentiation in rice caryopsis from the single-nucleus perspective and provides valuable resources to facilitate clarification of the molecular mechanism underlying caryopsis development in rice and other monocots.
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Affiliation(s)
- Han Zhou
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agriculture Sciences and School of Life Sciences, Peking University, Beijing, China
- Shandong Laboratory of Advanced Agricultural Sciences at Weifang, Peking University Institute of Advanced Agricultural Sciences, Weifang, Shandong, China
| | - Xing Wang Deng
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agriculture Sciences and School of Life Sciences, Peking University, Beijing, China
- Shandong Laboratory of Advanced Agricultural Sciences at Weifang, Peking University Institute of Advanced Agricultural Sciences, Weifang, Shandong, China
| | - Hang He
- State Key Laboratory of Protein and Plant Gene Research, School of Advanced Agriculture Sciences and School of Life Sciences, Peking University, Beijing, China
- Shandong Laboratory of Advanced Agricultural Sciences at Weifang, Peking University Institute of Advanced Agricultural Sciences, Weifang, Shandong, China
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18
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Luo M, Wu X, Xie L, Sun X, Wang N, Finnegan J, Helliwell C, Yao J, Zhang H, Wu X, Lu F, Ma L, Zhou B, Chaudhury A, Cao X, Hands P. Polycomb Repressive Complex 2 (PRC2) suppresses asexual embryo and autonomous endosperm formation in rice.. [DOI: 10.21203/rs.3.rs-1087314/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/19/2023]
Abstract
Abstract
Prevention of autonomous division of the egg apparatus and central cell in a female gametophyte before fertilization ensures successful reproduction in flowering plants. Here we show that rice ovules with PRC2 Osfie1 and Osfie2 double mutations exhibit asexual embryo and autonomous endosperm formation at a high frequency, while ovules with a single Osfie2 mutation display asexual pre-embryo-like structures at a lower frequency without fertilization. Confocal microscopy images indicate that the asexual embryos were mainly derived from eggs in the double mutants, while the asexual pre-embryos likely originated from eggs or synergids. Early onsetting, higher penetrance and better development of asexual embryos in the double mutants compared with those in Osfie2 suggest that autonomous endosperm facilitated the asexual embryo development. Transcriptomic analysis showed pluripotency factors such as male genome expressed OsBBM1 and OsWOX8/9 were activated in the asexual embryos. Similarly, the maternal alleles of the paternally expressed imprinted genes were activated in the autonomous endosperm. Our results suggest that the egg apparatus and central cell convergently adopt PRC2 to suppresses asexual embryo and autonomous endosperm formation possibly through silencing male genome-expressed genes.
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Affiliation(s)
- Ming Luo
- CSIRO Agriculture and Food, Box 1700, ACT 2601, Australia
| | - Xiaoba Wu
- Institute of Botany, Chinese Academy of Sciences
| | - Liqiong Xie
- Xinjiang Key Laboratory of Biological Resources and Genetic Engineering, School of Life Science and Technology, Xinjiang University, Urumqi 830046, P. R. China
| | - Xizhe Sun
- Division of Plant Science, Research School of Biology, the Australian National University, ACT 2601, Australia
| | - Ningning Wang
- Faculty of agronomy, Jilin Agricultural University, Changchun, 130118, P.R. China
| | - Jean Finnegan
- CSIRO Agriculture and Food, Box 1700, ACT 2601, Australia
| | | | | | - Hongyu Zhang
- Sate Key Laboratory of Gene Discovery and Utilization, Rice Research Institute, Sichuan Agricultural University, Wenjiang, Chengdu 611130, P. R. China
| | | | - Falong Lu
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences
| | - Lisong Ma
- Division of Plant Science, Research School of Biology, the Australian National University, ACT 2601, Australia
| | - Bing Zhou
- State Key Laboratory of Stem Cell and Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences; Beijing
| | | | - Xiaofeng Cao
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences
| | - Phil Hands
- CSIRO Agriculture and Food, Box 1700, ACT 2601, Australia
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19
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Pisupati R, Nizhynska V, Mollá Morales A, Nordborg M. On the causes of gene-body methylation variation in Arabidopsis thaliana. PLoS Genet 2023; 19:e1010728. [PMID: 37141384 DOI: 10.1371/journal.pgen.1010728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Revised: 05/16/2023] [Accepted: 03/31/2023] [Indexed: 05/06/2023] Open
Abstract
Gene-body methylation (gbM) refers to sparse CG methylation of coding regions, which is especially prominent in evolutionarily conserved house-keeping genes. It is found in both plants and animals, but is directly and stably (epigenetically) inherited over multiple generations in the former. Studies in Arabidopsis thaliana have demonstrated that plants originating from different parts of the world exhibit genome-wide differences in gbM, which could reflect direct selection on gbM, but which could also reflect an epigenetic memory of ancestral genetic and/or environmental factors. Here we look for evidence of such factors in F2 plants resulting from a cross between a southern Swedish line with low gbM and a northern Swedish line with high gbM, grown at two different temperatures. Using bisulfite-sequencing data with nucleotide-level resolution on hundreds of individuals, we confirm that CG sites are either methylated (nearly 100% methylation across sampled cells) or unmethylated (approximately 0% methylation across sampled cells), and show that the higher level of gbM in the northern line is due to more sites being methylated. Furthermore, methylation variants almost always show Mendelian segregation, consistent with their being directly and stably inherited through meiosis. To explore how the differences between the parental lines could have arisen, we focused on somatic deviations from the inherited state, distinguishing between gains (relative to the inherited 0% methylation) and losses (relative to the inherited 100% methylation) at each site in the F2 generation. We demonstrate that deviations predominantly affect sites that differ between the parental lines, consistent with these sites being more mutable. Gains and losses behave very differently in terms of the genomic distribution, and are influenced by the local chromatin state. We find clear evidence for different trans-acting genetic polymorphism affecting gains and losses, with those affecting gains showing strong environmental interactions (G×E). Direct effects of the environment were minimal. In conclusion, we show that genetic and environmental factors can change gbM at a cellular level, and hypothesize that these factors can also lead to transgenerational differences between individuals via the inclusion of such changes in the zygote. If true, this could explain genographic pattern of gbM with selection, and would cast doubt on estimates of epimutation rates from inbred lines in constant environments.
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Affiliation(s)
- Rahul Pisupati
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
- Vienna Graduate School of Population Genetics, Institut für Populationsgenetik, Vetmeduni, Vienna, Austria
| | - Viktoria Nizhynska
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Almudena Mollá Morales
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
| | - Magnus Nordborg
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter (VBC), Vienna, Austria
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20
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Dong X, Luo H, Yao J, Guo Q, Yu S, Zhang X, Cheng X, Meng D. Characterization of Genes That Exhibit Genotype-Dependent Allele-Specific Expression and Its Implications for the Development of Maize Kernel. Int J Mol Sci 2023; 24:ijms24054766. [PMID: 36902194 PMCID: PMC10002780 DOI: 10.3390/ijms24054766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Revised: 02/19/2023] [Accepted: 02/24/2023] [Indexed: 03/06/2023] Open
Abstract
Heterosis or hybrid vigor refers to the superior phenotypic traits of hybrids relative to their parental inbred lines. An imbalance between the expression levels of two parental alleles in the F1 hybrid has been suggested as a mechanism of heterosis. Here, based on genome-wide allele-specific expression analysis using RNA sequencing technology, 1689 genes exhibiting genotype-dependent allele-specific expression (genotype-dependent ASEGs) were identified in the embryos, and 1390 genotype-dependent ASEGs in the endosperm, of three maize F1 hybrids. Of these ASEGs, most were consistent in different tissues from one hybrid cross, but nearly 50% showed allele-specific expression from some genotypes but not others. These genotype-dependent ASEGs were mostly enriched in metabolic pathways of substances and energy, including the tricarboxylic acid cycle, aerobic respiration, and energy derivation by oxidation of organic compounds and ADP binding. Mutation and overexpression of one ASEG affected kernel size, which indicates that these genotype-dependent ASEGs may make important contributions to kernel development. Finally, the allele-specific methylation pattern on genotype-dependent ASEGs indicated that DNA methylation plays a potential role in the regulation of allelic expression for some ASEGs. In this study, a detailed analysis of genotype-dependent ASEGs in the embryo and endosperm of three different maize F1 hybrids will provide an index of genes for future research on the genetic and molecular mechanism of heterosis.
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Affiliation(s)
- Xiaomei Dong
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang 110866, China
- Shenyang City Key Laboratory of Maize Genomic Selection Breeding, Shenyang 110866, China
| | - Haishan Luo
- College of Agronomy, Shenyang Agricultural University, Shenyang 110866, China
| | - Jiabin Yao
- College of Agronomy, Shenyang Agricultural University, Shenyang 110866, China
| | - Qingfeng Guo
- College of Agronomy, Shenyang Agricultural University, Shenyang 110866, China
| | - Shuai Yu
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang 110866, China
- Shenyang City Key Laboratory of Maize Genomic Selection Breeding, Shenyang 110866, China
| | - Xiaoyu Zhang
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang 110866, China
- Shenyang City Key Laboratory of Maize Genomic Selection Breeding, Shenyang 110866, China
| | - Xipeng Cheng
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang 110866, China
- Shenyang City Key Laboratory of Maize Genomic Selection Breeding, Shenyang 110866, China
| | - Dexuan Meng
- College of Agronomy, Shenyang Agricultural University, Shenyang 110866, China
- Correspondence:
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21
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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: 7] [Impact Index Per Article: 7.0] [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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22
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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: 9] [Impact Index Per Article: 9.0] [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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23
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Li T, Yin L, Stoll CE, Lisch D, Zhao M. Conserved noncoding sequences and de novo Mutator insertion alleles are imprinted in maize. PLANT PHYSIOLOGY 2023; 191:299-316. [PMID: 36173333 PMCID: PMC9806621 DOI: 10.1093/plphys/kiac459] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2022] [Accepted: 08/30/2022] [Indexed: 05/20/2023]
Abstract
Genomic imprinting is an epigenetic phenomenon in which differential allele expression occurs in a parent-of-origin-dependent manner. Imprinting in plants is tightly linked to transposable elements (TEs), and it has been hypothesized that genomic imprinting may be a consequence of demethylation of TEs. Here, we performed high-throughput sequencing of ribonucleic acids from four maize (Zea mays) endosperms that segregated newly silenced Mutator (Mu) transposons and identified 110 paternally expressed imprinted genes (PEGs) and 139 maternally expressed imprinted genes (MEGs). Additionally, two potentially novel paternally suppressed MEGs are associated with de novo Mu insertions. In addition, we find evidence for parent-of-origin effects on expression of 407 conserved noncoding sequences (CNSs) in maize endosperm. The imprinted CNSs are largely localized within genic regions and near genes, but the imprinting status of the CNSs are largely independent of their associated genes. Both imprinted CNSs and PEGs have been subject to relaxed selection. However, our data suggest that although MEGs were already subject to a higher mutation rate prior to their being imprinted, imprinting may be the cause of the relaxed selection of PEGs. In addition, although DNA methylation is lower in the maternal alleles of both the maternally and paternally expressed CNSs (mat and pat CNSs), the difference between the two alleles in H3K27me3 levels was only observed in pat CNSs. Together, our findings point to the importance of both transposons and CNSs in genomic imprinting in maize.
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Affiliation(s)
- Tong Li
- Department of Biology, Miami University, Oxford, Ohio 45056, USA
- State Key Laboratory of Plant Physiology and Biochemistry, National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing 100193, P.R. China
| | - Liangwei Yin
- Department of Biology, Miami University, Oxford, Ohio 45056, USA
| | - Claire E Stoll
- Department of Biology, Miami University, Oxford, Ohio 45056, USA
| | - Damon Lisch
- Department of Botany and Plant Pathology, Purdue University, West Lafayette, Indiana 47907, USA
| | - Meixia Zhao
- Department of Microbiology and Cell Science, Institute of Food and Agricultural Sciences, University of Florida, Gainesville, Florida 32611, USA
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24
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Jia Z, Gao P, Yin F, Quilichini TD, Sheng H, Song J, Yang H, Gao J, Chen T, Yang B, Kochian LV, Zou J, Patterson N, Yang Q, Gillmor CS, Datla R, Li Q, Xiang D. Asymmetric gene expression in grain development of reciprocal crosses between tetraploid and hexaploid wheats. Commun Biol 2022; 5:1412. [PMID: 36564439 PMCID: PMC9789062 DOI: 10.1038/s42003-022-04374-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
Production of viable progeny from interploid crosses requires precise regulation of gene expression from maternal and paternal chromosomes, yet the transcripts contributed to hybrid seeds from polyploid parent species have rarely been explored. To investigate the genome-wide maternal and paternal contributions to polyploid grain development, we analyzed the transcriptomes of developing embryos, from zygote to maturity, alongside endosperm in two stages of development, using reciprocal crosses between tetraploid and hexaploid wheats. Reciprocal crosses between species with varied levels of ploidy displayed broad impacts on gene expression, including shifts in alternative splicing events in select crosses, as illustrated by active splicing events, enhanced protein synthesis and chromatin remodeling. Homoeologous gene expression was repressed on the univalent D genome in pentaploids, but this suppression was attenuated in crosses with a higher ploidy maternal parent. Imprinted genes were identified in endosperm and early embryo tissues, supporting predominant maternal effects on early embryogenesis. By systematically investigating the complex transcriptional networks in reciprocal-cross hybrids, this study presents a framework for understanding the genomic incompatibility and transcriptome shock that results from interspecific hybridization and uncovers the transcriptional impacts on hybrid seeds created from agriculturally-relevant polyploid species.
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Affiliation(s)
- Zhen Jia
- grid.35155.370000 0004 1790 4137National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Peng Gao
- grid.25152.310000 0001 2154 235XGlobal Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 4J8 Canada
| | - Feifan Yin
- grid.35155.370000 0004 1790 4137National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China ,grid.35155.370000 0004 1790 4137Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, 430070 Wuhan, China
| | - Teagen D. Quilichini
- grid.24433.320000 0004 0449 7958Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
| | - Huajin Sheng
- grid.25152.310000 0001 2154 235XGlobal Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 4J8 Canada
| | - Jingpu Song
- grid.24433.320000 0004 0449 7958Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
| | - Hui Yang
- grid.24433.320000 0004 0449 7958Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
| | - Jie Gao
- grid.35155.370000 0004 1790 4137National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Ting Chen
- grid.35155.370000 0004 1790 4137National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Bo Yang
- grid.35155.370000 0004 1790 4137National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Leon V. Kochian
- grid.25152.310000 0001 2154 235XGlobal Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 4J8 Canada
| | - Jitao Zou
- grid.24433.320000 0004 0449 7958Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
| | - Nii Patterson
- grid.24433.320000 0004 0449 7958Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
| | - Qingyong Yang
- grid.35155.370000 0004 1790 4137National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China ,grid.35155.370000 0004 1790 4137Hubei Key Laboratory of Agricultural Bioinformatics, College of Informatics, Huazhong Agricultural University, 430070 Wuhan, China
| | - C. Stewart Gillmor
- grid.512574.0Langebio, Unidad de Genómica Avanzada, Centro de Investigación y Estudios Avanzados del IPN (CINVESTAV-IPN), Irapuato, Guanajuato, 36821 México
| | - Raju Datla
- grid.25152.310000 0001 2154 235XGlobal Institute for Food Security, University of Saskatchewan, Saskatoon, SK S7N 4J8 Canada
| | - Qiang Li
- grid.35155.370000 0004 1790 4137National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, 430070 Wuhan, China
| | - Daoquan Xiang
- grid.24433.320000 0004 0449 7958Aquatic and Crop Resource Development, National Research Council Canada, 110 Gymnasium Place, Saskatoon, SK S7N 0W9 Canada
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25
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Han Q, Hung YH, Zhang C, Bartels A, Rea M, Yang H, Park C, Zhang XQ, Fischer RL, Xiao W, Hsieh TF. Loss of linker histone H1 in the maternal genome influences DEMETER-mediated demethylation and affects the endosperm DNA methylation landscape. FRONTIERS IN PLANT SCIENCE 2022; 13:1070397. [PMID: 36618671 PMCID: PMC9813442 DOI: 10.3389/fpls.2022.1070397] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Accepted: 12/01/2022] [Indexed: 06/17/2023]
Abstract
The Arabidopsis DEMETER (DME) DNA glycosylase demethylates the central cell genome prior to fertilization. This epigenetic reconfiguration of the female gamete companion cell establishes gene imprinting in the endosperm and is essential for seed viability. DME demethylates small and genic-flanking transposons as well as intergenic and heterochromatin sequences, but how DME is recruited to these loci remains unknown. H1.2 was identified as a DME-interacting protein in a yeast two-hybrid screen, and maternal genome H1 loss affects DNA methylation and expression of selected imprinted genes in the endosperm. Yet, the extent to which H1 influences DME demethylation and gene imprinting in the Arabidopsis endosperm has not been investigated. Here, we showed that without the maternal linker histones, DME-mediated demethylation is facilitated, particularly in the heterochromatin regions, indicating that H1-bound heterochromatins are barriers for DME demethylation. Loss of H1 in the maternal genome has a very limited effect on gene transcription or gene imprinting regulation in the endosperm; however, it variably influences euchromatin TE methylation and causes a slight hypermethylation and a reduced expression in selected imprinted genes. We conclude that loss of maternal H1 indirectly influences DME-mediated demethylation and endosperm DNA methylation landscape but does not appear to affect endosperm gene transcription and overall imprinting regulation.
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Affiliation(s)
- Qiang Han
- Department of Biology, Saint Louis University, St. Louis, MO, United States
| | - Yu-Hung Hung
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, United States
- Plants for Human Health Institute, North Carolina State University, Kannapolis, NC, United States
| | - Changqing Zhang
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, United States
- Plants for Human Health Institute, North Carolina State University, Kannapolis, NC, United States
| | - Arthur Bartels
- Department of Biology, Saint Louis University, St. Louis, MO, United States
| | - Matthew Rea
- Department of Biology, Saint Louis University, St. Louis, MO, United States
| | - Hanwen Yang
- Department of Biology, Saint Louis University, St. Louis, MO, United States
| | - Christine Park
- Department of Biology, Saint Louis University, St. Louis, MO, United States
| | - Xiang-Qian Zhang
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, United States
- Plants for Human Health Institute, North Carolina State University, Kannapolis, NC, United States
- College of Food Science and Engineering, Foshan University, Foshan, China
| | - Robert L. Fischer
- Department of Plant and Microbial Biology, University of California, Berkeley, Berkeley, CA, United States
| | - Wenyan Xiao
- Department of Biology, Saint Louis University, St. Louis, MO, United States
| | - Tzung-Fu Hsieh
- Department of Plant and Microbial Biology, North Carolina State University, Raleigh, NC, United States
- Plants for Human Health Institute, North Carolina State University, Kannapolis, NC, United States
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26
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Srikant T, Yuan W, Berendzen KW, Contreras-Garrido A, Drost HG, Schwab R, Weigel D. Canalization of genome-wide transcriptional activity in Arabidopsis thaliana accessions by MET1-dependent CG methylation. Genome Biol 2022; 23:263. [PMID: 36539836 PMCID: PMC9768921 DOI: 10.1186/s13059-022-02833-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Despite its conserved role on gene expression and transposable element (TE) silencing, genome-wide CG methylation differs substantially between wild Arabidopsis thaliana accessions. RESULTS To test our hypothesis that global reduction of CG methylation would reduce epigenomic, transcriptomic, and phenotypic diversity in A. thaliana accessions, we knock out MET1, which is required for CG methylation, in 18 early-flowering accessions. Homozygous met1 mutants in all accessions suffer from common developmental defects such as dwarfism and delayed flowering, in addition to accession-specific abnormalities in rosette leaf architecture, silique morphology, and fertility. Integrated analysis of genome-wide methylation, chromatin accessibility, and transcriptomes confirms that MET1 inactivation greatly reduces CG methylation and alters chromatin accessibility at thousands of loci. While the effects on TE activation are similarly drastic in all accessions, the quantitative effects on non-TE genes vary greatly. The global expression profiles of accessions become considerably more divergent from each other after genome-wide removal of CG methylation, although a few genes with diverse expression profiles across wild-type accessions tend to become more similar in mutants. Most differentially expressed genes do not exhibit altered chromatin accessibility or CG methylation in cis, suggesting that absence of MET1 can have profound indirect effects on gene expression and that these effects vary substantially between accessions. CONCLUSIONS Systematic analysis of MET1 requirement in different A. thaliana accessions reveals a dual role for CG methylation: for many genes, CG methylation appears to canalize expression levels, with methylation masking regulatory divergence. However, for a smaller subset of genes, CG methylation increases expression diversity beyond genetically encoded differences.
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Affiliation(s)
- Thanvi Srikant
- Department of Molecular Biology, Max Planck Institute for Biology Tübingen, Tübingen, Germany
- Present address: Institute of Molecular Plant Biology, Department of Biology, ETH Zürich, Zürich, Switzerland
| | - Wei Yuan
- Department of Molecular Biology, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Kenneth Wayne Berendzen
- Plant Transformation and Flow Cytometry Facility, ZMBP, University of Tübingen, Tübingen, Germany
| | | | - Hajk-Georg Drost
- Computational Biology Group, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Rebecca Schwab
- Department of Molecular Biology, Max Planck Institute for Biology Tübingen, Tübingen, Germany
| | - Detlef Weigel
- Department of Molecular Biology, Max Planck Institute for Biology Tübingen, Tübingen, Germany.
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27
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Conservation Study of Imprinted Genes in Maize Triparental Heterozygotic Kernels. Int J Mol Sci 2022; 23:ijms232315424. [PMID: 36499766 PMCID: PMC9735609 DOI: 10.3390/ijms232315424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/02/2022] [Accepted: 12/04/2022] [Indexed: 12/12/2022] Open
Abstract
Genomic imprinting is a classic epigenetic phenomenon related to the uniparental expression of genes. Imprinting variability exists in seeds and can contribute to observed parent-of-origin effects on seed development. Here, we conducted allelic expression of the embryo and endosperm from four crosses at 11 days after pollination (DAP). First, the F1 progeny of B73(♀) × Mo17(♂) and the inducer line CAU5 were used as parents to obtain reciprocal crosses of BM-C/C-BM. Additionally, the F1 progeny of Mo17(♀) × B73(♂) and CAU5 were used as parents to obtain reciprocal crosses of MB-C/C-MB. In total, 192 and 181 imprinted genes were identified in the BM-C/C-BM and MB-C/C-MB crosses, respectively. Then, by comparing the allelic expression of these imprinted genes in the reciprocal crosses of B73 and CAU5 (BC/CB), fifty-one Mo17-added non-conserved genes were identified as exhibiting imprinting variability. Fifty-one B73-added non-conserved genes were also identified by comparing the allelic expression of imprinted genes identified in BM-C/C-BM, MB-C/C-MB and MC/CM crosses. Specific Gene Ontology (GO) terms were not enriched in B73-added/Mo17-added non-conserved genes. Interestingly, the imprinting status of these genes was less conserved across other species. The cis-element distribution, tissue expression and subcellular location were similar between the B73-added/Mo17-added conserved and B73-added/Mo17-added non-conserved imprinted genes. Finally, genotypic and phenotypic analysis of one non-conserved gene showed that the mutation and overexpression of this gene may affect embryo and kernel size, which indicates that these non-conserved genes may also play an important role in kernel development. The findings of this study will be helpful for elucidating the imprinting mechanism of genes involved in maize kernel development.
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28
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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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29
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Sato H, Köhler C. Genomic imprinting regulates establishment and release of seed dormancy. CURRENT OPINION IN PLANT BIOLOGY 2022; 69:102264. [PMID: 35872392 DOI: 10.1016/j.pbi.2022.102264] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 05/12/2022] [Accepted: 06/22/2022] [Indexed: 06/15/2023]
Abstract
Seed dormancy enables plant seeds to time germination until environmental conditions become favorable for seedling survival. This trait has high adaptive value and is of great agricultural relevance. The endosperm is a reproductive tissue formed after fertilization that in addition to support embryo growth has major roles in establishing seed dormancy. Many genes adopt parent-of-origin specific expression patterns in the endosperm, a phenomenon that has been termed genomic imprinting. Imprinted genes are targeted by epigenetic mechanisms acting before and after fertilization. Recent studies revealed that imprinted genes are involved in establishing seed dormancy, highlighting a new mechanism of parental control over this adaptive trait. Here, we review the regulatory mechanisms establishing genomic imprinting and their effect on seed dormancy.
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Affiliation(s)
- Hikaru Sato
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Centre for Plant Biology, Uppsala, Sweden
| | - Claudia Köhler
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Centre for Plant Biology, Uppsala, Sweden; Department of Plant Reproductive Biology and Epigenetics, Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany.
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30
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Gent JI, Higgins KM, Swentowsky KW, Fu FF, Zeng Y, Kim DW, Dawe RK, Springer NM, Anderson SN. The maize gene maternal derepression of r1 encodes a DNA glycosylase that demethylates DNA and reduces siRNA expression in the endosperm. THE PLANT CELL 2022; 34:3685-3701. [PMID: 35775949 PMCID: PMC9516051 DOI: 10.1093/plcell/koac199] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2021] [Accepted: 06/27/2022] [Indexed: 06/01/2023]
Abstract
Demethylation of transposons can activate the expression of nearby genes and cause imprinted gene expression in the endosperm; this demethylation is hypothesized to lead to expression of transposon small interfering RNAs (siRNAs) that reinforce silencing in the next generation through transfer either into egg or embryo. Here we describe maize (Zea mays) maternal derepression of r1 (mdr1), which encodes a DNA glycosylase with homology to Arabidopsis thaliana DEMETER and which is partially responsible for demethylation of thousands of regions in endosperm. Instead of promoting siRNA expression in endosperm, MDR1 activity inhibits it. Methylation of most repetitive DNA elements in endosperm is not significantly affected by MDR1, with an exception of Helitrons. While maternally-expressed imprinted genes preferentially overlap with MDR1 demethylated regions, the majority of genes that overlap demethylated regions are not imprinted. Double mutant megagametophytes lacking both MDR1 and its close homolog DNG102 result in early seed failure, and double mutant microgametophytes fail pre-fertilization. These data establish DNA demethylation by glycosylases as essential in maize endosperm and pollen and suggest that neither transposon repression nor genomic imprinting is its main function in endosperm.
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Affiliation(s)
| | - Kaitlin M Higgins
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, Iowa 50011, USA
| | - Kyle W Swentowsky
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602, USA
| | - Fang-Fang Fu
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602, USA
- Co‐Innovation Center for Sustainable Forestry in Southern China, College of Forestry, Nanjing Forestry University, Nanjing 210037, China
| | - Yibing Zeng
- Department of Genetics, University of Georgia, Athens, Georgia 30602, USA
| | - Dong won Kim
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602, USA
| | - R Kelly Dawe
- Department of Plant Biology, University of Georgia, Athens, Georgia 30602, USA
- Department of Genetics, University of Georgia, Athens, Georgia 30602, USA
| | - Nathan M Springer
- Department of Plant and Microbial Biology, University of Minnesota, Saint Paul, Minnesota 55108, USA
| | - Sarah N Anderson
- Department of Genetics, Development, and Cell Biology, Iowa State University, Ames, Iowa 50011, USA
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31
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Dai D, Mudunkothge JS, Galli M, Char SN, Davenport R, Zhou X, Gustin JL, Spielbauer G, Zhang J, Barbazuk WB, Yang B, Gallavotti A, Settles AM. Paternal imprinting of dosage-effect defective1 contributes to seed weight xenia in maize. Nat Commun 2022; 13:5366. [PMID: 36100609 PMCID: PMC9470594 DOI: 10.1038/s41467-022-33055-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 08/30/2022] [Indexed: 11/13/2022] Open
Abstract
Historically, xenia effects were hypothesized to be unique genetic contributions of pollen to seed phenotype, but most examples represent standard complementation of Mendelian traits. We identified the imprinted dosage-effect defective1 (ded1) locus in maize (Zea mays) as a paternal regulator of seed size and development. Hypomorphic alleles show a 5–10% seed weight reduction when ded1 is transmitted through the male, while homozygous mutants are defective with a 70–90% seed weight reduction. Ded1 encodes an R2R3-MYB transcription factor expressed specifically during early endosperm development with paternal allele bias. DED1 directly activates early endosperm genes and endosperm adjacent to scutellum cell layer genes, while directly repressing late grain-fill genes. These results demonstrate xenia as originally defined: Imprinting of Ded1 causes the paternal allele to set the pace of endosperm development thereby influencing grain set and size. Xenia effects describe the genetic contribution of pollen to seed phenotypes. Here the authors show that paternal imprinting of Ded1 contributes to the xenia effect in maize by setting the pace of endosperm development.
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Affiliation(s)
- Dawei Dai
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611, USA
| | - Janaki S Mudunkothge
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611, USA
| | - Mary Galli
- Waksman Institute, Rutgers University, Piscataway, NJ, 08854, USA
| | - Si Nian Char
- Division of Plant Sciences, Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA
| | - Ruth Davenport
- Department of Biology, University of Florida, Gainesville, FL, 32611, USA
| | - Xiaojin Zhou
- Crop Functional Genome Research Center, Biotechnology Research Institute, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Jeffery L Gustin
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611, USA.,United States Department of Agriculture, Urbana, IL, 61801, USA
| | - Gertraud Spielbauer
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611, USA
| | - Junya Zhang
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611, USA
| | - W Brad Barbazuk
- Department of Biology, University of Florida, Gainesville, FL, 32611, USA
| | - Bing Yang
- Division of Plant Sciences, Bond Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA.,Donald Danforth Plant Science Center, St. Louis, MO, 63132, USA
| | - Andrea Gallavotti
- Waksman Institute, Rutgers University, Piscataway, NJ, 08854, USA.,Department of Plant Biology, Rutgers University, New Brunswick, NJ, 08901, USA
| | - A Mark Settles
- Horticultural Sciences Department, University of Florida, Gainesville, FL, 32611, USA. .,Bioengineering Branch, NASA Ames Research Center, Moffett Field, CA, 94035, USA.
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32
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Povilus RA, Friedman WE. Transcriptomes across fertilization and seed development in the water lily Nymphaea thermarum (Nymphaeales): evidence for epigenetic patterning during reproduction. PLANT REPRODUCTION 2022; 35:161-178. [PMID: 35184212 DOI: 10.1007/s00497-022-00438-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 01/19/2022] [Indexed: 06/14/2023]
Abstract
The first record of gene expression during seed development within the Nymphaeales provides evidence for a variety of biological processes, including dynamic epigenetic patterning during sexual reproduction in the water lily Nymphaea thermarum. Studies of gene expression during seed development have been performed for a growing collection of species from a phylogenetically broad sampling of flowering plants (angiosperms). However, angiosperm lineages whose origins predate the divergence of monocots and eudicots have been largely overlooked. In order to provide a new resource for understanding the early evolution of seed development in flowering plants, we sequenced transcriptomes of whole ovules and seeds from three key stages of reproductive development in the waterlily Nymphaea thermarum, an experimentally tractable member of the Nymphaeales. We first explore patterns of gene expression, beginning with mature ovules and continuing through fertilization into early- and mid-stages of seed development. We find patterns of gene expression that corroborate histological/morphological observations of seed development in this species, such as expression of genes involved in starch synthesis and transcription factors that have been associated with embryo and endosperm development in other species. We also find evidence for processes that were previously not known to be occurring during seed development in this species, such as epigenetic modification. We then examine the expression of genes associated with patterning DNA and histone methylation-processes that are essential for seed development in distantly related and structurally diverse monocots and eudicots. Around 89% of transcripts putatively homologous to DNA and histone methylation modifiers are expressed during seed development in N. thermarum, including homologs of genes known to pattern imprinting-related epigenetic modifications. Our results suggest that dynamic epigenetic patterning is a deeply conserved aspect of angiosperm seed development.
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Affiliation(s)
- Rebecca A Povilus
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA
- Whitehead Institute for Biomedical Research, Cambridge, MA, 02142, USA
| | - William E Friedman
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, 02138, USA.
- Arnold Arboretum of Harvard University, 1300 Centre Street, Boston, MA, 02131, USA.
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33
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Abstract
In angiosperms, double fertilization triggers the concomitant development of two closely juxtaposed tissues, the embryo and the endosperm. Successful seed development and germination require constant interactions between these tissues, which occur across their common interface. The embryo-endosperm interface is a complex and poorly understood compound apoplast comprising components derived from both tissues, across which nutrients transit to fuel embryo development. Interface properties, which affect molecular diffusion and thus communication, are themselves dynamically regulated by molecular and physical dialogues between the embryo and endosperm. We review the current understanding of embryo-endosperm interactions, with a focus on the structure, properties, and function of their shared interface. Concentrating on Arabidopsis, but with reference to other species, we aim to situate recent findings within the broader context of seed physiology, developmental biology, and genetic factors such as parental conflicts over resource allocation.
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Affiliation(s)
- Nicolas M Doll
- Department of Plant Biotechnology and Bioinformatics, Ghent University, Ghent, Belgium;
- VIB Center of Plant Systems Biology, Ghent, Belgium
| | - Gwyneth C Ingram
- Laboratoire Reproduction et Développement des Plantes, ENS de Lyon, CNRS, INRAE, Université de Lyon 1, Lyon, France;
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34
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Iwasaki M, Penfield S, Lopez-Molina L. Parental and Environmental Control of Seed Dormancy in Arabidopsis thaliana. ANNUAL REVIEW OF PLANT BIOLOGY 2022; 73:355-378. [PMID: 35138879 DOI: 10.1146/annurev-arplant-102820-090750] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Seed dormancy-the absence of seed germination under favorable germination conditions-is a plant trait that evolved to enhance seedling survival by avoiding germination under unsuitable environmental conditions. In Arabidopsis, dormancy levels are influenced by the seed coat composition, while the endosperm is essential to repress seed germination of dormant seeds upon their imbibition. Recent research has shown that the mother plant modulates its progeny seed dormancy in response to seasonal temperature changes by changing specific aspects of seed coat and endosperm development. This process involves genomic imprinting by means of epigenetic marks deposited in the seed progeny and regulators previously known to regulate flowering time. This review discusses and summarizes these discoveries and provides an update on our present understanding of the role of DOG1 and abscisic acid, two key contributors to dormancy.
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Affiliation(s)
- Mayumi Iwasaki
- Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland;
| | - Steven Penfield
- Department of Crop Genetics, John Innes Centre, Norwich Research Park, Norwich, United Kingdom
| | - Luis Lopez-Molina
- Department of Botany and Plant Biology, University of Geneva, Geneva, Switzerland;
- Institute of Genetics and Genomics in Geneva (iGE3), University of Geneva, Geneva, Switzerland
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35
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DNA methylation-free Arabidopsis reveals crucial roles of DNA methylation in regulating gene expression and development. Nat Commun 2022; 13:1335. [PMID: 35288562 PMCID: PMC8921224 DOI: 10.1038/s41467-022-28940-2] [Citation(s) in RCA: 77] [Impact Index Per Article: 38.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 02/16/2022] [Indexed: 12/17/2022] Open
Abstract
A contribution of DNA methylation to defense against invading nucleic acids and maintenance of genome integrity is uncontested; however, our understanding of the extent of involvement of this epigenetic mark in genome-wide gene regulation and plant developmental control is incomplete. Here, we knock out all five known DNA methyltransferases in Arabidopsis, generating DNA methylation-free plants. This quintuple mutant exhibits a suite of developmental defects, unequivocally demonstrating that DNA methylation is essential for multiple aspects of plant development. We show that CG methylation and non-CG methylation are required for a plethora of biological processes, including pavement cell shape, endoreduplication, cell death, flowering, trichome morphology, vasculature and meristem development, and root cell fate determination. Moreover, we find that DNA methylation has a strong dose-dependent effect on gene expression and repression of transposable elements. Taken together, our results demonstrate that DNA methylation is dispensable for Arabidopsis survival but essential for the proper regulation of multiple biological processes. Our understanding of the extent of involvement of DNA methylation in genome-wide gene regulation and plant developmental control is incomplete. Here, the authors knock out all five known DNA methyltransferases and show the developmental and gene expression changes in the DNA methylation-free Arabidopsis plants.
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36
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Xu Q, Wu L, Luo Z, Zhang M, Lai J, Li L, Springer NM, Li Q. DNA demethylation affects imprinted gene expression in maize endosperm. Genome Biol 2022; 23:77. [PMID: 35264226 PMCID: PMC8905802 DOI: 10.1186/s13059-022-02641-x] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 02/23/2022] [Indexed: 11/28/2022] Open
Abstract
Background DNA demethylation occurs in many species and is involved in diverse biological processes. However, the occurrence and role of DNA demethylation in maize remain unknown. Results We analyze loss-of-function mutants of two major genes encoding DNA demethylases. No significant change in DNA methylation has been detected in these mutants. However, we detect increased DNA methylation levels in the mutants around genes and some transposons. The increase in DNA methylation is accompanied by alteration in gene expression, with a tendency to show downregulation, especially for the genes that are preferentially expressed in endosperm. Imprinted expression of both maternally and paternally expressed genes changes in F1 hybrid with the mutant as female and the wild-type as male parental line, but not in the reciprocal hybrid. This alteration in gene expression is accompanied by allele-specific DNA methylation differences, suggesting that removal of DNA methylation of the maternal allele is required for the proper expression of these imprinted genes. Finally, we demonstrate that hypermethylation in the double mutant is associated with reduced binding of transcription factor to its target, and altered gene expression. Conclusions Our results suggest that active removal of DNA methylation is important for transcription factor binding and proper gene expression in maize endosperm.
Supplementary Information The online version contains supplementary material available at 10.1186/s13059-022-02641-x.
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Affiliation(s)
- Qiang Xu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Leiming Wu
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Zhixiang Luo
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Mei Zhang
- Key Laboratory of Plant Molecular Physiology, Institute of Botany, Chinese Academy of Sciences, Nanxincun 20, Fragrant Hill, Beijing, 100093, China
| | - Jinsheng Lai
- State Key Laboratory of Plant Physiology and Biochemistry and National Maize Improvement Center, Department of Plant Genetics and Breeding, China Agricultural University, Beijing, 100094, China
| | - Lin Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China
| | - Nathan M Springer
- Department of Plant and Microbial Biology, University of Minnesota, St. Paul, MN, 55108, USA
| | - Qing Li
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan, 430070, China. .,Hubei Hongshan Laboratory, Wuhan, 430070, China.
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37
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Huc J, Dziasek K, Pachamuthu K, Woh T, Köhler C, Borges F. Bypassing reproductive barriers in hybrid seeds using chemically induced epimutagenesis. THE PLANT CELL 2022; 34:989-1001. [PMID: 34792584 PMCID: PMC8894923 DOI: 10.1093/plcell/koab284] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Accepted: 11/09/2021] [Indexed: 05/13/2023]
Abstract
The triploid block, which prevents interploidy hybridizations in flowering plants, is characterized by a failure in endosperm development, arrest in embryogenesis, and seed collapse. Many genetic components of triploid seed lethality have been successfully identified in the model plant Arabidopsis thaliana, most notably the paternally expressed genes (PEGs), which are upregulated in tetraploid endosperm with paternal excess. Previous studies have shown that the paternal epigenome is a key determinant of the triploid block response, as the loss of DNA methylation in diploid pollen suppresses the triploid block almost completely. Here, we demonstrate that triploid seed collapse is bypassed in Arabidopsis plants treated with the DNA methyltransferase inhibitor 5-Azacytidine during seed germination and early growth. We identified strong suppressor lines showing stable transgenerational inheritance of hypomethylation in the CG context, as well as normalized expression of PEGs in triploid seeds. Importantly, differentially methylated loci segregate in the progeny of "epimutagenized" plants, which may allow epialleles involved in the triploid block response to be identified in future studies. Finally, we demonstrate that chemically induced epimutagenesis facilitates hybridization between different Capsella species, thus potentially emerging as a strategy for producing triploids and interspecific hybrids with high agronomic interest.
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Affiliation(s)
- Jonathan Huc
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000, Versailles, France
| | - Katarzyna Dziasek
- Department of Plant Biology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala, Sweden
| | - Kannan Pachamuthu
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000, Versailles, France
| | - Tristan Woh
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000, Versailles, France
| | - Claudia Köhler
- Department of Plant Biology, Uppsala Biocenter, Swedish University of Agricultural Sciences, Linnean Center of Plant Biology, Uppsala, Sweden
- Max Planck Institute of Molecular Plant Physiology, Potsdam-Golm, Germany
| | - Filipe Borges
- Institut Jean-Pierre Bourgin, INRAE, AgroParisTech, Université Paris-Saclay, 78000, Versailles, France
- Author for correspondence:
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38
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Nagata H, Ono A, Tonosaki K, Kawakatsu T, Sato Y, Yano K, Kishima Y, Kinoshita T. Temporal changes in transcripts of miniature inverted-repeat transposable elements during rice endosperm development. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 109:1035-1047. [PMID: 35128739 PMCID: PMC9314911 DOI: 10.1111/tpj.15698] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 01/19/2022] [Accepted: 01/27/2022] [Indexed: 06/14/2023]
Abstract
The repression of transcription from transposable elements (TEs) by DNA methylation is necessary to maintain genome integrity and prevent harmful mutations. However, under certain circumstances, TEs may escape from the host defense system and reactivate their transcription. In Arabidopsis (Arabidopsis thaliana) and rice (Oryza sativa), DNA demethylases target the sequences derived from TEs in the central cell, the progenitor cell for the endosperm in the female gametophyte. Genome-wide DNA demethylation is also observed in the endosperm after fertilization. In the present study, we used a custom microarray to survey the transcripts generated from TEs during rice endosperm development and at selected time points in the embryo as a control. The expression patterns of TE transcripts are dynamically up- and downregulated during endosperm development, especially those of miniature inverted-repeat TEs (MITEs). Some TE transcripts were directionally controlled, whereas the other DNA transposons and retrotransposons were not. We also discovered the NUCLEAR FACTOR Y binding motif, CCAAT, in the region near the 5' terminal inverted repeat of Youren, one of the transcribed MITEs in the endosperm. Our results uncover dynamic changes in TE activity during endosperm development in rice.
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Affiliation(s)
- Hiroki Nagata
- Kihara Institute for Biological Research, Yokohama City University641‐12 MaiokaTotsuka, YokohamaKanagawa244‐0813Japan
| | - Akemi Ono
- Kihara Institute for Biological Research, Yokohama City University641‐12 MaiokaTotsuka, YokohamaKanagawa244‐0813Japan
| | - Kaoru Tonosaki
- Kihara Institute for Biological Research, Yokohama City University641‐12 MaiokaTotsuka, YokohamaKanagawa244‐0813Japan
- Faculty of AgricultureIwate University3‐18‐8 UedaMoriokaIwate020‐8550Japan
| | - Taiji Kawakatsu
- Institute of Agrobiological Sciences, National Agriculture and Food Research Organization3‐1‐3 Kan‐nondaiTsukubaIbaraki305‐8604Japan
| | - Yutaka Sato
- Genetic Strains Research CenterNational Institute of GeneticsMishima, Shizuoka411‐8540Japan
| | - Kentaro Yano
- Department of Life SciencesSchool of Agriculture, Meiji University1‐1‐1 Higashi‐mitaKawasaki214‐8571Japan
| | - Yuji Kishima
- Research Faculty of AgricultureHokkaido UniversityKita‐9 Nishi‐9Kita‐ku, Sapporo060‐8589Japan
| | - Tetsu Kinoshita
- Kihara Institute for Biological Research, Yokohama City University641‐12 MaiokaTotsuka, YokohamaKanagawa244‐0813Japan
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39
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Lu D, Zhai J, Xi M. Regulation of DNA Methylation During Plant Endosperm Development. Front Genet 2022; 13:760690. [PMID: 35222527 PMCID: PMC8867698 DOI: 10.3389/fgene.2022.760690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 01/17/2022] [Indexed: 11/21/2022] Open
Abstract
The endosperm is a vital storage tissue in plant seeds. It provides nutrients to the embryos or the seedlings during seed development and germination. Although the genetic information in the endosperm cannot be passed directly to the next generation, its inherited epigenetic marks affect gene expression and its development and, consequently, embryo and seed growth. DNA methylation is a major form of epigenetic modification that can be investigated to understand the epigenome changes during reproductive development. Therefore, it is of great significance to explore the effects of endosperm DNA methylation on crop yield and traits. In this review, we discuss the changes in DNA methylation and the resulting imprinted gene expression levels during plant endosperm development, as well as their effects on seed development.
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Affiliation(s)
- Dongdong Lu
- Key Laboratory of Forest Genetics and Biotechnology of Ministry of Education, Nanjing Forestry University, Nanjing, China
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen, China
| | - Jixian Zhai
- Department of Biology, Southern University of Science and Technology, Shenzhen, China
- Institute of Plant and Food Science, Southern University of Science and Technology, Shenzhen, China
- Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes, Southern University of Science and Technology, Shenzhen, China
- *Correspondence: Jixian Zhai, ; Mengli Xi,
| | - Mengli Xi
- Key Laboratory of Forest Genetics and Biotechnology of Ministry of Education, Nanjing Forestry University, Nanjing, China
- *Correspondence: Jixian Zhai, ; Mengli Xi,
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40
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Montgomery SA, Berger F. The evolution of imprinting in plants: beyond the seed. PLANT REPRODUCTION 2021; 34:373-383. [PMID: 33914165 PMCID: PMC8566399 DOI: 10.1007/s00497-021-00410-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 04/12/2021] [Indexed: 05/14/2023]
Abstract
Genomic imprinting results in the biased expression of alleles depending on if the allele was inherited from the mother or the father. Despite the prevalence of sexual reproduction across eukaryotes, imprinting is only found in placental mammals, flowering plants, and some insects, suggesting independent evolutionary origins. Numerous hypotheses have been proposed to explain the selective pressures that favour the innovation of imprinted gene expression and each differs in their experimental support and predictions. Due to the lack of investigation of imprinting in land plants, other than angiosperms with triploid endosperm, we do not know whether imprinting occurs in species lacking endosperm and with embryos developing on maternal plants. Here, we discuss the potential for uncovering additional examples of imprinting in land plants and how these observations may provide additional support for one or more existing imprinting hypotheses.
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Affiliation(s)
- Sean A Montgomery
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr Gasse 3, 1030, Vienna, Austria
| | - Frédéric Berger
- Gregor Mendel Institute (GMI), Austrian Academy of Sciences, Vienna BioCenter (VBC), Dr. Bohr Gasse 3, 1030, Vienna, Austria.
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41
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Fang H, Shao Y, Wu G. Reprogramming of Histone H3 Lysine Methylation During Plant Sexual Reproduction. FRONTIERS IN PLANT SCIENCE 2021; 12:782450. [PMID: 34917115 PMCID: PMC8669150 DOI: 10.3389/fpls.2021.782450] [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: 09/24/2021] [Accepted: 11/08/2021] [Indexed: 06/14/2023]
Abstract
Plants undergo extensive reprogramming of chromatin status during sexual reproduction, a process vital to cell specification and pluri- or totipotency establishment. As a crucial way to regulate chromatin organization and transcriptional activity, histone modification can be reprogrammed during sporogenesis, gametogenesis, and embryogenesis in flowering plants. In this review, we first introduce enzymes required for writing, recognizing, and removing methylation marks on lysine residues in histone H3 tails, and describe their differential expression patterns in reproductive tissues, then we summarize their functions in the reprogramming of H3 lysine methylation and the corresponding chromatin re-organization during sexual reproduction in Arabidopsis, and finally we discuss the molecular significance of histone reprogramming in maintaining the pluri- or totipotency of gametes and the zygote, and in establishing novel cell fates throughout the plant life cycle. Despite rapid achievements in understanding the molecular mechanism and function of the reprogramming of chromatin status in plant development, the research in this area still remains a challenge. Technological breakthroughs in cell-specific epigenomic profiling in the future will ultimately provide a solution for this challenge.
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42
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Zhou Q, Guan P, Zhu Z, Cheng S, Zhou C, Wang H, Xu Q, Sung WK, Li G. ASMdb: a comprehensive database for allele-specific DNA methylation in diverse organisms. Nucleic Acids Res 2021; 50:D60-D71. [PMID: 34664666 PMCID: PMC8728259 DOI: 10.1093/nar/gkab937] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2021] [Revised: 09/27/2021] [Accepted: 09/30/2021] [Indexed: 11/18/2022] Open
Abstract
DNA methylation is known to be the most stable epigenetic modification and has been extensively studied in relation to cell differentiation, development, X chromosome inactivation and disease. Allele-specific DNA methylation (ASM) is a well-established mechanism for genomic imprinting and regulates imprinted gene expression. Previous studies have confirmed that certain special regions with ASM are susceptible and closely related to human carcinogenesis and plant development. In addition, recent studies have proven ASM to be an effective tumour marker. However, research on the functions of ASM in diseases and development is still extremely scarce. Here, we collected 4400 BS-Seq datasets and 1598 corresponding RNA-Seq datasets from 47 species, including human and mouse, to establish a comprehensive ASM database. We obtained the data on DNA methylation level, ASM and allele-specific expressed genes (ASEGs) and further analysed the ASM/ASEG distribution patterns of these species. In-depth ASM distribution analysis and differential methylation analysis conducted in nine cancer types showed results consistent with the reported changes in ASM in key tumour genes and revealed several potential ASM tumour-related genes. Finally, integrating these results, we constructed the first well-resourced and comprehensive ASM database for 47 species (ASMdb, www.dna-asmdb.com).
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Affiliation(s)
- Qiangwei Zhou
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China.,Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, 3D Genomics Research Center, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Pengpeng Guan
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China.,Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, 3D Genomics Research Center, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhixian Zhu
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China.,Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, 3D Genomics Research Center, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Sheng Cheng
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China.,Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, 3D Genomics Research Center, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Cong Zhou
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China.,Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, 3D Genomics Research Center, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Huanhuan Wang
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China.,Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, 3D Genomics Research Center, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Qian Xu
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China.,Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, 3D Genomics Research Center, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
| | - Wing-Kin Sung
- Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, 3D Genomics Research Center, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China.,Department of Computer Science, National University of Singapore, Singapore 117417, Singapore.,Department of Computational and Systems Biology, Genome Institute of Singapore, Singapore 138672, Singapore
| | - Guoliang Li
- National Key Laboratory of Crop Genetic Improvement, Hubei Hongshan Laboratory, Huazhong Agricultural University, Wuhan 430070, China.,Agricultural Bioinformatics Key Laboratory of Hubei Province, Hubei Engineering Technology Research Center of Agricultural Big Data, 3D Genomics Research Center, College of Informatics, Huazhong Agricultural University, Wuhan 430070, China
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43
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Evolution of CG Methylation Maintenance Machinery in Plants. EPIGENOMES 2021; 5:epigenomes5030019. [PMID: 34968368 PMCID: PMC8594673 DOI: 10.3390/epigenomes5030019] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 09/06/2021] [Accepted: 09/10/2021] [Indexed: 11/16/2022] Open
Abstract
Cytosine methylation is an epigenetic mark present in most eukaryotic genomes that contributes to the regulation of gene expression and the maintenance of genome stability. DNA methylation mostly occurs at CG sequences, where it is initially deposited by de novo DNA methyltransferases and propagated by maintenance DNA methyltransferases (DNMT) during DNA replication. In this review, we first summarize the mechanisms maintaining CG methylation in mammals that involve the DNA Methyltransferase 1 (DNMT1) enzyme and its cofactor, UHRF1 (Ubiquitin-like with PHD and RING Finger domain 1). We then discuss the evolutionary conservation and diversification of these two core factors in the plant kingdom and speculate on potential functions of novel homologues typically observed in land plants but not in mammals.
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Yang X, Wang X, Yao J, Duan D. Genome-Wide Mapping of Cytosine Methylation Revealed Dynamic DNA Methylation Patterns Associated with Sporophyte Development of Saccharina japonica. Int J Mol Sci 2021; 22:9877. [PMID: 34576045 PMCID: PMC8472486 DOI: 10.3390/ijms22189877] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2021] [Revised: 08/27/2021] [Accepted: 09/08/2021] [Indexed: 02/04/2023] Open
Abstract
Cytosine methylation plays vital roles in regulating gene expression and plant development. However, the function of DNA methylation in the development of macroalgae remains unclear. Through the genome-wide bisulfite sequencing of cytosine methylation in holdfast, stipe and blade, we obtained the complete 5-mC methylation landscape of Saccharina japonica sporophyte. Our results revealed that the total DNA methylation level of sporophyte was less than 0.9%, and the content of CHH contexts was dominant. Moreover, the distribution of CHH methylation within the genes exhibited exon-enriched characteristics. Profiling of DNA methylation in three parts revealed the diverse methylation pattern of sporophyte development. These pivotal DMRs were involved in cell motility, cell cycle and cell wall/membrane biogenesis. In comparison with stipe and blade, hypermethylation of mannuronate C5-epimerase in holdfast decreased the transcript abundance, which affected the synthesis of alginate, the key component of cell walls. Additionally, 5-mC modification participated in the regulation of blade and holdfast development by the glutamate content respectively via glutamine synthetase and amidophosphoribosyl transferase, which may act as the epigenetic regulation signal. Overall, our study revealed the global methylation characteristics of the well-defined holdfast, stipe and blade, and provided evidence for epigenetic regulation of sporophyte development in brown macroalgae.
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Affiliation(s)
- Xiaoqi Yang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (X.Y.); (X.W.); (J.Y.)
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiuliang Wang
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (X.Y.); (X.W.); (J.Y.)
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China
| | - Jianting Yao
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (X.Y.); (X.W.); (J.Y.)
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China
| | - Delin Duan
- CAS and Shandong Province Key Laboratory of Experimental Marine Biology, Center for Ocean Mega-Science, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China; (X.Y.); (X.W.); (J.Y.)
- Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), Qingdao 266071, China
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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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Sato H, Santos-González J, Köhler C. Combinations of maternal-specific repressive epigenetic marks in the endosperm control seed dormancy. eLife 2021; 10:e64593. [PMID: 34427186 PMCID: PMC8456740 DOI: 10.7554/elife.64593] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Accepted: 08/23/2021] [Indexed: 12/20/2022] Open
Abstract
Polycomb Repressive Complex 2 (PRC2)-mediated trimethylation of histone H3 on lysine 27 (H3K27me3) and methylation of histone 3 on lysine 9 (H3K9me) are two repressive epigenetic modifications that are typically localized in distinct regions of the genome. For reasons unknown, however, they co-occur in some organisms and special tissue types. In this study, we show that maternal alleles marked by H3K27me3 in the Arabidopsis endosperm were targeted by the H3K27me3 demethylase REF6 and became activated during germination. In contrast, maternal alleles marked by H3K27me3, H3K9me2, and CHG methylation (CHGm) are likely to be protected from REF6 targeting and remained silenced. Our study unveils that combinations of different repressive epigenetic modifications time a key adaptive trait by modulating access of REF6.
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Affiliation(s)
- Hikaru Sato
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Centre for Plant BiologyUppsalaSweden
| | - Juan Santos-González
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Centre for Plant BiologyUppsalaSweden
| | - Claudia Köhler
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Centre for Plant BiologyUppsalaSweden
- Max Planck Institute of Molecular Plant PhysiologyPotsdam-GolmGermany
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47
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Dai X, Wang J, Song Y, Liu Z, Xue T, Qiao M, Yu Y, Xin W, Xiang F. Cytosine methylation of the FWA promoter promotes direct in vitro shoot regeneration in Arabidopsis thaliana. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2021; 63:1491-1504. [PMID: 34292662 DOI: 10.1111/jipb.13156] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2021] [Accepted: 07/20/2021] [Indexed: 06/13/2023]
Abstract
Epigenetic modifications within promoter sequences can act as regulators of gene expression. Shoot regeneration is influenced by both DNA methylation and histone methylation, but the mechanistic basis of this regulation is obscure. Here, we identified 218 genes related to the regeneration capacity of callus that were differentially transcribed between regenerable calli (RC) and non-regenerable calli (NRC) in Arabidopsis thaliana. An analysis of the promoters of five of the differentially expressed genes (FWA, ACC1, TFL1, MAX3, and GRP3) pointed to an inverse relationship between cytosine methylation and transcription. The FWA promoter was demethylated and highly expressed in NRC, whereas it was methylated and expressed at low levels in RC. Explants of the hypomethylation mutants fwa-1 and fwa-2 showed strong levels of FWA expression and regenerated less readily than the wild type, suggesting that FWA inhibits direct in vitro shoot regeneration. WUSCHEL-RELATED HOMEOBOX 9 (WOX9), which is required for shoot apical meristem formation, was directly repressed by FWA. Overexpressing WOX9 partly rescued the shoot regeneration defect of fwa-2 plants. These findings suggest that cytosine methylation of the FWA promoter forms part of the regulatory system governing callus regenerability and direct in vitro shoot regeneration.
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Affiliation(s)
- Xuehuan Dai
- The Key Laboratory of the Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Jing Wang
- The Key Laboratory of the Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Yuguang Song
- The Key Laboratory of the Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
- Present address: Qufu Normal University, Qufu, 273165, China
| | - Zhenhua Liu
- The Key Laboratory of the Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
- Present address: Shandong University of Traditional Chinese Medicine, Jinan, 250355, China
| | - Tao Xue
- The Key Laboratory of the Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
- Present address: Huaibei Normal University, Huaibei, 235000, China
| | - Meng Qiao
- The Key Laboratory of the Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
| | - Yanchong Yu
- The Key Laboratory of the Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
- Present address: Qingdao Agricultural University, Qingdao, 266109, China
| | - Wei Xin
- The Key Laboratory of the Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
- Present address: Institute of Botany, The Chinese Academy of Sciences, Beijing, 100101, China
| | - Fengning Xiang
- The Key Laboratory of the Plant Development and Environmental Adaptation Biology, Ministry of Education, School of Life Sciences, Shandong University, Qingdao, 266237, China
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Rodrigues JA, Hsieh PH, Ruan D, Nishimura T, Sharma MK, Sharma R, Ye X, Nguyen ND, Nijjar S, Ronald PC, Fischer RL, Zilberman D. Divergence among rice cultivars reveals roles for transposition and epimutation in ongoing evolution of genomic imprinting. Proc Natl Acad Sci U S A 2021; 118:e2104445118. [PMID: 34272287 PMCID: PMC8307775 DOI: 10.1073/pnas.2104445118] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Parent-of-origin-dependent gene expression in mammals and flowering plants results from differing chromatin imprints (genomic imprinting) between maternally and paternally inherited alleles. Imprinted gene expression in the endosperm of seeds is associated with localized hypomethylation of maternally but not paternally inherited DNA, with certain small RNAs also displaying parent-of-origin-specific expression. To understand the evolution of imprinting mechanisms in Oryza sativa (rice), we analyzed imprinting divergence among four cultivars that span both japonica and indica subspecies: Nipponbare, Kitaake, 93-11, and IR64. Most imprinted genes are imprinted across cultivars and enriched for functions in chromatin and transcriptional regulation, development, and signaling. However, 4 to 11% of imprinted genes display divergent imprinting. Analyses of DNA methylation and small RNAs revealed that endosperm-specific 24-nt small RNA-producing loci show weak RNA-directed DNA methylation, frequently overlap genes, and are imprinted four times more often than genes. However, imprinting divergence most often correlated with local DNA methylation epimutations (9 of 17 assessable loci), which were largely stable within subspecies. Small insertion/deletion events and transposable element insertions accompanied 4 of the 9 locally epimutated loci and associated with imprinting divergence at another 4 of the remaining 8 loci. Correlating epigenetic and genetic variation occurred at key regulatory regions-the promoter and transcription start site of maternally biased genes, and the promoter and gene body of paternally biased genes. Our results reinforce models for the role of maternal-specific DNA hypomethylation in imprinting of both maternally and paternally biased genes, and highlight the role of transposition and epimutation in rice imprinting evolution.
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Affiliation(s)
- Jessica A Rodrigues
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Ping-Hung Hsieh
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Deling Ruan
- Department of Plant Pathology, University of California, Davis, CA 95616
| | - Toshiro Nishimura
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Manoj K Sharma
- Department of Plant Pathology, University of California, Davis, CA 95616
| | - Rita Sharma
- Department of Plant Pathology, University of California, Davis, CA 95616
| | - XinYi Ye
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Nicholas D Nguyen
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Sukhranjan Nijjar
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720
| | - Pamela C Ronald
- Department of Plant Pathology, University of California, Davis, CA 95616
- The Genome Center, University of California, Davis, CA 95616
| | - Robert L Fischer
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720;
| | - Daniel Zilberman
- Department of Plant and Microbial Biology, University of California, Berkeley, CA 94720;
- Department of Cell and Developmental Biology, The John Innes Centre, Norwich NR4 7UH, United Kingdom
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49
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The DME demethylase regulates sporophyte gene expression, cell proliferation, differentiation, and meristem resurrection. Proc Natl Acad Sci U S A 2021; 118:2026806118. [PMID: 34266952 PMCID: PMC8307533 DOI: 10.1073/pnas.2026806118] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
The angiosperm life cycle has alternating diploid (sporophyte) and haploid (gametophyte) generations. The sporophyte generation begins with fertilization of haploid gametes and the gametophyte generation begins after meiosis. In Arabidopsis, the DEMETER (DME) DNA demethylase is essential for reproduction and is expressed in the central cell and vegetative cell of the female and male gametophyte, respectively. Little is known about DME function in the sporophyte. We show that DME activity is required for sporophyte development—seed germination, root hair growth, and cellular proliferation and differentiation during development—and we identify sporophytic genes whose proper expression requires DME activity. Together, our study provides important clues about the genetic circuits regulated by the DME DNA demethylase that control Arabidopsis sporophyte development. The flowering plant life cycle consists of alternating haploid (gametophyte) and diploid (sporophyte) generations, where the sporophytic generation begins with fertilization of haploid gametes. In Arabidopsis, genome-wide DNA demethylation is required for normal development, catalyzed by the DEMETER (DME) DNA demethylase in the gamete companion cells of male and female gametophytes. In the sporophyte, postembryonic growth and development are largely dependent on the activity of numerous stem cell niches, or meristems. Analyzing Arabidopsis plants homozygous for a loss-of-function dme-2 allele, we show that DME influences many aspects of sporophytic growth and development. dme-2 mutants exhibited delayed seed germination, variable root hair growth, aberrant cellular proliferation and differentiation followed by enhanced de novo shoot formation, dysregulation of root quiescence and stomatal precursor cells, and inflorescence meristem (IM) resurrection. We also show that sporophytic DME activity exerts a profound effect on the transcriptome of developing Arabidopsis plants, including discrete groups of regulatory genes that are misregulated in dme-2 mutant tissues, allowing us to potentially link phenotypes to changes in specific gene expression pathways. These results show that DME plays a key role in sporophytic development and suggest that DME-mediated active DNA demethylation may be involved in the maintenance of stem cell activities during the sporophytic life cycle in Arabidopsis.
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50
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Yadav VK, Santos-González J, Köhler C. INT-Hi-C reveals distinct chromatin architecture in endosperm and leaf tissues of Arabidopsis. Nucleic Acids Res 2021; 49:4371-4385. [PMID: 33744975 PMCID: PMC8096224 DOI: 10.1093/nar/gkab191] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2020] [Revised: 02/10/2021] [Accepted: 03/06/2021] [Indexed: 12/13/2022] Open
Abstract
Higher-order chromatin structure undergoes striking changes in response to various developmental and environmental signals, causing distinct cell types to adopt specific chromatin organization. High throughput chromatin conformation capture (Hi-C) allows studying higher-order chromatin structure; however, this technique requires substantial amounts of starting material, which has limited the establishment of cell type-specific higher-order chromatin structure in plants. To overcome this limitation, we established a protocol that is applicable to a limited amount of nuclei by combining the INTACT (isolation of nuclei tagged in specific cell types) method and Hi-C (INT-Hi-C). Using this INT-Hi-C protocol, we generated Hi-C data from INTACT purified endosperm and leaf nuclei. Our INT-Hi-C data from leaf accurately reiterated chromatin interaction patterns derived from conventional leaf Hi-C data. We found that the higher-order chromatin organization of mixed leaf tissues and endosperm differs and that DNA methylation and repressive histone marks positively correlate with the chromatin compaction level. We furthermore found that self-looped interacting genes have increased expression in leaves and endosperm and that interacting intergenic regions negatively impact on gene expression in the endosperm. Last, we identified several imprinted genes involved in long-range and trans interactions exclusively in endosperm. Our study provides evidence that the endosperm adopts a distinct higher-order chromatin structure that differs from other cell types in plants and that chromatin interactions influence transcriptional activity.
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Affiliation(s)
- Vikash Kumar Yadav
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Centre for Plant Biology, Uppsala 75007, Sweden
| | - Juan Santos-González
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Centre for Plant Biology, Uppsala 75007, Sweden
| | - Claudia Köhler
- Department of Plant Biology, Uppsala BioCenter, Swedish University of Agricultural Sciences and Linnean Centre for Plant Biology, Uppsala 75007, Sweden
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