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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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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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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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Hojsgaard D, Schartl M. Skipping sex: A nonrecombinant genomic assemblage of complementary reproductive modules. Bioessays 2020; 43:e2000111. [PMID: 33169369 DOI: 10.1002/bies.202000111] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 09/26/2020] [Accepted: 09/29/2020] [Indexed: 02/03/2023]
Abstract
The unusual occurrence and developmental diversity of asexual eukaryotes remain a puzzle. De novo formation of a functioning asexual genome requires a unique assembly of sets of genes or gene states to disrupt cellular mechanisms of meiosis and gametogenesis, and to affect discrete components of sexuality and produce clonal or hemiclonal offspring. We highlight two usually overlooked but essential conditions to understand the molecular nature of clonal organisms, that is, a nonrecombinant genomic assemblage retaining modifiers of the sexual program, and a complementation between altered reproductive components. These subtle conditions are the basis for physiologically viable and genetically balanced transitions between generations. Genomic and developmental evidence from asexual animals and plants indicates the lack of complementation of molecular changes in the sexual reproductive program is likely the main cause of asexuals' rarity, and can provide an explanatory frame for the developmental diversity and lability of developmental patterns in some asexuals as well as for the discordant time to extinction estimations.
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Affiliation(s)
- Diego Hojsgaard
- Department of Systematics, Biodiversity and Evolution of Plants (with Herbarium), Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Goettingen, Germany
| | - Manfred Schartl
- Department of Developmental Biochemistry, Biocenter, University of Wuerzburg, Wuerzburg, Germany.,The Xiphophorus Genetic Stock Center, Department of Chemistry and Biochemistry, Texas State University, San Marcos, Texas, USA
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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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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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Garbus I, Selva JP, Pasten MC, Bellido AM, Carballo J, Albertini E, Echenique V. Characterization and discovery of miRNA and miRNA targets from apomictic and sexual genotypes of Eragrostis curvula. BMC Genomics 2019; 20:839. [PMID: 31718556 PMCID: PMC6852985 DOI: 10.1186/s12864-019-6169-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 10/02/2019] [Indexed: 01/01/2023] Open
Abstract
Background Weeping lovegrass (Eragrostis curvula [Shrad.] Nees) is a perennial grass found in semi-arid regions that is well adapted for growth in sandy soils and drought conditions. E. curvula constitutes a polymorphic complex that includes cytotypes with different ploidy levels (from 2x to 8x), where most polyploids are facultative apomicts, although both sexual reproduction and full apomixis have been reported in this species. Apomixis is thought to be associated with silencing of the sexual pathway, which would involve epigenetic mechanisms. However, a correlation between small RNAs and apomixis has not yet been conclusively established. Results Aiming to contribute to the elucidation of their role in the expression of apomixis, we constructed small RNA libraries from sexual and apomictic E. curvula genotypes via Illumina technology, characterized the small RNA populations, and conducted differential expression analysis by comparing these small RNAs with the E. curvula reference transcriptome. We found that the expression of two genes is repressed in the sexual genotype, which is associated with specific microRNA expression. Conclusion Our results support the hypothesis that in E. curvula the expression of apomixis leads to sexual repression.
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Affiliation(s)
- Ingrid Garbus
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS); CONICET, Bahía Blanca, Argentina.
| | - Juan Pablo Selva
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS); CONICET, Bahía Blanca, Argentina
| | - María Cielo Pasten
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS); CONICET, Bahía Blanca, Argentina
| | - Andrés Martín Bellido
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS); CONICET, Bahía Blanca, Argentina
| | - José Carballo
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS); 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); CONICET, Bahía Blanca, Argentina
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Carballo J, Santos BACM, Zappacosta D, Garbus I, Selva JP, Gallo CA, Díaz A, Albertini E, Caccamo M, Echenique V. A high-quality genome of Eragrostis curvula grass provides insights into Poaceae evolution and supports new strategies to enhance forage quality. Sci Rep 2019; 9:10250. [PMID: 31308395 PMCID: PMC6629639 DOI: 10.1038/s41598-019-46610-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 06/13/2019] [Indexed: 01/06/2023] Open
Abstract
The Poaceae constitute a taxon of flowering plants (grasses) that cover almost all Earth’s inhabitable range and comprises some of the genera most commonly used for human and animal nutrition. Many of these crops have been sequenced, like rice, Brachypodium, maize and, more recently, wheat. Some important members are still considered orphan crops, lacking a sequenced genome, but having important traits that make them attractive for sequencing. Among these traits is apomixis, clonal reproduction by seeds, present in some members of the Poaceae like Eragrostis curvula. A de novo, high-quality genome assembly and annotation for E. curvula have been obtained by sequencing 602 Mb of a diploid genotype using a strategy that combined long-read length sequencing with chromosome conformation capture. The scaffold N50 for this assembly was 43.41 Mb and the annotation yielded 56,469 genes. The availability of this genome assembly has allowed us to identify regions associated with forage quality and to develop strategies to sequence and assemble the complex tetraploid genotypes which harbor the apomixis control region(s). Understanding and subsequently manipulating the genetic drivers underlying apomixis could revolutionize agriculture.
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Affiliation(s)
- J Carballo
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS - CCT - CONICET Bahía Blanca) and Departamento de Agronomía, Universidad Nacional del Sur, Camino de la Carrindanga km 7, 8000, Bahía Blanca, Argentina
| | | | - D Zappacosta
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS - CCT - CONICET Bahía Blanca) and Departamento de Agronomía, Universidad Nacional del Sur, Camino de la Carrindanga km 7, 8000, Bahía Blanca, Argentina
| | - I Garbus
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS - CCT - CONICET Bahía Blanca) and Departamento de Agronomía, Universidad Nacional del Sur, Camino de la Carrindanga km 7, 8000, Bahía Blanca, Argentina
| | - J P Selva
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS - CCT - CONICET Bahía Blanca) and Departamento de Agronomía, Universidad Nacional del Sur, Camino de la Carrindanga km 7, 8000, Bahía Blanca, Argentina
| | - C A Gallo
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS - CCT - CONICET Bahía Blanca) and Departamento de Agronomía, Universidad Nacional del Sur, Camino de la Carrindanga km 7, 8000, Bahía Blanca, Argentina
| | - A Díaz
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS - CCT - CONICET Bahía Blanca) and Departamento de Agronomía, Universidad Nacional del Sur, Camino de la Carrindanga km 7, 8000, Bahía Blanca, Argentina
| | - E Albertini
- Università degli Studi di Perugia, Dip. di Scienze Agrarie, Alimentari e Ambientali, Borgo XX Giugno 74, 06121, Perugia, Italy
| | - M Caccamo
- NIAB, Huntingdon Road, Cambridge, CB3 0LE, UK.
| | - V Echenique
- Centro de Recursos Naturales Renovables de la Zona Semiárida (CERZOS - CCT - CONICET Bahía Blanca) and Departamento de Agronomía, Universidad Nacional del Sur, Camino de la Carrindanga km 7, 8000, Bahía Blanca, Argentina.
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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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Mancini M, Permingeat H, Colono C, Siena L, Pupilli F, Azzaro C, de Alencar Dusi DM, de Campos Carneiro VT, Podio M, Seijo JG, González AM, Felitti SA, Ortiz JPA, Leblanc O, Pessino SC. The MAP3K-Coding QUI-GON JINN ( QGJ) Gene Is Essential to the Formation of Unreduced Embryo Sacs in Paspalum. FRONTIERS IN PLANT SCIENCE 2018; 9:1547. [PMID: 30405677 PMCID: PMC6207905 DOI: 10.3389/fpls.2018.01547] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2018] [Accepted: 10/03/2018] [Indexed: 05/20/2023]
Abstract
Apomixis is a clonal mode of reproduction via seeds, which results from the failure of meiosis and fertilization in the sexual female reproductive pathway. In previous transcriptomic surveys, we identified a mitogen-activated protein kinase kinase kinase (N46) displaying differential representation in florets of sexual and apomictic Paspalum notatum genotypes. Here, we retrieved and characterized the N46 full cDNA sequence from sexual and apomictic floral transcriptomes. Phylogenetic analyses showed that N46 was a member of the YODA family, which was re-named QUI-GON JINN (QGJ). Differential expression in florets of sexual and apomictic plants was confirmed by qPCR. In situ hybridization experiments revealed expression in the nucellus of aposporous plants' ovules, which was absent in sexual plants. RNAi inhibition of QGJ expression in two apomictic genotypes resulted in significantly reduced rates of aposporous embryo sac formation, with respect to the level detected in wild type aposporous plants and transformation controls. The QGJ locus segregated independently of apospory. However, a probe derived from a related long non-coding RNA sequence (PN_LNC_QGJ) revealed RFLP bands cosegregating with the Paspalum apospory-controlling region (ACR). PN_LNC_QGJ is expressed in florets of apomictic plants only. Our results indicate that the activity of QGJ in the nucellus of apomictic plants is necessary to form non-reduced embryo sacs and that a long non-coding sequence with regulatory potential is similar to sequences located within the ACR.
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Affiliation(s)
- Micaela Mancini
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Hugo Permingeat
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Carolina Colono
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Lorena Siena
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Fulvio Pupilli
- Istituto di Bioscienze e BioRisorse, Consiglio Nazionale delle Ricerche, Perugia, Italy
| | - Celeste Azzaro
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | | | | | - Maricel Podio
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - José Guillermo Seijo
- Instituto de Botánica del Nordeste, CONICET-UNNE, Corrientes, Argentina
- Facultad de Ciencias Exactas y Naturales y Agrimensura, Universidad Nacional del Nordeste, Corrientes, Argentina
| | - Ana María González
- Instituto de Botánica del Nordeste, CONICET-UNNE, Corrientes, Argentina
- Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Corrientes, Argentina
| | - Silvina A. Felitti
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Juan Pablo A. Ortiz
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | | | - Silvina C. Pessino
- Instituto de Investigaciones en Ciencias Agrarias de Rosario, CONICET-UNR, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
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13
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De novo transcriptome sequencing and assembly from apomictic and sexual Eragrostis curvula genotypes. PLoS One 2017; 12:e0185595. [PMID: 29091722 PMCID: PMC5665505 DOI: 10.1371/journal.pone.0185595] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 09/15/2017] [Indexed: 11/19/2022] Open
Abstract
A long-standing goal in plant breeding has been the ability to confer apomixis to agriculturally relevant species, which would require a deeper comprehension of the molecular basis of apomictic regulatory mechanisms. Eragrostis curvula (Schrad.) Nees is a perennial grass that includes both sexual and apomictic cytotypes. The availability of a reference transcriptome for this species would constitute a very important tool toward the identification of genes controlling key steps of the apomictic pathway. Here, we used Roche/454 sequencing technologies to generate reads from inflorescences of E. curvula apomictic and sexual genotypes that were de novo assembled into a reference transcriptome. Near 90% of the 49568 assembled isotigs showed sequence similarity to sequences deposited in the public databases. A gene ontology analysis categorized 27448 isotigs into at least one of the three main GO categories. We identified 11475 SSRs, and several of them were assayed in E curvula germoplasm using SSR-based primers, providing a valuable set of molecular markers that could allow direct allele selection. The differential contribution to each library of the spliced forms of several transcripts revealed the existence of several isotigs produced via alternative splicing of single genes. The reference transcriptome presented and validated in this work will be useful for the identification of a wide range of gene(s) related to agronomic traits of E. curvula, including those controlling key steps of the apomictic pathway in this species, allowing the extrapolation of the findings to other plant species.
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Zappacosta DC, Ochogavía AC, Rodrigo JM, Romero JR, Meier MS, Garbus I, Pessino SC, Echenique VC. Increased apomixis expression concurrent with genetic and epigenetic variation in a newly synthesized Eragrostis curvula polyploid. Sci Rep 2014; 4:4423. [PMID: 24710346 PMCID: PMC3978503 DOI: 10.1038/srep04423] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 02/24/2014] [Indexed: 11/09/2022] Open
Abstract
Eragrostis curvula includes biotypes reproducing through obligate and facultative apomixis or, rarely, full sexuality. We previously generated a “tetraploid-dihaploid-tetraploid” series of plants consisting of a tetraploid apomictic plant (T), a sexual dihaploid plant (D) and a tetraploid artificial colchiploid (C). Initially, plant C was nearly 100% sexual. However, its capacity to form non-reduced embryo sacs dramatically increased over a four year period (2003–2007) to reach levels of 85–90%. Here, we confirmed high rates of apomixis in plant C, and used AFLPs and MSAPs to characterize the genetic and epigenetic variation observed in this plant in 2007 as compared to 2003. Of the polymorphic sequences, some had no coding potential whereas others were homologous to retrotransposons and/or protein-coding-like sequences. Our results suggest that in this particular plant system increased apomixis expression is concurrent with genetic and epigenetic modifications, possibly involving transposable elements.
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Affiliation(s)
- Diego C Zappacosta
- 1] Departamento de Agronomía, Universidad Nacional del Sur, 8000 Bahía Blanca, Argentina [2] CERZOS-CONICET, CCT-Bahía Blanca, 8000 Bahía Blanca, Argentina
| | - Ana C Ochogavía
- Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, 2000 Rosario, Argentina
| | - Juan M Rodrigo
- CERZOS-CONICET, CCT-Bahía Blanca, 8000 Bahía Blanca, Argentina
| | - José R Romero
- CERZOS-CONICET, CCT-Bahía Blanca, 8000 Bahía Blanca, Argentina
| | - Mauro S Meier
- CERZOS-CONICET, CCT-Bahía Blanca, 8000 Bahía Blanca, Argentina
| | - Ingrid Garbus
- CERZOS-CONICET, CCT-Bahía Blanca, 8000 Bahía Blanca, Argentina
| | - Silvina C Pessino
- Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, 2000 Rosario, Argentina
| | - Viviana C Echenique
- 1] Departamento de Agronomía, Universidad Nacional del Sur, 8000 Bahía Blanca, Argentina [2] CERZOS-CONICET, CCT-Bahía Blanca, 8000 Bahía Blanca, Argentina
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15
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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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Zhang J, John UP, Wang Y, Li X, Gunawardana D, Polotnianka RM, Spangenberg GC, Nan Z. Targeted mining of drought stress-responsive genes from EST resources in Cleistogenes songorica. JOURNAL OF PLANT PHYSIOLOGY 2011; 168:1844-1851. [PMID: 21684035 DOI: 10.1016/j.jplph.2011.04.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2010] [Revised: 04/02/2011] [Accepted: 04/06/2011] [Indexed: 05/30/2023]
Abstract
Cleistogenes songorica is an important perennial grass found in the pastoral steppe of Inner Mongolia. C. songorica flourishes in drought prone environments, and therefore provides an ideal candidate plant system for the identification of drought-tolerance conferring genes. We constructed cDNA libraries from leaves and roots of drought-stressed C. songorica seedlings. Expressed sequence tag (EST) sequencing of 5664 random cDNA clones produced 3579 high quality, trimmed sequences. The average read length of trimmed ESTs was 613bp. Clustering and assembly identified a non-redundant set of 1499 contigs, including 805 singleton unigenes and 694 multi-member unigenes. The resulting unigenes were functionally categorized according to the Gene Ontology (GO) hierarchy using the in house Bioinformatic Advanced Scientific Computing (BASC) annotation pipeline. Among the total 2.2Mbp of EST sequence data, 161 putative SSRs were found, a frequency similar to that previously observed in oat and Arabidopsis ESTs. Sixty-three unigenes were functionally annotated as being stress responsive, of which 22 were similar to genes implicated in drought stress response. Using quantitative real time RT-PCR, transcripts of 13 of these 22 genes were shown to be at least three fold more, or less abundant in drought-stressed leaves or roots, with 8 increased and 5 decreased in relative transcript abundance. The C. songorica EST and cDNA collections generated in this study are a valuable resource for microarray-based expression profiling, and functional genomics in order to elucidate their role, and to understand the underlying mechanisms of drought-tolerance in C. songorica.
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Affiliation(s)
- Jiyu Zhang
- Key Laboratory of Grassland Agro-Ecosystem, Ministry of Agriculture, College of Pastoral Agricultural Science and Technology, Lanzhou University, Lanzhou 730020, China
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Mallona I, Egea-Cortines M, Weiss J. Conserved and divergent rhythms of crassulacean acid metabolism-related and core clock gene expression in the cactus Opuntia ficus-indica. PLANT PHYSIOLOGY 2011; 156:1978-89. [PMID: 21677095 PMCID: PMC3149932 DOI: 10.1104/pp.111.179275] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
The cactus Opuntia ficus-indica is a constitutive Crassulacean acid metabolism (CAM) species. Current knowledge of CAM metabolism suggests that the enzyme phosphoenolpyruvate carboxylase kinase (PPCK) is circadian regulated at the transcriptional level, whereas phosphoenolpyruvate carboxylase (PEPC), malate dehydrogenase (MDH), NADP-malic enzyme (NADP-ME), and pyruvate phosphate dikinase (PPDK) are posttranslationally controlled. As little transcriptomic data are available from obligate CAM plants, we created an expressed sequence tag database derived from different organs and developmental stages. Sequences were assembled, compared with sequences in the National Center for Biotechnology Information nonredundant database for identification of putative orthologs, and mapped using Kyoto Encyclopedia of Genes and Genomes Orthology and Gene Ontology. We identified genes involved in circadian regulation and CAM metabolism for transcriptomic analysis in plants grown in long days. We identified stable reference genes for quantitative polymerase chain reaction and found that OfiSAND, like its counterpart in Arabidopsis (Arabidopsis thaliana), and OfiTUB are generally appropriate standards for use in the quantification of gene expression in O. ficus-indica. Three kinds of expression profiles were found: transcripts of OfiPPCK oscillated with a 24-h periodicity; transcripts of the light-active OfiNADP-ME and OfiPPDK genes adapted to 12-h cycles, while transcript accumulation patterns of OfiPEPC and OfiMDH were arrhythmic. Expression of the circadian clock gene OfiTOC1, similar to Arabidopsis, oscillated with a 24-h periodicity, peaking at night. Expression of OfiCCA1 and OfiPRR9, unlike in Arabidopsis, adapted best to a 12-h rhythm, suggesting that circadian clock gene interactions differ from those of Arabidopsis. Our results indicate that the evolution of CAM metabolism could be the result of modified circadian regulation at both the transcriptional and posttranscriptional levels.
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18
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Ochogavía AC, Seijo JG, González AM, Podio M, Duarte Silveira E, Machado Lacerda AL, Tavares de Campos Carneiro V, Ortiz JPA, Pessino SC. Characterization of retrotransposon sequences expressed in inflorescences of apomictic and sexual Paspalum notatum plants. ACTA ACUST UNITED AC 2011; 24:231-46. [PMID: 21394488 DOI: 10.1007/s00497-011-0165-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2010] [Accepted: 02/15/2011] [Indexed: 01/23/2023]
Abstract
Apomixis, an asexual mode of reproduction through seeds, holds much promise for agricultural advances. However, the molecular mechanisms underlying this trait are still poorly understood. We previously isolated several transcripts representing novel sequences differentially expressed in reproductive tissues of sexual and apomictic plants. Here, we report the characterization of two of these unknown RNA transcripts (experimental codes N17 and N22). Since original fragments showed no significant homologies to sequences at databases, preliminary genomic PCR experiments were carried out to discard possible contaminations. RACE extension on flanking regions provided longer sequences for the candidates and additional related transcripts, which revealed similarity to LTR retrotransposons carrying short transduplicated segments of protein-coding genes. Interestingly, some transduplicated segments corresponded to genes previously associated with apomictic development. Gene copy number estimations revealed a moderate representation of the elements in the genome, with significantly increased numbers in a sexual genotype with respect to an apomictic one. Genetic mapping of N17 showed that a copy of this particular element was located onto Paspalum notatum linkage group F3c, at a central non-recombinant region resembling a centromere. Expression analysis showed an increased activity of N17 and N22 sense strands in ovules of the sexual genotypes. A retrotransposon-specific differential display analysis aimed at detecting related sequences allowed the identification of a complex family, with the majority of its members represented in the sexual genotype. Our results suggest that these elements could be participating in regulatory pathways related to apomixis and sexuality.
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Affiliation(s)
- Ana Claudia Ochogavía
- Laboratorio Central de Investigaciones, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Parque Villarino, S2125ZAA, Zavalla, Santa Fe, Argentina
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Ochogavía AC, Cervigni G, Selva JP, Echenique VC, Pessino SC. Variation in cytosine methylation patterns during ploidy level conversions in Eragrostis curvula. PLANT MOLECULAR BIOLOGY 2009; 70:17-29. [PMID: 19160057 DOI: 10.1007/s11103-009-9454-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2008] [Accepted: 01/05/2009] [Indexed: 05/12/2023]
Abstract
In many species polyploidization involves rearrangements of the progenitor genomes, at both genetic and epigenetic levels. We analyzed the cytosine methylation status in a 'tetraploid-diploid-tetraploid' series of Eragrostis curvula with a common genetic background by using the MSAP (Methylation-sensitive Amplified Polymorphism) technique. Considerable levels of polymorphisms were detected during ploidy conversions. The total level of methylation observed was lower in the diploid genotype compared to the tetraploid ones. A significant proportion of the epigenetic modifications occurring during the tetraploid-diploid conversion reverted during the diploid-tetraploid one. Genetic and expression data from previous work were used to analyze correlation with methylation variation. All genetic, epigenetic and gene expression variation data correlated significantly when compared by pairs in simple Mantel tests. Dendrograms reflecting genetic, epigenetic and expression distances as well as principal coordinate analysis suggested that plants of identical ploidy levels present similar sets of data. Twelve (12) different genomic fragments displaying different methylation behavior during the ploidy conversions were isolated, sequenced and characterized.
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Affiliation(s)
- Ana C Ochogavía
- Facultad de Ciencias Agrarias, Universidad Nacional de Rosario Argentina, Parque Villarino, S2125ZAA, Zavalla, Provincia de Santa Fe, Argentina
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Cervigni GDL, Paniego N, Pessino S, Selva JP, Díaz M, Spangenberg G, Echenique V. Gene expression in diplosporous and sexual Eragrostis curvula genotypes with differing ploidy levels. PLANT MOLECULAR BIOLOGY 2008; 67:11-23. [PMID: 18311543 DOI: 10.1007/s11103-008-9305-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2007] [Accepted: 01/31/2008] [Indexed: 05/04/2023]
Abstract
The molecular nature of gene expression during the initiation and progress of diplosporous apomixis is still unknown. Moreover, the basis of the close correlation between diplospory and polyploidy is not clarified yet. A comparative expression analysis was performed based on expressed sequence tags (ESTs) sequencing and differential display in an Eragrostis curvula diplosporous tetraploid genotype (T, 4x apo), a sexual diploid derivative obtained from tissue culture (D, 2x sex) and an artificial sexual tetraploid obtained from the diploid seeds after colchicine treatment (C, 4x sex). From a total of 8,884 unigenes sequenced from inflorescence-derived libraries, 112 (1.26%) showed significant differential expression in individuals with different ploidy level and/or variable reproductive mode. Independent comparisons between plants with different reproductive mode (same ploidy) or different ploidy level (same reproductive mode) allowed the identification of genes modulated in response to diplosporous development or polyploidization, respectively. Surprisingly, a group of genes (Group 3) were differentially expressed or silenced only in the 4x sex plant, presenting similar levels of expression in the 4x apo and the 2x sex genotypes. A group of randomly selected differential genes was validated by QR-PCR. Differential display analysis showed that in general the 4x apo and 4x sex expression profiles were more related and different from the 2x sex one, but confirmed the existence of Group 3-type genes, in both inflorescences and leaves. The possible biological significance for the occurrence of this particular group of genes is discussed. In silico mapping onto the rice genome was used to identify candidates mapping to the region syntenic to the diplospory locus.
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Affiliation(s)
- Gerardo D L Cervigni
- Centro de Recursos Naturales Renovables de la Zona Semiárida- CONICET, Camino de La Carrindanga Km 7,0, Bahia Blanca, Argentina
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