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Carballo J, Achilli A, Hernández F, Bocchini M, Pasten MC, Marconi G, Albertini E, Zappacosta D, Echenique V. Differentially methylated genes involved in reproduction and ploidy levels in recent diploidized and tetraploidized Eragrostis curvula genotypes. PLANT REPRODUCTION 2024; 37:133-145. [PMID: 38055074 PMCID: PMC11180019 DOI: 10.1007/s00497-023-00490-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2023] [Accepted: 10/18/2023] [Indexed: 12/07/2023]
Abstract
Epigenetics studies changes in gene activity without changes in the DNA sequence. Methylation is an epigenetic mechanism important in many pathways, such as biotic and abiotic stresses, cell division, and reproduction. Eragrostis curvula is a grass species reproducing by apomixis, a clonal reproduction by seeds. This work employed the MCSeEd technique to identify deferentially methylated positions, regions, and genes in the CG, CHG, and CHH contexts in E. curvula genotypes with similar genomic backgrounds but with different reproductive modes and ploidy levels. In this way, we focused the analysis on the cvs. Tanganyika INTA (4x, apomictic), Victoria (2x, sexual), and Bahiense (4x, apomictic). Victoria was obtained from the diploidization of Tanganyika INTA, while Bahiense was produced from the tetraploidization of Victoria. This study showed that polyploid/apomictic genotypes had more differentially methylated positions and regions than the diploid sexual ones. Interestingly, it was possible to observe fewer differentially methylated positions and regions in CG than in the other contexts, meaning CG methylation is conserved across the genotypes regardless of the ploidy level and reproductive mode. In the comparisons between sexual and apomictic genotypes, we identified differentially methylated genes involved in the reproductive pathways, specifically in meiosis, cell division, and fertilization. Another interesting observation was that several differentially methylated genes between the diploid and the original tetraploid genotype recovered their methylation status after tetraploidization, suggesting that methylation is an important mechanism involved in reproduction and ploidy changes.
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Affiliation(s)
- J Carballo
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS-CCT-CONICET Bahía Blanca), Camino de La Carrindanga Km 7, 8000, Bahía Blanca, Argentina
| | - A Achilli
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS-CCT-CONICET Bahía Blanca), Camino de La Carrindanga Km 7, 8000, Bahía Blanca, Argentina
| | - F Hernández
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS-CCT-CONICET Bahía Blanca), Camino de La Carrindanga Km 7, 8000, Bahía Blanca, Argentina
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000, Bahía Blanca, Argentina
| | - M Bocchini
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, 06121, Perugia, Italy
| | - M C Pasten
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS-CCT-CONICET Bahía Blanca), Camino de La Carrindanga Km 7, 8000, Bahía Blanca, Argentina
| | - G Marconi
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, 06121, Perugia, Italy
| | - E Albertini
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, 06121, Perugia, Italy.
| | - D Zappacosta
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS-CCT-CONICET Bahía Blanca), Camino de La Carrindanga Km 7, 8000, Bahía Blanca, Argentina.
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000, Bahía Blanca, Argentina.
| | - V Echenique
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS-CCT-CONICET Bahía Blanca), Camino de La Carrindanga Km 7, 8000, Bahía Blanca, Argentina.
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000, Bahía Blanca, Argentina.
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Cornaro L, Banfi C, Cucinotta M, Colombo L, van Dijk PJ. Asexual reproduction through seeds: the complex case of diplosporous apomixis. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:2462-2478. [PMID: 36794770 DOI: 10.1093/jxb/erad054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 02/07/2023] [Indexed: 06/06/2023]
Abstract
Apomixis is considered a potentially revolutionary tool to generate high-quality food at a lower cost and shorter developmental time due to clonal seed production through apomeiosis and parthenogenesis. In the diplosporous type of apomixis, meiotic recombination and reduction are circumvented either by avoiding or failing meiosis or by a mitotic-like division. Here, we review the literature on diplospory, from early cytological studies dating back to the late 19th century to recent genetic findings. We discuss diplosporous developmental mechanisms, including their inheritance. Furthermore, we compare the strategies adopted to isolate the genes controlling diplospory with those to produce mutants forming unreduced gametes. Nowadays, the dramatically improved technologies of long-read sequencing and targeted CRISPR/Cas mutagenesis justify the expectation that natural diplospory genes will soon be identified. Their identification will answer questions such as how the apomictic phenotype can be superimposed upon the sexual pathway and how diplospory genes have evolved. This knowledge will contribute to the application of apomixis in agriculture.
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Affiliation(s)
- Letizia Cornaro
- Department of Biosciences, University of Milan, Via Giovanni Celoria 26, 20133, Milano, Italy
| | - Camilla Banfi
- Department of Biosciences, University of Milan, Via Giovanni Celoria 26, 20133, Milano, Italy
| | - Mara Cucinotta
- Department of Biosciences, University of Milan, Via Giovanni Celoria 26, 20133, Milano, Italy
| | - Lucia Colombo
- Department of Biosciences, University of Milan, Via Giovanni Celoria 26, 20133, Milano, Italy
| | - Peter J van Dijk
- KeyGene N.V., Agro Business Park 90, 6708 PW Wageningen, The Netherlands
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Carballo J, Bellido AM, Selva JP, Zappacosta D, Gallo CA, Albertini E, Caccamo M, Echenique V. From tetraploid to diploid, a pangenomic approach to identify genes lost during synthetic diploidization of Eragrostis curvula. FRONTIERS IN PLANT SCIENCE 2023; 14:1133986. [PMID: 36993842 PMCID: PMC10040859 DOI: 10.3389/fpls.2023.1133986] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 02/24/2023] [Indexed: 06/19/2023]
Abstract
INTRODUCTION In Eragrostis curvula, commonly known as weeping lovegrass, a synthetic diploidization event of the facultative apomictic tetraploid Tanganyika INTA cv. originated from the sexual diploid Victoria cv. Apomixis is an asexual reproduction by seeds in which the progeny is genetically identical to the maternal plant. METHODS To assess the genomic changes related to ploidy and to the reproductive mode occurring during diploidization, a mapping approach was followed to obtain the first E. curvula pangenome assembly. In this way, gDNA of Tanganyika INTA was extracted and sequenced in 2x250 Illumina pair-end reads and mapped against the Victoria genome assembly. The unmapped reads were used for variant calling, while the mapped reads were assembled using Masurca software. RESULTS The length of the assembly was 28,982,419 bp distributed in 18,032 contigs, and the variable genes annotated in these contigs rendered 3,952 gene models. Functional annotation of the genes showed that the reproductive pathway was differentially enriched. PCR amplification in gDNA and cDNA of Tanganyika INTA and Victoria was conducted to validate the presence/absence variation in five genes related to reproduction and ploidy. The polyploid nature of the Tanganyika INTA genome was also evaluated through the variant calling analysis showing the single nucleotide polymorphism (SNP) coverage and allele frequency distribution with a segmental allotetraploid pairing behavior. DISCUSSION The results presented here suggest that the genes were lost in Tanganyika INTA during the diploidization process that was conducted to suppress the apomictic pathway, affecting severely the fertility of Victoria cv.
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Affiliation(s)
- Jose Carballo
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - Andrés Martin Bellido
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - Juan Pablo Selva
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Diego Zappacosta
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Cristian Andres Gallo
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - Emidio Albertini
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Perugia, Italy
| | | | - Viviana Echenique
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
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Pasten MC, Carballo J, Gallardo J, Zappacosta D, Selva JP, Rodrigo JM, Echenique V, Garbus I. A combined transcriptome - miRNAome approach revealed that a kinesin gene is differentially targeted by a novel miRNA in an apomictic genotype of Eragrostis curvula. FRONTIERS IN PLANT SCIENCE 2022; 13:1012682. [PMID: 36247597 PMCID: PMC9563718 DOI: 10.3389/fpls.2022.1012682] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 09/14/2022] [Indexed: 06/06/2023]
Abstract
Weeping lovegrass (Eragrostis curvula [Shrad.] Nees) is a perennial grass typically established in semi-arid regions, with good adaptability to dry conditions and sandy soils. This polymorphic complex includes both sexual and apomictic cytotypes, with different ploidy levels (2x-8x). Diploids are known to be sexual, while most polyploids are facultative apomicts, and full apomicts have also been reported. Plant breeding studies throughout the years have focused on achieving the introgression of apomixis into species of agricultural relevance, but, given the complexity of the trait, a deeper understanding of the molecular basis of regulatory mechanisms of apomixis is still required. Apomixis is thought to be associated with silencing or disruption of the sexual pathway, and studies have shown it is influenced by epigenetic mechanisms. In a previous study, we explored the role of miRNA-mRNA interactions using two contrasting E. curvula phenotypes. Here, the sexual OTA-S, the facultative Don Walter and the obligate apomictic Tanganyika cDNA and sRNA libraries were inquired, searching for miRNA discovery and miRNA expression regulation of genes related to the reproductive mode. This allowed for the characterization of seven miRNAs and the validation of their miRNA-target interactions. Interestingly, a kinesin gene was found to be repressed in the apomictic cultivar Tanganyika, targeted by a novel miRNA that was found to be overexpressed in this genotype, suggestive of an involvement in the reproductive mode expression. Our work provided additional evidence of the contribution of the epigenetic regulation of the apomictic pathway.
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Affiliation(s)
- María Cielo Pasten
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - José Carballo
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
| | - Jimena Gallardo
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Diego Zappacosta
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Juan Pablo Selva
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Juan Manuel Rodrigo
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Viviana Echenique
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | - Ingrid Garbus
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS), Universidad Nacional del Sur-Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Bahía Blanca, Argentina
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Xu Y, Jia H, Tan C, Wu X, Deng X, Xu Q. Apomixis: genetic basis and controlling genes. HORTICULTURE RESEARCH 2022; 9:uhac150. [PMID: 36072837 PMCID: PMC9437720 DOI: 10.1093/hr/uhac150] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 06/27/2022] [Indexed: 05/12/2023]
Abstract
Apomixis is the phenomenon of clonal reproduction by seed. As apomixis can produce clonal progeny with exactly the same genotype as the maternal plant, it has an important application in genotype fixation and accelerating agricultural breeding strategies. The introduction of apomixis to major crops would bring many benefits to agriculture, including permanent fixation of superior genotypes and simplifying the procedures of hybrid seed production, as well as purification and rejuvenation of crops propagated vegetatively. Although apomixis naturally occurs in more than 400 plant species, it is rare among the major crops. Currently, with better understanding of apomixis, some achievements have been made in synthetic apomixis. However, due to prevailing limitations, there is still a long way to go to achieve large-scale application of apomixis to crop breeding. Here, we compare the developmental features of apomixis and sexual plant reproduction and review the recent identification of apomixis genes, transposons, epigenetic regulation, and genetic events leading to apomixis. We also summarize the possible strategies and potential genes for engineering apomixis into crop plants.
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Affiliation(s)
- Yuantao Xu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Huihui Jia
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Chunming Tan
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Xiaomeng Wu
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan, Hubei 430070, China
| | - Xiuxin Deng
- Key Laboratory of Horticultural Plant Biology (Ministry of Education), Huazhong Agricultural University, Wuhan, Hubei 430070, China
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Bellido AM, Souza Canadá ED, Permingeat HR, Echenique V. Genetic Transformation of Apomictic Grasses: Progress and Constraints. FRONTIERS IN PLANT SCIENCE 2021; 12:768393. [PMID: 34804102 PMCID: PMC8602796 DOI: 10.3389/fpls.2021.768393] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 10/05/2021] [Indexed: 05/17/2023]
Abstract
The available methods for plant transformation and expansion beyond its limits remain especially critical for crop improvement. For grass species, this is even more critical, mainly due to drawbacks in in vitro regeneration. Despite the existence of many protocols in grasses to achieve genetic transformation through Agrobacterium or biolistic gene delivery, their efficiencies are genotype-dependent and still very low due to the recalcitrance of these species to in vitro regeneration. Many plant transformation facilities for cereals and other important crops may be found around the world in universities and enterprises, but this is not the case for apomictic species, many of which are C4 grasses. Moreover, apomixis (asexual reproduction by seeds) represents an additional constraint for breeding. However, the transformation of an apomictic clone is an attractive strategy, as the transgene is immediately fixed in a highly adapted genetic background, capable of large-scale clonal propagation. With the exception of some species like Brachiaria brizantha which is planted in approximately 100 M ha in Brazil, apomixis is almost non-present in economically important crops. However, as it is sometimes present in their wild relatives, the main goal is to transfer this trait to crops to fix heterosis. Until now this has been a difficult task, mainly because many aspects of apomixis are unknown. Over the last few years, many candidate genes have been identified and attempts have been made to characterize them functionally in Arabidopsis and rice. However, functional analysis in true apomictic species lags far behind, mainly due to the complexity of its genomes, of the trait itself, and the lack of efficient genetic transformation protocols. In this study, we review the current status of the in vitro culture and genetic transformation methods focusing on apomictic grasses, and the prospects for the application of new tools assayed in other related species, with two aims: to pave the way for discovering the molecular pathways involved in apomixis and to develop new capacities for breeding purposes because many of these grasses are important forage or biofuel resources.
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Affiliation(s)
- Andrés M. Bellido
- Departamento de Agronomía, Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS – CCT – CONICET Bahía Blanca), Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
| | | | | | - Viviana Echenique
- Departamento de Agronomía, Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS – CCT – CONICET Bahía Blanca), Universidad Nacional del Sur (UNS), Bahía Blanca, Argentina
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Soliman M, Bocchini M, Stein J, Ortiz JPA, Albertini E, Delgado L. Environmental and Genetic Factors Affecting Apospory Expressivity in Diploid Paspalum rufum. PLANTS 2021; 10:plants10102100. [PMID: 34685909 PMCID: PMC8537111 DOI: 10.3390/plants10102100] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 09/22/2021] [Accepted: 09/27/2021] [Indexed: 11/30/2022]
Abstract
In angiosperms, gametophytic apomixis (clonal reproduction through seeds) is strongly associated with polyploidy and hybridization. The trait is facultative and its expressivity is highly variable between genotypes. Here, we used an F1 progeny derived from diploid apomictic (aposporic) genotypes of Paspalum rufum and two F2 families, derived from F1 hybrids with different apospory expressivity (%AES), to analyze the influence of the environment and the transgenerational transmission of the trait. In addition, AFLP markers were developed in the F1 population to identify genomic regions associated with the %AES. Cytoembryological analyses showed that the %AES was significantly influenced by different environments, but remained stable across the years. F1 and F2 progenies showed a wide range of %AES variation, but most hybrids were not significantly different from the parental genotypes. Maternal and paternal genetic linkage maps were built covering the ten expected linkage groups (LG). A single-marker analysis detected at least one region of 5.7 cM on LG3 that was significantly associated with apospory expressivity. Our results underline the importance of environmental influence in modulating apospory expressivity and identified a genomic region associated with apospory expressivity at the diploid level.
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Affiliation(s)
- Mariano Soliman
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Rosario S2125ZAA, Zavalla, Argentina; (M.S.); (J.S.); (J.P.A.O.)
| | - Marika Bocchini
- Department Agricultural, Food and Environmental Sciences, University of Perugia, 06121 Perugia, Italy; (M.B.); (E.A.)
| | - Juliana Stein
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Rosario S2125ZAA, Zavalla, Argentina; (M.S.); (J.S.); (J.P.A.O.)
| | - Juan Pablo A. Ortiz
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Rosario S2125ZAA, Zavalla, Argentina; (M.S.); (J.S.); (J.P.A.O.)
| | - Emidio Albertini
- Department Agricultural, Food and Environmental Sciences, University of Perugia, 06121 Perugia, Italy; (M.B.); (E.A.)
| | - Luciana Delgado
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR), CONICET, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Rosario S2125ZAA, Zavalla, Argentina; (M.S.); (J.S.); (J.P.A.O.)
- Correspondence:
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Carballo J, Zappacosta D, Selva JP, Caccamo M, Echenique V. Eragrostis curvula, a Model Species for Diplosporous Apomixis. PLANTS (BASEL, SWITZERLAND) 2021; 10:1818. [PMID: 34579351 PMCID: PMC8472828 DOI: 10.3390/plants10091818] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/21/2021] [Revised: 08/16/2021] [Accepted: 08/26/2021] [Indexed: 11/16/2022]
Abstract
Eragrostis curvula (Schrad.) Ness is a grass with a particular apomictic embryo sac development called Eragrostis type. Apomixis is a type of asexual reproduction that produces seeds without fertilization in which the resulting progeny is genetically identical to the mother plant and with the potential to fix the hybrid vigour from more than one generation, among other advantages. The absence of meiosis and the occurrence of only two rounds of mitosis instead of three during embryo sac development make this model unique and suitable to be transferred to economically important crops. Throughout this review, we highlight the advances in the knowledge of apomixis in E. curvula using different techniques such as cytoembryology, DNA methylation analyses, small-RNA-seq, RNA-seq, genome assembly, and genotyping by sequencing. The main bulk of evidence points out that apomixis is inherited as a single Mendelian factor, and it is regulated by genetic and epigenetic mechanisms controlled by a complex network. With all this information, we propose a model of the mechanisms involved in diplosporous apomixis in this grass. All the genetic and epigenetic resources generated in E. curvula to study the reproductive mode changed its status from an orphan to a well-characterised species.
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Affiliation(s)
- Jose Carballo
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS–CCT–CONICET Bahía Blanca), Camino de la Carrindanga km 7, Bahía Blanca 8000, Argentina; (J.C.); (J.P.S.); (V.E.)
| | - Diego Zappacosta
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS–CCT–CONICET Bahía Blanca), Camino de la Carrindanga km 7, Bahía Blanca 8000, Argentina; (J.C.); (J.P.S.); (V.E.)
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, Bahía Blanca 8000, Argentina
| | - Juan Pablo Selva
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS–CCT–CONICET Bahía Blanca), Camino de la Carrindanga km 7, Bahía Blanca 8000, Argentina; (J.C.); (J.P.S.); (V.E.)
- Departamento de Biología, Bioquímica y Farmacia, Universidad Nacional del Sur (UNS), San Juan 670, Bahía Blanca 8000, Argentina
| | - Mario Caccamo
- NIAB, 93 Lawrence Weaver Road, Cambridge CB3 0LE, UK;
| | - Viviana Echenique
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS–CCT–CONICET Bahía Blanca), Camino de la Carrindanga km 7, Bahía Blanca 8000, Argentina; (J.C.); (J.P.S.); (V.E.)
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, Bahía Blanca 8000, Argentina
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Carballo J, Zappacosta D, Marconi G, Gallardo J, Di Marsico M, Gallo CA, Caccamo M, Albertini E, Echenique V. Differential Methylation Patterns in Apomictic vs. Sexual Genotypes of the Diplosporous Grass Eragrostis curvula. PLANTS (BASEL, SWITZERLAND) 2021; 10:plants10050946. [PMID: 34068493 PMCID: PMC8150776 DOI: 10.3390/plants10050946] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2021] [Revised: 04/30/2021] [Accepted: 05/03/2021] [Indexed: 05/05/2023]
Abstract
DNA methylation is an epigenetic mechanism by which a methyl group is added to a cytosine or an adenine. When located in a gene/regulatory sequence it may repress or de-repress genes, depending on the context and species. Eragrostis curvula is an apomictic grass in which facultative genotypes increases the frequency of sexual pistils triggered by epigenetic mechanisms. The aim of the present study was to look for correlations between the reproductive mode and specific methylated genes or genomic regions. To do so, plants with contrasting reproductive modes were investigated through MCSeEd (Methylation Context Sensitive Enzyme ddRad) showing higher levels of DNA methylation in apomictic genotypes. Moreover, an increased proportion of differentially methylated positions over the regulatory regions were observed, suggesting its possible role in regulation of gene expression. Interestingly, the methylation pathway was also found to be self-regulated since two of the main genes (ROS1 and ROS4), involved in de-methylation, were found differentially methylated between genotypes with different reproductive behavior. Moreover, this work allowed us to detect several genes regulated by methylation that were previously found as differentially expressed in the comparisons between apomictic and sexual genotypes, linking DNA methylation to differences in reproductive mode.
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Affiliation(s)
- Jose Carballo
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS–CCT–CONICET Bahía Blanca), Camino de la Carrindanga km 7, 8000 Bahía Blanca, Argentina; (J.C.); (D.Z.); (J.G.); (C.A.G.)
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000 Bahía Blanca, Argentina
| | - Diego Zappacosta
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS–CCT–CONICET Bahía Blanca), Camino de la Carrindanga km 7, 8000 Bahía Blanca, Argentina; (J.C.); (D.Z.); (J.G.); (C.A.G.)
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000 Bahía Blanca, Argentina
| | - Gianpiero Marconi
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, 06121 Perugia, Italy; (G.M.); (M.D.M.)
| | - Jimena Gallardo
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS–CCT–CONICET Bahía Blanca), Camino de la Carrindanga km 7, 8000 Bahía Blanca, Argentina; (J.C.); (D.Z.); (J.G.); (C.A.G.)
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000 Bahía Blanca, Argentina
| | - Marco Di Marsico
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, 06121 Perugia, Italy; (G.M.); (M.D.M.)
| | - Cristian A. Gallo
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS–CCT–CONICET Bahía Blanca), Camino de la Carrindanga km 7, 8000 Bahía Blanca, Argentina; (J.C.); (D.Z.); (J.G.); (C.A.G.)
| | - Mario Caccamo
- NIAB, 93 Lawrence Weaver Road, Cambridge CB3 0LE, UK;
| | - Emidio Albertini
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, 06121 Perugia, Italy; (G.M.); (M.D.M.)
- Correspondence: (E.A.); (V.E.); Tel.: +39-075-585-6206 (E.A.); +54-291-486-1124 (V.E.)
| | - Viviana Echenique
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS–CCT–CONICET Bahía Blanca), Camino de la Carrindanga km 7, 8000 Bahía Blanca, Argentina; (J.C.); (D.Z.); (J.G.); (C.A.G.)
- Departamento de Agronomía, Universidad Nacional del Sur (UNS), San Andrés 800, 8000 Bahía Blanca, Argentina
- Correspondence: (E.A.); (V.E.); Tel.: +39-075-585-6206 (E.A.); +54-291-486-1124 (V.E.)
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Genes Modulating the Increase in Sexuality in the Facultative Diplosporous Grass Eragrostis curvula under Water Stress Conditions. Genes (Basel) 2020; 11:genes11090969. [PMID: 32825586 PMCID: PMC7564825 DOI: 10.3390/genes11090969] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 01/23/2023] Open
Abstract
Eragrostis curvula presents mainly facultative genotypes that reproduce by diplosporous apomixis, retaining a percentage of sexual pistils that increase under drought and other stressful situations, indicating that some regulators activated by stress could be affecting the apomixis/sexual switch. Water stress experiments were performed in order to associate the increase in sexual embryo sacs with the differential expression of genes in a facultative apomictic cultivar using cytoembryology and RNA sequencing. The percentage of sexual embryo sacs increased from 4 to 24% and 501 out of the 201,011 transcripts were differentially expressed (DE) between control and stressed plants. DE transcripts were compared with previous transcriptomes where apomictic and sexual genotypes were contrasted. The results point as candidates to transcripts related to methylation, ubiquitination, hormone and signal transduction pathways, transcription regulation and cell wall biosynthesis, some acting as a general response to stress and some that are specific to the reproductive mode. We suggest that a DNA glycosylase EcROS1-like could be demethylating, thus de-repressing a gene or genes involved in the sexuality pathways. Many of the other DE transcripts could be part of a complex mechanism that regulates apomixis and sexuality in this grass, the ones in the intersection between control/stress and apo/sex being the strongest candidates.
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Controlling Apomixis: Shared Features and Distinct Characteristics of Gene Regulation. Genes (Basel) 2020; 11:genes11030329. [PMID: 32245021 PMCID: PMC7140868 DOI: 10.3390/genes11030329] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/13/2020] [Accepted: 03/18/2020] [Indexed: 02/06/2023] Open
Abstract
In higher plants, sexual and asexual reproduction through seeds (apomixis) have evolved as alternative strategies. As apomixis leads to the formation of clonal offspring, its great potential for agricultural applications has long been recognized. However, the genetic basis and the molecular control underlying apomixis and its evolutionary origin are to date not fully understood. Both in sexual and apomictic plants, reproduction is tightly controlled by versatile mechanisms regulating gene expression, translation, and protein abundance and activity. Increasing evidence suggests that interrelated pathways including epigenetic regulation, cell-cycle control, hormonal pathways, and signal transduction processes are relevant for apomixis. Additional molecular mechanisms are being identified that involve the activity of DNA- and RNA-binding proteins, such as RNA helicases which are increasingly recognized as important regulators of reproduction. Together with other factors including non-coding RNAs, their association with ribosomes is likely to be relevant for the formation and specification of the apomictic reproductive lineage. Subsequent seed formation appears to involve an interplay of transcriptional activation and repression of developmental programs by epigenetic regulatory mechanisms. In this review, insights into the genetic basis and molecular control of apomixis are presented, also taking into account potential relations to environmental stress, and considering aspects of evolution.
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