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Khouider S, Gehring M. Parental dialectic: Epigenetic conversations in endosperm. CURRENT OPINION IN PLANT BIOLOGY 2024; 81:102591. [PMID: 38944896 DOI: 10.1016/j.pbi.2024.102591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [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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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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3
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Yang K, Tang Y, Li Y, Guo W, Hu Z, Wang X, Berger F, Li J. Two imprinted genes primed by DEMETER in the central cell and activated by WRKY10 in the endosperm. J Genet Genomics 2024:S1673-8527(24)00072-9. [PMID: 38599515 DOI: 10.1016/j.jgg.2024.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2024] [Revised: 04/02/2024] [Accepted: 04/02/2024] [Indexed: 04/12/2024]
Abstract
The early development of the endosperm is crucial for balancing the allocation of maternal nutrients to offspring. This process is believed to be evolutionarily associated with genomic imprinting, resulting in parentally biased allelic gene expression. Beyond FertilizationIndependentSeed (FIS) genes, the number of imprinted genes involved in early endosperm development and seed size determination remains limited. This study introduces two early endosperm-expressed HAIKU (IKU) downstream Candidate F-box 1 (ICF1) and ICF2, as maternally expressed imprinted genes (MEGs). Although these genes are also demethylated by DEMETER (DME) in the central cell, their activation differs from the direct DME-mediated activation seen in classical MEGs such as the FIS genes. Instead, ICF maternal alleles carry pre-established hypomethylation in their promoters, priming them for activation by the WRKY10 transcription factor in the endosperm. On the contrary, paternal alleles are predominantly suppressed by CG methylation. Furthermore, we find that ICF genes partially contribute to the small seed size observed in iku mutants. Our discovery reveals a two-step regulatory mechanism that highlights the important role of conventional transcription factors in the activation of imprinted genes, which was previously not fully recognized. Therefore, the mechanism provides a new dimension to understand the transcriptional regulation of imprinting in plant reproduction and development.
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Affiliation(s)
- Ke Yang
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China; Sanya Institute of Breeding and Multiplication, Hainan University, Sanya, Hainan 572025, China; School of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China; Hainan Yazhou Bay Seed Laboratory, Sanya, Hainan 572025, China
| | - Yuling Tang
- Sanya Institute of Breeding and Multiplication, Hainan University, Sanya, Hainan 572025, China; School of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China; Hainan Yazhou Bay Seed Laboratory, Sanya, Hainan 572025, China
| | - Yue Li
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Wenbin Guo
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Zhengdao Hu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Xuanpeng Wang
- Sanya Institute of Breeding and Multiplication, Hainan University, Sanya, Hainan 572025, China; School of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China; Hainan Yazhou Bay Seed Laboratory, Sanya, Hainan 572025, China
| | - Frédéric Berger
- Gregor Mendel Institute, Austrian Academy of Sciences, Vienna BioCenter, 1030 Vienna, Austria
| | - Jing Li
- Sanya Institute of Breeding and Multiplication, Hainan University, Sanya, Hainan 572025, China; School of Tropical Agriculture and Forestry, Hainan University, Haikou, Hainan 570228, China; Hainan Yazhou Bay Seed Laboratory, Sanya, Hainan 572025, China.
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Dew-Budd KJ, Chow HT, Kendall T, David BC, Rozelle JA, Mosher RA, Beilstein MA. Mating system is associated with seed phenotypes upon loss of RNA-directed DNA methylation in Brassicaceae. PLANT PHYSIOLOGY 2024; 194:2136-2148. [PMID: 37987565 DOI: 10.1093/plphys/kiad622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Revised: 10/03/2023] [Accepted: 10/23/2023] [Indexed: 11/22/2023]
Abstract
In plants, de novo DNA methylation is guided by 24-nt short interfering (si)RNAs in a process called RNA-directed DNA methylation (RdDM). Primarily targeted at transposons, RdDM causes transcriptional silencing and can indirectly influence expression of neighboring genes. During reproduction, a small number of siRNA loci are dramatically upregulated in the maternally derived seed coat, suggesting that RdDM might have a special function during reproduction. However, the developmental consequence of RdDM has been difficult to dissect because disruption of RdDM does not result in overt phenotypes in Arabidopsis (Arabidopsis thaliana), where the pathway has been most thoroughly studied. In contrast, Brassica rapa mutants lacking RdDM have a severe seed production defect, which is determined by the maternal sporophytic genotype. To explore the factors that underlie the different phenotypes of these species, we produced RdDM mutations in 3 additional members of the Brassicaceae family: Camelina sativa, Capsella rubella, and Capsella grandiflora. Among these 3 species, only mutations in the obligate outcrosser, C. grandiflora, displayed a seed production defect similar to Brassica rapa mutants, suggesting that mating system is a key determinant for reproductive phenotypes in RdDM mutants.
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Affiliation(s)
- Kelly J Dew-Budd
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Hiu Tung Chow
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Timmy Kendall
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Brandon C David
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - James A Rozelle
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Rebecca A Mosher
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
| | - Mark A Beilstein
- School of Plant Sciences, University of Arizona, Tucson, AZ 85721, USA
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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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Morgan EJ, Kaiser-Bunbury CN, Edwards PJ, Fleischer-Dogley F, Kettle CJ. Mate-choice for close kin is associated with improved offspring survival in Lodoicea maldivica, the largest-seeded plant in the world. Sci Rep 2023; 13:15305. [PMID: 37723314 PMCID: PMC10507110 DOI: 10.1038/s41598-023-41419-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Accepted: 08/26/2023] [Indexed: 09/20/2023] Open
Abstract
We studied spatial patterns of kinship in the offspring of the endangered Lodoicea maldivica, a dioecious palm that produces the largest seed of any plant. Previous research has suggested that restricted seed and pollen dispersal in populations resulted in strong spatial genetic structure. We used microsatellites to genotype young plants and their potential parents at four sites across the species' entire natural range. We determined the most likely parents of each young plant based on the spatial separation of each parent pair, their genetic relatedness, and the level of correlated paternity. We identified both parents (43 female, 54 male) for 139 of 493 young plants. Mean distance between parental pairs was 26.8 m. Correlated paternity was low (0.168), indicating that mother trees were often pollinated by several fathers. Parental pairs were more closely related than expected by chance, suggesting outbreeding depression. Our results highlight the apparent strong mate choice for close kin in parent pairs of surviving offspring. We discuss the alternative biological processes that could lead to this, including the potential for break-up of favourable allelic combinations necessary for the development of the palm's very large seed. Management implications include germinating seeds where they naturally fall, using a diverse range of male plants as pollen donors for hand pollination, and protecting the native community of gecko pollinators.
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Affiliation(s)
- Emma J Morgan
- ITES-Ecosystem Management, ETH Zürich, Universitätstrasse 16, 8092, Zurich, Switzerland.
| | - Christopher N Kaiser-Bunbury
- Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Penryn, UK
| | - Peter J Edwards
- IBZ-Institute of Integrative Biology, ETH Zürich, Universitätstrasse 16, 8092, Zurich, Switzerland
| | | | - Chris J Kettle
- ITES-Ecosystem Management, ETH Zürich, Universitätstrasse 16, 8092, Zurich, Switzerland
- Bioversity International, Via di San Domenico 1, 00153, Rome, Italy
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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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Ando A, Kirkbride RC, Qiao H, Chen ZJ. Endosperm and Maternal-specific expression of EIN2 in the endosperm affects endosperm cellularization and seed size in Arabidopsis. Genetics 2023; 223:iyac161. [PMID: 36282525 PMCID: PMC9910398 DOI: 10.1093/genetics/iyac161] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 10/05/2022] [Indexed: 11/13/2022] Open
Abstract
Seed size is related to plant evolution and crop yield and is affected by genetic mutations, imprinting, and genome dosage. Imprinting is a widespread epigenetic phenomenon in mammals and flowering plants. ETHYLENE INSENSITIVE2 (EIN2) encodes a membrane protein that links the ethylene perception to transcriptional regulation. Interestingly, during seed development EIN2 is maternally expressed in Arabidopsis and maize, but the role of EIN2 in seed development is unknown. Here, we show that EIN2 is expressed specifically in the endosperm, and the maternal-specific EIN2 expression affects temporal regulation of endosperm cellularization. As a result, seed size increases in the genetic cross using the ein2 mutant as the maternal parent or in the ein2 mutant. The maternal-specific expression of EIN2 in the endosperm is controlled by DNA methylation but not by H3K27me3 or by ethylene and several ethylene pathway genes tested. RNA-seq analysis in the endosperm isolated by laser-capture microdissection show upregulation of many endosperm-expressed genes such as AGAMOUS-LIKEs (AGLs) in the ein2 mutant or when the maternal EIN2 allele is not expressed. EIN2 does not interact with DNA and may act through ETHYLENE INSENSITIVE3 (EIN3), a DNA-binding protein present in sporophytic tissues, to activate target genes like AGLs, which in turn mediate temporal regulation of endosperm cellularization and seed size. These results provide mechanistic insights into endosperm and maternal-specific expression of EIN2 on endosperm cellularization and seed development, which could help improve seed production in plants and crops.
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Affiliation(s)
- Atsumi Ando
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Ryan C Kirkbride
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Hong Qiao
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Z Jeffrey Chen
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
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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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Paczesniak D, Pellino M, Goertzen R, Guenter D, Jahnke S, Fischbach A, Lovell JT, Sharbel TF. Seed size, endosperm and germination variation in sexual and apomictic Boechera. FRONTIERS IN PLANT SCIENCE 2022; 13:991531. [PMID: 36466233 PMCID: PMC9716183 DOI: 10.3389/fpls.2022.991531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 10/26/2022] [Indexed: 06/17/2023]
Abstract
Asexual reproduction results in offspring that are genetically identical to the mother. Among apomictic plants (reproducing asexually through seeds) many require paternal genetic contribution for proper endosperm development (pseudogamous endosperm). We examined phenotypic diversity in seed traits using a diverse panel of sexual and apomictic accessions from the genus Boechera. While genetic uniformity resulting from asexual reproduction is expected to reduce phenotypic diversity in seeds produced by apomictic individuals, pseudogamous endosperm, variable endosperm ploidy, and the deviations from 2:1 maternal:paternal genome ratio in endosperm can all contribute to increased phenotypic diversity among apomictic offspring. We characterized seed size variation in 64 diploid sexual and apomictic (diploid and triploid) Boechera lineages. In order to find out whether individual seed size was related to endosperm ploidy we performed individual seed measurements (projected area and mass) using the phenoSeeder robot system and flow cytometric seed screen. In order to test whether individual seed size had an effect on resulting fitness we performed a controlled growth experiment and recorded seedling life history traits (germination success, germination timing, and root growth rate). Seeds with triploid embryos were 33% larger than those with diploid embryos, but no average size difference was found between sexual and apomictic groups. We identified a maternal effect whereby chloroplast lineage 2 had 30% larger seeds than lineage 3, despite having broad and mostly overlapping geographic ranges. Apomictic seeds were not more uniform in size than sexual seeds, despite genetic uniformity of the maternal gametophyte in the former. Among specific embryo/endosperm ploidy combinations, seeds with tetraploid (automomous) endosperm were on average smaller, and the proportion of such seeds was highest in apomicts. Larger seeds germinated more quickly than small seeds, and lead to higher rates of root growth in young seedlings. Seed mass is under balancing selection in Boechera, and it is an important predictor of several traits, including germination probability and timing, root growth rates, and developmental abnormalities in apomictic accessions.
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Affiliation(s)
- Dorota Paczesniak
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Marco Pellino
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Richard Goertzen
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
| | - Devan Guenter
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
| | - Siegfried Jahnke
- Forschungszentrum Jülich, Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Jülich, Germany
| | - Andreas Fischbach
- Forschungszentrum Jülich, Institute of Bio- and Geosciences, IBG-2: Plant Sciences, Jülich, Germany
| | - John T. Lovell
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
| | - Timothy F. Sharbel
- Global Institute for Food Security (GIFS), University of Saskatchewan, Saskatoon, SK, Canada
- Breeding Research, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
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Li MM, Su QL, Zu JR, Xie L, Wei Q, Guo HR, Chen J, Zeng RZ, Zhang ZS. Triploid cultivars of Cymbidium act as a bridge in the formation of polyploid plants. FRONTIERS IN PLANT SCIENCE 2022; 13:1029915. [PMID: 36684754 PMCID: PMC9853991 DOI: 10.3389/fpls.2022.1029915] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Accepted: 09/23/2022] [Indexed: 06/17/2023]
Abstract
Triploid is considered a reproductive barrier and also a bridge in the formation of polyploids. However, few reports are available in Cymbidium. In this study, diploid 'Xiaofeng', sexual triploid 'Yuchan' and 'Huanghe' of Cymbidium were used to evaluate hybridization compatibility of the triploids. Results showed that the sexual triploids were fertile whether they were used as male or female parents. 'Yuchan' produced male gametes of 1x, 1x~2x, 2x, 2x~3x, and 3x at frequencies of 8.89%, 77.78%, 6.67%, 3.33%, and 3.33%, respectively; while 'Huanghe' produced 3.33% 1x, 80.00% 1x~2x, 8.89% 2x, 5.56% 2x~3x, and 2.22% 3x male gametes. The cross of 'Xiaofeng' with 'Yuchan' produced progenies with a wide range of ploidy levels, including one diploid, 34 2×~3× aneuploids, 12 triploids, and one tetraploid, indicating that male gametes produced by sexual triploid were fertile and could be transmitted and fused with egg cells. On the other hand, 10 progenies obtained from the cross of 'Yuchan' × 'Xiaofeng' were all aneuploids. The cross of 'Yuchan' with 'Huanghe' produced 40 progenies including three 2×~3× aneuploids, nine 3×~4× aneuploids, 21 tetraploids, six 4×~5× aneuploids, and one pentaploid, suggesting that 2x gametes, instead of the unreduced ones played a more important role in the formation of tetraploids. The survival rates of the hybrids were all above 80.00%, with the tetraploids at 96.67%. Cytological analysis revealed that during meiosis of sexual polyploids, two chromosome sets of the 2n gamete were inclined to enter into the same daughter cell, resulting in the production of 2x gametes. Our results indicate that the triploid cymbidiums are not reproductive barrier but serve as a bridge in the formation of polyploid plants.
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Affiliation(s)
- Man-Man Li
- Guangdong Province Key Laboratory of Plant Molecular Breeding, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Qing-Lian Su
- Guangzhou Flower Research Center, Guangzhou, China
| | - Jun-Rui Zu
- Guangdong Province Key Laboratory of Plant Molecular Breeding, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Li Xie
- Guangdong Province Key Laboratory of Plant Molecular Breeding, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Qian Wei
- Guangdong Province Key Laboratory of Plant Molecular Breeding, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - He-Rong Guo
- Guangdong Province Key Laboratory of Plant Molecular Breeding, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Jianjun Chen
- Mid-Florida Research and Education Center, Environmental Horticulture Department, Institute of Food and Agricultural Sciences, University of Florida, Apopka, FL, United States
| | - Rui-Zhen Zeng
- Guangdong Province Key Laboratory of Plant Molecular Breeding, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
| | - Zhi-Sheng Zhang
- Guangdong Province Key Laboratory of Plant Molecular Breeding, College of Forestry and Landscape Architecture, South China Agricultural University, Guangzhou, China
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12
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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: 0] [Impact Index Per Article: 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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13
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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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14
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RNA Pol IV induces antagonistic parent-of-origin effects on Arabidopsis endosperm. PLoS Biol 2022; 20:e3001602. [PMID: 35389984 PMCID: PMC9017945 DOI: 10.1371/journal.pbio.3001602] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 04/19/2022] [Accepted: 03/11/2022] [Indexed: 12/14/2022] Open
Abstract
Gene expression in endosperm-a seed tissue that mediates transfer of maternal resources to offspring-is under complex epigenetic control. We show here that plant-specific RNA polymerase IV (Pol IV) mediates parental control of endosperm gene expression. Pol IV is required for the production of small interfering RNAs that typically direct DNA methylation. We compared small RNAs (sRNAs), DNA methylation, and mRNAs in Arabidopsis thaliana endosperm from heterozygotes produced by reciprocally crossing wild-type (WT) plants to Pol IV mutants. We find that maternally and paternally acting Pol IV induce distinct effects on endosperm. Loss of maternal or paternal Pol IV impacts sRNAs and DNA methylation at different genomic sites. Strikingly, maternally and paternally acting Pol IV have antagonistic impacts on gene expression at some loci, divergently promoting or repressing endosperm gene expression. Antagonistic parent-of-origin effects have only rarely been described and are consistent with a gene regulatory system evolving under parental conflict.
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15
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Shivaprakash KN, Bawa KS. The Evolution of Placentation in Flowering Plants: A Possible Role for Kin Selection. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.784077] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Placentation refers to the mode of ovule attachment on the wall of the ovary. In multiovulate ovaries, placentation influences interactions among developing seeds with varying degrees of kinships. Placentation is a taxonomically informative character in flowering plants, yet little has been written about the origin and evolutionary trends of various placentation types in flowering plants since Puri’s and Stebbins’ work, over six decades and almost four decades ago, respectively. More recently, some authors have written about the evolution of placentation in certain groups, but an overall perspective for angiosperms is lacking. For 421 families of angiosperms, we collected data on placentation types and ovule number, and analyzed the data in the phylogenetic context using recent comprehensive phylogeny of angiosperms to test the hypotheses on the evolution of various placentation types and their association with ovule number. The distribution of placentation types across flowering plants suggests that axile placentation, followed by parietal and basal placentation, occurs more frequently than laminar and free central placentation that are very rare. Our results are more consistent with evolutionary trends proposed by Puri than by Stebbins and suggest that marginal placentation is the ancestral and most primitive placentation type, while axile is the most advanced. Placentation types show strong association with ovule number. Finally, our results on ovule number and placentation types indicate that most angiosperms may fall into two categories: one with one or few ovule(s) and basal placentation, and another with many ovules and parietal and axile placentation. Kin selection within ovaries may play a role in explaining the observed patterns. Overall, our results provide new insights into the evolution of placentation, particularly into the drivers underlying the diversification of various placentation types.
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16
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El-Sappah AH, Yan K, Huang Q, Islam MM, Li Q, Wang Y, Khan MS, Zhao X, Mir RR, Li J, El-Tarabily KA, Abbas M. Comprehensive Mechanism of Gene Silencing and Its Role in Plant Growth and Development. FRONTIERS IN PLANT SCIENCE 2021; 12:705249. [PMID: 34589097 PMCID: PMC8475493 DOI: 10.3389/fpls.2021.705249] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 08/10/2021] [Indexed: 05/19/2023]
Abstract
Gene silencing is a negative feedback mechanism that regulates gene expression to define cell fate and also regulates metabolism and gene expression throughout the life of an organism. In plants, gene silencing occurs via transcriptional gene silencing (TGS) and post-transcriptional gene silencing (PTGS). TGS obscures transcription via the methylation of 5' untranslated region (5'UTR), whereas PTGS causes the methylation of a coding region to result in transcript degradation. In this review, we summarized the history and molecular mechanisms of gene silencing and underlined its specific role in plant growth and crop production.
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Affiliation(s)
- Ahmed H. El-Sappah
- School of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, China
- Genetics Department, Faculty of Agriculture, Zagazig University, Zagazig, Egypt
- Key Laboratory of Sichuan Province for Refining Sichuan Tea, Yibin, China
| | - Kuan Yan
- School of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, China
- Key Laboratory of Sichuan Province for Refining Sichuan Tea, Yibin, China
| | - Qiulan Huang
- School of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, China
- Key Laboratory of Sichuan Province for Refining Sichuan Tea, Yibin, China
- College of Tea Science, Yibin University, Yibin, China
| | | | - Quanzi Li
- State Key Laboratory of Tree Genetics and Breeding, Chinese Academy of Forestry, Beijing, China
- Research Institute of Forestry, Chinese Academy of Forestry, Beijing, China
| | - Yu Wang
- School of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, China
- Key Laboratory of Sichuan Province for Refining Sichuan Tea, Yibin, China
| | - Muhammad Sarwar Khan
- Center of Agriculture Biochemistry and Biotechnology, University of Agriculture, Faisalabad, Pakistan
| | - Xianming Zhao
- School of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, China
- Key Laboratory of Sichuan Province for Refining Sichuan Tea, Yibin, China
| | - Reyazul Rouf Mir
- Division of Genetics and Plant Breeding, Faculty of Agriculture (FoA), Sher-e-Kashmir University of Agricultural Sciences and Technology (SKUAST–K), Sopore, India
| | - Jia Li
- School of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, China
- Key Laboratory of Sichuan Province for Refining Sichuan Tea, Yibin, China
| | - Khaled A. El-Tarabily
- Department of Biology, College of Science, United Arab Emirates University, Al-Ain, United Arab Emirates
- Harry Butler Institute, Murdoch University, Murdoch, WA, Australia
| | - Manzar Abbas
- School of Agriculture, Forestry and Food Engineering, Yibin University, Yibin, China
- Key Laboratory of Sichuan Province for Refining Sichuan Tea, Yibin, China
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17
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Kinser TJ, Smith RD, Lawrence AH, Cooley AM, Vallejo-Marín M, Conradi Smith GD, Puzey JR. Endosperm-based incompatibilities in hybrid monkeyflowers. THE PLANT CELL 2021; 33:2235-2257. [PMID: 33895820 PMCID: PMC8364248 DOI: 10.1093/plcell/koab117] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 04/15/2021] [Indexed: 05/31/2023]
Abstract
Endosperm is an angiosperm innovation central to their reproduction whose development, and thus seed viability, is controlled by genomic imprinting, where expression from certain genes is parent-specific. Unsuccessful imprinting has been linked to failed inter-specific and inter-ploidy hybridization. Despite their importance in plant speciation, the underlying mechanisms behind these endosperm-based barriers remain poorly understood. Here, we describe one such barrier between diploid Mimulus guttatus and tetraploid Mimulus luteus. The two parents differ in endosperm DNA methylation, expression dynamics, and imprinted genes. Hybrid seeds suffer from underdeveloped endosperm, reducing viability, or arrested endosperm and seed abortion when M. guttatus or M. luteus is seed parent, respectively, and transgressive methylation and expression patterns emerge. The two inherited M. luteus subgenomes, genetically distinct but epigenetically similar, are expressionally dominant over the M. guttatus genome in hybrid embryos and especially their endosperm, where paternal imprints are perturbed. In aborted seeds, de novo methylation is inhibited, potentially owing to incompatible paternal instructions of imbalanced dosage from M. guttatus imprints. We suggest that diverged epigenetic/regulatory landscapes between parental genomes induce epigenetic repatterning and global shifts in expression, which, in endosperm, may uniquely facilitate incompatible interactions between divergent imprinting schemes, potentially driving rapid barriers.
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Affiliation(s)
- Taliesin J. Kinser
- Biology Department, College of William and Mary, Williamsburg, Virginia 23185
| | - Ronald D. Smith
- Department of Applied Science, College of William and Mary, Williamsburg, Virginia 23185
| | - Amelia H. Lawrence
- Biology Department, College of William and Mary, Williamsburg, Virginia 23185
| | | | - Mario Vallejo-Marín
- Biological and Environmental Sciences, Faculty of Natural Sciences, University of Stirling, Stirling, Scotland FK9 4LA, UK
| | | | - Joshua R. Puzey
- Biology Department, College of William and Mary, Williamsburg, Virginia 23185
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18
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Elattar MA, Karikari B, Li S, Song S, Cao Y, Aslam M, Hina A, Abou-Elwafa SF, Zhao T. Identification and Validation of Major QTLs, Epistatic Interactions, and Candidate Genes for Soybean Seed Shape and Weight Using Two Related RIL Populations. Front Genet 2021; 12:666440. [PMID: 34122518 PMCID: PMC8195344 DOI: 10.3389/fgene.2021.666440] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 03/29/2021] [Indexed: 11/13/2022] Open
Abstract
Understanding the genetic mechanism underlying seed size, shape, and weight is essential for enhancing soybean cultivars. High-density genetic maps of two recombinant inbred line (RIL) populations, LM6 and ZM6, were evaluated across multiple environments to identify and validate M-QTLs as well as identify candidate genes behind major and stable quantitative trait loci (QTLs). A total of 239 and 43 M-QTLs were mapped by composite interval mapping (CIM) and mixed-model-based composite interval mapping (MCIM) approaches, from which 180 and 18, respectively, are novel QTLs. Twenty-two QTLs including four novel major QTLs were validated in the two RIL populations across multiple environments. Moreover, 18 QTLs showed significant AE effects, and 40 pairwise of the identified QTLs exhibited digenic epistatic effects. Thirty-four QTLs associated with seed flatness index (FI) were identified and reported here for the first time. Seven QTL clusters comprising several QTLs for seed size, shape, and weight on genomic regions of chromosomes 3, 4, 5, 7, 9, 17, and 19 were identified. Gene annotations, gene ontology (GO) enrichment, and RNA-seq analyses of the genomic regions of those seven QTL clusters identified 47 candidate genes for seed-related traits. These genes are highly expressed in seed-related tissues and nodules, which might be deemed as potential candidate genes regulating the seed size, weight, and shape traits in soybean. This study provides detailed information on the genetic basis of the studied traits and candidate genes that could be efficiently implemented by soybean breeders for fine mapping and gene cloning, and for marker-assisted selection (MAS) targeted at improving these traits individually or concurrently.
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Affiliation(s)
- Mahmoud A Elattar
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetic Improvement of Soybean (Ministry of Agriculture), State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China.,Agronomy Department, Faculty of Agriculture, Minia University, Minia, Egypt
| | - Benjamin Karikari
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetic Improvement of Soybean (Ministry of Agriculture), State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
| | - Shuguang Li
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetic Improvement of Soybean (Ministry of Agriculture), State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
| | - Shiyu Song
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetic Improvement of Soybean (Ministry of Agriculture), State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
| | - Yongce Cao
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetic Improvement of Soybean (Ministry of Agriculture), State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
| | - Muhammed Aslam
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetic Improvement of Soybean (Ministry of Agriculture), State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
| | - Aiman Hina
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetic Improvement of Soybean (Ministry of Agriculture), State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
| | | | - Tuanjie Zhao
- National Center for Soybean Improvement, Key Laboratory of Biology and Genetic Improvement of Soybean (Ministry of Agriculture), State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
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19
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Florez-Rueda AM, Fiscalini F, Roth M, Grossniklaus U, Städler T. Endosperm and Seed Transcriptomes Reveal Possible Roles for Small RNA Pathways in Wild Tomato Hybrid Seed Failure. Genome Biol Evol 2021; 13:6278300. [PMID: 34009298 PMCID: PMC8358227 DOI: 10.1093/gbe/evab107] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/10/2021] [Indexed: 01/10/2023] Open
Abstract
Crosses between the wild tomato species Solanum peruvianum and Solanum chilense result in hybrid seed failure (HSF), characterized by endosperm misdevelopment and embryo arrest. We previously showed that genomic imprinting, the parent-of-origin–dependent expression of alleles, is perturbed in the hybrid endosperm, with many of the normally paternally expressed genes losing their imprinted status. Here, we report transcriptome-based analyses of gene and small RNA (sRNA) expression levels. We identified 2,295 genes and 387 sRNA clusters as differentially expressed when comparing reciprocal hybrid seed to seeds and endosperms from the two within-species crosses. Our analyses uncovered a pattern of overdominance in endosperm gene expression in both hybrid cross directions, in marked contrast to the patterns of sRNA expression in whole seeds. Intriguingly, patterns of increased gene expression resemble the previously reported increased maternal expression proportions in hybrid endosperms. We identified physical clusters of sRNAs; differentially expressed sRNAs exhibit reduced transcript abundance in hybrid seeds of both cross directions. Moreover, sRNAs map to genes coding for key proteins involved in epigenetic regulation of gene expression, suggesting a regulatory feedback mechanism. We describe examples of genes that appear to be targets of sRNA-mediated gene silencing; in these cases, reduced sRNA abundance is concomitant with increased gene expression in hybrid seeds. Our analyses also show that S. peruvianum dominance impacts gene and sRNA expression in hybrid seeds. Overall, our study indicates roles for sRNA-mediated epigenetic regulation in HSF between closely related wild tomato species.
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Affiliation(s)
- Ana Marcela Florez-Rueda
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland.,Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, 8092 Zurich, Switzerland
| | - Flurin Fiscalini
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland
| | - Morgane Roth
- Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, 8092 Zurich, Switzerland
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, 8008 Zurich, Switzerland
| | - Thomas Städler
- Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, 8092 Zurich, Switzerland
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20
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Essential Role of the 14q32 Encoded miRNAs in Endocrine Tumors. Genes (Basel) 2021; 12:genes12050698. [PMID: 34066712 PMCID: PMC8151414 DOI: 10.3390/genes12050698] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Revised: 04/30/2021] [Accepted: 05/05/2021] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND The 14q32 cluster is among the largest polycistronic miRNA clusters. miRNAs encoded here have been implicated in tumorigenesis of multiple organs including endocrine glands. METHODS Critical review of miRNA studies performed in endocrine tumors have been performed. The potential relevance of 14q32 miRNAs through investigating their targets, and integrating the knowledge provided by literature data and bioinformatics predictions have been indicated. RESULTS Pituitary adenoma, papillary thyroid cancer and a particular subset of pheochromocytoma and adrenocortical cancer are characterized by the downregulation of miRNAs encoded by the 14q32 cluster. Pancreas neuroendocrine tumors, most of the adrenocortical cancer and medullary thyroid cancer are particularly distinct, as 14q32 miRNAs were overexpressed. In pheochromocytoma and growth-hormone producing pituitary adenoma, however, both increased and decreased expression of 14q32 miRNAs cluster members were observed. In the background of this phenomenon methodological, technical and biological factors are hypothesized and discussed. The functions of 14q32 miRNAs were also revealed by bioinformatics and literature data mining. CONCLUSIONS 14q32 miRNAs have a significant role in the tumorigenesis of endocrine organs. Regarding their stable expression in the circulation of healthy individuals, further investigation of 14q32 miRNAs could provide a potential for use as biomarkers (diagnostic or prognostic) in endocrine neoplasms.
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21
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Shortlidge EE, Carey SB, Payton AC, McDaniel SF, Rosenstiel TN, Eppley SM. Microarthropod contributions to fitness variation in the common moss Ceratodon purpureus. Proc Biol Sci 2021; 288:20210119. [PMID: 33784868 PMCID: PMC8059975 DOI: 10.1098/rspb.2021.0119] [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] [Indexed: 01/20/2023] Open
Abstract
The evolution of sustained plant–animal interactions depends critically upon genetic variation in the fitness benefits from the interaction. Genetic analyses of such interactions are limited to a few model systems, in part because genetic variation may be absent or the interacting species may be experimentally intractable. Here, we examine the role of sperm-dispersing microarthropods in shaping reproduction and genetic variation in mosses. We established experimental mesocosms with known moss genotypes and inferred the parents of progeny from mesocosms with and without microarthropods, using a pooled sequencing approach. Moss reproductive rates increased fivefold in the presence of microarthropods, relative to control mesocosms. Furthermore, the presence of microarthropods increased the total number of reproducing moss genotypes, and changed the rank-order of fitness of male and female moss genotypes. Interestingly, the genotypes that reproduced most frequently did not produce sporophytes with the most spores, highlighting the challenge of defining fitness in mosses. These results demonstrate that microarthropods provide a fitness benefit for mosses, and highlight the potential for biotic dispersal agents to alter fitness among moss genotypes.
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Affiliation(s)
- Erin E Shortlidge
- Department of Biology, Portland State University, PO Box 751, Portland, OR 97202-0751, USA
| | - Sarah B Carey
- Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611-8525, USA
| | - Adam C Payton
- Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611-8525, USA
| | - Stuart F McDaniel
- Department of Biology, University of Florida, PO Box 118525, Gainesville, FL 32611-8525, USA
| | - Todd N Rosenstiel
- Department of Biology, Portland State University, PO Box 751, Portland, OR 97202-0751, USA
| | - Sarah M Eppley
- Department of Biology, Portland State University, PO Box 751, Portland, OR 97202-0751, USA
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22
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Patten MM. On Being a Monkey's Uncle: Germline Chimerism in the Callitrichinae and the Evolution of Sibling Rivalry. Am Nat 2021; 197:502-508. [PMID: 33755537 DOI: 10.1086/713110] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
AbstractA typical monkey of the subfamily Callitrichinae has two or more cell lineages occupying its tissues: one from "itself," and one from its co-twin(s). Chimerism originates in utero when the twin placentae fuse, vascular anastomoses form between them, and cells are exchanged between conceptuses through their shared circulation. Previously it was thought that chimerism was limited to tissues of the hematopoietic cell lineage and that the germline was clonal, but subsequent empirical work has shown that chimerism may extend to many tissues, including the germline. To explore how natural selection on chimeric organisms should shape their social behavior, I construct an inclusive fitness model of sibling interactions that permits differing degrees of chimerism in the soma and germline. The model predicts that somatic chimerism should diminish sibling rivalry but that germline chimerism should typically intensify it. A further implication of the model is the possibility for intraorganismal conflict over developing phenotypes; as tissues may differ in their extent of chimerism-for example, placenta versus brain-their respective inclusive fitness may be maximized by different phenotypes. Communication between tissues in chimeric organisms might therefore be noisy, rapidly evolving, and fraught, as is common in systems with internal evolutionary conflicts of interest.
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23
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Tonosaki K, Ono A, Kunisada M, Nishino M, Nagata H, Sakamoto S, Kijima ST, Furuumi H, Nonomura KI, Sato Y, Ohme-Takagi M, Endo M, Comai L, Hatakeyama K, Kawakatsu T, Kinoshita T. Mutation of the imprinted gene OsEMF2a induces autonomous endosperm development and delayed cellularization in rice. THE PLANT CELL 2021; 33:85-103. [PMID: 33751094 PMCID: PMC8136911 DOI: 10.1093/plcell/koaa006] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2020] [Accepted: 10/29/2020] [Indexed: 05/22/2023]
Abstract
In angiosperms, endosperm development comprises a series of developmental transitions controlled by genetic and epigenetic mechanisms that are initiated after double fertilization. Polycomb repressive complex 2 (PRC2) is a key component of these mechanisms that mediate histone H3 lysine 27 trimethylation (H3K27me3); the action of PRC2 is well described in Arabidopsis thaliana but remains uncertain in cereals. In this study, we demonstrate that mutation of the rice (Oryza sativa) gene EMBRYONIC FLOWER2a (OsEMF2a), encoding a zinc-finger containing component of PRC2, causes an autonomous endosperm phenotype involving proliferation of the central cell nuclei with separate cytoplasmic domains, even in the absence of fertilization. Detailed cytological and transcriptomic analyses revealed that the autonomous endosperm can produce storage compounds, starch granules, and protein bodies specific to the endosperm. These events have not been reported in Arabidopsis. After fertilization, we observed an abnormally delayed developmental transition in the endosperm. Transcriptome and H3K27me3 ChIP-seq analyses using endosperm from the emf2a mutant identified downstream targets of PRC2. These included >100 transcription factor genes such as type-I MADS-box genes, which are likely required for endosperm development. Our results demonstrate that OsEMF2a-containing PRC2 controls endosperm developmental programs before and after fertilization.
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Affiliation(s)
- Kaoru Tonosaki
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka, Totsuka, Yokohama, Kanagawa 244-0813, Japan
- Department of Plant Biology and Genome Center, University of California, Davis, CA 95616, USA
- Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan
- Author for correspondence: (T.Ki.), (K.T.)
| | - Akemi Ono
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka, Totsuka, Yokohama, Kanagawa 244-0813, Japan
| | - Megumi Kunisada
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka, Totsuka, Yokohama, Kanagawa 244-0813, Japan
| | - Megumi Nishino
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka, Totsuka, Yokohama, Kanagawa 244-0813, Japan
| | - Hiroki Nagata
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka, Totsuka, Yokohama, Kanagawa 244-0813, Japan
| | - Shingo Sakamoto
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8562, Japan
| | - Saku T Kijima
- Bioproduction Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8562, Japan
| | - Hiroyasu Furuumi
- Genetic Strains Research Center, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Ken-Ichi Nonomura
- Plant Cytogenetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Yutaka Sato
- Genetic Strains Research Center, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan
| | - Masaru Ohme-Takagi
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan
| | - Masaki Endo
- Division of Applied Genetics, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8602, Japan
| | - Luca Comai
- Department of Plant Biology and Genome Center, University of California, Davis, CA 95616, USA
| | - Katsunori Hatakeyama
- Faculty of Agriculture, Iwate University, 3-18-8 Ueda, Morioka, Iwate 020-8550, Japan
| | - Taiji Kawakatsu
- Division of Biotechnology, Institute of Agrobiological Sciences, National Agriculture and Food Research Organization, Tsukuba, Ibaraki 305-8602, Japan
| | - Tetsu Kinoshita
- Kihara Institute for Biological Research, Yokohama City University, 641-12 Maioka, Totsuka, Yokohama, Kanagawa 244-0813, Japan
- Author for correspondence: (T.Ki.), (K.T.)
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24
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Paolo D, Rotasperti L, Schnittger A, Masiero S, Colombo L, Mizzotti C. The Arabidopsis MADS-Domain Transcription Factor SEEDSTICK Controls Seed Size via Direct Activation of E2Fa. PLANTS 2021; 10:plants10020192. [PMID: 33498552 PMCID: PMC7909557 DOI: 10.3390/plants10020192] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 01/08/2021] [Accepted: 01/16/2021] [Indexed: 02/06/2023]
Abstract
Seed size is the result of complex molecular networks controlling the development of the seed coat (of maternal origin) and the two fertilization products, the embryo and the endosperm. In this study we characterized the role of Arabidopsis thaliana MADS-domain transcription factor SEEDSTICK (STK) in seed size control. STK is known to regulate the differentiation of the seed coat as well as the structural and mechanical properties of cell walls in developing seeds. In particular, we further characterized stk mutant seeds. Genetic evidence (reciprocal crosses) of the inheritance of the small-seed phenotype, together with the provided analysis of cell division activity (flow cytometry), demonstrate that STK acts in the earlier phases of seed development as a maternal activator of growth. Moreover, we describe a molecular mechanism underlying this activity by reporting how STK positively regulates cell cycle progression via directly activating the expression of E2Fa, a key regulator of the cell cycle. Altogether, our results unveil a new genetic network active in the maternal control of seed size in Arabidopsis.
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Affiliation(s)
- Dario Paolo
- Dipartimento di BioScienze, Università degli Studi di Milano, 20133 Milano, Italy; (D.P.); (L.R.); (S.M.); (L.C.)
| | - Lisa Rotasperti
- Dipartimento di BioScienze, Università degli Studi di Milano, 20133 Milano, Italy; (D.P.); (L.R.); (S.M.); (L.C.)
| | - Arp Schnittger
- Abteilung für Entwicklungsbiologie, Institut für Pflanzenforschung und Mikrobiologie, Universität Hamburg, 22609 Hamburg, Germany;
| | - Simona Masiero
- Dipartimento di BioScienze, Università degli Studi di Milano, 20133 Milano, Italy; (D.P.); (L.R.); (S.M.); (L.C.)
| | - Lucia Colombo
- Dipartimento di BioScienze, Università degli Studi di Milano, 20133 Milano, Italy; (D.P.); (L.R.); (S.M.); (L.C.)
| | - Chiara Mizzotti
- Dipartimento di BioScienze, Università degli Studi di Milano, 20133 Milano, Italy; (D.P.); (L.R.); (S.M.); (L.C.)
- Correspondence: ; Tel.: +39-02-503-14838
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25
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Yang L, Xing F, He Q, Tahir ul Qamar M, Chen LL, Xing Y. Conserved Imprinted Genes between Intra-Subspecies and Inter-Subspecies Are Involved in Energy Metabolism and Seed Development in Rice. Int J Mol Sci 2020; 21:ijms21249618. [PMID: 33348666 PMCID: PMC7765902 DOI: 10.3390/ijms21249618] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/10/2020] [Accepted: 12/16/2020] [Indexed: 01/28/2023] Open
Abstract
Genomic imprinting is an epigenetic phenomenon in which a subset of genes express dependent on the origin of their parents. In plants, it is unclear whether imprinted genes are conserved between subspecies in rice. Here we identified imprinted genes from embryo and endosperm 5-7 days after pollination from three pairs of reciprocal hybrids, including inter-subspecies, japonica intra-subspecies, and indica intra-subspecies reciprocal hybrids. A total of 914 imprinted genes, including 546 in inter-subspecies hybrids, 211 in japonica intra-subspecies hybrids, and 286 in indica intra-subspecies hybrids. In general, the number of maternally expressed genes (MEGs) is more than paternally expressed genes (PEGs). Moreover, imprinted genes tend to be in mini clusters. The number of shared genes by R9N (reciprocal crosses between 9311 and Nipponbare) and R9Z (reciprocal crosses between 9311 and Zhenshan 97), R9N and RZN (reciprocal crosses between Zhonghua11 and Nipponbare), R9Z and RZN was 72, 46, and 16. These genes frequently involved in energy metabolism and seed development. Five imprinted genes (Os01g0151700, Os07g0103100, Os10g0340600, Os11g0679700, and Os12g0632800) are commonly detected in all three pairs of reciprocal hybrids and were validated by RT-PCR sequencing. Gene editing of two imprinted genes revealed that both genes conferred grain filling. Moreover, 15 and 27 imprinted genes with diverse functions in rice were shared with Arabidopsis and maize, respectively. This study provided valuable resources for identification of imprinting genes in rice or even in cereals.
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Affiliation(s)
- Lin Yang
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; (L.Y.); (Q.H.)
| | - Feng Xing
- College of Life Science, Xinyang Normal University, Xinyang 464000, China;
| | - Qin He
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; (L.Y.); (Q.H.)
| | - Muhammad Tahir ul Qamar
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, College of Life Science and Technology, Guangxi University, Nanning 530004, China;
| | - Ling-Ling Chen
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; (L.Y.); (Q.H.)
- Correspondence: (L.-L.C.); (Y.X.)
| | - Yongzhong Xing
- National Key Laboratory of Crop Genetic Improvement, Huazhong Agricultural University, Wuhan 430070, China; (L.Y.); (Q.H.)
- Correspondence: (L.-L.C.); (Y.X.)
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26
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27
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Kordyum EL, Mosyakin SL. Endosperm of Angiosperms and Genomic Imprinting. Life (Basel) 2020; 10:E104. [PMID: 32635326 PMCID: PMC7400472 DOI: 10.3390/life10070104] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Revised: 06/28/2020] [Accepted: 06/29/2020] [Indexed: 12/15/2022] Open
Abstract
Modern ideas about the role of epigenetic systems in the regulation of gene expression allow us to understand the mechanisms of vital activities in plants, such as genomic imprinting. It is important that genomic imprinting is known first and foremost for the endosperm, which not only provides an embryo with necessary nutrients, but also plays a special biological role in the formation of seeds and fruits. Available data on genomic imprinting in the endosperm have been obtained only for the triploid endosperm in model plants, which develops after double fertilization in a Polygonum-type embryo sac, the most common type among angiosperms. Here we provide a brief overview of a wide diversity of embryo sacs and endosperm types and ploidy levels, as well as their distribution in the angiosperm families, positioned according to the Angiosperm Phylogeny Group IV (APG IV) phylogenetic classification. Addition of the new, non-model taxa to study gene imprinting in seed development will extend our knowledge about the epigenetic mechanisms underlying angiosperm fertility.
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Affiliation(s)
- Elizabeth L. Kordyum
- Institute of Botany, National Academy of Sciences of Ukraine, 01004 Kyiv, Ukraine; or
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28
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Hitchcock TJ, Paracchini S, Gardner A. Genomic Imprinting As a Window into Human Language Evolution. Bioessays 2020; 41:e1800212. [PMID: 31132171 DOI: 10.1002/bies.201800212] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 03/22/2019] [Indexed: 01/20/2023]
Abstract
Humans spend large portions of their time and energy talking to one another, yet it remains unclear whether this activity is primarily selfish or altruistic. Here, it is shown how parent-of-origin specific gene expression-or "genomic imprinting"-may provide an answer to this question. First, it is shown why, regarding language, only altruistic or selfish scenarios are expected. Second, it is pointed out that an individual's maternal-origin and paternal-origin genes may have different evolutionary interests regarding investment into language, and that this intragenomic conflict may drive genomic imprinting which-as the direction of imprint depends upon whether investment into language is relatively selfish or altruistic-may be used to discriminate between these two possibilities. Third, predictions concerning the impact of various mutations and epimutations at imprinted loci on language pathologies are derived. In doing so, a framework is developed that highlights avenues for using intragenomic conflicts to investigate the evolutionary drivers of language.
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Affiliation(s)
- Thomas J Hitchcock
- School of Biology, University of St Andrews, Dyers Brae, St Andrews, KY16 9TH, UK
| | - Silvia Paracchini
- School of Medicine, University of St Andrews, North Haugh, St Andrews, KY16 9TF, UK
| | - Andy Gardner
- School of Biology, University of St Andrews, Dyers Brae, St Andrews, KY16 9TH, UK
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29
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Hina A, Cao Y, Song S, Li S, Sharmin RA, Elattar MA, Bhat JA, Zhao T. High-Resolution Mapping in Two RIL Populations Refines Major "QTL Hotspot" Regions for Seed Size and Shape in Soybean ( Glycine max L.). Int J Mol Sci 2020; 21:E1040. [PMID: 32033213 PMCID: PMC7038151 DOI: 10.3390/ijms21031040] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2019] [Revised: 01/30/2020] [Accepted: 02/01/2020] [Indexed: 01/10/2023] Open
Abstract
Seed size and shape are important traits determining yield and quality in soybean. However, the genetic mechanism and genes underlying these traits remain largely unexplored. In this regard, this study used two related recombinant inbred line (RIL) populations (ZY and K3N) evaluated in multiple environments to identify main and epistatic-effect quantitative trait loci (QTLs) for six seed size and shape traits in soybean. A total of 88 and 48 QTLs were detected through composite interval mapping (CIM) and mixed-model-based composite interval mapping (MCIM), respectively, and 15 QTLs were common among both methods; two of them were major (R2 > 10%) and novel QTLs (viz., qSW-1-1ZN and qSLT-20-1K3N). Additionally, 51 and 27 QTLs were identified for the first time through CIM and MCIM methods, respectively. Colocalization of QTLs occurred in four major QTL hotspots/clusters, viz., "QTL Hotspot A", "QTL Hotspot B", "QTL Hotspot C", and "QTL Hotspot D" located on Chr06, Chr10, Chr13, and Chr20, respectively. Based on gene annotation, gene ontology (GO) enrichment, and RNA-Seq analysis, 23 genes within four "QTL Hotspots" were predicted as possible candidates, regulating soybean seed size and shape. Network analyses demonstrated that 15 QTLs showed significant additive x environment (AE) effects, and 16 pairs of QTLs showing epistatic effects were also detected. However, except three epistatic QTLs, viz., qSL-13-3ZY, qSL-13-4ZY, and qSW-13-4ZY, all the remaining QTLs depicted no main effects. Hence, the present study is a detailed and comprehensive investigation uncovering the genetic basis of seed size and shape in soybeans. The use of a high-density map identified new genomic regions providing valuable information and could be the primary target for further fine mapping, candidate gene identification, and marker-assisted breeding (MAB).
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Affiliation(s)
- Aiman Hina
- Ministry of Agriculture (MOA) Key Laboratory of Biology and Genetic Improvement of Soybean (General), State Key Laboratory for Crop Genetics and Germplasm Enhancement, Soybean Research Institute, National Center for Soybean Improvement, Nanjing Agricultural University, Nanjing 210095, China; (A.H.); (S.S.); (S.L.); (R.A.S.); (M.A.E.)
| | - Yongce Cao
- Shaanxi Key Laboratory of Chinese Jujube; College of Life Science, Yan’an University, Yan’an 716000, China;
| | - Shiyu Song
- Ministry of Agriculture (MOA) Key Laboratory of Biology and Genetic Improvement of Soybean (General), State Key Laboratory for Crop Genetics and Germplasm Enhancement, Soybean Research Institute, National Center for Soybean Improvement, Nanjing Agricultural University, Nanjing 210095, China; (A.H.); (S.S.); (S.L.); (R.A.S.); (M.A.E.)
| | - Shuguang Li
- Ministry of Agriculture (MOA) Key Laboratory of Biology and Genetic Improvement of Soybean (General), State Key Laboratory for Crop Genetics and Germplasm Enhancement, Soybean Research Institute, National Center for Soybean Improvement, Nanjing Agricultural University, Nanjing 210095, China; (A.H.); (S.S.); (S.L.); (R.A.S.); (M.A.E.)
| | - Ripa Akter Sharmin
- Ministry of Agriculture (MOA) Key Laboratory of Biology and Genetic Improvement of Soybean (General), State Key Laboratory for Crop Genetics and Germplasm Enhancement, Soybean Research Institute, National Center for Soybean Improvement, Nanjing Agricultural University, Nanjing 210095, China; (A.H.); (S.S.); (S.L.); (R.A.S.); (M.A.E.)
| | - Mahmoud A. Elattar
- Ministry of Agriculture (MOA) Key Laboratory of Biology and Genetic Improvement of Soybean (General), State Key Laboratory for Crop Genetics and Germplasm Enhancement, Soybean Research Institute, National Center for Soybean Improvement, Nanjing Agricultural University, Nanjing 210095, China; (A.H.); (S.S.); (S.L.); (R.A.S.); (M.A.E.)
| | - Javaid Akhter Bhat
- Ministry of Agriculture (MOA) Key Laboratory of Biology and Genetic Improvement of Soybean (General), State Key Laboratory for Crop Genetics and Germplasm Enhancement, Soybean Research Institute, National Center for Soybean Improvement, Nanjing Agricultural University, Nanjing 210095, China; (A.H.); (S.S.); (S.L.); (R.A.S.); (M.A.E.)
| | - Tuanjie Zhao
- Ministry of Agriculture (MOA) Key Laboratory of Biology and Genetic Improvement of Soybean (General), State Key Laboratory for Crop Genetics and Germplasm Enhancement, Soybean Research Institute, National Center for Soybean Improvement, Nanjing Agricultural University, Nanjing 210095, China; (A.H.); (S.S.); (S.L.); (R.A.S.); (M.A.E.)
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30
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Abstract
Transcriptomic studies have proven powerful and effective as a tool to study the molecular underpinnings of plant development. Still, it remains challenging to disentangle cell- or tissue-specific transcriptomes in complex structures like the plant seed. In particular, the embryo of flowering plants is embedded in the endosperm, a nurturing tissue, which, in turn, is enclosed by the maternal seed coat. Here, we describe laser-assisted microdissection (LAM) to isolate highly pure embryo tissue from whole seeds. This technique is applicable to virtually any plant seed, and we illustrate the use of LAM to isolate embryos from species of the Boechera and Solanum genera. LAM is a tool that will greatly help to increase the repertoires of tissue-specific transcriptomes, including those of embryos and parts thereof, in nonmodel plants.
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31
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Ingram GC. Family plot: the impact of the endosperm and other extra-embryonic seed tissues on angiosperm zygotic embryogenesis. F1000Res 2020; 9. [PMID: 32055398 PMCID: PMC6961419 DOI: 10.12688/f1000research.21527.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/10/2020] [Indexed: 12/22/2022] Open
Abstract
The zygotic embryos of angiosperms develop buried deep within seeds and surrounded by two main extra-embryonic tissues: the maternally derived seed coat tissues and the zygotic endosperm. Generally, these tissues are considered to play an important role in nurturing the developing embryo by acting as conduits for maternally derived nutrients. They are also critical for key seed traits (dormancy establishment and control, longevity, and physical resistance) and thus for seed and seedling survival. However, recent studies have highlighted the fact that extra-embryonic tissues in the seed also physically and metabolically limit embryonic development and that unique mechanisms may have evolved to overcome specific developmental and genetic constraints associated with the seed habit in angiosperms. The aim of this review is to illustrate how these studies have begun to reveal the highly complex physical and physiological relationship between extra-embryonic tissues and the developing embryo. Where possible I focus on Arabidopsis because of space constraints, but other systems will be cited where relevant.
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Affiliation(s)
- Gwyneth C Ingram
- Laboratoire Reproduction et Développement des Plantes, University of Lyon, ENS de Lyon, UCB Lyon 1, CNRS, INRAE, Lyon, France
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32
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Mainieri A, Haig D. Retrotransposon gag-like 1 (RTL1) and the molecular evolution of self-targeting imprinted microRNAs. Biol Direct 2019; 14:18. [PMID: 31640745 PMCID: PMC6805670 DOI: 10.1186/s13062-019-0250-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2019] [Accepted: 09/26/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Transcription of the antisense strand of RTL1 produces a sense mRNA that is targeted for degradation by antisense microRNAs transcribed from the sense strand. Translation of the mRNA produces a retrotransposon-derived protein that is implicated in placental development. The sense and antisense transcripts are oppositely imprinted: sense mRNAs are expressed from the paternally-derived chromosome, antisense microRNAs from the maternally-derived chromosome. RESULTS Two microRNAs at the RTL1 locus, miR-431 and the rodent-specific miR-434, are derived from within tandem repeats. We present an evolutionary model for the establishment of a new self-targeting microRNA derived from within a tandem repeat that inhibits production of RTL1 protein when maternally-derived in heterozygotes but not when paternally-derived. CONCLUSIONS The interaction of sense and antisense transcripts can be interpreted as a form of communication between maternally-derived and paternally-derived RTL1 alleles that possesses many of the features of a greenbeard effect. This interaction is evolutionary stable, unlike a typical greenbeard effect, because of the necessary complementarity between microRNAs and mRNA transcribed from opposite strands of the same double helix. We conjecture that microRNAs and mRNA cooperate to reduce demands on mothers when an allele is paired with itself in homozygous offspring. REVIEWERS This article was reviewed by Eugene Berezikov and Bernard Crespi.
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Affiliation(s)
- Avantika Mainieri
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA
| | - David Haig
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, MA, USA.
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33
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Karikari B, Chen S, Xiao Y, Chang F, Zhou Y, Kong J, Bhat JA, Zhao T. Utilization of Interspecific High-Density Genetic Map of RIL Population for the QTL Detection and Candidate Gene Mining for 100-Seed Weight in Soybean. FRONTIERS IN PLANT SCIENCE 2019; 10:1001. [PMID: 31552060 PMCID: PMC6737081 DOI: 10.3389/fpls.2019.01001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2019] [Accepted: 07/17/2019] [Indexed: 05/26/2023]
Abstract
Seed-weight is one of the most important traits determining soybean yield. Hence, it is prerequisite to have detailed understanding of the genetic basis regulating seed-weight for the development of improved cultivars. In this regard, the present study used high-density interspecific linkage map of NJIR4P recombinant inbred population evaluated in four different environments to detect stable Quantitative trait loci (QTLs) as well as mine candidate genes for 100-seed weight. In total, 19 QTLs distributed on 12 chromosomes were identified in all individual environments plus combined environment, out of which seven were novel and eight are stable identified in more than one environment. However, all the novel QTLs were minor (R 2 < 10%). The remaining 12 QTLs detected in this study were co-localized with the earlier reported QTLs with narrow genomic regions, and out of these only 2 QTLs were major (R 2 > 10%) viz., qSW-17-1 and qSW-17-4. Beneficial alleles of all identified QTLs were derived from cultivated soybean parent (Nannong493-1). Based on Protein ANalysis THrough Evolutionary Relationships, gene annotation information, and literature search, 29 genes within 5 stable QTLs were predicted to be possible candidate genes that might regulate seed-weight/size in soybean. However, it needs further validation to confirm their role in seed development. In conclusion, the present study provides better understanding of trait genetics and candidate gene information through the use high-density inter-specific bin map, and also revealed considerable scope for genetic improvement of 100-seed weight in soybean using marker-assisted breeding.
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Affiliation(s)
| | | | | | | | | | | | - Javaid Akhter Bhat
- Soybean Research Institution, National Center for Soybean Improvement, Key Laboratory of Biology and Genetics and Breeding for Soybean, Ministry of Agriculture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
| | - Tuanjie Zhao
- Soybean Research Institution, National Center for Soybean Improvement, Key Laboratory of Biology and Genetics and Breeding for Soybean, Ministry of Agriculture, State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing, China
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34
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Tuteja R, McKeown PC, Ryan P, Morgan CC, Donoghue MTA, Downing T, O'Connell MJ, Spillane C. Paternally Expressed Imprinted Genes under Positive Darwinian Selection in Arabidopsis thaliana. Mol Biol Evol 2019; 36:1239-1253. [PMID: 30913563 PMCID: PMC6526901 DOI: 10.1093/molbev/msz063] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Genomic imprinting is an epigenetic phenomenon where autosomal genes display uniparental expression depending on whether they are maternally or paternally inherited. Genomic imprinting can arise from parental conflicts over resource allocation to the offspring, which could drive imprinted loci to evolve by positive selection. We investigate whether positive selection is associated with genomic imprinting in the inbreeding species Arabidopsis thaliana. Our analysis of 140 genes regulated by genomic imprinting in the A. thaliana seed endosperm demonstrates they are evolving more rapidly than expected. To investigate whether positive selection drives this evolutionary acceleration, we identified orthologs of each imprinted gene across 34 plant species and elucidated their evolutionary trajectories. Increased positive selection was sought by comparing its incidence among imprinted genes with nonimprinted controls. Strikingly, we find a statistically significant enrichment of imprinted paternally expressed genes (iPEGs) evolving under positive selection, 50.6% of the total, but no such enrichment for positive selection among imprinted maternally expressed genes (iMEGs). This suggests that maternally- and paternally expressed imprinted genes are subject to different selective pressures. Almost all positively selected amino acids were fixed across 80 sequenced A. thaliana accessions, suggestive of selective sweeps in the A. thaliana lineage. The imprinted genes under positive selection are involved in processes important for seed development including auxin biosynthesis and epigenetic regulation. Our findings support a genomic imprinting model for plants where positive selection can affect paternally expressed genes due to continued conflict with maternal sporophyte tissues, even when parental conflict is reduced in predominantly inbreeding species.
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Affiliation(s)
- Reetu Tuteja
- Genetics & Biotechnology Lab, Plant & AgriBiosciences Research Centre (PABC), School of Natural Sciences, Ryan Institute, National University of Ireland Galway, Galway, Ireland.,Center for Genomics and Systems Biology, New York University, New York, NY
| | - Peter C McKeown
- Genetics & Biotechnology Lab, Plant & AgriBiosciences Research Centre (PABC), School of Natural Sciences, Ryan Institute, National University of Ireland Galway, Galway, Ireland
| | - Pat Ryan
- Genetics & Biotechnology Lab, Plant & AgriBiosciences Research Centre (PABC), School of Natural Sciences, Ryan Institute, National University of Ireland Galway, Galway, Ireland
| | - Claire C Morgan
- School of Biotechnology, Faculty of Biological Sciences, Dublin City University, Dublin, Ireland.,Division of Diabetes, Endocrinology and Metabolism, Imperial College London, London, United Kingdom
| | - Mark T A Donoghue
- Genetics & Biotechnology Lab, Plant & AgriBiosciences Research Centre (PABC), School of Natural Sciences, Ryan Institute, National University of Ireland Galway, Galway, Ireland.,Memorial Sloan Kettering Cancer Center, New York, NY
| | - Tim Downing
- School of Biotechnology, Faculty of Biological Sciences, Dublin City University, Dublin, Ireland
| | - Mary J O'Connell
- Computational and Molecular Evolutionary Biology Research Group, School of Biology, Faculty of Biological Sciences, The University of Leeds, Leeds, United Kingdom.,Computational and Molecular Evolutionary Biology Group, School of Life Sciences, University of Nottingham, Nottingham, United Kingdom
| | - Charles Spillane
- Genetics & Biotechnology Lab, Plant & AgriBiosciences Research Centre (PABC), School of Natural Sciences, Ryan Institute, National University of Ireland Galway, Galway, Ireland
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Pignatta D, Novitzky K, Satyaki PRV, Gehring M. A variably imprinted epiallele impacts seed development. PLoS Genet 2018; 14:e1007469. [PMID: 30395602 PMCID: PMC6237401 DOI: 10.1371/journal.pgen.1007469] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 11/15/2018] [Accepted: 10/05/2018] [Indexed: 12/17/2022] Open
Abstract
The contribution of epigenetic variation to phenotypic variation is unclear. Imprinted genes, because of their strong association with epigenetic modifications, represent an opportunity for the discovery of such phenomena. In mammals and flowering plants, a subset of genes are expressed from only one parental allele in a process called gene imprinting. Imprinting is associated with differential DNA methylation and chromatin modifications between parental alleles. In flowering plants imprinting occurs in a seed tissue - endosperm. Proper endosperm development is essential for the production of viable seeds. We previously showed that in Arabidopsis thaliana intraspecific imprinting variation is correlated with naturally occurring DNA methylation polymorphisms. Here, we investigated the mechanisms and function of allele-specific imprinting of the class IV homeodomain leucine zipper (HD-ZIP) transcription factor HDG3. In imprinted strains, HDG3 is expressed primarily from the methylated paternally inherited allele. We manipulated the methylation state of endogenous HDG3 in a non-imprinted strain and demonstrated that methylation of a proximal transposable element is sufficient to promote HDG3 expression and imprinting. Gain of HDG3 imprinting was associated with earlier endosperm cellularization and changes in seed weight. These results indicate that epigenetic variation alone is sufficient to explain imprinting variation and demonstrate that epialleles can underlie variation in seed development phenotypes.
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Affiliation(s)
- Daniela Pignatta
- Whitehead Institute for Biomedical Research, Cambridge, MA, United States of America
| | - Katherine Novitzky
- Whitehead Institute for Biomedical Research, Cambridge, MA, United States of America
| | - P. R. V. Satyaki
- Whitehead Institute for Biomedical Research, Cambridge, MA, United States of America
| | - Mary Gehring
- Whitehead Institute for Biomedical Research, Cambridge, MA, United States of America
- Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, United States of America
- * E-mail:
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38
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Intersexual conflict over seed size is stronger in more outcrossed populations of a mixed-mating plant. Proc Natl Acad Sci U S A 2018; 115:11561-11566. [PMID: 30282740 DOI: 10.1073/pnas.1810979115] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
In polyandrous species, fathers benefit from attracting greater maternal investment toward their offspring at the expense of the offspring of other males, while mothers should usually allocate resources equally among offspring. This conflict can lead to an evolutionary arms race between the sexes, manifested through antagonistic genes whose expression in offspring depends upon the parent of origin. The arms race may involve an increase in the strength of maternally versus paternally derived alleles engaged in a "tug of war" over maternal provisioning or repeated "recognition-avoidance" coevolution where growth-enhancing paternally derived alleles evolve to escape recognition by maternal genes targeted to suppress their effect. Here, we develop predictions to distinguish between these two mechanisms when considering crosses among populations that have reached different equilibria in this intersexual arms race. We test these predictions using crosses within and among populations of Dalechampia scandens (Euphorbiaceae) that presumably have experienced different intensities of intersexual conflict, as inferred from their historical differences in mating system. In crosses where the paternal population was more outcrossed than the maternal population, hybrid seeds were larger than those normally produced in the maternal population, whereas when the maternal population was more outcrossed, hybrid seeds were smaller than normal. These results confirm the importance of mating systems in determining the intensity of intersexual conflict over maternal investment and provide strong support for a tug-of-war mechanism operating in this conflict. They also yield clear predictions for the fitness consequences of gene flow among populations with different mating histories.
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DNA demethylase ROS1 negatively regulates the imprinting of DOGL4 and seed dormancy in Arabidopsis thaliana. Proc Natl Acad Sci U S A 2018; 115:E9962-E9970. [PMID: 30266793 DOI: 10.1073/pnas.1812847115] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Genomic imprinting is a form of epigenetic regulation resulting in differential gene expression that reflects the parent of origin. In plants, imprinted gene expression predominantly occurs in the seed endosperm. Maternal-specific DNA demethylation by the DNA demethylase DME frequently underlies genomic imprinting in endosperm. Whether other more ubiquitously expressed DNA demethylases regulate imprinting is unknown. Here, we found that the DNA demethylase ROS1 regulates the imprinting of DOGL4 DOGL4 is expressed from the maternal allele in endosperm and displays preferential methylation and suppression of the paternal allele. We found that ROS1 negatively regulates imprinting by demethylating the paternal allele, preventing its hypermethylation and complete silencing. Furthermore, we found that DOGL4 negatively affects seed dormancy and response to the phytohormone abscisic acid and that ROS1 controls these processes by regulating DOGL4 Our results reveal roles for ROS1 in mitigating imprinted gene expression and regulating seed dormancy.
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Roth M, Florez-Rueda AM, Paris M, Städler T. Wild tomato endosperm transcriptomes reveal common roles of genomic imprinting in both nuclear and cellular endosperm. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 95:1084-1101. [PMID: 29953688 DOI: 10.1111/tpj.14012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 06/01/2018] [Accepted: 06/20/2018] [Indexed: 05/06/2023]
Abstract
Genomic imprinting is a conspicuous feature of the endosperm, a triploid tissue nurturing the embryo and synchronizing angiosperm seed development. An unknown subset of imprinted genes (IGs) is critical for successful seed development and should have highly conserved functions. Recent genome-wide studies have found limited conservation of IGs among distantly related species, but there is a paucity of data from closely related lineages. Moreover, most studies focused on model plants with nuclear endosperm development, and comparisons with properties of IGs in cellular-type endosperm development are lacking. Using laser-assisted microdissection, we characterized parent-specific expression in the cellular endosperm of three wild tomato lineages (Solanum section Lycopersicon). We identified 1025 candidate IGs and 167 with putative homologs previously identified as imprinted in distantly related taxa with nuclear-type endosperm. Forty-two maternally expressed genes (MEGs) and 17 paternally expressed genes (PEGs) exhibited conserved imprinting status across all three lineages, but differences in power to assess imprinted expression imply that the actual degree of conservation might be higher than that directly estimated (20.7% for PEGs and 10.4% for MEGs). Regardless, the level of shared imprinting status was higher for PEGs than for MEGs, indicating dissimilar evolutionary trajectories. Expression-level data suggest distinct epigenetic modulation of MEGs and PEGs, and gene ontology analyses revealed MEGs and PEGs to be enriched for different functions. Importantly, our data provide evidence that MEGs and PEGs interact in modulating both gene expression and the endosperm cell cycle, and uncovered conserved cellular functions of IGs uniting taxa with cellular- and nuclear-type endosperm.
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Affiliation(s)
- Morgane Roth
- Plant Ecological Genetics, Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, 8092, Zurich, Switzerland
| | - Ana M Florez-Rueda
- Plant Ecological Genetics, Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, 8092, Zurich, Switzerland
| | - Margot Paris
- Plant Ecological Genetics, Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, 8092, Zurich, Switzerland
| | - Thomas Städler
- Plant Ecological Genetics, Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, 8092, Zurich, Switzerland
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Erdmann RM, Satyaki PRV, Klosinska M, Gehring M. A Small RNA Pathway Mediates Allelic Dosage in Endosperm. Cell Rep 2018; 21:3364-3372. [PMID: 29262317 DOI: 10.1016/j.celrep.2017.11.078] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Revised: 09/18/2017] [Accepted: 11/21/2017] [Indexed: 12/12/2022] Open
Abstract
Balance between maternal and paternal genomes within the triploid endosperm is necessary for normal seed development. The majority of endosperm genes are expressed in a 2:1 maternal:paternal ratio, reflecting genomic DNA content. Here, we find that the 2:1 transcriptional ratio is, unexpectedly, actively regulated. In A. thaliana and A. lyrata, endosperm 24-nt small RNAs are reduced in transposable elements and enriched in genes compared with the embryo. We find an inverse relationship between the parent of origin of sRNAs and mRNAs, with genes more likely to be associated with maternally than paternally biased sRNAs. Disruption of the Pol IV sRNA pathway causes a shift toward maternal allele mRNA expression for many genes. Furthermore, paternal inheritance of an RNA Pol IV mutation is sufficient to rescue seed abortion caused by excess paternal genome dosage. Thus, RNA Pol IV mediates the transcriptional balance between maternally and paternally inherited genomes in endosperm.
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Affiliation(s)
- Robert M Erdmann
- Whitehead Institute for Biomedical Research, Cambridge, MA 02142, USA; Department of Biology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Maja Klosinska
- 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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42
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Bawa KS. Kin selection and the evolution of plant reproductive traits. Proc Biol Sci 2017; 283:rspb.2016.0789. [PMID: 27852800 PMCID: PMC5124086 DOI: 10.1098/rspb.2016.0789] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 06/24/2016] [Indexed: 11/12/2022] Open
Abstract
Competition among developing seeds and sibling rivalry within multiovulated ovaries can be deleterious for both the maternal parent and the siblings. Increased genetic relatedness of seeds within the ovary may foster kin selection and reduce the deleterious consequences of sibling competition. The pollen parent may also be selected for siring all progeny within a fruit. I propose a series of hypotheses to explain the evolution of a number of reproductive traits in angiosperms in the context of kin selection and sibling rivalry within the ovaries of angiosperms. I present evidence to show that a single-pollen parent, indeed, often sires seeds within multiovulated ovaries. Various types of pollen aggregations and transfer of such pollen masses to the stigmas of flowers by specialized pollinators make this increased genetic relatedness possible. An alternative mode to reduce sibling rivalry may be the reduction of ovule number to one, an evolutionary trend that has independently occurred many times in flowering plants. Finally, I build on previously established correlations to predict two sets of correlations among reproductive traits. In the first case, large showy flowers, transfer of pollen en masse by specialized pollinators, and multiovulated ovaries and multisided fruits seem to be correlated. In the second case, the previously established correlations among small and inconspicuous flowers, pollination by wind, water or generalist insects, flowers and fruits with few or single ovules and seeds, respectively, may also include monoecy or dioecy. Although correlations among many of these traits have been established in the past, I invoke kin selection and sibling competition to explain the evolution of correlated traits as two distinct evolutionary pathways in angiosperms.
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Affiliation(s)
- Kamaljit S Bawa
- Department of Biology, University of Massachusetts, Boston, MA 02125-3393, USA .,Ashoka Trust for Research in Ecology and the Environment, Bangalore, Karnataka 560064, India
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Yuan J, Chen S, Jiao W, Wang L, Wang L, Ye W, Lu J, Hong D, You S, Cheng Z, Yang DL, Chen ZJ. Both maternally and paternally imprinted genes regulate seed development in rice. THE NEW PHYTOLOGIST 2017; 216:373-387. [PMID: 28295376 DOI: 10.1111/nph.14510] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Accepted: 02/01/2017] [Indexed: 05/20/2023]
Abstract
Genetic imprinting refers to the unequal expression of paternal and maternal alleles of a gene in sexually reproducing organisms, including mammals and flowering plants. Although many imprinted genes have been identified in plants, the functions of these imprinted genes have remained largely uninvestigated. We report genome-wide analysis of gene expression, DNA methylation and small RNAs in the rice endosperm and functional tests of five imprinted genes during seed development using Clustered Regularly Interspaced Short Palindromic Repeats/CRISPR-associated gene9 (CRISPR/Cas9) gene editing technology. In the rice endosperm, we identified 162 maternally expressed genes (MEGs) and 95 paternally expressed genes (PEGs), which were associated with miniature inverted-repeat transposable elements, imprinted differentially methylated loci and some 21-22 small interfering RNAs (siRNAs) and long noncoding RNAs (lncRNAs). Remarkably, one-third of MEGs and nearly one-half of PEGs were associated with grain yield quantitative trait loci. Most MEGs and some PEGs were expressed specifically in the endosperm. Disruption of two MEGs increased the amount of small starch granules and reduced grain and embryo size, whereas mutation of three PEGs reduced starch content and seed fertility. Our data indicate that both MEGs and PEGs in rice regulate nutrient metabolism and endosperm development, which optimize seed development and offspring fitness to facilitate parental-offspring coadaptation. These imprinted genes and mechanisms could be used to improve the grain yield of rice and other cereal crops.
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Affiliation(s)
- Jingya Yuan
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, 1 Weigang Road, Nanjing, 210095, China
| | - Sushu Chen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, 1 Weigang Road, Nanjing, 210095, China
| | - Wu Jiao
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, 1 Weigang Road, Nanjing, 210095, China
| | - Longfei Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, 1 Weigang Road, Nanjing, 210095, China
| | - Limei Wang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, 1 Weigang Road, Nanjing, 210095, China
| | - Wenxue Ye
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, 1 Weigang Road, Nanjing, 210095, China
| | - Jie Lu
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology and Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, TX, 78712, USA
| | - Delin Hong
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, 1 Weigang Road, Nanjing, 210095, China
| | - Siliang You
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, 1 Weigang Road, Nanjing, 210095, China
| | - Zhukuan Cheng
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 1 West Beichen Road, Beijing, 100101, China
| | - Dong-Lei Yang
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, 1 Weigang Road, Nanjing, 210095, China
| | - Z Jeffrey Chen
- State Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, 1 Weigang Road, Nanjing, 210095, China
- Department of Molecular Biosciences, Institute for Cellular and Molecular Biology and Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, TX, 78712, USA
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Schinkel CCF, Kirchheimer B, Dullinger S, Geelen D, De Storme N, Hörandl E. Pathways to polyploidy: indications of a female triploid bridge in the alpine species Ranunculus kuepferi (Ranunculaceae). PLANT SYSTEMATICS AND EVOLUTION = ENTWICKLUNGSGESCHICHTE UND SYSTEMATIK DER PFLANZEN 2017; 303:1093-1108. [PMID: 29081576 PMCID: PMC5640749 DOI: 10.1007/s00606-017-1435-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 06/14/2017] [Indexed: 05/05/2023]
Abstract
Polyploidy is one of the most important evolutionary processes in plants. In natural populations, polyploids usually emerge from unreduced gametes which either fuse with reduced ones, resulting in triploid offspring (triploid bridge), or with other unreduced gametes, resulting in tetraploid embryos. The frequencies of these two pathways, and male versus female gamete contributions, however, are largely unexplored. Ranunculus kuepferi occurs with diploid, triploid and autotetraploid cytotypes in the Alps, whereby diploids are mostly sexual, while tetraploids are facultative apomicts. To test for the occurrence of polyploidization events by triploid bridge, we investigated 551 plants of natural populations via flow cytometric seed screening. We assessed ploidy shifts in the embryo to reconstruct female versus male gamete contributions to polyploid embryo and/or endosperm formation. Seed formation via unreduced egg cells (BIII hybrids) occurred in all three cytotypes, while only in one case both gametes were unreduced. Polyploids further formed seeds with reduced, unfertilized egg cells (polyhaploids and aneuploids). Pollen was highly variable in diameter, but only pollen >27 μm was viable, whereby diploids produced higher proportions of well-developed pollen. Pollen size was not informative for the formation of unreduced pollen. These results suggest that a female triploid bridge via unreduced egg cells is the major pathway toward polyploidization in R. kuepferi, maybe as a consequence of constraints of endosperm development. Triploids resulting from unreduced male gametes were not observed, which explains the lack of obligate sexual tetraploid individuals and populations. Unreduced egg cell formation in diploids represents the first step toward apomixis.
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Affiliation(s)
- Christoph C. F. Schinkel
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University of Goettingen, Untere Karspüle 2, 37073 Göttingen, Germany
| | - Bernhard Kirchheimer
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Stefan Dullinger
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Danny Geelen
- Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Nico De Storme
- Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University of Goettingen, Untere Karspüle 2, 37073 Göttingen, Germany
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45
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Satyaki PRV, Gehring M. DNA methylation and imprinting in plants: machinery and mechanisms. Crit Rev Biochem Mol Biol 2017; 52:163-175. [PMID: 28118754 DOI: 10.1080/10409238.2017.1279119] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Imprinting is an epigenetic phenomenon in which genes are expressed selectively from either the maternal or paternal alleles. In plants, imprinted gene expression is found in a tissue called the endosperm. Imprinting is often set by a unique epigenomic configuration in which the maternal chromosomes are less DNA methylated than their paternal counterparts. In this review, we synthesize studies that paint a detailed molecular portrait of the distinctive endosperm methylome. We will also discuss the molecular machinery that shapes and modifies this methylome, and the role of DNA methylation in imprinting.
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Affiliation(s)
- P R V Satyaki
- a Whitehead Institute for Biomedical Research , Cambridge , MA , USA
| | - Mary Gehring
- a Whitehead Institute for Biomedical Research , Cambridge , MA , USA.,b Department of Biology , Massachusetts Institute of Technology , Cambridge , MA , USA
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46
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Schinkel CCF, Kirchheimer B, Dullinger S, Geelen D, De Storme N, Hörandl E. Pathways to polyploidy: indications of a female triploid bridge in the alpine species Ranunculus kuepferi (Ranunculaceae). PLANT SYSTEMATICS AND EVOLUTION = ENTWICKLUNGSGESCHICHTE UND SYSTEMATIK DER PFLANZEN 2017; 303:1093-1108. [PMID: 29081576 DOI: 10.1007/s00606-017-1435-1436] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 06/14/2017] [Indexed: 05/20/2023]
Abstract
Polyploidy is one of the most important evolutionary processes in plants. In natural populations, polyploids usually emerge from unreduced gametes which either fuse with reduced ones, resulting in triploid offspring (triploid bridge), or with other unreduced gametes, resulting in tetraploid embryos. The frequencies of these two pathways, and male versus female gamete contributions, however, are largely unexplored. Ranunculus kuepferi occurs with diploid, triploid and autotetraploid cytotypes in the Alps, whereby diploids are mostly sexual, while tetraploids are facultative apomicts. To test for the occurrence of polyploidization events by triploid bridge, we investigated 551 plants of natural populations via flow cytometric seed screening. We assessed ploidy shifts in the embryo to reconstruct female versus male gamete contributions to polyploid embryo and/or endosperm formation. Seed formation via unreduced egg cells (BIII hybrids) occurred in all three cytotypes, while only in one case both gametes were unreduced. Polyploids further formed seeds with reduced, unfertilized egg cells (polyhaploids and aneuploids). Pollen was highly variable in diameter, but only pollen >27 μm was viable, whereby diploids produced higher proportions of well-developed pollen. Pollen size was not informative for the formation of unreduced pollen. These results suggest that a female triploid bridge via unreduced egg cells is the major pathway toward polyploidization in R. kuepferi, maybe as a consequence of constraints of endosperm development. Triploids resulting from unreduced male gametes were not observed, which explains the lack of obligate sexual tetraploid individuals and populations. Unreduced egg cell formation in diploids represents the first step toward apomixis.
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Affiliation(s)
- Christoph C F Schinkel
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University of Goettingen, Untere Karspüle 2, 37073 Göttingen, Germany
| | - Bernhard Kirchheimer
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Stefan Dullinger
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, 1030 Vienna, Austria
| | - Danny Geelen
- Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Nico De Storme
- Department of Plant Production, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, 9000 Ghent, Belgium
| | - Elvira Hörandl
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), University of Goettingen, Untere Karspüle 2, 37073 Göttingen, Germany
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47
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He S, Sun Y, Yang Q, Zhang X, Huang Q, Zhao P, Sun M, Liu J, Qian W, Qin G, Gu H, Qu LJ. A Novel Imprinted Gene NUWA Controls Mitochondrial Function in Early Seed Development in Arabidopsis. PLoS Genet 2017; 13:e1006553. [PMID: 28095407 PMCID: PMC5283763 DOI: 10.1371/journal.pgen.1006553] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Revised: 01/31/2017] [Accepted: 12/24/2016] [Indexed: 12/28/2022] Open
Abstract
Imprinted genes display biased expression of paternal and maternal alleles and are only found in mammals and flowering plants. Compared to several hundred imprinted genes that are functionally characterized in mammals, very few imprinted genes were confirmed in plants and even fewer of them have been functionally investigated. Here, we report a new imprinted gene, NUWA, in plants. NUWA is an essential gene, because loss of its function resulted in reduced transmission through the female gametophyte and defective cell/nuclear proliferation in early Arabidopsis embryo and endosperm. NUWA is a maternally expressed imprinted gene, as only the maternal allele of NUWA is transcribed and translated from gametogenesis to the 16-cell globular embryo stage after fertilization, and the de novo transcription of the maternal allele of NUWA starts from the zygote stage. Different from other identified plant imprinted genes whose encoded proteins are mostly localized to the nucleus, the NUWA protein was localized to the mitochondria and was essential for mitochondria function. Our work uncovers a novel imprinted gene of a previously unidentified type, namely, a maternal-specific expressed nuclear gene with its encoded protein localizing to and controlling the function of the maternally inherited mitochondria. This reveals a unique mechanism of maternal control of the mitochondria and adds an extra layer of complexity to the regulation of nucleus-organelle coordination during early plant development.
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Affiliation(s)
- Shan He
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Yan Sun
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Qian Yang
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Xiangyu Zhang
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Qingpei Huang
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Peng Zhao
- Department of Cell and Development Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, China
| | - Mengxiang Sun
- Department of Cell and Development Biology, College of Life Science, State Key Laboratory of Hybrid Rice, Wuhan University, Wuhan, China
| | - Jingjing Liu
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Weiqiang Qian
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Genji Qin
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
| | - Hongya Gu
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
- The National Plant Gene Research Center (Beijing), Beijing, China
| | - Li-Jia Qu
- State Key Laboratory of Protein and Plant Gene Research, Peking-Tsinghua Center for Life Sciences, School of Life Sciences, Peking University, Beijing, China
- The National Plant Gene Research Center (Beijing), Beijing, China
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48
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Affiliation(s)
- Manus M Patten
- Department of Biology, Regents Hall, Georgetown University, Washington, DC 20057, USA
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49
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Florez-Rueda AM, Paris M, Schmidt A, Widmer A, Grossniklaus U, Städler T. Genomic Imprinting in the Endosperm Is Systematically Perturbed in Abortive Hybrid Tomato Seeds. Mol Biol Evol 2016; 33:2935-2946. [PMID: 27601611 PMCID: PMC5062328 DOI: 10.1093/molbev/msw175] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Hybrid seed failure represents an important postzygotic barrier to interbreeding among species of wild tomatoes (Solanum section Lycopersicon) and other flowering plants. We studied genome-wide changes associated with hybrid seed abortion in the closely related Solanum peruvianum and S. chilense where hybrid crosses yield high proportions of inviable seeds due to endosperm failure and arrested embryo development. Based on differences of seed size in reciprocal hybrid crosses and developmental evidence implicating endosperm failure, we hypothesized that perturbed genomic imprinting is involved in this strong postzygotic barrier. Consequently, we surveyed the transcriptomes of developing endosperms from intra- and inter-specific crosses using tissues isolated by laser-assisted microdissection. We implemented a novel approach to estimate parent-of-origin–specific expression using both homozygous and heterozygous nucleotide differences between parental individuals and identified candidate imprinted genes. Importantly, we uncovered systematic shifts of “normal” (intraspecific) maternal:paternal transcript proportions in hybrid endosperms; the average maternal proportion of gene expression increased in both crossing directions but was stronger with S. peruvianum in the maternal role. These genome-wide shifts almost entirely eliminated paternally expressed imprinted genes in S. peruvianum hybrid endosperm but also affected maternally expressed imprinted genes and all other assessed genes. These profound, systematic changes in parental expression proportions suggest that core processes of transcriptional regulation are functionally compromised in hybrid endosperm and contribute to hybrid seed failure.
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Affiliation(s)
- Ana M Florez-Rueda
- Plant Ecological Genetics, Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, Zurich, Switzerland
| | - Margot Paris
- Plant Ecological Genetics, Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, Zurich, Switzerland
| | - Anja Schmidt
- Plant Developmental Genetics, Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Alex Widmer
- Plant Ecological Genetics, Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, Zurich, Switzerland
| | - Ueli Grossniklaus
- Plant Developmental Genetics, Department of Plant and Microbial Biology & Zurich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Thomas Städler
- Plant Ecological Genetics, Institute of Integrative Biology & Zurich-Basel Plant Science Center, ETH Zurich, Zurich, Switzerland
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50
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Oneal E, Willis JH, Franks RG. Disruption of endosperm development is a major cause of hybrid seed inviability between Mimulus guttatus and Mimulus nudatus. THE NEW PHYTOLOGIST 2016; 210:1107-20. [PMID: 26824345 PMCID: PMC4833662 DOI: 10.1111/nph.13842] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Accepted: 11/30/2015] [Indexed: 05/06/2023]
Abstract
Divergence of developmental mechanisms within populations could lead to hybrid developmental failure, and might be a factor driving speciation in angiosperms. We investigate patterns of endosperm and embryo development in Mimulus guttatus and the closely related, serpentine endemic Mimulus nudatus, and compare them to those of reciprocal hybrid seed. We address whether disruption in hybrid seed development is the primary source of reproductive isolation between these sympatric taxa. M. guttatus and M. nudatus differ in the pattern and timing of endosperm and embryo development. Some hybrid seeds exhibit early disruption of endosperm development and are completely inviable, while others develop relatively normally at first, but later exhibit impaired endosperm proliferation and low germination success. These developmental patterns are reflected in mature hybrid seeds, which are either small and flat (indicating little to no endosperm) or shriveled (indicating reduced endosperm volume). Hybrid seed inviability forms a potent reproductive barrier between M. guttatus and M. nudatus. We shed light on the extent of developmental variation between closely related species within the M. guttatus species complex, an important ecological model system, and provide a partial mechanism for the hybrid barrier between M. guttatus and M. nudatus.
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Affiliation(s)
- Elen Oneal
- Department of Biology, Duke University, 3319 French Family Science Center, 125 Science Drive, Durham, NC 27705, USA
| | - John H. Willis
- Department of Biology, Duke University, 3319 French Family Science Center, 125 Science Drive, Durham, NC 27705, USA
| | - Robert G. Franks
- Department of Genetics, North Carolina State University, 2548 Thomas Hall, Raleigh, NC 27695, USA
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