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Dusi DMA, Alves ER, Cabral GB, Mello LV, Rigden DJ, Silveira ÉD, Alves-Ferreira M, Guimarães LA, Gomes ACMM, Rodrigues JCM, Carneiro VTC. An exonuclease V homologue is expressed predominantly during early megasporogenesis in apomictic Brachiaria brizantha. PLANTA 2023; 258:5. [PMID: 37219749 DOI: 10.1007/s00425-023-04162-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Accepted: 05/15/2023] [Indexed: 05/24/2023]
Abstract
MAIN CONCLUSION An exonuclease V homologue from apomictic Brachiaria brizantha is expressed and localized in nucellar cells at key moments when these cells differentiate to give rise to unreduced gametophytes. Brachiaria is a genus of forage grasses with economical and agricultural importance to Brazil. Brachiaria reproduces by aposporic apomixis, in which unreduced embryo sacs, derived from nucellar cells, other than the megaspore mother cell (MMC), are formed. The unreduced embryo sacs produce an embryo without fertilization resulting in clones of the mother plant. Comparative gene expression analysis in ovaries of sexual and apomictic Brachiaria spp. revealed a sequence from B. brizantha that showed a distinct pattern of expression in ovaries of sexual and apomictic plants. In this work, we describe a gene named BbrizExoV with strong identity to exonuclease V (Exo V) genes from other grasses. Sequence analysis in signal prediction tools showed that BbrizExoV might have dual localization, depending on the translation point. A longer form to the nucleus and a shorter form which would be directed to the chloroplast. This is also the case for monocot sequences analyzed from other species. The long form of BbrizExoV protein localizes to the nucleus of onion epidermal cells. Analysis of ExoV proteins from dicot species, with exception of Arabidopsis thaliana ExoVL protein, showed only one localization. Using a template-based AlphaFold 2 modelling approach the structure of BbrizExoV in complex with metal and ssDNA was predicted based on the holo structure of the human counterpart. Features predicted to define ssDNA binding but a lack of sequence specificity are shared between the human enzyme and BbrizExoV. Expression analyses indicated the precise site and timing of transcript accumulation during ovule development, which coincides with the differentiation of nucelar cells to form the typical aposporic four-celled unreduced gametophyte. A putative function for this protein is proposed based on its homology and expression pattern.
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Affiliation(s)
- Diva M A Dusi
- Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Cx. Postal 02372, Brasilia, DF, 70770-917, Brazil
| | - Elizângela R Alves
- Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Cx. Postal 02372, Brasilia, DF, 70770-917, Brazil
- Department of Celular Biology, University of Brasilia, Brasília, DF, 70910-900, Brazil
| | - Gláucia B Cabral
- Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Cx. Postal 02372, Brasilia, DF, 70770-917, Brazil
| | - Luciane V Mello
- School of Life Sciences, University of Liverpool, Crown St, Liverpool, L69 7ZB, UK
| | - Daniel J Rigden
- Institute of Systems, Molecular and Integrative Biology, University of Liverpool, Crown St, Liverpool, L69 7ZB, UK
| | - Érica D Silveira
- Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Cx. Postal 02372, Brasilia, DF, 70770-917, Brazil
- Department of Genetics, Universidade Federal do Rio de Janeiro, Av. Prof. Rodolpho Paulo Rocco, s/n Prédio do CCS Instituto de Biologia, Rio de Janeiro, RJ, Brazil
| | - Márcio Alves-Ferreira
- Department of Genetics, Universidade Federal do Rio de Janeiro, Av. Prof. Rodolpho Paulo Rocco, s/n Prédio do CCS Instituto de Biologia, Rio de Janeiro, RJ, Brazil
| | - Larissa A Guimarães
- Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Cx. Postal 02372, Brasilia, DF, 70770-917, Brazil
- Department of Celular Biology, University of Brasilia, Brasília, DF, 70910-900, Brazil
| | - Ana Cristina M M Gomes
- Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Cx. Postal 02372, Brasilia, DF, 70770-917, Brazil
| | - Júlio C M Rodrigues
- Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Cx. Postal 02372, Brasilia, DF, 70770-917, Brazil.
| | - Vera T C Carneiro
- Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Cx. Postal 02372, Brasilia, DF, 70770-917, Brazil.
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Ferreira LG, Dusi DMA, Irsigler AST, Gomes ACMM, Florentino LH, Mendes MA, Colombo L, Carneiro VTC. Identification of IPT9 in Brachiaria brizantha (syn. Urochloa brizantha) and expression analyses during ovule development in sexual and apomictic plants. Mol Biol Rep 2023; 50:4887-4897. [PMID: 37072653 DOI: 10.1007/s11033-023-08295-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Accepted: 01/17/2023] [Indexed: 04/20/2023]
Abstract
BACKGROUND In Brachiaria sexual reproduction, during ovule development, a nucellar cell differentiates into a megaspore mother cell (MMC) that, through meiosis and mitosis, gives rise to a reduced embryo sac. In aposporic apomictic Brachiaria, next to the MMC, other nucellar cells differentiate into aposporic initials that enter mitosis directly forming an unreduced embryo sac. The IPT (isopentenyltransferase) family comprises key genes in the cytokinin (CK) pathway which are expressed in Arabidopsis during ovule development. BbrizIPT9, a B. brizantha (syn. Urochloa brizantha) IPT9 gene, highly similar to genes of other Poaceae plants, also shows similarity with Arabidopsis IPT9, AtIPT9. In this work, we aimed to investigate association of BbrizIPT9 with ovule development in sexual and apomictic plants. METHODS AND RESULTS RT-qPCR showed higher BbrizIPT9 expression in the ovaries of sexual than in the apomictic B. brizantha. Results of in-situ hybridization showed strong signal of BbrizIPT9 in the MMC of both plants, at the onset of megasporogenesis. By analyzing AtIPT9 knockdown mutants, we verified enlarged nucellar cell, next to the MMC, in a percentage significantly higher than in the wild type, suggesting that knockout of AtIPT9 gene triggered the differentiation of extra MMC-like cells. CONCLUSIONS Our results indicate that AtIPT9 might be involved in the proper differentiation of a single MMC during ovule development. The expression of a BbrizIPT9, localized in male and female sporocytes, and lower in apomicts than in sexuals, and effect of IPT9 knockout in Arabidopsis, suggest involvement of IPT9 in early ovule development.
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Affiliation(s)
- Luciana G Ferreira
- Department of Biology, University of Brasília - UnB, Campus Darcy Ribeiro S/N - Asa Norte, Brasília, DF, 70.910-900, Brazil
- Embrapa Genetic Resources and Biotechnology, Parque Estação Biológica, PqEB Av. W5 Norte., Caixa Postal 02372, Brasília, DF, 70.770-917, Brazil
| | - Diva M A Dusi
- Embrapa Genetic Resources and Biotechnology, Parque Estação Biológica, PqEB Av. W5 Norte., Caixa Postal 02372, Brasília, DF, 70.770-917, Brazil
| | - André S T Irsigler
- Embrapa Genetic Resources and Biotechnology, Parque Estação Biológica, PqEB Av. W5 Norte., Caixa Postal 02372, Brasília, DF, 70.770-917, Brazil
| | - Ana C M M Gomes
- Embrapa Genetic Resources and Biotechnology, Parque Estação Biológica, PqEB Av. W5 Norte., Caixa Postal 02372, Brasília, DF, 70.770-917, Brazil
| | - Lilian H Florentino
- Embrapa Genetic Resources and Biotechnology, Parque Estação Biológica, PqEB Av. W5 Norte., Caixa Postal 02372, Brasília, DF, 70.770-917, Brazil
| | - Marta A Mendes
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133, Milan, Italy.
| | - Lucia Colombo
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133, Milan, Italy
| | - Vera T C Carneiro
- Department of Biology, University of Brasília - UnB, Campus Darcy Ribeiro S/N - Asa Norte, Brasília, DF, 70.910-900, Brazil.
- Embrapa Genetic Resources and Biotechnology, Parque Estação Biológica, PqEB Av. W5 Norte., Caixa Postal 02372, Brasília, DF, 70.770-917, Brazil.
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Niccolò T, Anderson AW, Emidio A. Apomixis: oh, what a tangled web we have! PLANTA 2023; 257:92. [PMID: 37000270 PMCID: PMC10066125 DOI: 10.1007/s00425-023-04124-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 03/21/2023] [Indexed: 06/19/2023]
Abstract
Apomixis is a complex evolutionary trait with many possible origins. Here we discuss various clues and causes, ultimately proposing a model harmonizing the three working hypotheses on the topic. Asexual reproduction through seeds, i.e., apomixis, is the holy grail of plant biology. Its implementation in modern breeding could be a game-changer for agriculture. It has the potential to generate clonal crops and maintain valuable complex genotypes and their associated heterotic traits without inbreeding depression. The genetic basis and origins of apomixis are still unclear. There are three central hypothesis for the development of apomixis that could be: i) a deviation from the sexual developmental program caused by an asynchronous development, ii) environmentally triggered through epigenetic regulations (a polyphenism of sex), iii) relying on one or more genes/alleles. Because of the ever-increasing complexity of the topic, the path toward a detailed understanding of the mechanisms underlying apomixis remains unclear. Here, we discuss the most recent advances in the evolution perspective of this multifaceted trait. We incorporated our understanding of the effect of endogenous effectors, such as small RNAs, epigenetic regulation, hormonal pathways, protein turnover, and cell wall modification in response to an upside stress. This can be either endogenous (hybridization or polyploidization) or exogenous environmental stress, mainly due to oxidative stress and the corresponding ROS (Reacting Oxygen Species) effectors. Finally, we graphically represented this tangled web.
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Affiliation(s)
- Terzaroli Niccolò
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno 74, 06121, Perugia, Italy.
| | - Aaron W Anderson
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno 74, 06121, Perugia, Italy
- Fulbright Scholar From Department of Plant Sciences, University of California, Davis, USA
| | - Albertini Emidio
- Dipartimento di Scienze Agrarie, Alimentari e Ambientali, Università degli Studi di Perugia, Borgo XX Giugno 74, 06121, Perugia, Italy
- Consorzio Interuniversitario per le Biotecnologie (CIB), Trieste, Italy
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Koehler AD, Rossi ML, Carneiro VTC, Cabral GB, Martinelli AP, Dusi DMA. Anther development in Brachiaria brizantha (syn. Urochloa brizantha) and perspective for microspore in vitro culture. PROTOPLASMA 2023; 260:571-587. [PMID: 35947212 DOI: 10.1007/s00709-022-01802-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 07/31/2022] [Indexed: 06/15/2023]
Abstract
Brachiaria, a genus from the Poaceae family, is largely cultivated as forage in Brazil. Among the most cultivated varieties of Brachiaria spp., B. brizantha cv. Marandu (syn. Urochloa brizantha) is of great agronomical importance due to the large areas cultivated with this species. This cultivar is apomictic and tetraploid. Sexual diploid genotype is available for this species. The difference in levels of ploidy among sexual and apomictic plants contributes to hindering Brachiaria breeding programs. The induction of haploids and double haploids is of great interest for the generation of new genotypes with potential use in intraspecific crosses. A key factor for the success of this technique is identifying adequate microspore developmental stages for efficient embryogenesis induction. Knowledge of the morphological changes during microsporogenesis and microgametogenesis and sporophytic tissues composing the anther is critical for identifying the stages in which microspores present a higher potential for embryogenic callus and somatic embryo through in vitro culture. In this work, morphological markers were associated with anther and pollen grain developmental stages, through histological analysis. Anther development was divided into 11 stages using morphological and cytological characteristics, from anther with archesporial cells to anther dehiscence. The morphological characteristics of each stage are presented. In addition, the response of stage 8 anthers to in vitro culture indicates microspores initiating somatic embryogenic pathway.
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Affiliation(s)
- Andréa D Koehler
- University of Sao Paulo, CENA, Av. Centenario 303, Piracicaba, SP, 13416-903, Brazil
- Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Cx.Postal 02372, Brasilia, DF, 70.770-917, Brazil
| | - Mônica L Rossi
- University of Sao Paulo, CENA, Av. Centenario 303, Piracicaba, SP, 13416-903, Brazil
| | - Vera T C Carneiro
- Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Cx.Postal 02372, Brasilia, DF, 70.770-917, Brazil
| | - Glaucia B Cabral
- Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Cx.Postal 02372, Brasilia, DF, 70.770-917, Brazil
| | - Adriana P Martinelli
- University of Sao Paulo, CENA, Av. Centenario 303, Piracicaba, SP, 13416-903, Brazil
| | - Diva M A Dusi
- Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Cx.Postal 02372, Brasilia, DF, 70.770-917, Brazil.
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da Silveira SR, Koehler AD, Mendes Gomes ACM, Cabral GB, de Campos Carneiro VT, de Alencar Dusi DM, Martinelli AP. Somatic Embryogenesis of Brachiaria brizantha (Syn. Urochloa brizantha) Analyzed by In Situ Hybridization. Methods Mol Biol 2022; 2527:247-263. [PMID: 35951196 DOI: 10.1007/978-1-0716-2485-2_18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In situ hybridization with mRNA probes enables the detection and localization of gene expression in plant somatic embryogenesis samples. BbrizSERK is a gene that is expressed in embryogenic cells and tissues of Brachiaria. Here we describe methods used for in situ hybridization to localize BbrizSERK transcripts during somatic embryogenesis of Brachiaria brizantha according to the plant material and observations intended, using paraffin or butyl methyl methacrylate resin-embedded samples, as well as a method for whole-mount preparation applicable for the analysis of other genes involved in embryogenic processes, along with other in vitro processes.
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Affiliation(s)
- Sylvia Rodrigues da Silveira
- Plant Biotechnology Lab, Center of Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, SP, Brazil
| | - Andréa Dias Koehler
- Plant Biotechnology Lab, Center of Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, SP, Brazil
| | - Ana Cristina M Mendes Gomes
- Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Brasilia, DF, Brazil
| | - Glaucia Barbosa Cabral
- Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Brasilia, DF, Brazil
| | | | - Diva Maria de Alencar Dusi
- Brazilian Agricultural Research Corporation (Embrapa), Embrapa Genetic Resources and Biotechnology, Brasilia, DF, Brazil.
| | - Adriana Pinheiro Martinelli
- Plant Biotechnology Lab, Center of Nuclear Energy in Agriculture, University of São Paulo, Piracicaba, SP, Brazil.
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Ferreira RCU, da Costa Lima Moraes A, Chiari L, Simeão RM, Vigna BBZ, de Souza AP. An Overview of the Genetics and Genomics of the Urochloa Species Most Commonly Used in Pastures. FRONTIERS IN PLANT SCIENCE 2021; 12:770461. [PMID: 34966402 PMCID: PMC8710810 DOI: 10.3389/fpls.2021.770461] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 11/17/2021] [Indexed: 06/14/2023]
Abstract
Pastures based on perennial monocotyledonous plants are the principal source of nutrition for ruminant livestock in tropical and subtropical areas across the globe. The Urochloa genus comprises important species used in pastures, and these mainly include Urochloa brizantha, Urochloa decumbens, Urochloa humidicola, and Urochloa ruziziensis. Despite their economic relevance, there is an absence of genomic-level information for these species, and this lack is mainly due to genomic complexity, including polyploidy, high heterozygosity, and genomes with a high repeat content, which hinders advances in molecular approaches to genetic improvement. Next-generation sequencing techniques have enabled the recent release of reference genomes, genetic linkage maps, and transcriptome sequences, and this information helps improve our understanding of the genetic architecture and molecular mechanisms involved in relevant traits, such as the apomictic reproductive mode. However, more concerted research efforts are still needed to characterize germplasm resources and identify molecular markers and genes associated with target traits. In addition, the implementation of genomic selection and gene editing is needed to reduce the breeding time and expenditure. In this review, we highlight the importance and characteristics of the four main species of Urochloa used in pastures and discuss the current findings from genetic and genomic studies and research gaps that should be addressed in future research.
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Affiliation(s)
| | - Aline da Costa Lima Moraes
- Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas (UNICAMP), Campinas, Brazil
| | - Lucimara Chiari
- Embrapa Gado de Corte, Brazilian Agricultural Research Corporation, Campo Grande, Brazil
| | - Rosangela Maria Simeão
- Embrapa Gado de Corte, Brazilian Agricultural Research Corporation, Campo Grande, Brazil
| | | | - Anete Pereira de Souza
- Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas (UNICAMP), Campinas, Brazil
- Department of Plant Biology, Biology Institute, University of Campinas (UNICAMP), Campinas, Brazil
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Fernández H, Grossmann J, Gagliardini V, Feito I, Rivera A, Rodríguez L, Quintanilla LG, Quesada V, Cañal MJ, Grossniklaus U. Sexual and Apogamous Species of Woodferns Show Different Protein and Phytohormone Profiles. FRONTIERS IN PLANT SCIENCE 2021; 12:718932. [PMID: 34868105 PMCID: PMC8633544 DOI: 10.3389/fpls.2021.718932] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 09/23/2021] [Indexed: 06/13/2023]
Abstract
The gametophyte of ferns reproduces either by sexual or asexual means. In the latter, apogamy represents a peculiar case of apomixis, in which an embryo is formed from somatic cells. A proteomic and physiological approach was applied to the apogamous fern Dryopteris affinis ssp. affinis and its sexual relative D. oreades. The proteomic analysis compared apogamous vs. female gametophytes, whereas the phytohormone study included, in addition to females, three apogamous stages (filamentous, spatulate, and cordate). The proteomic profiles revealed a total of 879 proteins and, after annotation, different regulation was found in 206 proteins of D. affinis and 166 of its sexual counterpart. The proteins upregulated in D. affinis are mostly associated to protein metabolism (including folding, transport, and proteolysis), ribosome biogenesis, gene expression and translation, while in the sexual counterpart, they account largely for starch and sucrose metabolism, generation of energy and photosynthesis. Likewise, ultra-performance liquid chromatography-tandem spectrometry (UHPLC-MS/MS) was used to assess the levels of indol-3-acetic acid (IAA); the cytokinins: 6-benzylaminopurine (BA), trans-Zeatine (Z), trans-Zeatin riboside (ZR), dyhidrozeatine (DHZ), dyhidrozeatin riboside (DHZR), isopentenyl adenine (iP), isopentenyl adenosine (iPR), abscisic acid (ABA), the gibberellins GA3 and GA4, salicylic acid (SA), and the brassinosteroids: brassinolide (BL) and castasterone (CS). IAA, the cytokinins Z, ZR, iPR, the gibberellin GA4, the brassinosteoids castasterone, and ABA accumulated more in the sexual gametophyte than in the apogamous one. When comparing the three apogamous stages, BA and SA peaked in filamentous, GA3 and BL in spatulate and DHRZ in cordate gametophytes. The results point to the existence of large metabolic differences between apogamous and sexual gametophytes, and invite to consider the fern gametophyte as a good experimental system to deepen our understanding of plant reproduction.
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Affiliation(s)
- Helena Fernández
- Area of Plant Physiology, Department of Organisms and Systems Biology, Oviedo University, Oviedo, Spain
| | - Jonas Grossmann
- Functional Genomics Center, Zurich, Switzerland
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Valeria Gagliardini
- Department of Plant and Microbial Biology & Zurich and Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Isabel Feito
- Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Finca Experimental La Mata, Grado, Spain
| | - Alejandro Rivera
- Area of Plant Physiology, Department of Organisms and Systems Biology, Oviedo University, Oviedo, Spain
| | - Lucía Rodríguez
- Servicio Regional de Investigación y Desarrollo Agroalimentario (SERIDA), Finca Experimental La Mata, Grado, Spain
| | - Luis G. Quintanilla
- Department of Biology and Geology, Physics and Inorganic Chemistry, Rey Juan Carlos University, Móstoles, Spain
| | - Víctor Quesada
- Department of Biochemistry and Molecular Biology, Institute of Oncology of the Principality of Asturias, Oviedo University, Móstoles, Spain
| | - Mª Jesús Cañal
- Area of Plant Physiology, Department of Organisms and Systems Biology, Oviedo University, Oviedo, Spain
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology & Zurich and Basel Plant Science Center, University of Zurich, Zurich, Switzerland
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A study of the heterochronic sense/antisense RNA representation in florets of sexual and apomictic Paspalum notatum. BMC Genomics 2021; 22:185. [PMID: 33726667 PMCID: PMC7962388 DOI: 10.1186/s12864-021-07450-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/18/2021] [Indexed: 11/10/2022] Open
Abstract
Background Apomixis, an asexual mode of plant reproduction, is a genetically heritable trait evolutionarily related to sexuality, which enables the fixation of heterozygous genetic combinations through the development of maternal seeds. Recently, reference floral transcriptomes were generated from sexual and apomictic biotypes of Paspalum notatum, one of the most well-known plant models for the study of apomixis. However, the transcriptome dynamics, the occurrence of apomixis vs. sexual expression heterochronicity across consecutive developmental steps and the orientation of transcription (sense/antisense) remain unexplored. Results We produced 24 Illumina TruSeq®/ Hiseq 1500 sense/antisense floral transcriptome libraries covering four developmental stages (premeiosis, meiosis, postmeiosis, and anthesis) in biological triplicates, from an obligate apomictic and a full sexual genotype. De novo assemblies with Trinity yielded 103,699 and 100,114 transcripts for the apomictic and sexual samples respectively. A global comparative analysis involving reads from all developmental stages revealed 19,352 differentially expressed sense transcripts, of which 13,205 (68%) and 6147 (32%) were up- and down-regulated in apomictic samples with respect to the sexual ones. Interestingly, 100 differentially expressed antisense transcripts were detected, 55 (55%) of them up- and 45 (45%) down-regulated in apomictic libraries. A stage-by-stage comparative analysis showed a higher number of differentially expressed candidates due to heterochronicity discrimination: the highest number of differential sense transcripts was detected at premeiosis (23,651), followed by meiosis (22,830), postmeiosis (19,100), and anthesis (17,962), while the highest number of differential antisense transcripts were detected at anthesis (495), followed by postmeiosis (164), meiosis (120) and premeiosis (115). Members of the AP2, ARF, MYB and WRKY transcription factor families, as well as the auxin, jasmonate and cytokinin plant hormone families appeared broadly deregulated. Moreover, the chronological expression profile of several well-characterized apomixis controllers was examined in detail. Conclusions This work provides a quantitative sense/antisense gene expression catalogue covering several subsequent reproductive developmental stages from premeiosis to anthesis for apomictic and sexual P. notatum, with potential to reveal heterochronic expression between reproductive types and discover sense/antisense mediated regulation. We detected a contrasting transcriptional and hormonal control in apomixis and sexuality as well as specific sense/antisense modulation occurring at the onset of parthenogenesis. Supplementary Information The online version contains supplementary material available at 10.1186/s12864-021-07450-3.
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Fiaz S, Wang X, Younas A, Alharthi B, Riaz A, Ali H. Apomixis and strategies to induce apomixis to preserve hybrid vigor for multiple generations. GM CROPS & FOOD 2021; 12:57-70. [PMID: 32877304 PMCID: PMC7553744 DOI: 10.1080/21645698.2020.1808423] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Accepted: 08/06/2020] [Indexed: 11/16/2022]
Abstract
Hybrid seeds of several important crops with supreme qualities including yield, biotic and abiotic stress tolerance have been cultivated for decades. Thus far, a major challenge with hybrid seeds is that they do not have the ability to produce plants with the same qualities over subsequent generations. Apomixis, an asexual mode of reproduction by avoiding meiosis, exists naturally in flowering plants, and ultimately leads to seed production. Apomixis has the potential to preserve hybrid vigor for multiple generations in economically important plant genotypes. The evolution and genetics of asexual seed production are unclear, and much more effort will be required to determine the genetic architecture of this phenomenon. To fix hybrid vigor, synthetic apomixis has been suggested. The development of MiMe (mitosis instead of meiosis) genotypes has been utilized for clonal gamete production. However, the identification and parental origin of genes responsible for synthetic apomixis are little known and need further clarification. Genome modifications utilizing genome editing technologies (GETs), such as clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein (cas), a reverse genetics tool, have paved the way toward the utilization of emerging technologies in plant molecular biology. Over the last decade, several genes in important crops have been successfully edited. The vast availability of GETs has made functional genomics studies easy to conduct in crops important for food security. Disruption in the expression of genes specific to egg cell MATRILINEAL (MTL) through the CRISPR/Cas genome editing system promotes the induction of haploid seed, whereas triple knockout of the Baby Boom (BBM) genes BBM1, BBM2, and BBM3 cause embryo arrest and abortion, which can be fully rescued by male-transmitted BBM1. The establishment of synthetic apomixis by engineering the MiMe genotype by genome editing of BBM1 expression or disruption of MTL leads to clonal seed production and heritability for multiple generations. In the present review, we discuss current developments related to the use of CRISPR/Cas technology in plants and the possibility of promoting apomixis in crops to preserve hybrid vigor. In addition, genetics, evolution, epigenetic modifications, and strategies for MiMe genotype development are discussed in detail.
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Affiliation(s)
- Sajid Fiaz
- Department of Plant Breeding and Genetics, The University of Haripur 22620 , Khyber Pakhtunkhwa, Pakistan
| | - Xiukang Wang
- College of Life Sciences, Yan'an University , Yan'an, Shaanxi, China
| | - Afifa Younas
- Department of Botany, Lahore College for Women University , Lahore, Pakistan
| | - Badr Alharthi
- College of Science and Engineering, Flinders University , Adelaide, Australia
- University College of Khurma, Taif University , Taif, Saudi Arabia
| | - Adeel Riaz
- Biotechnology Research Institute, Chinese Academy of Agricultural Sciences , Beijing, China
| | - Habib Ali
- Department of Agricultural Engineering, Khawaja Fareed University of Engineering and Information Technology , Rahim Yar Khan, Pakistan
- Department of Entomology, Sub-Campus Depalpur, University of Agriculture Faisalabad , Faisalabad, Pakistan
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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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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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12
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Ortiz JPA, Leblanc O, Rohr C, Grisolia M, Siena LA, Podio M, Colono C, Azzaro C, Pessino SC. Small RNA-seq reveals novel regulatory components for apomixis in Paspalum notatum. BMC Genomics 2019; 20:487. [PMID: 31195966 PMCID: PMC6567921 DOI: 10.1186/s12864-019-5881-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 06/04/2019] [Indexed: 12/31/2022] Open
Abstract
Background Apomixis is considered an evolutionary deviation of the sexual reproductive pathway leading to the generation of clonal maternal progenies by seeds. Recent evidence from model and non-model species suggested that this trait could be modulated by epigenetic mechanisms involving small RNAs (sRNAs). Here we profiled floral sRNAs originated from apomictic and sexual Paspalum notatum genotypes in order to identify molecular pathways under epigenetic control that might be involved in the transition from sexuality to agamospermy. Results The mining of genes participating in sRNA-directed pathways from floral Paspalum transcriptomic resources showed these routes are functional during reproductive development, with several members differentially expressed in apomictic and sexual plants. Triplicate floral sRNA libraries derived from apomictic and a sexual genotypes were characterized by using high-throughput sequencing technology. EdgeR was apply to compare the number of sRNA reads between sexual and apomictic libraries that map over all Paspalum floral transcripts. A total of 1525 transcripts showed differential sRNA representation, including genes related to meiosis, plant hormone signaling, biomolecules transport, transcription control and cell cycle. Survey for miRNA precursors on transcriptome and genome references allowed the discovery of 124 entities, including 40 conserved and 8 novel ones. Fifty-six clusters were differentially represented in apomictic and sexual plants. All differentially expressed miRNAs were up-regulated in apomictic libraries but miR2275, which showed different family members with opposed representation. Examination of predicted miRNAs targets detected 374 potential candidates. Considering sRNA, miRNAs and target surveys together, 14 genes previously described as related with auxin metabolism, transport and signaling were detected, including AMINO ACID/AUXIN PERMEASE 15, IAA-AMIDO SYNTHETASE GH3–8, IAA30, miR160, miR167, miR164, miR319, ARF2, ARF8, ARF10, ARF12, AFB2, PROLIFERATING CELL FACTOR 6 and NITRATE TRANSPORTER 1.1. Conclusions This work provides a comprehensive survey of the sRNA differential representation in flowers of sexual and apomictic Paspalum notatum plants. An integration of the small RNA profiling data presented here and previous transcriptomic information suggests that sRNA-mediated regulation of auxin pathways is pivotal in promoting apomixis. These results will underlie future functional characterization of the molecular components mediating the switch from sexuality to apomixis. Electronic supplementary material The online version of this article (10.1186/s12864-019-5881-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Juan Pablo A Ortiz
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR, CONICET-UNR), Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Olivier Leblanc
- Institut de Recherche pour le Développement (IRD), Université de Montpellier, Montpellier, France
| | - Cristian Rohr
- Instituto de Agrobiotecnología de Rosario (INDEAR), Rosario, Argentina
| | - Mauricio Grisolia
- Instituto de Agrobiotecnología de Rosario (INDEAR), Rosario, Argentina
| | - Lorena A Siena
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR, CONICET-UNR), Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Maricel Podio
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR, CONICET-UNR), Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Carolina Colono
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR, CONICET-UNR), Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Celeste Azzaro
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR, CONICET-UNR), Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina
| | - Silvina C Pessino
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR, CONICET-UNR), Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Argentina.
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Kaushal P, Dwivedi KK, Radhakrishna A, Srivastava MK, Kumar V, Roy AK, Malaviya DR. Partitioning Apomixis Components to Understand and Utilize Gametophytic Apomixis. FRONTIERS IN PLANT SCIENCE 2019; 10:256. [PMID: 30906306 PMCID: PMC6418048 DOI: 10.3389/fpls.2019.00256] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 02/18/2019] [Indexed: 05/07/2023]
Abstract
Apomixis is a method of reproduction to generate clonal seeds and offers tremendous potential to fix heterozygosity and hybrid vigor. The process of apomictic seed development is complex and comprises three distinct components, viz., apomeiosis (leading to formation of unreduced egg cell), parthenogenesis (development of embryo without fertilization) and functional endosperm development. Recently, in many crops, these three components are reported to be uncoupled leading to their partitioning. This review provides insight into the recent status of our understanding surrounding partitioning apomixis components in gametophytic apomictic plants and research avenues that it offers to help understand the biology of apomixis. Possible consequences leading to diversity in seed developmental pathways, resources to understand apomixis, inheritance and identification of candidate gene(s) for partitioned components, as well as contribution towards creation of variability are all discussed. The potential of Panicum maximum, an aposporous crop, is also discussed as a model crop to study partitioning principle and effects. Modifications in cytogenetic status, as well as endosperm imprinting effects arising due to partitioning effects, opens up new opportunities to understand and utilize apomixis components, especially towards synthesizing apomixis in crops.
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Affiliation(s)
- Pankaj Kaushal
- ICAR-National Institute of Biotic Stress Management, Raipur, India
| | | | | | | | - Vinay Kumar
- ICAR-National Institute of Biotic Stress Management, Raipur, India
| | - Ajoy Kumar Roy
- ICAR-Indian Grassland and Fodder Research Institute, Jhansi, India
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CABRAL GLAUCIAB, CARNEIRO VERAT, GOMES ANACRISTINAM, LACERDA ANALUIZA, MARTINELLI ADRIANAP, DUSI DIVAM. Genetic transformation of Brachiaria brizantha cv. Marandu by biolistics. ACTA ACUST UNITED AC 2018; 90:1789-1797. [DOI: 10.1590/0001-3765201820170842] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2017] [Accepted: 12/18/2017] [Indexed: 11/22/2022]
Affiliation(s)
- GLAUCIA B. CABRAL
- Embrapa - Recursos Genéticos e Biotecnologia, Brazil; Universidade de São Paulo, Brazil
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Ferreira LG, de Alencar Dusi DM, Irsigler AST, Gomes ACMM, Mendes MA, Colombo L, de Campos Carneiro VT. GID1 expression is associated with ovule development of sexual and apomictic plants. PLANT CELL REPORTS 2018; 37:293-306. [PMID: 29080908 DOI: 10.1007/s00299-017-2230-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2017] [Accepted: 10/18/2017] [Indexed: 06/07/2023]
Abstract
BbrizGID1 is expressed in the nucellus of apomictic Brachiaria brizantha, previous to aposporous initial differentiation. AtGID1a overexpression triggers differentiation of Arabidopsis thaliana MMC-like cells, suggesting its involvement in ovule development. GIBBERELLIN-INSENSITIVE DWARF1 (GID1) is a gibberellin receptor previously identified in plants and associated with reproductive development, including ovule formation. In this work, we characterized the Brachiaria brizantha GID1 gene (BbrizGID1). BbrizGID1 showed up to 92% similarity to GID1-like gibberellin receptors of other plants of the Poaceae family and around 58% to GID1-like gibberellin receptors of Arabidopsis thaliana. BbrizGID1 was more expressed in ovaries at megasporogenesis than in ovaries at megagametogenesis of both sexual and apomictic plants. In ovules, BbrizGID1 transcripts were detected in the megaspore mother cell (MMC) of sexual and apomictic B. brizantha. Only in the apomictic plants, expression was also observed in the surrounding nucellar cells, a region in which aposporous initial cells differentiate to form the aposporic embryo sac. AtGID1a ectopic expression in Arabidopsis determines the formation of MMC-like cells in the nucellus, close to the MMC, that did not own MMC identity. Our results suggest that GID1 might be involved in the proper differentiation of a single MMC during ovule development and provide valuable information on the role of GID1 in sexual and apomictic reproduction.
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Affiliation(s)
- Luciana Gomes Ferreira
- Department of Biology, University of Brasília-UnB, Campus Darcy Ribeiro S/N-Asa Norte, Brasília, DF, 70910-900, Brazil
- Embrapa Genetic Resources and Biotechnology, Parque Estação Biológica, PqEB Av. W5 Norte, Caixa Postal 02372, Brasília, DF, 70770-917, Brazil
| | - Diva Maria de Alencar Dusi
- Embrapa Genetic Resources and Biotechnology, Parque Estação Biológica, PqEB Av. W5 Norte, Caixa Postal 02372, Brasília, DF, 70770-917, Brazil
| | - André Southernman Teixeira Irsigler
- Embrapa Genetic Resources and Biotechnology, Parque Estação Biológica, PqEB Av. W5 Norte, Caixa Postal 02372, Brasília, DF, 70770-917, Brazil
| | - Ana Cristina Meneses Mendes Gomes
- Embrapa Genetic Resources and Biotechnology, Parque Estação Biológica, PqEB Av. W5 Norte, Caixa Postal 02372, Brasília, DF, 70770-917, Brazil
| | - Marta Adelina Mendes
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133, Milan, Italy
| | - Lucia Colombo
- Dipartimento di Bioscienze, Università degli Studi di Milano, Via Celoria 26, 20133, Milan, Italy
| | - Vera Tavares de Campos Carneiro
- Department of Biology, University of Brasília-UnB, Campus Darcy Ribeiro S/N-Asa Norte, Brasília, DF, 70910-900, Brazil.
- Embrapa Genetic Resources and Biotechnology, Parque Estação Biológica, PqEB Av. W5 Norte, Caixa Postal 02372, Brasília, DF, 70770-917, Brazil.
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Tang Q, Zang G, Cheng C, Luan M, Dai Z, Xu Y, Yang Z, Zhao L, Su J. Diplosporous development in Boehmeria tricuspis: Insights from de novo transcriptome assembly and comprehensive expression profiling. Sci Rep 2017; 7:46043. [PMID: 28382950 PMCID: PMC5382578 DOI: 10.1038/srep46043] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2016] [Accepted: 03/07/2017] [Indexed: 01/05/2023] Open
Abstract
Boehmeria tricuspis includes sexually reproducing diploid and apomictic triploid individuals. Previously, we established that triploid B. tricuspis reproduces through obligate diplospory. To understand the molecular basis of apomictic development in B. tricuspis, we sequenced and compared transcriptomic profiles of the flowers of sexual and apomictic plants at four key developmental stages. A total of 283,341 unique transcripts were obtained from 1,463 million high-quality paired-end reads. In total, 18,899 unigenes were differentially expressed between the reproductive types at the four stages. By classifying the transcripts into gene ontology categories of differentially expressed genes, we showed that differential plant hormone signal transduction, cell cycle regulation, and transcription factor regulation are possibly involved in apomictic development and/or a polyploidization response in B. tricuspis. Furthermore, we suggest that specific gene families are possibly related to apomixis and might have important effects on diplosporous floral development. These results make a notable contribution to our understanding of the molecular basis of diplosporous development in B. tricuspis.
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Affiliation(s)
- Qing Tang
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Gonggu Zang
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Chaohua Cheng
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Mingbao Luan
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Zhigang Dai
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Ying Xu
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Zemao Yang
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Lining Zhao
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
| | - Jianguang Su
- Institute of Bast Fiber Crops, Chinese Academy of Agricultural Sciences, 348 West Xianjiahu Road, Changsha, Hunan, China
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18
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Abstract
Apomixis, commonly defined as asexual reproduction through seed, is a reproductive trait that occurs in only a few minor crops, but would be highly valuable in major crops. Apomixis results in seed-derived progenies that are genetically identical to their maternal parent. The advantage of apomixis would lie in seed propagation of elite food, feed, and biofuel crops that are heterozygous such as hybrid corn and switchgrass or self-pollinating crops for which no commercial-scale hybrid production system is available. While hybrid plants often outperform parental lines in growth and higher yields, production of hybrid seed is accomplished through carefully controlled, labor intensive crosses. Both small farmers in developing countries who produce their own seed and commercial companies that market hybrid seed could benefit from the establishment of engineered apomixis in plants. In this chapter, we review what has been learned from studying natural apomicts and mutations in sexual plants leading to apomixis-like development, plus discuss how the components of apomixis could be successfully engineered in plants.
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Affiliation(s)
- Joann A Conner
- Horticulture Department, NESPAL/University of Georgia-Tifton Campus, 2356 Rainwater Road, Tifton, GA, 31794, USA.
| | - Peggy Ozias-Akins
- Horticulture Department, NESPAL/University of Georgia-Tifton Campus, 2356 Rainwater Road, Tifton, GA, 31794, USA
- Institute of Plant Breeding, Genetics and Genomics, University of Georgia-Tifton Campus, Tifton, GA, USA
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Abstract
Apomixis (asexual seed formation) is the result of a plant gaining the ability to bypass the most fundamental aspects of sexual reproduction: meiosis and fertilization. Without the need for male fertilization, the resulting seed germinates a plant that develops as a maternal clone. This dramatic shift in reproductive process has been documented in many flowering plant species, although no major seed crops have been shown to be capable of apomixis. The ability to generate maternal clones and therefore rapidly fix desirable genotypes in crop species could accelerate agricultural breeding strategies. The potential of apomixis as a next-generation breeding technology has contributed to increasing interest in the mechanisms controlling apomixis. In this review, we discuss the progress made toward understanding the genetic and molecular control of apomixis. Research is currently focused on two fronts. One aims to identify and characterize genes causing apomixis in apomictic species that have been developed as model species. The other aims to engineer or switch the sexual seed formation pathway in non-apomictic species, to one that mimics apomixis. Here we describe the major apomictic mechanisms and update knowledge concerning the loci that control them, in addition to presenting candidate genes that may be used as tools for switching the sexual pathway to an apomictic mode of reproduction in crops.
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Poschenrieder C, Tolrà R, Hajiboland R, Arroyave C, Barceló J. Mechanisms of Hyper-resistance and Hyper-tolerance to Aluminum in Plants. ALUMINUM STRESS ADAPTATION IN PLANTS 2015. [DOI: 10.1007/978-3-319-19968-9_5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Barcaccia G, Albertini E. Apomixis in plant reproduction: a novel perspective on an old dilemma. PLANT REPRODUCTION 2013; 26:159-79. [PMID: 23852378 PMCID: PMC3747320 DOI: 10.1007/s00497-013-0222-y] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 06/23/2013] [Indexed: 05/19/2023]
Abstract
Seed is one of the key factors of crop productivity. Therefore, a comprehension of the mechanisms underlying seed formation in cultivated plants is crucial for the quantitative and qualitative progress of agricultural production. In angiosperms, two pathways of reproduction through seed exist: sexual or amphimictic, and asexual or apomictic; the former is largely exploited by seed companies for breeding new varieties, whereas the latter is receiving continuously increasing attention from both scientific and industrial sectors in basic research projects. If apomixis is engineered into sexual crops in a controlled manner, its impact on agriculture will be broad and profound. In fact, apomixis will allow clonal seed production and thus enable efficient and consistent yields of high-quality seeds, fruits, and vegetables at lower costs. The development of apomixis technology is expected to have a revolutionary impact on agricultural and food production by reducing cost and breeding time, and avoiding the complications that are typical of sexual reproduction (e.g., incompatibility barriers) and vegetative propagation (e.g., viral transfer). However, the development of apomixis technology in agriculture requires a deeper knowledge of the mechanisms that regulate reproductive development in plants. This knowledge is a necessary prerequisite to understanding the genetic control of the apomictic process and its deviations from the sexual process. Our molecular understanding of apomixis will be greatly advanced when genes that are specifically or differentially expressed during embryo and embryo sac formation are discovered. In our review, we report the main findings on this subject by examining two approaches: i) analysis of the apomictic process in natural apomictic species to search for genes controlling apomixis and ii) analysis of gene mutations resembling apomixis or its components in species that normally reproduce sexually. In fact, our opinion is that a novel perspective on this old dilemma pertaining to the molecular control of apomixis can emerge from a cross-check among candidate genes in natural apomicts and a high-throughput analysis of sexual mutants.
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Affiliation(s)
- Gianni Barcaccia
- Laboratory of Genetics and Genomics, DAFNAE, University of Padova, Campus of Agripolis, Viale dell’Università 16, 35020 Legnaro, Italy
| | - Emidio Albertini
- Department of Applied Biology, University of Perugia, Borgo XX Giugno 74, 06121 Perugia, Italy
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Ma K, Hu CG, Xu B, Yao JL. Regeneration and Agrobacterium-mediated transformation of the apomictic species Eulaliopsis binata. Appl Biochem Biotechnol 2013; 171:543-52. [PMID: 23873641 DOI: 10.1007/s12010-013-0391-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2013] [Accepted: 07/08/2013] [Indexed: 11/30/2022]
Abstract
Protocols for regeneration and Agrobacterium-mediated transformation of the apomictic species Eulaliopsis binata were developed. Initially, seeds of four genotypes of E. binata were incubated on a callus induction Murashige and Skoog (MS) basal medium supplemented with three concentrations of 2,4-dichlorophenoxyacetic acid (2,4-D). It was found that 36.2 % of explants developed highly friable callus on medium containing 3.0 mg l(-1) 2,4-D. Based on frequency of callus induction, the genotype Neixiang was selected for regeneration and transformation. Callus incubated on MS basal medium supplemented with 0.2 mg l(-1) α-naphthalene acetic acid and 6.0 mg l(-1) 6-furfuryl-aminopurine developed shoots. Subsequently, Agrobacterium tumefaciens strain EHA105-harboring a plasmid pCAMBIA1381 carrying a hygromycin phosphotransferase (hpt) resistance gene and a synthetic green fluorescent protein (GFP) gene, both driven by the cauliflower mosaic virus 35S promoter-was used for transformation system. Putative transgenic callus was obtained following two cycles of hygromycin selection. Expression of the transgene(s) in putative transgenic callus was analyzed using the GFP detection. Molecular identification of putative transformed shoots was performed by polymerase chain reaction and Southern blot analysis to confirm presence and integration of the hpt gene.
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Affiliation(s)
- Kai Ma
- College of Horticulture and Forestry, Huazhong Agricultural University, Wuhan, People's Republic of China
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Lacerda ALM, Dusi DMDA, Alves ER, Rodrigues JCM, Gomes ACMM, Carneiro VTDC. Expression analyses of Brachiaria brizantha genes encoding ribosomal proteins BbrizRPS8, BbrizRPS15a, and BbrizRPL41 during development of ovaries and anthers. PROTOPLASMA 2013; 250:505-514. [PMID: 22833119 DOI: 10.1007/s00709-012-0433-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Accepted: 07/10/2012] [Indexed: 06/01/2023]
Abstract
Brachiaria brizantha is a forage grass of the Poaceae family. Introduced from Africa, it is largely used for beef cattle production in Brazil. Brachiaria reproduces sexually or asexually by apomixis, and development of biotechnological tools for gene transfer is being researched to support the breeding programs. The molecular bases of reproduction have not yet been fully elucidated; it is known that gametophyte formation and main reproductive events occur inside the anthers and ovaries. There is therefore much interest in identifying genes expressed in these organs and their corresponding upstream regulatory sequences. In this work we characterized three cDNA from ovaries of B. brizantha plants (CL 09, CL10, and CL21) which show similarity in databases with genes encoding ribosomal proteins S8, S15a, and L41 and were named BbrizRPS8, BbrizRPS15a, and BbrizRPL41, respectively. These clones show higher expression in ovaries, anthers and roots, mitotically active tissues, when compared to leaves of B. brizantha. Localization of transcripts of BbrizRPS8, BbrizRPS15a, and BbrizRPL41 was investigated in the reproductive organs, ovaries, and anthers, from the beginning of development up to maturity. Their activity was higher in early stages of anther development, while expression was detected in all developmental stages in the ovaries, except for BbrizS15a, which was detected only in synergids of apomictic plants.
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Affiliation(s)
- Ana Luiza Machado Lacerda
- Embrapa Genetic Resources and Biotechnology, Parque Estação Biológica, Brasília, Federal District, Brazil
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Rodriguez-Leal D, Vielle-Calzada JP. Regulation of apomixis: learning from sexual experience. CURRENT OPINION IN PLANT BIOLOGY 2012; 15:549-55. [PMID: 23000434 DOI: 10.1016/j.pbi.2012.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2012] [Revised: 07/17/2012] [Accepted: 09/05/2012] [Indexed: 05/10/2023]
Abstract
Apomixis is a natural form of asexual reproduction through seeds that leads to viable offspring genetically identical to the mother plant. New evidence from sexual model species indicates that the regulation of female gametogenesis and seed formation is also directed by epigenetic mechanisms that are crucial to control events that distinguish sexuality from apomixis, with important implications for our understanding of the evolutionary forces that shape structural variation and diversity in plant reproduction.
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Affiliation(s)
- Daniel Rodriguez-Leal
- Group of Reproductive Development and Apomixis, Laboratorio Nacional de Genómica para la Biodiversidad, CINVESTAV, Irapuato, Guanajuato, Mexico
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