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Bellucci M, Caceres ME, Paolocci F, Vega JM, Ortiz JPA, Ceccarelli M, De Marchis F, Pupilli F. ORIGIN OF RECOGNITION COMPLEX 3 controls the development of maternal excess endosperm in the Paspalum simplex agamic complex (Poaceae). JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:3074-3093. [PMID: 36812152 DOI: 10.1093/jxb/erad069] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Accepted: 02/21/2023] [Indexed: 05/21/2023]
Abstract
Pseudogamous apomixis in Paspalum simplex generates seeds with embryos genetically identical to the mother plant and endosperms deviating from the canonical 2(maternal):1(paternal) parental genome contribution into a maternal excess 4m:1p genome ratio. In P. simplex, the gene homologous to that coding for subunit 3 of the ORIGIN OF RECOGNITION COMPLEX (PsORC3) exists in three isogenic forms: PsORC3a is apomixis specific and constitutively expressed in developing endosperm whereas PsORCb and PsORCc are up-regulated in sexual endosperms and silenced in apomictic ones. This raises the question of how the different arrangement and expression profiles of these three ORC3 isogenes are linked to seed development in interploidy crosses generating maternal excess endosperms. We demonstrate that down-regulation of PsORC3b in sexual tetraploid plants is sufficient to restore seed fertility in interploidy 4n×2n crosses and, in turn, its expression level at the transition from proliferating to endoreduplication endosperm developmental stages dictates the fate of these seeds. Furthermore, we show that only when being maternally inherited can PsORC3c up-regulate PsORC3b. Our findings lay the basis for an innovative route-based on ORC3 manipulation-to introgress the apomictic trait into sexual crops and overcome the fertilization barriers in interploidy crosses.
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Affiliation(s)
- Michele Bellucci
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
| | - Maria Eugenia Caceres
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
| | - Francesco Paolocci
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
| | - Juan Manuel Vega
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET-UNR and Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | - Juan Pablo Amelio Ortiz
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET-UNR and Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | - Marilena Ceccarelli
- Department of Chemistry, Biology and Biotechnology, University of Perugia, 06123, Perugia, Italy
| | - Francesca De Marchis
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
| | - Fulvio Pupilli
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
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Niccolò T, Anderson AW, Emidio A. Apomixis: oh, what a tangled web we have! PLANTA 2023; 257:92. [PMID: 37000270 PMCID: PMC10066125 DOI: 10.1007/s00425-023-04124-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 03/21/2023] [Indexed: 06/19/2023]
Abstract
Apomixis is a complex evolutionary trait with many possible origins. Here we discuss various clues and causes, ultimately proposing a model harmonizing the three working hypotheses on the topic. Asexual reproduction through seeds, i.e., apomixis, is the holy grail of plant biology. Its implementation in modern breeding could be a game-changer for agriculture. It has the potential to generate clonal crops and maintain valuable complex genotypes and their associated heterotic traits without inbreeding depression. The genetic basis and origins of apomixis are still unclear. There are three central hypothesis for the development of apomixis that could be: i) a deviation from the sexual developmental program caused by an asynchronous development, ii) environmentally triggered through epigenetic regulations (a polyphenism of sex), iii) relying on one or more genes/alleles. Because of the ever-increasing complexity of the topic, the path toward a detailed understanding of the mechanisms underlying apomixis remains unclear. Here, we discuss the most recent advances in the evolution perspective of this multifaceted trait. We incorporated our understanding of the effect of endogenous effectors, such as small RNAs, epigenetic regulation, hormonal pathways, protein turnover, and cell wall modification in response to an upside stress. This can be either endogenous (hybridization or polyploidization) or exogenous environmental stress, mainly due to oxidative stress and the corresponding ROS (Reacting Oxygen Species) effectors. Finally, we graphically represented this tangled web.
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Affiliation(s)
- Terzaroli Niccolò
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno 74, 06121, Perugia, Italy.
| | - Aaron W Anderson
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno 74, 06121, Perugia, Italy
- Fulbright Scholar From Department of Plant Sciences, University of California, Davis, USA
| | - Albertini Emidio
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno 74, 06121, Perugia, Italy
- Consorzio Interuniversitario per le Biotecnologie (CIB), Trieste, Italy
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3
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Mau M, Mandáková TM, Ma X, Ebersbach J, Zou L, Lysak MA, Sharbel TF. Evolution of an Apomixis-Specific Allele Class in Supernumerary Chromatin of Apomictic Boechera. FRONTIERS IN PLANT SCIENCE 2022; 13:890038. [PMID: 35720540 PMCID: PMC9198585 DOI: 10.3389/fpls.2022.890038] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Accepted: 05/03/2022] [Indexed: 06/06/2023]
Abstract
Asexual reproduction through seeds in plants (i.e., apomixis) is a heritable trait, and apomixis- linked loci have been identified in multiple species. However, direct identification of genomic elements is typically hindered as apomixis-linked loci and are commonly found in recombination-suppressed and repetitive regions. Heterochromatinized elements, such as B chromosomes and other supernumerary chromosomal DNA fragments have long been known to be associated with asexuality in both plants and animals and are prime candidate regions for the evolution of multiple apomixis factors controlling the individual elements of apomixis. Here, we examined molecular evolution, gene regulation, and chromosomal location of a male apomeiosis factor (UPG2), a long noncoding RNA gene, in sexual and apomictic Boechera with and without male apomeiosis (i.e., balanced and unbalanced apomicts). We revealed the origin of the gene in the apomixis genome on an apomixis-specific, supernumerary heterochromatic Boechera chromosome (Boe1). The UPG2 is active in the tapetum at male meiosis. We found allele classes specific to apomictic and sexual Boechera accessions and a third class that shares the features of both and points to a convergent transition state. Sex alleles are found only in some of the sexual accessions and have higher nucleotide divergence and lower transcriptional activity compared to apo alleles. These data demonstrate selective pressure to maintain the function of UPG2 for unreduced pollen formation in apomicts as the occasional transmission of the allele from unbalanced apomicts into sexual organisms that lead to pseudogenization and functional decay of copies in sexual organisms.
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Affiliation(s)
- Martin Mau
- Apomixis Research Group, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
- Department of Plant Sciences, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK, Canada
| | | | - Xingliang Ma
- Department of Plant Sciences, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK, Canada
| | - Jana Ebersbach
- Saskatoon Research and Development Centre, Saskatoon, SK, Canada
| | - Lifang Zou
- Department of Plant Sciences, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK, Canada
| | - Martin A. Lysak
- Central European Institute of Technology, Masaryk University, Brno, Czechia
| | - Timothy F. Sharbel
- Apomixis Research Group, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
- Department of Plant Sciences, College of Agriculture and Bioresources, University of Saskatchewan, Saskatoon, SK, Canada
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4
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Aguilera PM, Galdeano F, Ortiz JPA, Quarin CL, Espinoza F. Construction of AFLP-based cosegregation groups of tetraploid Plicatula species and identification of markers linked to apomixis. RODRIGUÉSIA 2022. [DOI: 10.1590/2175-7860202273085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Abstract Most species of Plicatula are important native forages. This work aimed to build framework cosegregation groups of the apomictic tetraploid race of Paspalum guenoarum cv. Rojas and localize the locus controlling apomixis in the species. An interspecific population derived from crossing a completely sexual tetraploid plant of P. plicatulum and an apomictic tetraploid individual of P. guenoarum cv. Rojas was used. Both, disomic and tetrasomic inheritance were detected in both parental genotypes. In P. guenoarum, ten cosegregation groups were built, including 50 markers expanding for 583 cM. The estimated genome coverage was 63.95%. The apomixis locus was located in the linkage group M8, together with seven other loci (four paternal and three biparental markers). The group extended for 59 cM. The four paternal markers showed strong linkage to apomixis, and two of them mapped at 4 and 7 cM at both sides of the locus. Five female linkage groups were constructed with markers segregating from P. plicatulum. One of them (F3) being homologous to the male group carrying apomixis. The linkage groups presented here constitute the first genetic frame for species of Plicatula group. Moreover, molecular markers linked to apomixis in P. guenoarum can assist fundamental research and breeding programs.
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Epigenetic Modifications in Plant Development and Reproduction. EPIGENOMES 2021; 5:epigenomes5040025. [PMID: 34968249 PMCID: PMC8715465 DOI: 10.3390/epigenomes5040025] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 11/14/2021] [Accepted: 11/16/2021] [Indexed: 01/27/2023] Open
Abstract
Plants are exposed to highly fluctuating effects of light, temperature, weather conditions, and many other environmental factors throughout their life. As sessile organisms, unlike animals, they are unable to escape, hide, or even change their position. Therefore, the growth and development of plants are largely determined by interaction with the external environment. The success of this interaction depends on the ability of the phenotype plasticity, which is largely determined by epigenetic regulation. In addition to how environmental factors can change the patterns of genes expression, epigenetic regulation determines how genetic expression changes during the differentiation of one cell type into another and how patterns of gene expression are passed from one cell to its descendants. Thus, one genome can generate many ‘epigenomes’. Epigenetic modifications acquire special significance during the formation of gametes and plant reproduction when epigenetic marks are eliminated during meiosis and early embryogenesis and later reappear. However, during asexual plant reproduction, when meiosis is absent or suspended, epigenetic modifications that have arisen in the parental sporophyte can be transmitted to the next clonal generation practically unchanged. In plants that reproduce sexually and asexually, epigenetic variability has different adaptive significance. In asexuals, epigenetic regulation is of particular importance for imparting plasticity to the phenotype when, apart from mutations, the genotype remains unchanged for many generations of individuals. Of particular interest is the question of the possibility of transferring acquired epigenetic memory to future generations and its potential role for natural selection and evolution. All these issues will be discussed to some extent in this review.
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6
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Karunarathne P, Hojsgaard D. Single Independent Autopolyploidization Events From Distinct Diploid Gene Pools and Residual Sexuality Support Range Expansion of Locally Adapted Tetraploid Genotypes in a South American Grass. Front Genet 2021; 12:736088. [PMID: 34671384 PMCID: PMC8520906 DOI: 10.3389/fgene.2021.736088] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Accepted: 09/07/2021] [Indexed: 12/02/2022] Open
Abstract
Polyploidy plays a major role in plant evolution. The establishment of new polyploids is often a consequence of a single or few successful polyploidization events occurring within a species’ evolutionary trajectory. New polyploid lineages can play different roles in plant diversification and go through several evolutionary stages influenced by biotic and abiotic constraints and characterized by extensive genetic changes. The study of such changes has been crucial for understanding polyploid evolution. Here, we use the multiploid-species Paspalum intermedium to study population-level genetic and morphological variation and ecological differentiation in polyploids. Using flow cytometry, amplified fragment length polymorphism (AFLP) genetic markers, environmental variables, and morphological data, we assessed variations in ploidy, reproductive modes, and the genetic composition in 35 natural populations of P. intermedium along a latitudinal gradient in South America. Our analyses show that apomictic auto-tetraploids are of multiple independent origin. While overall genetic variation was higher in diploids, both diploids and tetraploids showed significant variation within and among populations. The spatial distribution of genetic variation provides evidence for a primary origin of the contact zone between diploids and tetraploids and further supports the hypothesis of geographic displacement between cytotypes. In addition, a strong link between the ecological differentiation of cytotypes and spatial distribution of genetic variation was observed. Overall, the results indicate that polyploidization in P. intermedium is a recurrent phenomenon associated to a shift in reproductive mode and that multiple polyploid lineages from genetically divergent diploids contributed to the successful establishment of local polyploid populations and dispersal into new environments.
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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, Goettingen, Germany.,Georg-August University School of Science, University of Goettingen, Goettingen, Germany.,Evolutionary Biology Center, Uppsala University, Uppsala, Sweden
| | - Diego Hojsgaard
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Goettingen, Germany.,Taxonomy & Evolutionary Biology, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, Germany
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Soliman M, Podio M, Marconi G, Di Marsico M, Ortiz JPA, Albertini E, Delgado L. Differential Epigenetic Marks Are Associated with Apospory Expressivity in Diploid Hybrids of Paspalum rufum. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10040793. [PMID: 33920644 PMCID: PMC8072704 DOI: 10.3390/plants10040793] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2021] [Revised: 04/13/2021] [Accepted: 04/15/2021] [Indexed: 06/12/2023]
Abstract
Apomixis seems to emerge from the deregulation of preexisting genes involved in sexuality by genetic and/or epigenetic mechanisms. The trait is associated with polyploidy, but diploid individuals of Paspalum rufum can form aposporous embryo sacs and develop clonal seeds. Moreover, diploid hybrid families presented a wide apospory expressivity variation. To locate methylation changes associated with apomixis expressivity, we compare relative DNA methylation levels, at CG, CHG, and CHH contexts, between full-sib P. rufum diploid genotypes presenting differential apospory expressivity. The survey was performed using a methylation content-sensitive enzyme ddRAD (MCSeEd) strategy on samples at premeiosis/meiosis and postmeiosis stages. Based on the relative methylation level, principal component analysis and heatmaps, clearly discriminate samples with contrasting apospory expressivity. Differential methylated contigs (DMCs) showed 14% of homology to known transcripts of Paspalum notatum reproductive transcriptome, and almost half of them were also differentially expressed between apomictic and sexual samples. DMCs showed homologies to genes involved in flower growth, development, and apomixis. Moreover, a high proportion of DMCs aligned on genomic regions associated with apomixis in Setaria italica. Several stage-specific differential methylated sequences were identified as associated with apospory expressivity, which could guide future functional gene characterization in relation to apomixis success at diploid and tetraploid levels.
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Affiliation(s)
- Mariano Soliman
- CONICET-UNR/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), Universidad Nacional de Rosario, Zavalla S2123, Argentina; (M.S.); (M.P.); (J.P.A.O.)
| | - Maricel Podio
- CONICET-UNR/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), Universidad Nacional de Rosario, Zavalla S2123, Argentina; (M.S.); (M.P.); (J.P.A.O.)
| | - Gianpiero Marconi
- Department Agricultural, Food and Environmental Sciences, University of Perugia, 06121 Perugia, Italy; (G.M.); (M.D.M.)
| | - Marco Di Marsico
- Department Agricultural, Food and Environmental Sciences, University of Perugia, 06121 Perugia, Italy; (G.M.); (M.D.M.)
| | - Juan Pablo A. Ortiz
- CONICET-UNR/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), Universidad Nacional de Rosario, Zavalla S2123, Argentina; (M.S.); (M.P.); (J.P.A.O.)
| | - Emidio Albertini
- Department Agricultural, Food and Environmental Sciences, University of Perugia, 06121 Perugia, Italy; (G.M.); (M.D.M.)
| | - Luciana Delgado
- CONICET-UNR/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), Universidad Nacional de Rosario, Zavalla S2123, Argentina; (M.S.); (M.P.); (J.P.A.O.)
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8
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Mau M, Liiving T, Fomenko L, Goertzen R, Paczesniak D, Böttner L, Sharbel TF. The spread of infectious asexuality through haploid pollen. THE NEW PHYTOLOGIST 2021; 230:804-820. [PMID: 33421128 DOI: 10.1111/nph.17174] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 12/26/2020] [Indexed: 05/16/2023]
Abstract
The mechanisms of initiation and transmission of apomixis (asexual reproduction through seeds) in natural plant populations are important for understanding the evolution of reproductive variation. Here, we used the phylogenetic diversity of the genus Boechera (Brassicaceae), together with natural diversity in pollen types produced by apomictic lines, to test whether hybridization triggers the transition to asexuality, and whether a 'triploid bridge' is required for the formation of polyploid apomicts. We performed crosses between diploid sexual recipient and diploid apomictic donor lines and tested whether the mating system (interspecific hybridization vs intraspecific outcrossing) or pollen type (haploid vs diploid) influenced the transmission of apomixis from diploid apomictic donors into sexual recipients. We used genetic markers and flow cytometric analyses of embryo and endosperm in seeds to infer the reproductive mode. Within a single generation, initiation of both diploid and polyploid apomixis in sexual Boechera can occur. Diploid apomixis is transmitted through haploid pollen (infectious asexuality) and polyploids can form through multiple pathways. The three functional elements of apomixis occasionally segregate. Variation in pollen ploidy and the segregation of apomixis elements drive reproductive diversity of hybrids and outcrosses and can be utilized for apomixis initiation in crop breeding programs.
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Affiliation(s)
- Martin Mau
- Apomixis Research Group, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, D-06466, Germany
- Global Institute for Food Security, University of Saskatchewan, 110 Gymnasium Place, Saskatoon, SK, S7N5C2, Canada
| | - Tiina Liiving
- Apomixis Research Group, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, D-06466, Germany
- Global Institute for Food Security, University of Saskatchewan, 110 Gymnasium Place, Saskatoon, SK, S7N5C2, Canada
| | - Liza Fomenko
- Global Institute for Food Security, University of Saskatchewan, 110 Gymnasium Place, Saskatoon, SK, S7N5C2, Canada
| | - Richard Goertzen
- Global Institute for Food Security, University of Saskatchewan, 110 Gymnasium Place, Saskatoon, SK, S7N5C2, Canada
| | - Dorota Paczesniak
- Apomixis Research Group, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, D-06466, Germany
- Global Institute for Food Security, University of Saskatchewan, 110 Gymnasium Place, Saskatoon, SK, S7N5C2, Canada
| | - Laura Böttner
- Apomixis Research Group, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, D-06466, Germany
| | - Timothy F Sharbel
- Apomixis Research Group, Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Gatersleben, D-06466, Germany
- Global Institute for Food Security, University of Saskatchewan, 110 Gymnasium Place, Saskatoon, SK, S7N5C2, Canada
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Ortiz JPA, Pupilli F, Acuña CA, Leblanc O, Pessino SC. How to Become an Apomixis Model: The Multifaceted Case of Paspalum. Genes (Basel) 2020; 11:E974. [PMID: 32839398 PMCID: PMC7564465 DOI: 10.3390/genes11090974] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 12/12/2022] Open
Abstract
In the past decades, the grasses of the Paspalum genus have emerged as a versatile model allowing evolutionary, genetic, molecular, and developmental studies on apomixis as well as successful breeding applications. The rise of such an archetypal system progressed through integrative phases, which were essential to draw conclusions based on solid standards. Here, we review the steps adopted in Paspalum to establish the current body of knowledge on apomixis and provide model breeding programs for other agronomically important apomictic crops. In particular, we discuss the need for previous detailed cytoembryological and cytogenetic germplasm characterization; the establishment of sexual and apomictic materials of identical ploidy level; the development of segregating populations useful for inheritance analysis, positional mapping, and epigenetic control studies; the development of omics data resources; the identification of key molecular pathways via comparative gene expression studies; the accurate molecular characterization of genomic loci governing apomixis; the in-depth functional analysis of selected candidate genes in apomictic and model species; the successful building of a sexual/apomictic combined breeding scheme.
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Affiliation(s)
- Juan Pablo A. Ortiz
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, S2125ZAA Zavalla, Argentina;
| | - Fulvio Pupilli
- Institute of Biosciences and Bioresources (IBBR-CNR), 06128 Perugia, Italy;
| | - Carlos A. Acuña
- Instituto de Botánica del Nordeste (IBONE), CONICET, Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, 3400 Corrientes, Argentina;
| | - Olivier Leblanc
- UMR DIADE, IRD, Univ. Montpellier, 34090 Montpellier, France;
| | - Silvina C. Pessino
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, S2125ZAA Zavalla, Argentina;
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10
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Rathore P, Raina SN, Kumar S, Bhat V. Retro-Element Gypsy-163 Is Differentially Methylated in Reproductive Tissues of Apomictic and Sexual Plants of Cenchrus ciliaris. Front Genet 2020; 11:795. [PMID: 32849800 PMCID: PMC7387646 DOI: 10.3389/fgene.2020.00795] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 07/03/2020] [Indexed: 11/18/2022] Open
Abstract
Apomixis, an asexual mode of reproduction through seeds, has immense scope for crop improvement due to its ability to fix hybrid vigor. In C. ciliaris, a predominantly apomictically reproducing range grass, apomixis is genetically controlled by an apospory-specific-genomic-region (ASGR) which is enriched with retrotransposons. Earlier studies showed insertional polymorphisms of a few ASGR-specific retrotransposons between apomictic and sexual plants of C. ciliaris. REs are mainly regulated at the transcriptional level through cytosine methylation. To understand the possible association of ASGR-specific retrotransposon to apomixis, the extent and pattern of differential methylation of Gy163 RE and its impact on transcription were investigated in two genotypes each of apomictic and sexual plants of C. ciliaris. We observed that Gy163 encodes for an integrase domain of RE Ty3-Gypsy, is differentially methylated between reproductive tissues of apomictic and sexual plants. However, leaf tissues did not exhibit differential methylation between apomictic and sexual plants. Among the three contexts (CG, CHG, and CHH) of cytosine methylation, the maximum variation was observed in CHH context in reproductive (at aposporous initial and mature embryo sac stages) tissues of apomictic plants implicating RdDM pathway in methylation of Gy163. Quantitative PCR analysis showed that Gy163 transcripts are expressed more in the reproductive tissues of apomictic plants compared to that in the sexual plants, which was negatively correlated with the methylation level. Thus, the study helps in understanding the role of RE present in ASGR in epigenetic regulation of apomictic mode of reproduction in C. ciliaris.
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Affiliation(s)
- Priyanka Rathore
- Department of Botany, Faculty of Science, University of Delhi, New Delhi, India
| | - Soom Nath Raina
- Amity Institute of Biotechnology, Amity University, Noida, India
| | - Suresh Kumar
- Division of Biochemistry, ICAR-Indian Agricultural Research Institute, New Delhi, India
| | - Vishnu Bhat
- Department of Botany, Faculty of Science, University of Delhi, New Delhi, India
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11
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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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12
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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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14
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Coexpression and Transcriptome analyses identify active Apomixis-related genes in Paspalum notatum leaves. BMC Genomics 2020; 21:78. [PMID: 31992196 PMCID: PMC6986084 DOI: 10.1186/s12864-020-6518-z] [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: 06/26/2019] [Accepted: 01/20/2020] [Indexed: 11/12/2022] Open
Abstract
Background Paspalum notatum exhibits both sexual and apomictic cytotypes and, thus, is considered a good model for studies of apomixis because it facilitates comparative approaches. In this work, transcriptome sequencing was used to compare contrasting P. notatum cytotypes to identify differential expression patterns and candidate genes involved in the regulation of expression of this trait. Results We built a comprehensive transcriptome using leaf and inflorescence from apomictic tetraploids and sexual diploids/tetraploids and a coexpression network based on pairwise correlations between transcript expression profiles. We identified genes exclusively expressed in each cytotype and genes differentially expressed between pairs of cytotypes. Gene Ontology enrichment analyses were performed to better interpret the data. We de novo assembled 114,306 reference transcripts. In total, 536 candidate genes possibly associated with apomixis were detected through statistical analyses of the differential expression data, and several interacting genes potentially linked to the apomixis-controlling region, genes that have already been reported in the literature, and their neighbors were transcriptionally related in the coexpression network. Conclusions Apomixis is a highly desirable trait in modern agriculture due to the maintenance of the characteristics of the mother plant in the progeny. The reference transcriptome, candidate genes and their coexpression network identified in this work represent rich resources for future grass breeding programs.
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Albertini E, Barcaccia G, Carman JG, Pupilli F. Did apomixis evolve from sex or was it the other way around? JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2951-2964. [PMID: 30854543 DOI: 10.1093/jxb/erz109] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 02/25/2019] [Indexed: 05/20/2023]
Abstract
In angiosperms, there are two pathways of reproduction through seeds: sexual, or amphimictic, and asexual, or apomictic. The essential feature of apomixis is that an embryo in an ovule is formed autonomously. It may form from a cell of the nucellus or integuments in an otherwise sexual ovule, a process referred to as adventitious embryony. Alternatively, the embryo may form by parthenogenesis from an unreduced egg that forms in an unreduced embryo sac. The latter may form from an ameiotic megasporocyte, in which case it is referred to as diplospory, or from a cell of the nucellus or integument, in which case it is referred to as apospory. Progeny of apomictic plants are generally identical to the mother plant. Apomixis has been seen over the years as either a gain- or loss-of-function over sexuality, implying that the latter is the default condition. Here, we consider an additional point of view, that apomixis may be anciently polyphenic with sex and that both reproductive phenisms involve anciently canalized components of complex molecular processes. This polyphenism viewpoint suggests that apomixis fails to occur in obligately sexual eukaryotes because genetic or epigenetic modifications have silenced the primitive sex apomixis switch and/or disrupted molecular capacities for apomixis. In eukaryotes where sex and apomixis are clearly polyphenic, apomixis exponentially drives clonal fecundity during reproductively favorable conditions, while stress induces sex for stress-tolerant spore or egg formation. The latter often guarantees species survival during environmentally harsh seasons.
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Affiliation(s)
- Emidio Albertini
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Perugia, Italy
| | - Gianni Barcaccia
- Laboratory of Genomics, Department of Agronomy, Food, Natural Resources, Animals and the Environment (DAFNAE), University of Padova Legnaro, PD, Italy
| | - John G Carman
- Department of Plants, Soils and Climate, Utah State University, Logan, Utah, USA
| | - Fulvio Pupilli
- Institute of Biosciences and Bioresources, Research Division of Perugia, National Research Council (CNR), Perugia, Italy
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Brukhin V, Osadtchiy JV, Florez-Rueda AM, Smetanin D, Bakin E, Nobre MS, Grossniklaus U. The Boechera Genus as a Resource for Apomixis Research. FRONTIERS IN PLANT SCIENCE 2019; 10:392. [PMID: 31001306 PMCID: PMC6454215 DOI: 10.3389/fpls.2019.00392] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 03/14/2019] [Indexed: 05/03/2023]
Abstract
The genera Boechera (A. Löve et D. Löve) and Arabidopsis, the latter containing the model plant Arabidopsis thaliana, belong to the same clade within the Brassicaceae family. Boechera is the only among the more than 370 genera in the Brassicaceae where apomixis is well documented. Apomixis refers to the asexual reproduction through seed, and a better understanding of the underlying mechanisms has great potential for applications in agriculture. The Boechera genus currently includes 110 species (of which 38 are reported to be triploid and thus apomictic), which are distributed mostly in the North America. The apomictic lineages of Boechera occur at both the diploid and triploid level and show signs of a hybridogenic origin, resulting in a modification of their chromosome structure, as reflected by alloploidy, aneuploidy, substitutions of homeologous chromosomes, and the presence of aberrant chromosomes. In this review, we discuss the advantages of the Boechera genus to study apomixis, consider its modes of reproduction as well as the inheritance and possible mechanisms controlling apomixis. We also consider population genetic aspects and a possible role of hybridization at the origin of apomixis in Boechera. The molecular tools available to study Boechera, such as transformation techniques, laser capture microdissection, analysis of transcriptomes etc. are also discussed. We survey available genome assemblies of Boechera spp. and point out the challenges to assemble the highly heterozygous genomes of apomictic species. Due to these challenges, we argue for the application of an alternative reference-free method for the comparative analysis of such genomes, provide an overview of genomic sequencing data in the genus Boechera suitable for such analysis, and provide examples of its application.
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Affiliation(s)
- Vladimir Brukhin
- Theodosius Dobzhansky Center for Genome Bioinformatics, St. Petersburg State University, Saint Petersburg, Russia
- Department of Plant Embryology and Reproductive Biology, Komarov Botanical Institute RAS, Saint Petersburg, Russia
| | - Jaroslaw V. Osadtchiy
- Department of Plant Embryology and Reproductive Biology, Komarov Botanical Institute RAS, Saint Petersburg, Russia
| | - Ana Marcela Florez-Rueda
- Department of Plant and Microbial Biology, Zürich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Dmitry Smetanin
- Department of Plant and Microbial Biology, Zürich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Evgeny Bakin
- Theodosius Dobzhansky Center for Genome Bioinformatics, St. Petersburg State University, Saint Petersburg, Russia
- Bioinformatics Institute, Saint Petersburg, Russia
| | - Margarida Sofia Nobre
- Department of Plant and Microbial Biology, Zürich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology, Zürich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
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Kaushal P, Dwivedi KK, Radhakrishna A, Srivastava MK, Kumar V, Roy AK, Malaviya DR. Partitioning Apomixis Components to Understand and Utilize Gametophytic Apomixis. FRONTIERS IN PLANT SCIENCE 2019; 10:256. [PMID: 30906306 PMCID: PMC6418048 DOI: 10.3389/fpls.2019.00256] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 02/18/2019] [Indexed: 05/07/2023]
Abstract
Apomixis is a method of reproduction to generate clonal seeds and offers tremendous potential to fix heterozygosity and hybrid vigor. The process of apomictic seed development is complex and comprises three distinct components, viz., apomeiosis (leading to formation of unreduced egg cell), parthenogenesis (development of embryo without fertilization) and functional endosperm development. Recently, in many crops, these three components are reported to be uncoupled leading to their partitioning. This review provides insight into the recent status of our understanding surrounding partitioning apomixis components in gametophytic apomictic plants and research avenues that it offers to help understand the biology of apomixis. Possible consequences leading to diversity in seed developmental pathways, resources to understand apomixis, inheritance and identification of candidate gene(s) for partitioned components, as well as contribution towards creation of variability are all discussed. The potential of Panicum maximum, an aposporous crop, is also discussed as a model crop to study partitioning principle and effects. Modifications in cytogenetic status, as well as endosperm imprinting effects arising due to partitioning effects, opens up new opportunities to understand and utilize apomixis components, especially towards synthesizing apomixis in crops.
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Affiliation(s)
- Pankaj Kaushal
- ICAR-National Institute of Biotic Stress Management, Raipur, India
| | | | | | | | - Vinay Kumar
- ICAR-National Institute of Biotic Stress Management, Raipur, India
| | - Ajoy Kumar Roy
- ICAR-Indian Grassland and Fodder Research Institute, Jhansi, India
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18
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Galla G, Siena LA, Ortiz JPA, Baumlein H, Barcaccia G, Pessino SC, Bellucci M, Pupilli F. A Portion of the Apomixis Locus of Paspalum Simplex is Microsyntenic with an Unstable Chromosome Segment Highly Conserved Among Poaceae. Sci Rep 2019; 9:3271. [PMID: 30824748 PMCID: PMC6397161 DOI: 10.1038/s41598-019-39649-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2018] [Accepted: 01/16/2019] [Indexed: 01/04/2023] Open
Abstract
The introgression of apomixis in major seed crops, would guarantee self-seeding of superior heterotic seeds over generations. In the grass species Paspalum simplex, apomixis is controlled by a single locus in which recombination is blocked. In the perspective of isolating the genetic determinants of apomixis, we report data on sequencing, in silico mapping and expression analysis of some of the genes contained in two cloned genomic regions of the apomixis locus of P. simplex. In silico mapping allowed us to identify a conserved synteny group homoeologous to the apomixis locus, located on a telomeric position of chromosomes 12, 8, 3 and 4 of rice, Sorghum bicolor, Setaria italica and Brachypodium distachyum, respectively, and on a more centromeric position of maize chromosome 1. Selected genes of the apomixis locus expressed sense and antisense transcripts in reproductively committed cells of sexual and apomictic ovules. Some of the genes considered here expressed apomixis-specific allelic variants which showed partial non-overlapping expression patterns with alleles shared by sexual and apomictic reproductive phenotypes. Our findings open new routes for the isolation of the genetic determinants of apomixis and, in perspective, for its introgression in crop grasses.
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Affiliation(s)
- Giulio Galla
- Department of Agriculture Food Natural resources Animals and Environment (DAFNAE), University of Padova, 35020, Legnaro (PD), Italy
| | - Lorena A Siena
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET-UNR, Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | - Juan Pablo A Ortiz
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET-UNR, Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | - Helmut Baumlein
- The Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), D-06466, Gatersleben, Germany
| | - Gianni Barcaccia
- Department of Agriculture Food Natural resources Animals and Environment (DAFNAE), University of Padova, 35020, Legnaro (PD), Italy
| | - Silvina C Pessino
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET-UNR, Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, S2125ZAA, Zavalla, Argentina
| | - Michele Bellucci
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy
| | - Fulvio Pupilli
- Institute of Biosciences and Bioresources (IBBR), National Research Council (CNR), 06128, Perugia, Italy.
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Worthington M, Ebina M, Yamanaka N, Heffelfinger C, Quintero C, Zapata YP, Perez JG, Selvaraj M, Ishitani M, Duitama J, de la Hoz JF, Rao I, Dellaporta S, Tohme J, Arango J. Translocation of a parthenogenesis gene candidate to an alternate carrier chromosome in apomictic Brachiaria humidicola. BMC Genomics 2019; 20:41. [PMID: 30642244 PMCID: PMC6332668 DOI: 10.1186/s12864-018-5392-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Accepted: 12/18/2018] [Indexed: 12/05/2022] Open
Abstract
Background The apomictic reproductive mode of Brachiaria (syn. Urochloa) forage species allows breeders to faithfully propagate heterozygous genotypes through seed over multiple generations. In Brachiaria, reproductive mode segregates as single dominant locus, the apospory-specific genomic region (ASGR). The AGSR has been mapped to an area of reduced recombination on Brachiaria decumbens chromosome 5. A primer pair designed within ASGR-BABY BOOM-like (BBML), the candidate gene for the parthenogenesis component of apomixis in Pennisetum squamulatum, was diagnostic for reproductive mode in the closely related species B. ruziziensis, B. brizantha, and B. decumbens. In this study, we used a mapping population of the distantly related commercial species B. humidicola to map the ASGR and test for conservation of ASGR-BBML sequences across Brachiaria species. Results Dense genetic maps were constructed for the maternal and paternal genomes of a hexaploid (2n = 6x = 36) B. humidicola F1 mapping population (n = 102) using genotyping-by-sequencing, simple sequence repeat, amplified fragment length polymorphism, and transcriptome derived single nucleotide polymorphism markers. Comparative genomics with Setaria italica provided confirmation for x = 6 as the base chromosome number of B. humidicola. High resolution molecular karyotyping indicated that the six homologous chromosomes of the sexual female parent paired at random, whereas preferential pairing of subgenomes was observed in the apomictic male parent. Furthermore, evidence for compensated aneuploidy was found in the apomictic parent, with only five homologous linkage groups identified for chromosome 5 and seven homologous linkage groups of chromosome 6. The ASGR mapped to B. humidicola chromosome 1, a region syntenic with chromosomes 1 and 7 of S. italica. The ASGR-BBML specific PCR product cosegregated with the ASGR in the F1 mapping population, despite its location on a different carrier chromosome than B. decumbens. Conclusions The first dense molecular maps of B. humidicola provide strong support for cytogenetic evidence indicating a base chromosome number of six in this species. Furthermore, these results show conservation of the ASGR across the Paniceae in different chromosomal backgrounds and support postulation of the ASGR-BBML as candidate genes for the parthenogenesis component of apomixis. Electronic supplementary material The online version of this article (10.1186/s12864-018-5392-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Margaret Worthington
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia. .,Present address: Department of Horticulture, University of Arkansas, 306 Plant Sciences Bldg, Fayetteville, AR, 72701, USA.
| | - Masumi Ebina
- National Agriculture and Food Research Organization (NARO), Institute of Livestock and Grassland Science, Nasushiobara, Tochigi, 392-2793, Japan
| | - Naoki Yamanaka
- Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki, 305-8686, Japan
| | - Christopher Heffelfinger
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, 06520, USA
| | - Constanza Quintero
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
| | | | | | - Michael Selvaraj
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
| | - Manabu Ishitani
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
| | - Jorge Duitama
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia.,Present address: Systems and Computing Engineering Department, Universidad de los Andes, Bogotá, Colombia
| | - Juan Fernando de la Hoz
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia.,Present address: Bioinformatics Interdepartmental Ph.D. Program, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Idupulapati Rao
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia.,Present address: Plant Polymer Research Unit (PPL), National Center for Agricultural Utilization Research (NCAUR), Agricultural Research Service, United States Department of Agriculture (ARS-USDA), 1815 N. University St., Peoria, IL, 61604, USA
| | - Stephen Dellaporta
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, 06520, USA
| | - Joe Tohme
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
| | - Jacobo Arango
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
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20
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Zappacosta D, Gallardo J, Carballo J, Meier M, Rodrigo JM, Gallo CA, Selva JP, Stein J, Ortiz JPA, Albertini E, Echenique V. A High-Density Linkage Map of the Forage Grass Eragrostis curvula and Localization of the Diplospory Locus. FRONTIERS IN PLANT SCIENCE 2019; 10:918. [PMID: 31354781 PMCID: PMC6640543 DOI: 10.3389/fpls.2019.00918] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2018] [Accepted: 06/28/2019] [Indexed: 05/05/2023]
Abstract
Eragrostis curvula (Schrad.) Nees (weeping lovegrass) is an apomictic species native to Southern Africa that is used as forage grass in semiarid regions of Argentina. Apomixis is a mechanism for clonal propagation through seeds that involves the avoidance of meiosis to generate an unreduced embryo sac (apomeiosis), parthenogenesis, and viable endosperm formation in a fertilization-dependent or -independent manner. Here, we constructed the first saturated linkage map of tetraploid E. curvula using both traditional (AFLP and SSR) and high-throughput molecular markers (GBS-SNP) and identified the locus controlling diplospory. We also identified putative regulatory regions affecting the expressivity of this trait and syntenic relationships with genomes of other grass species. We obtained a tetraploid mapping population from a cross between a full sexual genotype (OTA-S) with a facultative apomictic individual of cv. Don Walter. Phenotypic characterization of F1 hybrids by cytoembryological analysis yielded a 1:1 ratio of apomictic vs. sexual plants (34:27, X 2 = 0.37), which agrees with the model of inheritance of a single dominant genetic factor. The final number of markers was 1,114 for OTA-S and 2,019 for Don Walter. These markers were distributed into 40 linkage groups per parental genotype, which is consistent with the number of E. curvula chromosomes (containing 2 to 123 markers per linkage group). The total length of the OTA-S map was 1,335 cM, with an average marker density of 1.22 cM per marker. The Don Walter map was 1,976.2 cM, with an average marker density of 0.98 cM/marker. The locus responsible for diplospory was mapped on Don Walter linkage group 3, with other 65 markers. QTL analyses of the expressivity of diplospory in the F1 hybrids revealed the presence of two main QTLs, located 3.27 and 15 cM from the diplospory locus. Both QTLs explained 28.6% of phenotypic variation. Syntenic analysis allowed us to establish the groups of homologs/homeologs for each linkage map. The genetic linkage map reported in this study, the first such map for E. curvula, is the most saturated map for the genus Eragrostis and one of the most saturated maps for a polyploid forage grass species.
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Affiliation(s)
- Diego Zappacosta
- Departamento de Agronomía, Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS-CONICET, CCT Bahía Blanca), Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - Jimena Gallardo
- Departamento de Agronomía, Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS-CONICET, CCT Bahía Blanca), Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - José Carballo
- Departamento de Agronomía, Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS-CONICET, CCT Bahía Blanca), Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - Mauro Meier
- Laboratorio Biotecnológico, Asociación de Cooperativas Argentinas Coop. Ltd., Pergamino, Argentina
| | - Juan Manuel Rodrigo
- Departamento de Agronomía, Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS-CONICET, CCT Bahía Blanca), Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - Cristian A. Gallo
- Departamento de Agronomía, Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS-CONICET, CCT Bahía Blanca), Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - Juan Pablo Selva
- Departamento de Agronomía, Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS-CONICET, CCT Bahía Blanca), Universidad Nacional del Sur, Bahía Blanca, Argentina
| | - Juliana Stein
- Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR, CONICET-UNR), Zavalla, Argentina
| | - Juan Pablo A. Ortiz
- Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR, CONICET-UNR), Zavalla, Argentina
| | - Emidio Albertini
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Perugia, Italy
- Emidio Albertini,
| | - Viviana Echenique
- Departamento de Agronomía, Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS-CONICET, CCT Bahía Blanca), Universidad Nacional del Sur, Bahía Blanca, Argentina
- *Correspondence: Viviana Echenique,
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León-Martínez G, Vielle-Calzada JP. Apomixis in flowering plants: Developmental and evolutionary considerations. Curr Top Dev Biol 2019; 131:565-604. [DOI: 10.1016/bs.ctdb.2018.11.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Colono C, Ortiz JPA, Permingeat HR, Souza Canada ED, Siena LA, Spoto N, Galdeano F, Espinoza F, Leblanc O, Pessino SC. A Plant-Specific TGS1 Homolog Influences Gametophyte Development in Sexual Tetraploid Paspalum notatum Ovules. FRONTIERS IN PLANT SCIENCE 2019; 10:1566. [PMID: 31850040 PMCID: PMC6895069 DOI: 10.3389/fpls.2019.01566] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Accepted: 11/08/2019] [Indexed: 05/04/2023]
Abstract
Aposporous apomictic plants form clonal maternal seeds by inducing the emergence of non-reduced (2n) embryo sacs in the ovule nucellus and the development of embryos by parthenogenesis. In previous work, we reported a plant-specific TRIMETHYLGUANOSINE SYNTHASE 1 (TGS1) gene (PN_TGS1-like) showing expression levels positively correlated with sexuality rates in facultative apomictic Paspalum notatum. PN_ TGS1-like displayed contrasting in situ hybridization patterns in apomictic and sexual plant ovules from premeiosis to anthesis. Here we transformed sexual P. notatum with a TGS1-like antisense construction under a constitutive promoter, in order to produce lines with reduced transcript representation. Antisense plants developed prominent trichomes on the adaxial leaf surface, a trait absent from control genotypes. Reproductive development analysis revealed occasional formation of twin ovules. While control individuals typically displayed a single meiotic embryo sac per ovule, antisense lines showed 12.93-15.79% of ovules bearing extra nuclei, which can be assigned to aposporous-like embryo sacs (AES-like) or, alternatively, to gametophytes with a misguided cell fate development. Moreover, around 8.42-9.52% of ovules showed what looked like a combination of meiotic and aposporous-like sacs. Besides, 32.5% of ovules at early developmental stages displayed nucellar cells with prominent nuclei resembling apospory initials (AIs), which surrounded the megaspore mother cell (MMC) or the MMC-derived meiotic products. Two or more concurrent meiosis events were never detected, which suggest a non-reduced nature for the extra nuclei observed in the mature ovules, unless they were generated by proliferation and misguided differentiation of the legitimate meiotic products. The antisense lines produced a similar amount of viable even-sized pollen with respect to control genotypes, and formed an equivalent full seed set (∼9% of total seeds) after self-pollination. Flow cytometry analyses of caryopses derived from antisense lines revealed that all full seeds had originated from meiotic embryo sacs (i.e. by sexuality). A reduction of 25.55% in the germination percentage was detected when comparing antisense lines with controls. Our results indicate that PN_ TGS1-like influences ovule, gametophyte and possibly embryo development.
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Affiliation(s)
- Carolina Colono
- Molecular Biology Laboratory, IICAR, CONICET, Universidad Nacional de Rosario, Rosario, Argentina
| | - Juan Pablo A. Ortiz
- Molecular Biology Laboratory, IICAR, CONICET, Universidad Nacional de Rosario, Rosario, Argentina
| | - Hugo R. Permingeat
- Molecular Biology Laboratory, IICAR, CONICET, Universidad Nacional de Rosario, Rosario, Argentina
| | | | - Lorena A. Siena
- Molecular Biology Laboratory, IICAR, CONICET, Universidad Nacional de Rosario, Rosario, Argentina
| | - Nicolás Spoto
- Molecular Biology Laboratory, IICAR, CONICET, Universidad Nacional de Rosario, Rosario, Argentina
| | - Florencia Galdeano
- Genetics Laboratory, IBONE, CONICET, Universidad Nacional del Nordeste, Corrientes, Argentina
| | - Francisco Espinoza
- Genetics Laboratory, IBONE, CONICET, Universidad Nacional del Nordeste, Corrientes, Argentina
| | | | - Silvina C. Pessino
- Molecular Biology Laboratory, IICAR, CONICET, Universidad Nacional de Rosario, Rosario, Argentina
- *Correspondence: Silvina C. Pessino,
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The vesicle trafficking regulator PN_SCD1 is demethylated and overexpressed in florets of apomictic Paspalum notatum genotypes. Sci Rep 2018; 8:3030. [PMID: 29445151 PMCID: PMC5812994 DOI: 10.1038/s41598-018-21220-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 01/31/2018] [Indexed: 01/01/2023] Open
Abstract
Apomixis (asexual reproduction through seeds) is considered a deviation of the sexual reproductive pathway leading to the development of clonal progenies genetically identical to the mother plant. Here we used the Methylation-Sensitive Amplification Polymorphism (MSAP) technique to characterize cytosine methylation patterns occurring in florets of sexual and aposporous Paspalum notatum genotypes, in order to identify epigenetically-controlled genes putatively involved in apomixis development. From twelve polymorphic MSAP-derived sequences, one (PN_6.6, later renamed PN_SCD1) was selected due to its relevant annotation and differential representation in apomictic and sexual floral transcriptome libraries. PN_SCD1 encodes the DENN domain/WD repeat-containing protein SCD1, which interacts with RAB GTPases- and/or MAPKs to promote specialized cell division, functions in clathrin-mediated membrane transport and acts as potential substrate receptor of CUL4 E3 ubiquitin ligases. Quantitative RT-PCR and comparative RNAseq analyses of laser microdissected nucellar cells confirmed PN_SCD1 upregulation in florets of apomictic plants and revealed that overexpression takes place just before the onset of apospory initials. Moreover, we found that several SCD1 molecular partners are expressed in P. notatum florets and upregulated in apomictic plants. Our results disclosed a specific vesicle trafficking molecular pathway epigenetically modulated during apomixis.
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Ortiz JPA, Revale S, Siena LA, Podio M, Delgado L, Stein J, Leblanc O, Pessino SC. A reference floral transcriptome of sexual and apomictic Paspalum notatum. BMC Genomics 2017; 18:318. [PMID: 28431521 PMCID: PMC5399859 DOI: 10.1186/s12864-017-3700-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 04/11/2017] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Paspalum notatum Flügge is a subtropical grass native to South America, which includes sexual diploid and apomictic polyploid biotypes. In the past decade, a number of apomixis-associated genes were discovered in this species through genetic mapping and differential expression surveys. However, the scarce information on Paspalum sequences available in public databanks limited annotations and functional predictions for these candidates. RESULTS We used a long-read 454/Roche FLX+ sequencing strategy to produce robust reference transcriptome datasets from florets of sexual and apomictic Paspalum notatum genotypes and delivered a list of transcripts showing differential representation in both reproductive types. Raw data originated from floral samples collected from premeiosis to anthesis was assembled in three libraries: i) sexual (SEX), ii) apomictic (APO) and iii) global (SEX + APO). A group of physically-supported Paspalum mRNA and EST sequences matched with high level of confidence to both sexual and apomictic libraries. A preliminary trial allowed discovery of the whole set of putative alleles/paralogs corresponding to 23 previously identified apomixis-associated candidate genes. Moreover, a list of 3,732 transcripts and several co-expression and protein -protein interaction networks associated with apomixis were identified. CONCLUSIONS The use of the 454/Roche FLX+ transcriptome database will allow the detailed characterization of floral alleles/paralogs of apomixis candidate genes identified in prior and future work. Moreover, it was used to reveal additional candidate genes differentially represented in apomictic and sexual flowers. Gene ontology (GO) analyses of this set of transcripts indicated that the main molecular pathways altered in the apomictic genotype correspond to specific biological processes, like biotic and abiotic stress responses, growth, development, cell death and senescence. This data collection will be of interest to the plant reproduction research community and, particularly, to Paspalum breeding projects.
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Affiliation(s)
- Juan Pablo A Ortiz
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR)-CONICET/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino, Provincia de Santa Fe, Zavalla, S2125ZAA, Argentina
| | - Santiago Revale
- Instituto de Agrobiotecnología de Rosario (INDEAR), Ocampo 210 bis, Provincia de Santa Fe, Rosario, 2000, Argentina.,Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Lorena A Siena
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR)-CONICET/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino, Provincia de Santa Fe, Zavalla, S2125ZAA, Argentina
| | - Maricel Podio
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR)-CONICET/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino, Provincia de Santa Fe, Zavalla, S2125ZAA, Argentina
| | - Luciana Delgado
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR)-CONICET/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino, Provincia de Santa Fe, Zavalla, S2125ZAA, Argentina
| | - Juliana Stein
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR)-CONICET/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino, Provincia de Santa Fe, Zavalla, S2125ZAA, Argentina
| | - Olivier Leblanc
- UMR 232, Institut de Recherche pour le Développement, Université de Montpellier, Montpellier, 34394, France
| | - Silvina C Pessino
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR)-CONICET/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino, Provincia de Santa Fe, Zavalla, S2125ZAA, Argentina.
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Siena LA, Ortiz JPA, Calderini O, Paolocci F, Cáceres ME, Kaushal P, Grisan S, Pessino SC, Pupilli F. An apomixis-linked ORC3-like pseudogene is associated with silencing of its functional homolog in apomictic Paspalum simplex. JOURNAL OF EXPERIMENTAL BOTANY 2016; 67:1965-78. [PMID: 26842983 DOI: 10.1093/jxb/erw018] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Apomixis in plants consists of asexual reproduction by seeds. Here we characterized at structural and functional levels an apomixis-linked sequence of Paspalum simplex homologous to subunit 3 of the ORIGIN RECOGNITION COMPLEX (ORC3). ORC is a multiprotein complex which controls DNA replication and cell differentiation in eukaryotes. Three PsORC3 copies were identified, each one characterized by a specific expression profile. Of these, PsORC3a, specific for apomictic genotypes, is a pseudogene that was poorly and constitutively expressed in all developmental stages of apomictic flowers, whereas PsORC3b, the putative functional gene in sexual flowers, showed a precise time-related regulation. Sense transcripts of PsORC3 were expressed in the female cell lineage of both apomictic and sexual reproductive phenotypes, and in aposporous initials. Although strong expression was detected in sexual early endosperm, no expression was present in the apomictic endosperm. Antisense PsORC3 transcripts were revealed exclusively in apomictic germ cell lineages. Defective orc3 mutants of rice and Arabidopsis showed normal female gametophytes although the embryo and endosperm were arrested at early phases of development. We hypothesize that PsORC3a is associated with the down-regulation of its functional homolog and with the development of apomictic endosperm which deviates from the canonical 2(maternal):1(paternal) genome ratio.
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Affiliation(s)
- Lorena A Siena
- Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, (S2125ZAA) Zavalla, Argentina Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR-CONICET-UNR), Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, (S2125ZAA) Zavalla, Argentina
| | - Juan Pablo A Ortiz
- Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, (S2125ZAA) Zavalla, Argentina Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR-CONICET-UNR), Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, (S2125ZAA) Zavalla, Argentina
| | - Ornella Calderini
- Istituto di Bioscienze e Biorisorse (IBBR-CNR), via della Madonna alta 130, I-06128 Perugia, Italy
| | - Francesco Paolocci
- Istituto di Bioscienze e Biorisorse (IBBR-CNR), via della Madonna alta 130, I-06128 Perugia, Italy
| | - Maria E Cáceres
- Istituto di Bioscienze e Biorisorse (IBBR-CNR), via della Madonna alta 130, I-06128 Perugia, Italy
| | - Pankaj Kaushal
- Istituto di Bioscienze e Biorisorse (IBBR-CNR), via della Madonna alta 130, I-06128 Perugia, Italy
| | - Simone Grisan
- Istituto di Bioscienze e Biorisorse (IBBR-CNR), via della Madonna alta 130, I-06128 Perugia, Italy
| | - Silvina C Pessino
- Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, (S2125ZAA) Zavalla, Argentina Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR-CONICET-UNR), Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, (S2125ZAA) Zavalla, Argentina
| | - Fulvio Pupilli
- Istituto di Bioscienze e Biorisorse (IBBR-CNR), via della Madonna alta 130, I-06128 Perugia, Italy
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Abstract
Apomixis (asexual seed formation) is the result of a plant gaining the ability to bypass the most fundamental aspects of sexual reproduction: meiosis and fertilization. Without the need for male fertilization, the resulting seed germinates a plant that develops as a maternal clone. This dramatic shift in reproductive process has been documented in many flowering plant species, although no major seed crops have been shown to be capable of apomixis. The ability to generate maternal clones and therefore rapidly fix desirable genotypes in crop species could accelerate agricultural breeding strategies. The potential of apomixis as a next-generation breeding technology has contributed to increasing interest in the mechanisms controlling apomixis. In this review, we discuss the progress made toward understanding the genetic and molecular control of apomixis. Research is currently focused on two fronts. One aims to identify and characterize genes causing apomixis in apomictic species that have been developed as model species. The other aims to engineer or switch the sexual seed formation pathway in non-apomictic species, to one that mimics apomixis. Here we describe the major apomictic mechanisms and update knowledge concerning the loci that control them, in addition to presenting candidate genes that may be used as tools for switching the sexual pathway to an apomictic mode of reproduction in crops.
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Shirasawa K, Hand ML, Henderson ST, Okada T, Johnson SD, Taylor JM, Spriggs A, Siddons H, Hirakawa H, Isobe S, Tabata S, Koltunow AMG. A reference genetic linkage map of apomictic Hieracium species based on expressed markers derived from developing ovule transcripts. ANNALS OF BOTANY 2015; 115:567-80. [PMID: 25538115 PMCID: PMC4343286 DOI: 10.1093/aob/mcu249] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
BACKGROUND AND AIMS Apomixis in plants generates clonal progeny with a maternal genotype through asexual seed formation. Hieracium subgenus Pilosella (Asteraceae) contains polyploid, highly heterozygous apomictic and sexual species. Within apomictic Hieracium, dominant genetic loci independently regulate the qualitative developmental components of apomixis. In H. praealtum, LOSS OF APOMEIOSIS (LOA) enables formation of embryo sacs without meiosis and LOSS OF PARTHENOGENESIS (LOP) enables fertilization-independent seed formation. A locus required for fertilization-independent endosperm formation (AutE) has been identified in H. piloselloides. Additional quantitative loci appear to influence the penetrance of the qualitative loci, although the controlling genes remain unknown. This study aimed to develop the first genetic linkage maps for sexual and apomictic Hieracium species using simple sequence repeat (SSR) markers derived from expressed transcripts within the developing ovaries. METHODS RNA from microdissected Hieracium ovule cell types and ovaries was sequenced and SSRs were identified. Two different F1 mapping populations were created to overcome difficulties associated with genome complexity and asexual reproduction. SSR markers were analysed within each mapping population to generate draft linkage maps for apomictic and sexual Hieracium species. KEY RESULTS A collection of 14 684 Hieracium expressed SSR markers were developed and linkage maps were constructed for Hieracium species using a subset of the SSR markers. Both the LOA and LOP loci were successfully assigned to linkage groups; however, AutE could not be mapped using the current populations. Comparisons with lettuce (Lactuca sativa) revealed partial macrosynteny between the two Asteraceae species. CONCLUSIONS A collection of SSR markers and draft linkage maps were developed for two apomictic and one sexual Hieracium species. These maps will support cloning of controlling genes at LOA and LOP loci in Hieracium and should also assist with identification of quantitative loci that affect the expressivity of apomixis. Future work will focus on mapping AutE using alternative populations.
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Affiliation(s)
- Kenta Shirasawa
- Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan and Commonwealth Scientific and Industrial Research Organization (CSIRO), Agriculture Flagship, Waite Campus, Hartley Grove, Urrbrae, South Australia 5064, Australia
| | - Melanie L Hand
- Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan and Commonwealth Scientific and Industrial Research Organization (CSIRO), Agriculture Flagship, Waite Campus, Hartley Grove, Urrbrae, South Australia 5064, Australia
| | - Steven T Henderson
- Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan and Commonwealth Scientific and Industrial Research Organization (CSIRO), Agriculture Flagship, Waite Campus, Hartley Grove, Urrbrae, South Australia 5064, Australia
| | - Takashi Okada
- Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan and Commonwealth Scientific and Industrial Research Organization (CSIRO), Agriculture Flagship, Waite Campus, Hartley Grove, Urrbrae, South Australia 5064, Australia
| | - Susan D Johnson
- Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan and Commonwealth Scientific and Industrial Research Organization (CSIRO), Agriculture Flagship, Waite Campus, Hartley Grove, Urrbrae, South Australia 5064, Australia
| | - Jennifer M Taylor
- Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan and Commonwealth Scientific and Industrial Research Organization (CSIRO), Agriculture Flagship, Waite Campus, Hartley Grove, Urrbrae, South Australia 5064, Australia
| | - Andrew Spriggs
- Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan and Commonwealth Scientific and Industrial Research Organization (CSIRO), Agriculture Flagship, Waite Campus, Hartley Grove, Urrbrae, South Australia 5064, Australia
| | - Hayley Siddons
- Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan and Commonwealth Scientific and Industrial Research Organization (CSIRO), Agriculture Flagship, Waite Campus, Hartley Grove, Urrbrae, South Australia 5064, Australia
| | - Hideki Hirakawa
- Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan and Commonwealth Scientific and Industrial Research Organization (CSIRO), Agriculture Flagship, Waite Campus, Hartley Grove, Urrbrae, South Australia 5064, Australia
| | - Sachiko Isobe
- Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan and Commonwealth Scientific and Industrial Research Organization (CSIRO), Agriculture Flagship, Waite Campus, Hartley Grove, Urrbrae, South Australia 5064, Australia
| | - Satoshi Tabata
- Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan and Commonwealth Scientific and Industrial Research Organization (CSIRO), Agriculture Flagship, Waite Campus, Hartley Grove, Urrbrae, South Australia 5064, Australia
| | - Anna M G Koltunow
- Kazusa DNA Research Institute, 2-6-7 Kazusa-Kamatari, Kisarazu, Chiba 292-0818, Japan and Commonwealth Scientific and Industrial Research Organization (CSIRO), Agriculture Flagship, Waite Campus, Hartley Grove, Urrbrae, South Australia 5064, Australia
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Vašut RJ, Vijverberg K, van Dijk PJ, de Jong H. Fluorescent in situ hybridization shows DIPLOSPOROUS located on one of the NOR chromosomes in apomictic dandelions (Taraxacum) in the absence of a large hemizygous chromosomal region. Genome 2015; 57:609-20. [PMID: 25760668 DOI: 10.1139/gen-2014-0143] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Apomixis in dandelions (Taraxacum: Asteraceae) is encoded by two unlinked dominant loci and a third yet undefined genetic factor: diplosporous omission of meiosis (DIPLOSPOROUS, DIP), parthenogenetic embryo development (PARTHENOGENESIS, PAR), and autonomous endosperm formation, respectively. In this study, we determined the chromosomal position of the DIP locus in Taraxacum by using fluorescent in situ hybridization (FISH) with bacterial artificial chromosomes (BACs) that genetically map within 1.2-0.2 cM of DIP. The BACs showed dispersed fluorescent signals, except for S4-BAC 83 that displayed strong unique signals as well. Under stringent blocking of repeats by C0t-DNA fragments, only a few fluorescent foci restricted to defined chromosome regions remained, including one on the nucleolus organizer region (NOR) chromosomes that contains the 45S rDNAs. FISH with S4-BAC 83 alone and optimal blocking showed discrete foci in the middle of the long arm of one of the NOR chromosomes only in triploid and tetraploid diplosporous dandelions, while signals in sexual diploids were lacking. This agrees with the genetic model of a single dose, dominant DIP allele, absent in sexuals. The length of the DIP region is estimated to cover a region of 1-10 Mb. FISH in various accessions of Taraxacum and the apomictic sister species Chondrilla juncea, confirmed the chromosomal position of DIP within Taraxacum but not outside the genus. Our results endorse that, compared to other model apomictic species, expressing either diplospory or apospory, the genome of Taraxacum shows a more similar and less diverged chromosome structure at the DIP locus. The different levels of allele sequence divergence at apomeiosis loci may reflect different terms of asexual reproduction. The association of apomeiosis loci with repetitiveness, dispersed repeats, and retrotransposons commonly observed in apomictic species may imply a functional role of these shared features in apomictic reproduction, as is discussed.
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Affiliation(s)
- Radim J Vašut
- Laboratory of Genetics, Wageningen University and Research Centre, P.O. Box 309, NL-6700 AH Wageningen, the Netherlands
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Podio M, Cáceres ME, Samoluk SS, Seijo JG, Pessino SC, Ortiz JPA, Pupilli F. A methylation status analysis of the apomixis-specific region in Paspalum spp. suggests an epigenetic control of parthenogenesis. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:6411-24. [PMID: 25180110 DOI: 10.1093/jxb/eru354] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Apomixis, a clonal plant reproduction by seeds, is controlled in Paspalum spp. by a single locus which is blocked in terms of recombination. Partial sequence analysis of the apomixis locus revealed structural features of heterochromatin, namely the presence of repetitive elements, gene degeneration, and de-regulation. To test the epigenetic control of apomixis, a study on the distribution of cytosine methylation at the apomixis locus and the effect of artificial DNA demethylation on the mode of reproduction was undertaken in two apomictic Paspalum species. The 5-methylcytosine distribution in the apomixis-controlling genomic region was studied in P. simplex by methylation-sensitive restriction fragment length polymorphism (RFLP) analysis and in P. notatum by fluorescene in situ hybridization (FISH). The effect of DNA demethylation was studied on the mode of reproduction of P. simplex by progeny test analysis of apomictic plants treated with the demethylating agent 5'-azacytidine. A high level of cytosine methylation was detected at the apomixis-controlling genomic region in both species. By analysing a total of 374 open pollination progeny, it was found that artificial demethylation had little or no effect on apospory, whereas it induced a significant depression of parthenogenesis. The results suggested that factors controlling repression of parthenogenesis might be inactivated in apomictic Paspalum by DNA methylation.
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Affiliation(s)
- Maricel Podio
- Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino s/n CC 14 (S2125 ZAA), Zavalla, Santa Fe, Argentina Instituto de Botánica del Nordeste (IBONE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Sargento Cabral 2131, 3400 Corrientes, Argentina
| | - Maria E Cáceres
- CNR-Istituto di Bioscienze e Biorisorse, Research Division: Perugia, Via della Madonna alta 130, I-06128 Perugia, Italy
| | - Sergio S Samoluk
- Instituto de Botánica del Nordeste (IBONE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Sargento Cabral 2131, 3400 Corrientes, Argentina
| | - José G Seijo
- Instituto de Botánica del Nordeste (IBONE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Sargento Cabral 2131, 3400 Corrientes, Argentina
| | - Silvina C Pessino
- Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino s/n CC 14 (S2125 ZAA), Zavalla, Santa Fe, Argentina
| | - Juan Pablo A Ortiz
- Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino s/n CC 14 (S2125 ZAA), Zavalla, Santa Fe, Argentina Instituto de Botánica del Nordeste (IBONE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Sargento Cabral 2131, 3400 Corrientes, Argentina
| | - Fulvio Pupilli
- CNR-Istituto di Bioscienze e Biorisorse, Research Division: Perugia, Via della Madonna alta 130, I-06128 Perugia, Italy
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Ortiz JPA, Quarin CL, Pessino SC, Acuña C, Martínez EJ, Espinoza F, Hojsgaard DH, Sartor ME, Cáceres ME, Pupilli F. Harnessing apomictic reproduction in grasses: what we have learned from Paspalum. ANNALS OF BOTANY 2013; 112:767-87. [PMID: 23864004 PMCID: PMC3747805 DOI: 10.1093/aob/mct152] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Accepted: 05/13/2013] [Indexed: 05/19/2023]
Abstract
BACKGROUND Apomixis is an alternative route of plant reproduction that produces individuals genetically identical to the mother plant through seeds. Apomixis is desirable in agriculture, because it guarantees the perpetuation of superior genotypes (i.e. heterotic hybrid seeds) by self-seeding without loss of hybrid vigour. The Paspalum genus, an archetypal model system for mining apomixis gene(s), is composed of about 370 species that have extremely diverse reproductive systems, including self-incompatibility, self-fertility, full sexual reproduction, and facultative or obligate apomixis. Barriers to interspecific hybridization are relaxed in this genus, allowing the production of new hybrids from many different parental combinations. Paspalum is also tolerant to various parental genome contributions to the endosperm, allowing analyses of how sexually reproducing crop species might escape from dosage effects in the endosperm. SCOPE In this article, the available literature characterizing apomixis in Paspalum spp. and its use in breeding is critically reviewed. In particular, a comparison is made across species of the structure and function of the genomic region controlling apomixis in order to identify a common core region shared by all apomictic Paspalum species and where apomixis genes are likely to be localized. Candidate genes are discussed, either as possible genetic determinants (including homologs to signal transduction and RNA methylation genes) or as downstream factors (such as cell-to-cell signalling and auxin response genes) depending, respectively, on their co-segregation with apomixis or less. Strategies to validate the role of candidate genes in apomictic process are also discussed, with special emphasis on plant transformation in natural apomictic species.
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Affiliation(s)
- Juan Pablo A. Ortiz
- Instituto de Botánica del Nordeste (IBONE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Corrientes, Argentina
- Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Camilo L. Quarin
- Instituto de Botánica del Nordeste (IBONE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Corrientes, Argentina
| | - Silvina C. Pessino
- Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Carlos Acuña
- Instituto de Botánica del Nordeste (IBONE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Corrientes, Argentina
| | - Eric J. Martínez
- Instituto de Botánica del Nordeste (IBONE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Corrientes, Argentina
| | - Francisco Espinoza
- Instituto de Botánica del Nordeste (IBONE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Corrientes, Argentina
| | - Diego H. Hojsgaard
- Albrecht-von-Haller Institute for Plant Sciences, Department of Systematic Botany, Georg-August-University of Göttingen, Göttingen, Germany
| | - Maria E. Sartor
- Instituto de Botánica del Nordeste (IBONE-CONICET), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Corrientes, Argentina
| | - Maria E. Cáceres
- CNR-Istituto di Genetica Vegetale, Research Division: Perugia, Via della Madonna alta 130, I-06128 Perugia, Italy
| | - Fulvio Pupilli
- CNR-Istituto di Genetica Vegetale, Research Division: Perugia, Via della Madonna alta 130, I-06128 Perugia, Italy
- For correspondence. E-mail
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Conner JA, Gunawan G, Ozias-Akins P. Recombination within the apospory specific genomic region leads to the uncoupling of apomixis components in Cenchrus ciliaris. PLANTA 2013; 238:51-63. [PMID: 23553451 DOI: 10.1007/s00425-013-1873-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 03/11/2013] [Indexed: 05/07/2023]
Abstract
Apomixis enables the clonal propagation of maternal genotypes through seed. If apomixis could be harnessed via genetic engineering or introgression, it would have a major economic impact for agricultural crops. In the grass species Pennisetum squamulatum and Cenchrus ciliaris (syn. P. ciliare), apomixis is controlled by a single dominant "locus", the apospory-specific genomic region (ASGR). For P. squamulatum, 18 published sequenced characterized amplified region (SCAR) markers have been identified which always co-segregate with apospory. Six of these markers are conserved SCARs in the closely related species, C. ciliaris and co-segregate with the trait. A screen of progeny from a cross of sexual × apomictic C. ciliaris genotypes identified a plant, A8, retaining two of the six ASGR-linked SCAR markers. Additional and newly identified ASGR-linked markers were generated to help identify the extent of recombination within the ASGR. Based on analysis of missing markers, the A8 recombinant plant has lost a significant portion of the ASGR but continues to form aposporous embryo sacs. Seedlings produced from aposporous embryo sacs are 6× in ploidy level and hence the A8 recombinant does not express parthenogenesis. The recombinant A8 plant represents a step forward in reducing the complexity of the ASGR locus to determine the factor(s) required for aposporous embryo sac formation and documents the separation of expression of the two components of apomixis in C. ciliaris.
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Affiliation(s)
- Joann A Conner
- Department of Horticulture, University of Georgia Tifton Campus, Tifton, GA, 31973, USA.
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Podio M, Rodríguez MP, Felitti S, Stein J, Martínez EJ, Siena LA, Quarin CL, Pessino SC, Ortiz JPA. Sequence characterization, in silico mapping and cytosine methylation analysis of markers linked to apospory in Paspalum notatum. Genet Mol Biol 2012; 35:827-37. [PMID: 23271945 PMCID: PMC3526092 DOI: 10.1590/s1415-47572012005000070] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 07/01/2012] [Indexed: 12/20/2022] Open
Abstract
In previous studies we reported the identification of several AFLP, RAPD and RFLP molecular markers linked to apospory in Paspalum notatum. The objective of this work was to sequence these markers, obtain their flanking regions by chromosome walking and perform an in silico mapping analysis in rice and maize. The methylation status of two apospory-related sequences was also assessed using methylation-sensitive RFLP experiments. Fourteen molecular markers were analyzed and several protein-coding sequences were identified. Copy number estimates and RFLP linkage analysis showed that the sequence PnMAI3 displayed 2–4 copies per genome and linkage to apospory. Extension of this marker by chromosome walking revealed an additional protein-coding sequence mapping in silico in the apospory-syntenic regions of rice and maize. Approximately 5 kb corresponding to different markers were characterized through the global sequencing procedure. A more refined analysis based on sequence information indicated synteny with segments of chromosomes 2 and 12 of rice and chromosomes 3 and 5 of maize. Two loci associated with apomixis locus were tested in methylation-sensitive RFLP experiments using genomic DNA extracted from leaves. Although both target sequences were methylated no methylation polymorphisms associated with the mode of reproduction were detected.
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Affiliation(s)
- Maricel Podio
- Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Santa Fe, Argentina. ; Instituto de Botánica del Nordeste, Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Corrientes, Argentina
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Silveira ED, Guimarães LA, de Alencar Dusi DM, da Silva FR, Martins NF, do Carmo Costa MM, Alves-Ferreira M, de Campos Carneiro VT. Expressed sequence-tag analysis of ovaries of Brachiaria brizantha reveals genes associated with the early steps of embryo sac differentiation of apomictic plants. PLANT CELL REPORTS 2012; 31:403-16. [PMID: 22068439 DOI: 10.1007/s00299-011-1175-y] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 10/10/2011] [Accepted: 10/12/2011] [Indexed: 05/23/2023]
Abstract
In apomixis, asexual mode of plant reproduction through seeds, an unreduced megagametophyte is formed due to circumvented or altered meiosis. The embryo develops autonomously from the unreduced egg cell, independently of fertilization. Brachiaria is a genus of tropical forage grasses that reproduces sexually or by apomixis. A limited number of studies have reported the sequencing of apomixis-related genes and a few Brachiaria sequences have been deposited at genebank databases. This work shows sequencing and expression analyses of expressed sequence-tags (ESTs) of Brachiaria genus and points to transcripts from ovaries with preferential expression at megasporogenesis in apomictic plants. From the 11 differentially expressed sequences from immature ovaries of sexual and apomictic Brachiaria brizantha obtained from macroarray analysis, 9 were preferentially detected in ovaries of apomicts, as confirmed by RT-qPCR. A putative involvement in early steps of Panicum-type embryo sac differentiation of four sequences from B. brizantha ovaries: BbrizHelic, BbrizRan, BbrizSec13 and BbrizSti1 is suggested. Two of these, BbrizSti1 and BbrizHelic, with similarity to a gene coding to stress induced protein and a helicase, respectively, are preferentially expressed in the early stages of apomictic ovaries development, especially in the nucellus, in a stage previous to the differentiation of aposporous initials, as verified by in situ hybridization.
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Affiliation(s)
- Erica Duarte Silveira
- Embrapa Genetic Resources and Biotechnology, Parque Estação Biológica, PqEB, Av. W5 Norte (final) Caixa Postal 02372, 70770917, Brasília DF, Brazil
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Selva JP, C. Pessino S, S. Meier M, C. Echenique V. Identification of Candidate Genes Related to Polyploidy and/or Apomixis in <i>Eragrostis curvula</i>. ACTA ACUST UNITED AC 2012. [DOI: 10.4236/ajps.2012.33049] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Okada T, Ito K, Johnson SD, Oelkers K, Suzuki G, Houben A, Mukai Y, Koltunow AM. Chromosomes carrying meiotic avoidance loci in three apomictic eudicot Hieracium subgenus Pilosella species share structural features with two monocot apomicts. PLANT PHYSIOLOGY 2011; 157:1327-41. [PMID: 21896890 PMCID: PMC3252177 DOI: 10.1104/pp.111.181164] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 09/03/2011] [Indexed: 05/02/2023]
Abstract
The LOSS OF APOMEIOSIS (LOA) locus is one of two dominant loci known to control apomixis in the eudicot Hieracium praealtum. LOA stimulates the differentiation of somatic aposporous initial cells after the initiation of meiosis in ovules. Aposporous initial cells undergo nuclear proliferation close to sexual megaspores, forming unreduced aposporous embryo sacs, and the sexual program ceases. LOA-linked genetic markers were used to isolate 1.2 Mb of LOA-associated DNAs from H. praealtum. Physical mapping defined the genomic region essential for LOA function between two markers, flanking 400 kb of identified sequence and central unknown sequences. Cytogenetic and sequence analyses revealed that the LOA locus is located on a single chromosome near the tip of the long arm and surrounded by extensive, abundant complex repeat and transposon sequences. Chromosomal features and LOA-linked markers are conserved in aposporous Hieracium caespitosum and Hieracium piloselloides but absent in sexual Hieracium pilosella. Their absence in apomictic Hieracium aurantiacum suggests that meiotic avoidance may have evolved independently in aposporous subgenus Pilosella species. The structure of the hemizygous chromosomal region containing the LOA locus in the three Hieracium subgenus Pilosella species resembles that of the hemizygous apospory-specific genomic regions in monocot Pennisetum squamulatum and Cenchrus ciliaris. Analyses of partial DNA sequences at these loci show no obvious conservation, indicating that they are unlikely to share a common ancestral origin. This suggests convergent evolution of repeat-rich hemizygous chromosomal regions containing apospory loci in these monocot and eudicot species, which may be required for the function and maintenance of the trait.
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Affiliation(s)
| | | | | | | | | | | | | | - Anna M. Koltunow
- Commonwealth Scientific and Industrial Research Organization Plant Industry, Glen Osmond, South Australia 5064, Australia (T.O., S.D.J., K.O., A.M.K.); Laboratory of Plant Molecular Genetics, Division of Natural Science, Osaka Kyoiku University, Kashiwara, Osaka 582–8582, Japan (K.I., G.S., Y.M.); Leibniz Institute of Plant Genetics and Crop Plant Research, 06466 Gatersleben, Germany (A.H.)
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Hojsgaard DH, Martínez EJ, Acuña CA, Quarin CL, Pupilli F. A molecular map of the apomixis-control locus in Paspalum procurrens and its comparative analysis with other species of Paspalum. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2011; 123:959-71. [PMID: 21713535 DOI: 10.1007/s00122-011-1639-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 06/13/2011] [Indexed: 05/22/2023]
Abstract
Since apomixis was first mapped in Paspalum, the absence of recombination that characterizes the related locus appeared to be the most difficult bottleneck to overcome for the dissection of the genetic determinants that control this trait. An approach to break the block of recombination was developed in this genus through an among-species comparative mapping strategy. A new apomictic species, P. procurrens (Q4094) was crossed with a sexual plant of P. simplex and their progeny was classified for reproductive mode with the aid of morphological, embryological and genetic analyses. On this progeny, a set of heterologous rice RFLP markers strictly co-segregating in coupling phase with apomixis was identified. These markers were all located on the telomeric region of the long arm of the chromosome 12 of rice. In spite of the lack of recombination exhibited by the apomixis-linked markers in P. procurrens, a comparative mapping analysis among P. simplex, P. malacophyllum, P. notatum and P. procurrens, allowed us to identify a small group of markers co-segregating with apomixis in all these species. These markers bracketed a chromosome region that likely contains all the genetic determinants of apomictic reproduction in Paspalum. The implications of this new inter-specific approach for overcoming the block of recombination to isolate the genetic determinants of apomixis and gain a better comprehension of genome structure of apomictic chromosome region are discussed.
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Affiliation(s)
- D H Hojsgaard
- CNR-Institute for Plant Genetics, Research Division of Perugia, Via della Madonna alta 130, 06128 Perugia, Italy
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Cloning plants by seeds: Inheritance models and candidate genes to increase fundamental knowledge for engineering apomixis in sexual crops. J Biotechnol 2011; 159:291-311. [PMID: 21906637 DOI: 10.1016/j.jbiotec.2011.08.028] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2011] [Revised: 08/16/2011] [Accepted: 08/17/2011] [Indexed: 01/02/2023]
Abstract
Apomixis is desirable in agriculture as a reproductive strategy for cloning plants by seeds. Because embryos derive from the parthenogenic development of apomeiotic egg cells, apomixis excludes fertilization in addition to meiotic segregation and recombination, resulting in offspring that are exact replicas of the parent. Introgression of apomixis from wild relatives to crop species and transformation of sexual genotypes into apomictically reproducing ones are long-held goals of plant breeding. In fact, it is generally accepted that the introduction of apomixis into agronomically important crops will have revolutionary implications for agriculture. This review deals with the current genetic and molecular findings that have been collected from model species to elucidate the mechanisms of apomeiosis, parthenogenesis and apomixis as a whole. Our goal is to critically determine whether biotechnology can combine key genes known to control the expression of the processes miming the main components of apomixis in plants. Two natural apomicts, as the eudicot Hypericum perforatum L. (St. John's wort) and the monocot Paspalum spp. (crowngrass), and the sexual model species Arabidopsis thaliana are ideally suited for such investigations at the genomic and biotechnological levels. Some novel views and original concepts have been faced on this review, including (i) the parallel between Y-chromosome and apomixis-bearing chromosome (e.g., comparative genomic analyses revealed common features as repression of recombination events, accumulation of transposable elements and degeneration of genes) from the most primitive (Hypericum-type) to the most advanced (Paspalum-type) in evolutionary terms, and (ii) the link between apomixis and gene-specific silencing mechanisms (i.e., likely based on chromatin remodelling factors), with merging lines of evidence regarding the role of auxin in cell fate specification of embryo sac and egg cell development in Arabidopsis. The production of engineered plants exhibiting apomictic-like phenotypes is critically reviewed and discussed.
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Singh M, Goel S, Meeley RB, Dantec C, Parrinello H, Michaud C, Leblanc O, Grimanelli D. Production of viable gametes without meiosis in maize deficient for an ARGONAUTE protein. THE PLANT CELL 2011; 23:443-58. [PMID: 21325139 PMCID: PMC3077773 DOI: 10.1105/tpc.110.079020] [Citation(s) in RCA: 130] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Revised: 12/31/2010] [Accepted: 01/24/2011] [Indexed: 05/18/2023]
Abstract
Apomixis is a form of asexual reproduction through seeds in angiosperms. Apomictic plants bypass meiosis and fertilization, developing offspring that are genetically identical to their mother. In a genetic screen for maize (Zea mays) mutants mimicking aspects of apomixis, we identified a dominant mutation resulting in the formation of functional unreduced gametes. The mutant shows defects in chromatin condensation during meiosis and subsequent failure to segregate chromosomes. The mutated locus codes for AGO104, a member of the ARGONAUTE family of proteins. AGO104 accumulates specifically in somatic cells surrounding the female meiocyte, suggesting a mobile signal rather than cell-autonomous control. AGO104 is necessary for non-CG methylation of centromeric and knob-repeat DNA. Digital gene expression tag profiling experiments using high-throughput sequencing show that AGO104 influences the transcription of many targets in the ovaries, with a strong effect on centromeric repeats. AGO104 is related to Arabidopsis thaliana AGO9, but while AGO9 acts to repress germ cell fate in somatic tissues, AGO104 acts to repress somatic fate in germ cells. Our findings show that female germ cell development in maize is dependent upon conserved small RNA pathways acting non-cell-autonomously in the ovule. Interfering with this repression leads to apomixis-like phenotypes in maize.
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Affiliation(s)
- Manjit Singh
- Institut de Recherche pour le Développement, Plant Genome and Development Laboratory, UMR5096, 34394 Montpellier, France
| | - Shalendra Goel
- Institut de Recherche pour le Développement, Plant Genome and Development Laboratory, UMR5096, 34394 Montpellier, France
| | | | - Christelle Dantec
- Montpellier GenomiX, Institut de Génomique Fonctionelle, 34094 Montpellier, France
| | - Hugues Parrinello
- Montpellier GenomiX, Institut de Génomique Fonctionelle, 34094 Montpellier, France
| | - Caroline Michaud
- Institut de Recherche pour le Développement, Plant Genome and Development Laboratory, UMR5096, 34394 Montpellier, France
| | - Olivier Leblanc
- Institut de Recherche pour le Développement, Plant Genome and Development Laboratory, UMR5096, 34394 Montpellier, France
| | - Daniel Grimanelli
- Institut de Recherche pour le Développement, Plant Genome and Development Laboratory, UMR5096, 34394 Montpellier, France
- Address correspondence to
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Kumar GR, Sakthivel K, Sundaram R, Neeraja C, Balachandran S, Rani NS, Viraktamath B, Madhav M. Allele mining in crops: Prospects and potentials. Biotechnol Adv 2010; 28:451-61. [DOI: 10.1016/j.biotechadv.2010.02.007] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2009] [Revised: 09/21/2009] [Accepted: 09/25/2009] [Indexed: 12/26/2022]
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Polegri L, Calderini O, Arcioni S, Pupilli F. Specific expression of apomixis-linked alleles revealed by comparative transcriptomic analysis of sexual and apomictic Paspalum simplex Morong flowers. JOURNAL OF EXPERIMENTAL BOTANY 2010; 61:1869-83. [PMID: 20231327 DOI: 10.1093/jxb/erq054] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
Apomixis is defined as clonal reproduction by seed. A comparative transcriptomic analysis was undertaken between apomictic and sexual genotypes of Paspalum simplex Morong to identify apomixis-related polymorphisms at the level of mRNA. cDNA-AFLP (amplified fragment length polymorphism) profiling of apomictic and sexual flowers at several stages of development yielded 202 amplicons that showed several kinds of expression specificities. Among these, the large majority consisted of amplicons that were present only in specific stages of development of the apomictic flowers. Ten percent of polymorphic amplicons were present with almost identical intensity in all stages of the apomictic flowers and never in the sexual flowers. Reverse transcription-PCR (RT-PCR) and Southern analyses of these amplicons showed that they belong to constitutively expressed alleles that are specifically present on the apomixis-controlling locus of P. simplex. The most frequent biological functions inferred from the sequence homology of the apomixis-linked alleles were related to signal transduction and nucleic acid/protein-binding activities. Most of these apomixis-linked alleles showed nonsense and frameshift mutations, revealing their probable pseudogene nature. None of the amplicons that were present only in specific stages of development of the apomictic flowers co-segregated with apomixis, indicating they did not originate from additional apomictic alleles but more probably from differential regulation of the same allele in apomictic and sexual flowers. The molecular functions inferred from sequence analysis of these latter amplicons were related to seed storage protein and regulatory genes of various types. The results are discussed regarding the possible role in apomictic reproduction of the differentially expressed genes in relation to their specificity of expression and inferred molecular functions.
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Affiliation(s)
- Livia Polegri
- CNR-Institute for Plant Genetics, Research Division: Perugia, Via della Madonna alta 130, I-06128 Perugia, Italy
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Talent N. Evolution of gametophytic apomixis in flowering plants: an alternative model from Maloid Rosaceae. Theory Biosci 2009; 128:121-38. [DOI: 10.1007/s12064-009-0061-4] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Accepted: 02/02/2009] [Indexed: 11/29/2022]
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Conner JA, Goel S, Gunawan G, Cordonnier-Pratt MM, Johnson VE, Liang C, Wang H, Pratt LH, Mullet JE, DeBarry J, Yang L, Bennetzen JL, Klein PE, Ozias-Akins P. Sequence analysis of bacterial artificial chromosome clones from the apospory-specific genomic region of Pennisetum and Cenchrus. PLANT PHYSIOLOGY 2008; 147:1396-411. [PMID: 18508959 PMCID: PMC2442526 DOI: 10.1104/pp.108.119081] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2008] [Accepted: 05/25/2008] [Indexed: 05/18/2023]
Abstract
Apomixis, asexual reproduction through seed, is widespread among angiosperm families. Gametophytic apomixis in Pennisetum squamulatum and Cenchrus ciliaris is controlled by the apospory-specific genomic region (ASGR), which is highly conserved and macrosyntenic between these species. Thirty-two ASGR bacterial artificial chromosomes (BACs) isolated from both species and one ASGR-recombining BAC from P. squamulatum, which together cover approximately 2.7 Mb of DNA, were used to investigate the genomic structure of this region. Phrap assembly of 4,521 high-quality reads generated 1,341 contiguous sequences (contigs; 730 from the ASGR and 30 from the ASGR-recombining BAC in P. squamulatum, plus 580 from the C. ciliaris ASGR). Contigs containing putative protein-coding regions unrelated to transposable elements were identified based on protein similarity after Basic Local Alignment Search Tool X analysis. These putative coding regions were further analyzed in silico with reference to the rice (Oryza sativa) and sorghum (Sorghum bicolor) genomes using the resources at Gramene (www.gramene.org) and Phytozome (www.phytozome.net) and by hybridization against sorghum BAC filters. The ASGR sequences reveal that the ASGR (1) contains both gene-rich and gene-poor segments, (2) contains several genes that may play a role in apomictic development, (3) has many classes of transposable elements, and (4) does not exhibit large-scale synteny with either rice or sorghum genomes but does contain multiple regions of microsynteny with these species.
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Affiliation(s)
- Joann A Conner
- Department of Horticulture, University of Georgia, Tifton, Georgia 31793-0748, USA
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Affiliation(s)
- Peggy Ozias-Akins
- Department of Horticulture, University of Georgia Tifton Campus, Tifton, Georgia;
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Farrar K, Donnison IS. Construction and screening of BAC libraries made from Brachypodium genomic DNA. Nat Protoc 2007; 2:1661-74. [PMID: 17641631 DOI: 10.1038/nprot.2007.204] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Bacterial artificial chromosome (BAC) libraries are the large DNA insert libraries of choice and valuable tools for the map-based cloning of target quantitative trait loci, physical mapping, molecular cytogenetics and comparative genomics. The protocol reported here is a simplified method used to produce and screen BAC libraries from Brachypodium species and other related grasses. Intact nuclei, containing high molecular weight (HMW) DNA, are isolated and embedded in agarose plugs. The HMW DNA is digested using an appropriate restriction enzyme and size-fractionated using pulsed-field gel electrophoresis. The DNA is isolated by dialysis, ligated into pre-prepared vector and electroporated into competent Escherichia coli cells. A PCR-based method for screening the library is also described. The entire protocol takes at least 6 weeks to complete.
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Affiliation(s)
- Kerrie Farrar
- Institute of Grassland and Environmental Research, Plas Gogerddan, Aberystwyth SY23 4AR, UK
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