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Rojek J, Ohad N. The phenomenon of autonomous endosperm in sexual and apomictic plants. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4324-4348. [PMID: 37155961 PMCID: PMC10433939 DOI: 10.1093/jxb/erad168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 05/04/2023] [Indexed: 05/10/2023]
Abstract
Endosperm is a key nutritive tissue that supports the developing embryo or seedling, and serves as a major nutritional source for human and livestock feed. In sexually-reproducing flowering plants, it generally develops after fertilization. However, autonomous endosperm (AE) formation (i.e. independent of fertilization) is also possible. Recent findings of AE loci/ genes and aberrant imprinting in native apomicts, together with a successful initiation of parthenogenesis in rice and lettuce, have enhanced our understanding of the mechanisms bridging sexual and apomictic seed formation. However, the mechanisms driving AE development are not well understood. This review presents novel aspects related to AE development in sexual and asexual plants underlying stress conditions as the primary trigger for AE. Both application of hormones to unfertilized ovules and mutations that impair epigenetic regulation lead to AE development in sexual Arabidopsis thaliana, which may point to a common pathway for both phenomena. Apomictic-like AE development under experimental conditions can take place due to auxin-dependent gene expression and/or DNA methylation.
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Affiliation(s)
- Joanna Rojek
- Department of Plant Cytology and Embryology, Faculty of Biology, University of Gdansk, Gdansk, Poland
| | - Nir Ohad
- School of Plant Sciences and Food Security, Tel Aviv University, Tel Aviv, Israel
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Lipinska P, Pawlak P, Warzych E. Species and embryo genome origin affect lipid droplets in preimplantation embryos. Front Cell Dev Biol 2023; 11:1187832. [PMID: 37250899 PMCID: PMC10217358 DOI: 10.3389/fcell.2023.1187832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 04/26/2023] [Indexed: 05/31/2023] Open
Abstract
Mammalian embryo development is affected by multiple metabolism processes, among which energy metabolism seems to be crucial. Therefore the ability and the scale of lipids storage in different preimplantation stages might affect embryos quality. The aim of the present studies was to show a complex characterization of lipid droplets (LD) during subsequent embryo developmental stages. It was performed on two species (bovine and porcine) as well as on embryos with different embryo origin [after in vitro fertilization (IVF) and after parthenogenetic activation (PA)]. Embryos after IVF/PA were collected at precise time points of development at the following stages: zygote, 2-cell, 4-cell, 8/16-cell, morula, early blastocyst, expanded blastocyst. LD were stained with BODIPY 493/503 dye, embryos were visualized under a confocal microscope and images were analyzed with the ImageJ Fiji software. The following parameters were analyzed: lipid content, LD number, LD size and LD area within the total embryo. The most important results show that lipid parameters in the IVF vs. PA bovine embryos differ at the most crucial moments of embryonic development (zygote, 8-16-cell, blastocyst), indicating possible dysregulations of lipid metabolism in PA embryos. When bovine vs. porcine species are compared, we observe higher lipid content around EGA stage and lower lipid content at the blastocyst stage for bovine embryos, which indicates different demand for energy depending on the species. We conclude that lipid droplets parameters significantly differ among developmental stages and between species but also can be affected by the genome origin.
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Li X, Zou C, Li M, Fang C, Li K, Liu Z, Li C. Transcriptome Analysis of In Vitro Fertilization and Parthenogenesis Activation during Early Embryonic Development in Pigs. Genes (Basel) 2021; 12:genes12101461. [PMID: 34680856 PMCID: PMC8535918 DOI: 10.3390/genes12101461] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Revised: 09/14/2021] [Accepted: 09/15/2021] [Indexed: 11/16/2022] Open
Abstract
Parthenogenesis activation (PA), as an important artificial breeding method, can stably preserve the dominant genotype of a species. However, the delayed development of PA embryos is still overly severe and largely leads to pre-implantation failure in pigs. The mechanisms underlying the deficiencies of PA embryos have not been completely understood. For further understanding of the molecular mechanism behind PA embryo failure, we performed transcriptome analysis among pig oocytes (meiosis II, MII) and early embryos at three developmental stages (zygote, morula, and blastocyst) in vitro fertilization (IVF) and PA group. Totally, 11,110 differentially expressed genes (DEGs), 4694 differentially expressed lincRNAs (DELs) were identified, and most DEGs enriched the regulation of apoptotic processes. Through cis- and trans-manner functional prediction, we found that hub lincRNAs were mostly involved in abnormal parthenogenesis embryonic development. In addition, twenty DE imprinted genes showed that some paternally imprinted genes in IVF displayed higher expression than that in PA. Notably, we identified that three DELs of imprinted genes (MEST, PLAGL1, and DIRAS3) were up regulated in IVF, and there was no significant change in PA group. Disordered expression of key genes for embryonic development might play key roles in abnormal parthenogenesis embryonic development. Our study indicates that embryos derived from different production techniques have varied in vitro development to the blastocyst stage, and they also affect the transcription level of corresponding genes, such as imprinted genes. This work will help future research on these genes and molecular-assisted breeding for pig parthenotes.
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Affiliation(s)
- Xin Li
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of the Ministry of Education and Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China; (X.L.); (C.Z.); (M.L.); (C.F.)
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Cheng Zou
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of the Ministry of Education and Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China; (X.L.); (C.Z.); (M.L.); (C.F.)
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Mengxun Li
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of the Ministry of Education and Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China; (X.L.); (C.Z.); (M.L.); (C.F.)
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Chengchi Fang
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of the Ministry of Education and Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China; (X.L.); (C.Z.); (M.L.); (C.F.)
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
| | - Kui Li
- Agricultural Genome Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518124, China;
- State Key Laboratory of Animal Nutrition, Key Laboratory of Animal Genetics Breeding and Reproduction of Ministry of Agriculture and Rural Affairs of China, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
| | - Zhiguo Liu
- State Key Laboratory of Animal Nutrition, Key Laboratory of Animal Genetics Breeding and Reproduction of Ministry of Agriculture and Rural Affairs of China, Institute of Animal Sciences, Chinese Academy of Agricultural Sciences, Beijing 100193, China
- Correspondence: (Z.L.); (C.L.)
| | - Changchun Li
- Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of the Ministry of Education and Key Laboratory of Swine Genetics and Breeding of the Ministry of Agriculture, Huazhong Agricultural University, Wuhan 430070, China; (X.L.); (C.Z.); (M.L.); (C.F.)
- The Cooperative Innovation Center for Sustainable Pig Production, Wuhan 430070, China
- Correspondence: (Z.L.); (C.L.)
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Amiri A, Bandani AR. Facultative deuterotokous parthenogenesis in Callosobruchus maculatus. ZOOL ANZ 2021. [DOI: 10.1016/j.jcz.2021.01.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Zhang Z, Conner J, Guo Y, Ozias-Akins P. Haploidy in Tobacco Induced by PsASGR-BBML Transgenes via Parthenogenesis. Genes (Basel) 2020; 11:E1072. [PMID: 32932590 PMCID: PMC7564442 DOI: 10.3390/genes11091072] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/10/2020] [Accepted: 09/10/2020] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Engineering apomixis in sexually reproducing plants has been long desired because of the potential to fix hybrid vigor. Validating the functionality of genes originated from apomictic species that contribute to apomixis upon transfer to sexually reproducing species is an important step. The PsASGR-BABYBOOM-like (PsASGR-BBML) gene from Pennisetum squamulatum confers parthenogenesis in this apomict, and its functionality was demonstrated in several sexually reproducing monocots but not in any dicots. METHODS We introduced the PsASGR-BBML gene regulated by egg cell-specific promoters, either AtDD45 or AtRKD2, into tobacco, and analyzed progeny of the transgenic lines resulting from self-pollination and crossing by flow cytometry. RESULTS We identified haploid progeny at a frequency lower than 1% in the AtDD45pro lines, while at a frequency of 9.3% for an octoploid (2n = 8x) AtRKD2pro line. Haploid production in the T2 generation, derived from the tetraploid T1 offspring of this original octoploid AtRKD2pro line, was also observed. Pollinated by homozygous transgenic tobacco carrying a DsRed marker gene, 4x progeny of the AtRKD2pro line yielded parthenogenetic embryos identified as DsRed negative. We verified that the DsRed negative seedlings recovered were haploid (2x). CONCLUSION The PsASGR-BBML gene regulated by egg cell-specific promoters could enable parthenogenesis in tobacco, a dicotyledon species.
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Affiliation(s)
| | | | | | - Peggy Ozias-Akins
- Department of Horticulture and Institute of Plant Breeding, Genetics & Genomics, University of Georgia, Tifton, GA 31793, USA; (Z.Z.); (J.C.); (Y.G.)
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Scheben A, Hojsgaard D. Can We Use Gene-Editing to Induce Apomixis in Sexual Plants? Genes (Basel) 2020; 11:E781. [PMID: 32664641 PMCID: PMC7397034 DOI: 10.3390/genes11070781] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Revised: 07/08/2020] [Accepted: 07/09/2020] [Indexed: 12/12/2022] Open
Abstract
Apomixis, the asexual formation of seeds, is a potentially valuable agricultural trait. Inducing apomixis in sexual crop plants would, for example, allow breeders to fix heterosis in hybrid seeds and rapidly generate doubled haploid crop lines. Molecular models explain the emergence of functional apomixis, i.e., apomeiosis + parthenogenesis + endosperm development, as resulting from a combination of genetic or epigenetic changes that coordinate altered molecular and developmental steps to form clonal seeds. Apomixis-like features and synthetic clonal seeds have been induced with limited success in the sexual plants rice and maize by using gene editing to mutate genes related to meiosis and fertility or via egg-cell specific expression of embryogenesis genes. Inducing functional apomixis and increasing the penetrance of apomictic seed production will be important for commercial deployment of the trait. Optimizing the induction of apomixis with gene editing strategies that use known targets as well as identifying alternative targets will be possible by better understanding natural genetic variation in apomictic species. With the growing availability of genomic data and precise gene editing tools, we are making substantial progress towards engineering apomictic crops.
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Affiliation(s)
- Armin Scheben
- Simons Center for Quantitative Biology, Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA;
| | - Diego Hojsgaard
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Untere Karspuele 2, 37073 Goettingen, Germany
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Karunarathne P, Reutemann AV, Schedler M, Glücksberg A, Martínez EJ, Honfi AI, Hojsgaard DH. Sexual modulation in a polyploid grass: a reproductive contest between environmentally inducible sexual and genetically dominant apomictic pathways. Sci Rep 2020; 10:8319. [PMID: 32433575 PMCID: PMC7239852 DOI: 10.1038/s41598-020-64982-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 04/25/2020] [Indexed: 12/24/2022] Open
Abstract
In systems alternating between sexual and asexual reproduction, sex increases under unfavorable environmental conditions. In plants producing sexual and asexual (apomictic) seeds, studies on the influence of environmental factors on sex are equivocal. We used Paspalum intermedium to study environmental effects on the expression of sexual and apomictic developments, and on resulting reproductive fitness variables. Flow cytometric and embryological analyses were performed to characterize ploidy and reproductive modes, and effects of local climatic conditions on sexual and apomictic ovule and seed frequencies were determined. Seed set and germination data were collected and used to estimate reproductive fitness. Frequencies of sexual and apomictic ovules and seeds were highly variable within and among populations. Apomictic development exhibited higher competitive ability but lower overall fitness. Frequencies of sexual reproduction in facultative apomictic plants increased at lower temperatures and wider mean diurnal temperature ranges. We identified a two-fold higher fitness advantage of sexuality and a Tug of War between factors intrinsic to apomixis and environmental stressors promoting sexuality which influence the distribution of sex in apomictic populations. This points toward a crucial role of local ecological conditions in promoting a reshuffling of genetic variability that may be shaping the adaptative landscape in apomictic P. intermedium plants.
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Affiliation(s)
- Piyal Karunarathne
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Untere Karspuele 2, 37073, Goettingen, Germany.
- Georg-August University School of Science, University of Goettingen, Goettingen, Germany.
| | - Anna V Reutemann
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Untere Karspuele 2, 37073, Goettingen, Germany
- Instituto de Botánica del Nordeste (IBONE), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), CC209, 3400, Corrientes, Argentina
| | - Mara Schedler
- Instituto de Botánica del Nordeste (IBONE), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), CC209, 3400, Corrientes, Argentina
| | - Adriana Glücksberg
- Instituto de Botánica del Nordeste (IBONE), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), CC209, 3400, Corrientes, Argentina
| | - Eric J Martínez
- Instituto de Botánica del Nordeste (IBONE), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), CC209, 3400, Corrientes, Argentina
| | - Ana I Honfi
- Programa de Estudios Florísticos y Genética Vegetal, Instituto de Biología Subtropical (CONICET-UNaM), Facultad de Ciencias Exactas, Químicas y Naturales, Universidad Nacional de Misiones, Rivadavia 2370, 3300, Posadas, Misiones, Argentina
| | - Diego H Hojsgaard
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Untere Karspuele 2, 37073, Goettingen, Germany.
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Hojsgaard D. Apomixis Technology: Separating the Wheat from the Chaff. Genes (Basel) 2020; 11:E411. [PMID: 32290084 PMCID: PMC7231277 DOI: 10.3390/genes11040411] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 04/03/2020] [Accepted: 04/08/2020] [Indexed: 02/06/2023] Open
Abstract
Projections indicate that current plant breeding approaches will be unable to incorporate the global crop yields needed to deliver global food security. Apomixis is a disruptive innovation by which a plant produces clonal seeds capturing heterosis and gene combinations of elite phenotypes. Introducing apomixis into hybrid cultivars is a game-changing development in the current plant breeding paradigm that will accelerate the generation of high-yield cultivars. However, apomixis is a developmentally complex and genetically multifaceted trait. The central problem behind current constraints to apomixis breeding is that the genomic configuration and molecular mechanism that initiate apomixis and guide the formation of a clonal seed are still unknown. Today, not a single explanation about the origin of apomixis offer full empirical coverage, and synthesizing apomixis by manipulating individual genes has failed or produced little success. Overall evidence suggests apomixis arise from a still unknown single event molecular mechanism with multigenic effects. Disentangling the genomic basis and complex genetics behind the emergence of apomixis in plants will require the use of novel experimental approaches benefiting from Next Generation Sequencing technologies and targeting not only reproductive genes, but also the epigenetic and genomic configurations associated with reproductive phenotypes in homoploid sexual and apomictic carriers. A comprehensive picture of most regulatory changes guiding apomixis emergence will be central for successfully installing apomixis into the target species by exploiting genetic modification techniques.
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Affiliation(s)
- Diego Hojsgaard
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, Georg-August-University of Göttingen, Untere Karspüle 2, D-37073-1 Göttingen, Germany
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Controlling Apomixis: Shared Features and Distinct Characteristics of Gene Regulation. Genes (Basel) 2020; 11:genes11030329. [PMID: 32245021 PMCID: PMC7140868 DOI: 10.3390/genes11030329] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/13/2020] [Accepted: 03/18/2020] [Indexed: 02/06/2023] Open
Abstract
In higher plants, sexual and asexual reproduction through seeds (apomixis) have evolved as alternative strategies. As apomixis leads to the formation of clonal offspring, its great potential for agricultural applications has long been recognized. However, the genetic basis and the molecular control underlying apomixis and its evolutionary origin are to date not fully understood. Both in sexual and apomictic plants, reproduction is tightly controlled by versatile mechanisms regulating gene expression, translation, and protein abundance and activity. Increasing evidence suggests that interrelated pathways including epigenetic regulation, cell-cycle control, hormonal pathways, and signal transduction processes are relevant for apomixis. Additional molecular mechanisms are being identified that involve the activity of DNA- and RNA-binding proteins, such as RNA helicases which are increasingly recognized as important regulators of reproduction. Together with other factors including non-coding RNAs, their association with ribosomes is likely to be relevant for the formation and specification of the apomictic reproductive lineage. Subsequent seed formation appears to involve an interplay of transcriptional activation and repression of developmental programs by epigenetic regulatory mechanisms. In this review, insights into the genetic basis and molecular control of apomixis are presented, also taking into account potential relations to environmental stress, and considering aspects of evolution.
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Vijverberg K, Ozias-Akins P, Schranz ME. Identifying and Engineering Genes for Parthenogenesis in Plants. FRONTIERS IN PLANT SCIENCE 2019; 10:128. [PMID: 30838007 PMCID: PMC6389702 DOI: 10.3389/fpls.2019.00128] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 01/24/2019] [Indexed: 05/16/2023]
Abstract
Parthenogenesis is the spontaneous development of an embryo from an unfertilized egg cell. It naturally occurs in a variety of plant and animal species. In plants, parthenogenesis usually is found in combination with apomeiosis (the omission of meiosis) and pseudogamous or autonomous (with or without central cell fertilization) endosperm formation, together known as apomixis (clonal seed production). The initiation of embryogenesis in vivo and in vitro has high potential in plant breeding methods, particularly for the instant production of homozygous lines from haploid gametes [doubled haploids (DHs)], the maintenance of vigorous F1-hybrids through clonal seed production after combining it with apomeiosis, reverse breeding approaches, and for linking diploid and polyploid gene pools. Because of this large interest, efforts to identify gene(s) for parthenogenesis from natural apomicts have been undertaken by using map-based cloning strategies and comparative gene expression studies. In addition, engineering parthenogenesis in sexual model species has been investigated via mutagenesis and gain-of-function strategies. These efforts have started to pay off, particularly by the isolation of the PsASGR-BabyBoom-Like from apomictic Pennisetum, a gene proven to be transferable to and functional in sexual pearl millet, rice, and maize. This review aims to summarize the current knowledge on parthenogenesis, the possible gene candidates also outside the grasses, and the use of these genes in plant breeding protocols. It shows that parthenogenesis is able to inherit and function independently from apomeiosis and endosperm formation, is expressed and active in the egg cell, and can induce embryogenesis in polyploid, diploid as well as haploid egg cells in plants. It also shows the importance of genes involved in the suppression of transcription and modifications thereof at one hand, and in embryogenesis for which transcription is allowed or artificially overexpressed on the other, in parthenogenetic reproduction. Finally, it emphasizes the importance of functional endosperm to allow for successful embryo growth and viable seed production.
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Affiliation(s)
- Kitty Vijverberg
- Biosystematics Group, Experimental Plant Sciences, Wageningen University and Research, Wageningen, Netherlands
- *Correspondence: Kitty Vijverberg,
| | - Peggy Ozias-Akins
- Department of Horticulture, Institute of Plant Breeding, Genetics and Genomics, University of Georgia, Tifton Campus, Tifton, GA, United States
| | - M. Eric Schranz
- Biosystematics Group, Experimental Plant Sciences, Wageningen University and Research, Wageningen, Netherlands
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