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da Costa Lima Moraes A, Mollinari M, Ferreira RCU, Aono A, de Castro Lara LA, Pessoa-Filho M, Barrios SCL, Garcia AAF, do Valle CB, de Souza AP, Vigna BBZ. Advances in genomic characterization of Urochloa humidicola: exploring polyploid inheritance and apomixis. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2023; 136:238. [PMID: 37919432 DOI: 10.1007/s00122-023-04485-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 10/11/2023] [Indexed: 11/04/2023]
Abstract
KEY MESSAGE We present the highest-density genetic map for the hexaploid Urochloa humidicola. SNP markers expose genetic organization, reproduction, and species origin, aiding polyploid and tropical forage research. Tropical forage grasses are an important food source for animal feeding, with Urochloa humidicola, also known as Koronivia grass, being one of the main pasture grasses for poorly drained soils in the tropics. However, genetic and genomic resources for this species are lacking due to its genomic complexity, including high heterozygosity, evidence of segmental allopolyploidy, and reproduction by apomixis. These complexities hinder the application of marker-assisted selection (MAS) in breeding programs. Here, we developed the highest-density linkage map currently available for the hexaploid tropical forage grass U. humidicola. This map was constructed using a biparental F1 population generated from a cross between the female parent H031 (CIAT 26146), the only known sexual genotype for the species, and the apomictic male parent H016 (BRS cv. Tupi). The linkage analysis included 4873 single nucleotide polymorphism (SNP) markers with allele dosage information. It allowed mapping of the ASGR locus and apospory phenotype to linkage group 3, in a region syntenic with chromosome 3 of Urochloa ruziziensis and chromosome 1 of Setaria italica. We also identified hexaploid haplotypes for all individuals, assessed the meiotic configuration, and estimated the level of preferential pairing in parents during the meiotic process, which revealed the autopolyploid origin of sexual H031 in contrast to apomictic H016, which presented allopolyploid behavior in preferential pairing analysis. These results provide new information regarding the genetic organization, mode of reproduction, and allopolyploid origin of U. humidicola, potential SNPs markers associated with apomixis for MAS and resources for research on polyploids and tropical forage grasses.
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Affiliation(s)
- Aline da Costa Lima Moraes
- Department of Plant Biology, Biology Institute, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | - Marcelo Mollinari
- Department of Horticultural Science, Bioinformatics Research Center, North Carolina State University, Raleigh, NC, USA
| | | | - Alexandre Aono
- Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
| | | | | | | | | | | | - Anete Pereira de Souza
- Department of Plant Biology, Biology Institute, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
- Center for Molecular Biology and Genetic Engineering (CBMEG), University of Campinas (UNICAMP), Campinas, São Paulo, Brazil
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Aguilera PM, Galdeano F, Ortiz JPA, Quarin CL, Espinoza F. Construction of AFLP-based cosegregation groups of tetraploid Plicatula species and identification of markers linked to apomixis. RODRIGUÉSIA 2022. [DOI: 10.1590/2175-7860202273085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Abstract Most species of Plicatula are important native forages. This work aimed to build framework cosegregation groups of the apomictic tetraploid race of Paspalum guenoarum cv. Rojas and localize the locus controlling apomixis in the species. An interspecific population derived from crossing a completely sexual tetraploid plant of P. plicatulum and an apomictic tetraploid individual of P. guenoarum cv. Rojas was used. Both, disomic and tetrasomic inheritance were detected in both parental genotypes. In P. guenoarum, ten cosegregation groups were built, including 50 markers expanding for 583 cM. The estimated genome coverage was 63.95%. The apomixis locus was located in the linkage group M8, together with seven other loci (four paternal and three biparental markers). The group extended for 59 cM. The four paternal markers showed strong linkage to apomixis, and two of them mapped at 4 and 7 cM at both sides of the locus. Five female linkage groups were constructed with markers segregating from P. plicatulum. One of them (F3) being homologous to the male group carrying apomixis. The linkage groups presented here constitute the first genetic frame for species of Plicatula group. Moreover, molecular markers linked to apomixis in P. guenoarum can assist fundamental research and breeding programs.
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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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Jones C, De Vega J, Worthington M, Thomas A, Gasior D, Harper J, Doonan J, Fu Y, Bosch M, Corke F, Arango J, Cardoso JA, de la Cruz Jimenez J, Armstead I, Fernandez-Fuentes N. A Comparison of Differential Gene Expression in Response to the Onset of Water Stress Between Three Hybrid Brachiaria Genotypes. FRONTIERS IN PLANT SCIENCE 2021; 12:637956. [PMID: 33815444 PMCID: PMC8017340 DOI: 10.3389/fpls.2021.637956] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Accepted: 02/19/2021] [Indexed: 05/08/2023]
Abstract
Brachiaria (Trin.) Griseb. (syn. Urochloa P. Beauv.) is a C4 grass genus belonging to the Panicoideae. Native to Africa, these grasses are now widely grown as forages in tropical areas worldwide and are the subject of intensive breeding, particularly in South America. Tolerance to abiotic stresses such as aluminum and drought are major breeding objectives. In this study, we present the transcriptomic profiling of leaves and roots of three Brachiaria interspecific hybrid genotypes with the onset of water stress, Br12/3659-17 (gt-17), Br12/2360-9 (gt-9), and Br12/3868-18 (gt-18), previously characterized as having good, intermediate and poor tolerance to drought, respectively, in germplasm evaluation programs. RNA was extracted from leaf and root tissue of plants at estimated growing medium water contents (EWC) of 35, 15, and 5%. Differentially expressed genes (DEGs) were compared between different EWCs, 35/15, 15/5, and 35/5 using DESeq2. Overall, the proportions of DEGs enriched in all three genotypes varied in a genotype-dependent manner in relation to EWC comparison, with intermediate and sensitive gt-9 and gt-18 being more similar to each other than to drought tolerant gt-17. More specifically, GO terms relating to carbohydrate and cell wall metabolism in the leaves were enriched by up-regulated DEGs in gt-9 and gt-18, but by down-regulated DEGs in gt-17. Across all genotypes, analysis of DEG enzyme activities indicated an excess of down-regulated putative apoplastic peroxidases in the roots as water stress increased. This suggests that changes in root cell-wall architecture may be an important component of the response to water stress in Brachiaria.
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Affiliation(s)
- Charlotte Jones
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | | | - Margaret Worthington
- Department of Horticulture, University of Arkansas, Fayetteville, AR, United States
| | - Ann Thomas
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Dagmara Gasior
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - John Harper
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - John Doonan
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Yuan Fu
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Maurice Bosch
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Fiona Corke
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Jacobo Arango
- International Center for Tropical Agriculture, Cali, Colombia
| | | | - Juan de la Cruz Jimenez
- School of Agriculture and Environment, Faculty of Science, The University of Western Australia, Crawley, WA, Australia
| | - Ian Armstead
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
| | - Narcis Fernandez-Fuentes
- Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth, United Kingdom
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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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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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7
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Deo TG, Ferreira RCU, Lara LAC, Moraes ACL, Alves-Pereira A, de Oliveira FA, Garcia AAF, Santos MF, Jank L, de Souza AP. High-Resolution Linkage Map With Allele Dosage Allows the Identification of Regions Governing Complex Traits and Apospory in Guinea Grass ( Megathyrsus maximus). FRONTIERS IN PLANT SCIENCE 2020; 11:15. [PMID: 32161603 PMCID: PMC7054243 DOI: 10.3389/fpls.2020.00015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Accepted: 01/08/2020] [Indexed: 05/11/2023]
Abstract
Forage grasses are mainly used in animal feed to fatten cattle and dairy herds, and guinea grass (Megathyrsus maximus) is considered one of the most productive of the tropical forage crops that reproduce by seeds. Due to the recent process of domestication, this species has several genomic complexities, such as autotetraploidy and aposporous apomixis. Consequently, approaches that relate phenotypic and genotypic data are incipient. In this context, we built a linkage map with allele dosage and generated novel information of the genetic architecture of traits that are important for the breeding of M. maximus. From a full-sib progeny, a linkage map containing 858 single nucleotide polymorphism (SNP) markers with allele dosage information expected for an autotetraploid was obtained. The high genetic variability of the progeny allowed us to map 10 quantitative trait loci (QTLs) related to agronomic traits, such as regrowth capacity and total dry matter, and 36 QTLs related to nutritional quality, which were distributed among all homology groups (HGs). Various overlapping regions associated with the quantitative traits suggested QTL hotspots. In addition, we were able to map one locus that controls apospory (apo-locus) in HG II. A total of 55 different gene families involved in cellular metabolism and plant growth were identified from markers adjacent to the QTLs and APOSPORY locus using the Panicum virgatum genome as a reference in comparisons with the genomes of Arabidopsis thaliana and Oryza sativa. Our results provide a better understanding of the genetic basis of reproduction by apomixis and traits important for breeding programs that considerably influence animal productivity as well as the quality of meat and milk.
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Affiliation(s)
- Thamiris G. Deo
- Center for Molecular Biology and Genetic Engineering, University of Campinas, Campinas, Brazil
| | - Rebecca C. U. Ferreira
- Center for Molecular Biology and Genetic Engineering, University of Campinas, Campinas, Brazil
| | - Letícia A. C. Lara
- Genetics Department, Escola Superior de Agricultura “Luiz de Queiroz,” University of São Paulo, Piracicaba, Brazil
| | - Aline C. L. Moraes
- Plant Biology Department, Biology Institute, University of Campinas, Campinas, Brazil
| | | | - Fernanda A. de Oliveira
- Center for Molecular Biology and Genetic Engineering, University of Campinas, Campinas, Brazil
| | - Antonio A. F. Garcia
- Genetics Department, Escola Superior de Agricultura “Luiz de Queiroz,” University of São Paulo, Piracicaba, Brazil
| | - Mateus F. Santos
- Embrapa Beef Cattle, Brazilian Agricultural Research Corporation, Campo Grande, Brazil
| | - Liana Jank
- Embrapa Beef Cattle, Brazilian Agricultural Research Corporation, Campo Grande, Brazil
| | - Anete P. de Souza
- Center for Molecular Biology and Genetic Engineering, University of Campinas, Campinas, Brazil
- Plant Biology Department, Biology Institute, University of Campinas, Campinas, Brazil
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Albertini E, Barcaccia G, Carman JG, Pupilli F. Did apomixis evolve from sex or was it the other way around? JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:2951-2964. [PMID: 30854543 DOI: 10.1093/jxb/erz109] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 02/25/2019] [Indexed: 05/20/2023]
Abstract
In angiosperms, there are two pathways of reproduction through seeds: sexual, or amphimictic, and asexual, or apomictic. The essential feature of apomixis is that an embryo in an ovule is formed autonomously. It may form from a cell of the nucellus or integuments in an otherwise sexual ovule, a process referred to as adventitious embryony. Alternatively, the embryo may form by parthenogenesis from an unreduced egg that forms in an unreduced embryo sac. The latter may form from an ameiotic megasporocyte, in which case it is referred to as diplospory, or from a cell of the nucellus or integument, in which case it is referred to as apospory. Progeny of apomictic plants are generally identical to the mother plant. Apomixis has been seen over the years as either a gain- or loss-of-function over sexuality, implying that the latter is the default condition. Here, we consider an additional point of view, that apomixis may be anciently polyphenic with sex and that both reproductive phenisms involve anciently canalized components of complex molecular processes. This polyphenism viewpoint suggests that apomixis fails to occur in obligately sexual eukaryotes because genetic or epigenetic modifications have silenced the primitive sex apomixis switch and/or disrupted molecular capacities for apomixis. In eukaryotes where sex and apomixis are clearly polyphenic, apomixis exponentially drives clonal fecundity during reproductively favorable conditions, while stress induces sex for stress-tolerant spore or egg formation. The latter often guarantees species survival during environmentally harsh seasons.
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Affiliation(s)
- Emidio Albertini
- Department of Agricultural, Food and Environmental Sciences, University of Perugia, Perugia, Italy
| | - Gianni Barcaccia
- Laboratory of Genomics, Department of Agronomy, Food, Natural Resources, Animals and the Environment (DAFNAE), University of Padova Legnaro, PD, Italy
| | - John G Carman
- Department of Plants, Soils and Climate, Utah State University, Logan, Utah, USA
| | - Fulvio Pupilli
- Institute of Biosciences and Bioresources, Research Division of Perugia, National Research Council (CNR), Perugia, Italy
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Worthington M, Ebina M, Yamanaka N, Heffelfinger C, Quintero C, Zapata YP, Perez JG, Selvaraj M, Ishitani M, Duitama J, de la Hoz JF, Rao I, Dellaporta S, Tohme J, Arango J. Translocation of a parthenogenesis gene candidate to an alternate carrier chromosome in apomictic Brachiaria humidicola. BMC Genomics 2019; 20:41. [PMID: 30642244 PMCID: PMC6332668 DOI: 10.1186/s12864-018-5392-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2018] [Accepted: 12/18/2018] [Indexed: 12/05/2022] Open
Abstract
Background The apomictic reproductive mode of Brachiaria (syn. Urochloa) forage species allows breeders to faithfully propagate heterozygous genotypes through seed over multiple generations. In Brachiaria, reproductive mode segregates as single dominant locus, the apospory-specific genomic region (ASGR). The AGSR has been mapped to an area of reduced recombination on Brachiaria decumbens chromosome 5. A primer pair designed within ASGR-BABY BOOM-like (BBML), the candidate gene for the parthenogenesis component of apomixis in Pennisetum squamulatum, was diagnostic for reproductive mode in the closely related species B. ruziziensis, B. brizantha, and B. decumbens. In this study, we used a mapping population of the distantly related commercial species B. humidicola to map the ASGR and test for conservation of ASGR-BBML sequences across Brachiaria species. Results Dense genetic maps were constructed for the maternal and paternal genomes of a hexaploid (2n = 6x = 36) B. humidicola F1 mapping population (n = 102) using genotyping-by-sequencing, simple sequence repeat, amplified fragment length polymorphism, and transcriptome derived single nucleotide polymorphism markers. Comparative genomics with Setaria italica provided confirmation for x = 6 as the base chromosome number of B. humidicola. High resolution molecular karyotyping indicated that the six homologous chromosomes of the sexual female parent paired at random, whereas preferential pairing of subgenomes was observed in the apomictic male parent. Furthermore, evidence for compensated aneuploidy was found in the apomictic parent, with only five homologous linkage groups identified for chromosome 5 and seven homologous linkage groups of chromosome 6. The ASGR mapped to B. humidicola chromosome 1, a region syntenic with chromosomes 1 and 7 of S. italica. The ASGR-BBML specific PCR product cosegregated with the ASGR in the F1 mapping population, despite its location on a different carrier chromosome than B. decumbens. Conclusions The first dense molecular maps of B. humidicola provide strong support for cytogenetic evidence indicating a base chromosome number of six in this species. Furthermore, these results show conservation of the ASGR across the Paniceae in different chromosomal backgrounds and support postulation of the ASGR-BBML as candidate genes for the parthenogenesis component of apomixis. Electronic supplementary material The online version of this article (10.1186/s12864-018-5392-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Margaret Worthington
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia. .,Present address: Department of Horticulture, University of Arkansas, 306 Plant Sciences Bldg, Fayetteville, AR, 72701, USA.
| | - Masumi Ebina
- National Agriculture and Food Research Organization (NARO), Institute of Livestock and Grassland Science, Nasushiobara, Tochigi, 392-2793, Japan
| | - Naoki Yamanaka
- Japan International Research Center for Agricultural Sciences (JIRCAS), 1-1 Ohwashi, Tsukuba, Ibaraki, 305-8686, Japan
| | - Christopher Heffelfinger
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, 06520, USA
| | - Constanza Quintero
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
| | | | | | - Michael Selvaraj
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
| | - Manabu Ishitani
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
| | - Jorge Duitama
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia.,Present address: Systems and Computing Engineering Department, Universidad de los Andes, Bogotá, Colombia
| | - Juan Fernando de la Hoz
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia.,Present address: Bioinformatics Interdepartmental Ph.D. Program, University of California, Los Angeles, Los Angeles, CA, 90095, USA
| | - Idupulapati Rao
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia.,Present address: Plant Polymer Research Unit (PPL), National Center for Agricultural Utilization Research (NCAUR), Agricultural Research Service, United States Department of Agriculture (ARS-USDA), 1815 N. University St., Peoria, IL, 61604, USA
| | - Stephen Dellaporta
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, 06520, USA
| | - Joe Tohme
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
| | - Jacobo Arango
- International Center for Tropical Agriculture (CIAT), A.A. 6713, Cali, Colombia
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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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Ortiz JPA, Revale S, Siena LA, Podio M, Delgado L, Stein J, Leblanc O, Pessino SC. A reference floral transcriptome of sexual and apomictic Paspalum notatum. BMC Genomics 2017; 18:318. [PMID: 28431521 PMCID: PMC5399859 DOI: 10.1186/s12864-017-3700-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 04/11/2017] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Paspalum notatum Flügge is a subtropical grass native to South America, which includes sexual diploid and apomictic polyploid biotypes. In the past decade, a number of apomixis-associated genes were discovered in this species through genetic mapping and differential expression surveys. However, the scarce information on Paspalum sequences available in public databanks limited annotations and functional predictions for these candidates. RESULTS We used a long-read 454/Roche FLX+ sequencing strategy to produce robust reference transcriptome datasets from florets of sexual and apomictic Paspalum notatum genotypes and delivered a list of transcripts showing differential representation in both reproductive types. Raw data originated from floral samples collected from premeiosis to anthesis was assembled in three libraries: i) sexual (SEX), ii) apomictic (APO) and iii) global (SEX + APO). A group of physically-supported Paspalum mRNA and EST sequences matched with high level of confidence to both sexual and apomictic libraries. A preliminary trial allowed discovery of the whole set of putative alleles/paralogs corresponding to 23 previously identified apomixis-associated candidate genes. Moreover, a list of 3,732 transcripts and several co-expression and protein -protein interaction networks associated with apomixis were identified. CONCLUSIONS The use of the 454/Roche FLX+ transcriptome database will allow the detailed characterization of floral alleles/paralogs of apomixis candidate genes identified in prior and future work. Moreover, it was used to reveal additional candidate genes differentially represented in apomictic and sexual flowers. Gene ontology (GO) analyses of this set of transcripts indicated that the main molecular pathways altered in the apomictic genotype correspond to specific biological processes, like biotic and abiotic stress responses, growth, development, cell death and senescence. This data collection will be of interest to the plant reproduction research community and, particularly, to Paspalum breeding projects.
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Affiliation(s)
- Juan Pablo A Ortiz
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR)-CONICET/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino, Provincia de Santa Fe, Zavalla, S2125ZAA, Argentina
| | - Santiago Revale
- Instituto de Agrobiotecnología de Rosario (INDEAR), Ocampo 210 bis, Provincia de Santa Fe, Rosario, 2000, Argentina.,Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, OX3 7BN, UK
| | - Lorena A Siena
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR)-CONICET/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino, Provincia de Santa Fe, Zavalla, S2125ZAA, Argentina
| | - Maricel Podio
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR)-CONICET/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino, Provincia de Santa Fe, Zavalla, S2125ZAA, Argentina
| | - Luciana Delgado
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR)-CONICET/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino, Provincia de Santa Fe, Zavalla, S2125ZAA, Argentina
| | - Juliana Stein
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR)-CONICET/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino, Provincia de Santa Fe, Zavalla, S2125ZAA, Argentina
| | - Olivier Leblanc
- UMR 232, Institut de Recherche pour le Développement, Université de Montpellier, Montpellier, 34394, France
| | - Silvina C Pessino
- Instituto de Investigaciones en Ciencias Agrarias de Rosario (IICAR)-CONICET/Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Campo Experimental Villarino, Provincia de Santa Fe, Zavalla, S2125ZAA, Argentina.
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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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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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A Parthenogenesis Gene Candidate and Evidence for Segmental Allopolyploidy in Apomictic Brachiaria decumbens. Genetics 2016; 203:1117-32. [PMID: 27206716 PMCID: PMC4937464 DOI: 10.1534/genetics.116.190314] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/14/2016] [Indexed: 12/19/2022] Open
Abstract
Apomixis, asexual reproduction through seed, enables breeders to identify and faithfully propagate superior heterozygous genotypes by seed without the disadvantages of vegetative propagation or the expense and complexity of hybrid seed production. The availability of new tools such as genotyping by sequencing and bioinformatics pipelines for species lacking reference genomes now makes the construction of dense maps possible in apomictic species, despite complications including polyploidy, multisomic inheritance, self-incompatibility, and high levels of heterozygosity. In this study, we developed saturated linkage maps for the maternal and paternal genomes of an interspecific Brachiaria ruziziensis (R. Germ. and C. M. Evrard) × B. decumbens Stapf. F1 mapping population in order to identify markers linked to apomixis. High-resolution molecular karyotyping and comparative genomics with Setaria italica (L.) P. Beauv provided conclusive evidence for segmental allopolyploidy in B. decumbens, with strong preferential pairing of homologs across the genome and multisomic segregation relatively more common in chromosome 8. The apospory-specific genomic region (ASGR) was mapped to a region of reduced recombination on B. decumbens chromosome 5. The Pennisetum squamulatum (L.) R.Br. PsASGR-BABY BOOM-like (psASGR–BBML)-specific primer pair p779/p780 was in perfect linkage with the ASGR in the F1 mapping population and diagnostic for reproductive mode in a diversity panel of known sexual and apomict Brachiaria (Trin.) Griseb. and P. maximum Jacq. germplasm accessions and cultivars. These findings indicate that ASGR–BBML gene sequences are highly conserved across the Paniceae and add further support for the postulation of the ASGR–BBML as candidate genes for the apomictic function of parthenogenesis.
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Vigna BBZ, Santos JCS, Jungmann L, do Valle CB, Mollinari M, Pastina MM, Pagliarini MS, Garcia AAF, Souza AP. Evidence of Allopolyploidy in Urochloa humidicola Based on Cytological Analysis and Genetic Linkage Mapping. PLoS One 2016; 11:e0153764. [PMID: 27104622 PMCID: PMC4841517 DOI: 10.1371/journal.pone.0153764] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 04/04/2016] [Indexed: 01/30/2023] Open
Abstract
The African species Urochloa humidicola (Rendle) Morrone & Zuloaga (syn. Brachiaria humidicola (Rendle) Schweick.) is an important perennial forage grass found throughout the tropics. This species is polyploid, ranging from tetra to nonaploid, and apomictic, which makes genetic studies challenging; therefore, the number of currently available genetic resources is limited. The genomic architecture and evolution of U. humidicola and the molecular markers linked to apomixis were investigated in a full-sib F1 population obtained by crossing the sexual accession H031 and the apomictic cultivar U. humidicola cv. BRS Tupi, both of which are hexaploid. A simple sequence repeat (SSR)-based linkage map was constructed for the species from 102 polymorphic and specific SSR markers based on simplex and double-simplex markers. The map consisted of 49 linkage groups (LGs) and had a total length of 1702.82 cM, with 89 microsatellite loci and an average map density of 10.6 cM. Eight homology groups (HGs) were formed, comprising 22 LGs, and the other LGs remained ungrouped. The locus that controls apospory (apo-locus) was mapped in LG02 and was located 19.4 cM from the locus Bh027.c.D2. In the cytological analyses of some hybrids, bi- to hexavalents at diakinesis were observed, as well as two nucleoli in some meiocytes, smaller chromosomes with preferential allocation within the first metaphase plate and asynchronous chromosome migration to the poles during anaphase. The linkage map and the meiocyte analyses confirm previous reports of hybridization and suggest an allopolyploid origin of the hexaploid U. humidicola. This is the first linkage map of an Urochloa species, and it will be useful for future quantitative trait locus (QTL) analysis after saturation of the map and for genome assembly and evolutionary studies in Urochloa spp. Moreover, the results of the apomixis mapping are consistent with previous reports and confirm the need for additional studies to search for a co-segregating marker.
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Affiliation(s)
- Bianca B. Z. Vigna
- University of Campinas (UNICAMP), Center of Molecular Biology and Genetic Engineering (CBMEG), CP 6010, CEP 13083–970, Campinas, SP, Brazil
- Embrapa Pecuária Sudeste, CP 399, CEP 13560–970, São Carlos, SP, Brazil
| | - Jean C. S. Santos
- University of Campinas (UNICAMP), Center of Molecular Biology and Genetic Engineering (CBMEG), CP 6010, CEP 13083–970, Campinas, SP, Brazil
| | - Leticia Jungmann
- Embrapa Gado de Corte, Av. Radio Maia, 830, CEP 79106–550, Campo Grande, MS, Brazil
| | - Cacilda B. do Valle
- Embrapa Gado de Corte, Av. Radio Maia, 830, CEP 79106–550, Campo Grande, MS, Brazil
| | - Marcelo Mollinari
- University of São Paulo, Escola Superior de Agricultura Luiz de Queiroz, Department of Genetics, CP 83, CEP 13400–970, Piracicaba, SP, Brazil
| | - Maria M. Pastina
- Embrapa Milho e Sorgo, Rod. MG 424, Km 65, CEP 35701–970, Sete Lagoas, MG, Brazil
| | - Maria Suely Pagliarini
- University of Maringá (UEM), Department of Genetics and Cell Biology, Av. Colombo, 5790, Zona 7, CEP 87020–900, Maringá, PR, Brazil
| | - Antonio A. F. Garcia
- University of São Paulo, Escola Superior de Agricultura Luiz de Queiroz, Department of Genetics, CP 83, CEP 13400–970, Piracicaba, SP, Brazil
| | - Anete P. Souza
- University of Campinas (UNICAMP), Center of Molecular Biology and Genetic Engineering (CBMEG), CP 6010, CEP 13083–970, Campinas, SP, Brazil
- University of Campinas (UNICAMP), Biology Institute, Department of Plant Biology, CP6109, CEP 13083–970, Campinas, SP, Brazil
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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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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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Conner JA, Gunawan G, Ozias-Akins P. Recombination within the apospory specific genomic region leads to the uncoupling of apomixis components in Cenchrus ciliaris. PLANTA 2013; 238:51-63. [PMID: 23553451 DOI: 10.1007/s00425-013-1873-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 03/11/2013] [Indexed: 05/07/2023]
Abstract
Apomixis enables the clonal propagation of maternal genotypes through seed. If apomixis could be harnessed via genetic engineering or introgression, it would have a major economic impact for agricultural crops. In the grass species Pennisetum squamulatum and Cenchrus ciliaris (syn. P. ciliare), apomixis is controlled by a single dominant "locus", the apospory-specific genomic region (ASGR). For P. squamulatum, 18 published sequenced characterized amplified region (SCAR) markers have been identified which always co-segregate with apospory. Six of these markers are conserved SCARs in the closely related species, C. ciliaris and co-segregate with the trait. A screen of progeny from a cross of sexual × apomictic C. ciliaris genotypes identified a plant, A8, retaining two of the six ASGR-linked SCAR markers. Additional and newly identified ASGR-linked markers were generated to help identify the extent of recombination within the ASGR. Based on analysis of missing markers, the A8 recombinant plant has lost a significant portion of the ASGR but continues to form aposporous embryo sacs. Seedlings produced from aposporous embryo sacs are 6× in ploidy level and hence the A8 recombinant does not express parthenogenesis. The recombinant A8 plant represents a step forward in reducing the complexity of the ASGR locus to determine the factor(s) required for aposporous embryo sac formation and documents the separation of expression of the two components of apomixis in C. ciliaris.
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Affiliation(s)
- Joann A Conner
- Department of Horticulture, University of Georgia Tifton Campus, Tifton, GA, 31973, USA.
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Podio M, Rodríguez MP, Felitti S, Stein J, Martínez EJ, Siena LA, Quarin CL, Pessino SC, Ortiz JPA. Sequence characterization, in silico mapping and cytosine methylation analysis of markers linked to apospory in Paspalum notatum. Genet Mol Biol 2012; 35:827-37. [PMID: 23271945 PMCID: PMC3526092 DOI: 10.1590/s1415-47572012005000070] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2012] [Accepted: 07/01/2012] [Indexed: 12/20/2022] Open
Abstract
In previous studies we reported the identification of several AFLP, RAPD and RFLP molecular markers linked to apospory in Paspalum notatum. The objective of this work was to sequence these markers, obtain their flanking regions by chromosome walking and perform an in silico mapping analysis in rice and maize. The methylation status of two apospory-related sequences was also assessed using methylation-sensitive RFLP experiments. Fourteen molecular markers were analyzed and several protein-coding sequences were identified. Copy number estimates and RFLP linkage analysis showed that the sequence PnMAI3 displayed 2–4 copies per genome and linkage to apospory. Extension of this marker by chromosome walking revealed an additional protein-coding sequence mapping in silico in the apospory-syntenic regions of rice and maize. Approximately 5 kb corresponding to different markers were characterized through the global sequencing procedure. A more refined analysis based on sequence information indicated synteny with segments of chromosomes 2 and 12 of rice and chromosomes 3 and 5 of maize. Two loci associated with apomixis locus were tested in methylation-sensitive RFLP experiments using genomic DNA extracted from leaves. Although both target sequences were methylated no methylation polymorphisms associated with the mode of reproduction were detected.
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Affiliation(s)
- Maricel Podio
- Laboratorio de Biología Molecular, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Zavalla, Santa Fe, Argentina. ; Instituto de Botánica del Nordeste, Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste, Corrientes, Argentina
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Vijverberg K, Milanovic-Ivanovic S, Bakx-Schotman T, van Dijk PJ. Genetic fine-mapping of DIPLOSPOROUS in Taraxacum (dandelion; Asteraceae) indicates a duplicated DIP-gene. BMC PLANT BIOLOGY 2010; 10:154. [PMID: 20659311 PMCID: PMC3017824 DOI: 10.1186/1471-2229-10-154] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2010] [Accepted: 07/26/2010] [Indexed: 05/05/2023]
Abstract
BACKGROUND DIPLOSPOROUS (DIP) is the locus for diplospory in Taraxacum, associated to unreduced female gamete formation in apomicts. Apomicts reproduce clonally through seeds, including apomeiosis, parthenogenesis, and autonomous or pseudogamous endosperm formation. In Taraxacum, diplospory results in first division restitution (FDR) nuclei, and inherits as a dominant, monogenic trait, independent from the other apomixis elements. A preliminary genetic linkage map indicated that the DIP-locus lacks suppression of recombination, which is unique among all other map-based cloning efforts of apomeiosis to date. FDR as well as apomixis as a whole are of interest in plant breeding, allowing for polyploidization and fixation of hybrid vigor, respectively. No dominant FDR or apomixis genes have yet been isolated. Here, we zoom-in to the DIP-locus by largely extending our initial mapping population, and by analyzing (local) suppression of recombination and allele sequence divergence (ASD). RESULTS We identified 24 recombinants between two most closely linked molecular markers to DIP in an F1-population of 2227 plants that segregates for diplospory and lacks parthenogenesis. Both markers segregated c. 1:1 in the entire population, indicating a 1:1 segregation rate of diplospory. Fine-mapping showed three amplified fragment length polymorphisms (AFLPs) closest to DIP at 0.2 cM at one flank and a single AFLP at 0.4 cM at the other flank. Our data lacked strong evidence for ASD at marker regions close to DIP. An unexpected bias towards diplosporous plants among the recombinants (20 out of 24) was found. One third of these diplosporous recombinants showed incomplete penetrance of 50-85% diplospory. CONCLUSIONS Our data give interesting new insights into the structure of the diplospory locus in Taraxacum. We postulate a locus with a minimum of two DIP-genes and possibly including one or two enhancers or cis-regulatory elements on the basis of the bias towards diplosporous recombinants and incomplete penetrance of diplospory in some of them. We define the DIP-locus to 0.6 cM, which is estimated to cover approximately 200-300 Kb, with the closest marker at 0.2 cM. Our results confirm the minor role of suppression of recombination and ASD around DIP, making it an excellent candidate to isolate via a chromosome-walking approach.
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Affiliation(s)
- Kitty Vijverberg
- Netherlands Institute of Ecology (NIOO-KNAW), Centre for Terrestrial Ecology, NL 6666GA Heteren, The Netherlands
- Current Address: Plant Genetics, IWWR, Radboud University Nijmegen, Heyendaalseweg 135, NL-6525AJ Nijmegen, The Netherlands
| | - Slavica Milanovic-Ivanovic
- Netherlands Institute of Ecology (NIOO-KNAW), Centre for Terrestrial Ecology, NL 6666GA Heteren, The Netherlands
| | - Tanja Bakx-Schotman
- Netherlands Institute of Ecology (NIOO-KNAW), Centre for Terrestrial Ecology, NL 6666GA Heteren, The Netherlands
| | - Peter J van Dijk
- Netherlands Institute of Ecology (NIOO-KNAW), Centre for Terrestrial Ecology, NL 6666GA Heteren, The Netherlands
- Current Address: Keygene NV, NL-6708PW Wageningen, The Netherlands
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Borges do Valle C, Suely Pagliarini M. Biology, Cytogenetics, and Breeding of Brachiaria. ACTA ACUST UNITED AC 2009. [DOI: 10.1201/9781420047400.ch5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/28/2023]
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23
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Tucker MR, Koltunow AMG. Sexual and asexual (apomictic) seed development in flowering plants: molecular, morphological and evolutionary relationships. FUNCTIONAL PLANT BIOLOGY : FPB 2009; 36:490-504. [PMID: 32688664 DOI: 10.1071/fp09078] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2009] [Accepted: 04/21/2009] [Indexed: 05/10/2023]
Abstract
Reproduction in the flowering plants (angiosperms) is a dynamic process that relies upon the formation of inflorescences, flowers and eventually seed. Most angiosperms reproduce sexually by generating gametes via meiosis that fuse during fertilisation to initiate embryo and seed development, thereby perpetuating the processes of adaptation and evolution. Despite this, sex is not a ubiquitous reproductive strategy. Some angiosperms have evolved an alternate form of reproduction termed apomixis, which avoids meiosis during gamete formation and leads to the production of embryos without paternal contribution. Therefore, apomixis results in the production of clonal progeny through seed. The molecular nature and evolutionary origin of apomixis remain unclear, but recent studies suggest that apomixis evolved from the same molecular framework supporting sex. In this review, we consider physical and molecular relationships between the two pathways, with a particular focus on the initial stages of female reproduction where apomixis deviates from the sexual pathway. We also consider theories that explain the origin of apomictic processes from sexual progenitors. Detailed characterisation of the relationship between sex and apomixis in an evolutionary and developmental sense is an important step towards understanding how apomixis might be successfully integrated into agriculturally important, but currently sexual crops.
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Affiliation(s)
- Matthew R Tucker
- CSIRO Plant Industry, PO Box 350, Glen Osmond, SA 5064, Australia
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24
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Laspina NV, Vega T, Seijo JG, González AM, Martelotto LG, Stein J, Podio M, Ortiz JPA, Echenique VC, Quarin CL, Pessino SC. Gene expression analysis at the onset of aposporous apomixis in Paspalum notatum. PLANT MOLECULAR BIOLOGY 2008; 67:615-28. [PMID: 18481185 DOI: 10.1007/s11103-008-9341-5] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2007] [Accepted: 05/01/2008] [Indexed: 05/19/2023]
Abstract
Apomixis is a route of asexual reproduction through seeds, that progresses in the absence of meiosis and fertilization to generate maternal clonal progenies. Gametophytic apomicts are usually polyploid and probably arose from sexual ancestors through a limited number of mutations in the female reproductive pathway. A differential display analysis was carried out on immature inflorescences of sexual and apomictic tetraploid genotypes of Paspalum notatum, in order to identify genes associated with the emergence of apospory. Analysis of approximately 10,000 transcripts led to the identification of 94 high-quality differentially expressed sequences. Assembling analysis, plus validation, rendered 65 candidate unigenes, organized as 14 contigs and 51 singletons. Thirty-four unigenes were isolated from apomictic plants and 31 from sexual ones. A total of 45 (69.2%) unigenes were functionally categorized. While several of the differentially expressed sequences appeared to be components of an extracellular receptor kinase (ERK) signal transduction cascade, others seemed to participate in a variety of central cellular processes like cell-cycle control, protein turnover, intercellular signalling, transposon activity, transcriptional regulation and endoplasmic reticulum-mediated biosynthesis. In silico mapping revealed that a particular group of five genes silenced in apomictic plants clustered in a rice genomic area syntenic with the region governing apospory in Paspalum notatum and Brachiaria brizantha. Two of these genes mapped within the set of apo-homologues in P. notatum. Four genes previously reported to be controlled by ploidy were identified among those expressed differentially between apomictic and sexual plants. In situ hybridization experiments were performed for selected clones.
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Affiliation(s)
- Natalia V Laspina
- Facultad de Ciencias Agrarias, Universidad Nacional de Rosario, Parque Villarino S/N, S2125ZAA Zavalla, Rosario, Santa Fe, Argentina
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25
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Gamete formation without meiosis in Arabidopsis. Nature 2008; 451:1121-4. [DOI: 10.1038/nature06557] [Citation(s) in RCA: 158] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2007] [Accepted: 12/20/2007] [Indexed: 11/08/2022]
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Affiliation(s)
- Peggy Ozias-Akins
- Department of Horticulture, University of Georgia Tifton Campus, Tifton, Georgia;
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Catanach AS, Erasmuson SK, Podivinsky E, Jordan BR, Bicknell R. Deletion mapping of genetic regions associated with apomixis in Hieracium. Proc Natl Acad Sci U S A 2006; 103:18650-5. [PMID: 17047034 PMCID: PMC1693717 DOI: 10.1073/pnas.0605588103] [Citation(s) in RCA: 102] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Although apomixis has been quoted as a technology with the potential to deliver benefits similar in scale to those achieved with the Green Revolution, very little is currently known of the genetic mechanisms that control this trait in plants. To address this issue, we developed Hieracium, a genus of daisies native to Eurasia and North America, as a genetic model to study apomixis. In a molecular mapping study, we defined the number of genetic loci involved in apomixis, and we explored dominance and linkage relationships between these loci. To avoid difficulties often encountered with inheritance studies of apomicts, we based our mapping effort on the use of deletion mutagenesis, coupled with amplified fragment length polymorphism (AFLP) as a genomic fingerprinting tool. The results indicate that apomixis in Hieracium caespitosum is controlled at two principal loci, one of which regulates events associated with the avoidance of meiosis (apomeiosis) and the other, an unlinked locus that controls events associated with the avoidance of fertilization (parthenogenesis). AFLP bands identified as central to both loci were isolated, sequenced, and used to develop sequence-characterized amplified region (SCAR) markers. The validity of the AFLP markers was verified by using a segregating population generated by hybridization. The validity of the SCAR markers was verified by their pattern of presence/absence in specific mutants. The mutants, markers, and genetic data derived from this work are now being used to isolate genes controlling apomixis in this system.
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Affiliation(s)
- Andrew S. Catanach
- *Agriculture and Life Sciences Division, Lincoln University, P.O. Box 84, Lincoln 7647, New Zealand
| | - Sylvia K. Erasmuson
- New Zealand Institute for Crop and Food Research Ltd., Private Bag 4704, Christchurch 8140, New Zealand; and
| | - Ellen Podivinsky
- Environmental Science and Research Ltd., P.O. Box 29-181, Christchurch, New Zealand
| | - Brian R. Jordan
- *Agriculture and Life Sciences Division, Lincoln University, P.O. Box 84, Lincoln 7647, New Zealand
| | - Ross Bicknell
- New Zealand Institute for Crop and Food Research Ltd., Private Bag 4704, Christchurch 8140, New Zealand; and
- To whom correspondence should be addressed. E-mail:
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Stein J, Quarin CL, Martínez EJ, Pessino SC, Ortiz JPA. Tetraploid races of Paspalum notatum show polysomic inheritance and preferential chromosome pairing around the apospory-controlling locus. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2004; 109:186-91. [PMID: 14985979 DOI: 10.1007/s00122-004-1614-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2003] [Accepted: 01/28/2004] [Indexed: 05/20/2023]
Abstract
The objective of this work was to determine the type of inheritance (disomic/polysomic) in tetraploid (2 n=4 x=40) Paspalum notatum and investigate the transmission pattern of the chromosome region associated with apospory. An F(1) family segregating for the reproductive mode (aposporous vs non-aposporous) was generated by crossing a tetraploid sexual plant as female parent with an apomictic individual as pollen donor. Pollen mother cells from both parental plants were examined to ascertain chromosome-pairing behavior at meiosis. The high rate of quadrivalent chromosome associations indicated an autotetraploid origin of the species, although bivalent pairing and occasional univalents were detected. The observation of a lagging bivalent, a bridge of chromatin, or two aligned laggards in the aposporous parent suggested a chromosome inversion in this strain. Segregation ratios of AFLP markers and the proportion of linkages in repulsion versus coupling phase denoted tetrasomic inheritance, but markers displaying disomic ratios were also observed. Preferential chromosome pairing (disomic inheritance) in the chromosome segment related to apospory was detected. The possible relationship between a chromosome rearrangement and the inheritance of apospory is discussed.
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Affiliation(s)
- J Stein
- Laboratorio de Fisiología Vegetal, Facultad de Ciencias Agrarias, Universidad Nacional de Rosario (UNR), CC14, 2125 Zavalla, Pcia. de Santa Fe, Argentina
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Akiyama Y, Conner JA, Goel S, Morishige DT, Mullet JE, Hanna WW, Ozias-Akins P. High-resolution physical mapping in Pennisetum squamulatum reveals extensive chromosomal heteromorphism of the genomic region associated with apomixis. PLANT PHYSIOLOGY 2004; 134:1733-41. [PMID: 15064383 PMCID: PMC419846 DOI: 10.1104/pp.103.033969] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2003] [Revised: 01/07/2004] [Accepted: 01/07/2004] [Indexed: 05/18/2023]
Abstract
Gametophytic apomixis is asexual reproduction as a consequence of parthenogenetic development of a chromosomally unreduced egg. The trait leads to the production of embryos with a maternal genotype, i.e. progeny are clones of the maternal plant. The application of the trait in agriculture could be a tremendous tool for crop improvement through conventional and nonconventional breeding methods. Unfortunately, there are no major crops that reproduce by apomixis, and interspecific hybridization with wild relatives has not yet resulted in commercially viable germplasm. Pennisetum squamulatum is an aposporous apomict from which the gene(s) for apomixis has been transferred to sexual pearl millet by backcrossing. Twelve molecular markers that are linked with apomixis coexist in a tight linkage block called the apospory-specific genomic region (ASGR), and several of these markers have been shown to be hemizygous in the polyploid genome of P. squamulatum. High resolution genetic mapping of these markers has not been possible because of low recombination in this region of the genome. We now show the physical arrangement of bacterial artificial chromosomes containing apomixis-linked molecular markers by high resolution fluorescence in situ hybridization on pachytene chromosomes. The size of the ASGR, currently defined as the entire hemizygous region that hybridizes with apomixis-linked bacterial artificial chromosomes, was estimated on pachytene and mitotic chromosomes to be approximately 50 Mbp (a quarter of the chromosome). The ASGR includes highly repetitive sequences from an Opie-2-like retrotransposon family that are particularly abundant in this region of the genome.
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Affiliation(s)
- Yukio Akiyama
- Department of Horticulture, University of Georgia, Tifton, Georgia 31793-0748, USA
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31
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Vijverberg K, Van Der Hulst RGM, Lindhout P, Van Dijk PJ. A genetic linkage map of the diplosporous chromosomal region in Taraxacum officinale (common dandelion; Asteraceae). TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 2004; 108:725-32. [PMID: 14564398 DOI: 10.1007/s00122-003-1474-y] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2003] [Accepted: 09/10/2003] [Indexed: 05/09/2023]
Abstract
In this study, we mapped the diplosporous chromosomal region in Taraxacum officinale, by using amplified fragment length polymorphism technology (AFLP) in 73 plants from a segregating population. Taraxacum serves as a model system to investigate the genetics, ecology, and evolution of apomixis. The genus includes sexual diploid as well as apomictic polyploid, mostly triploid, plants. Apomictic Taraxacum is diplosporous, parthenogenetic, and has autonomous endosperm formation. Previous studies have indicated that these three apomixis elements are controlled by more than one locus in Taraxacum and that diplospory inherits as a dominant, monogenic trait ( Ddd; DIP). A bulked segregant analysis provided 34 AFLP markers that were linked to DIP and were, together with two microsatellite markers, used for mapping the trait. The map length was 18.6 cM and markers were found on both sides of DIP, corresponding to 5.9 and 12.7 cM, respectively. None of the markers completely co-segregated with DIP. Eight markers were selected for PCR-based marker development, of which two were successfully converted. In contrast to all other mapping studies of apomeiosis to date, our results showed no evidence for suppression of recombination around the DIP locus in Taraxacum. No obvious evidence for sequence divergence between the DIP and non- DIP homologous loci was found, and no hemizygosity at the DIP locus was detected. These results may indicate that apomixis is relatively recent in Taraxacum.
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Affiliation(s)
- K Vijverberg
- Centre for Terrestrial Ecology, Netherlands Institute of Ecology, Boterhoeksestraat 48, 6666 GA Heteren, The Netherlands.
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32
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Jessup RW, Burson BL, Burow O, Wang YW, Chang C, Li Z, Paterson AH, Hussey MA. Segmental allotetraploidy and allelic interactions in buffelgrass (Pennisetum ciliare (L.) Link syn. Cenchrus ciliaris L.) as revealed by genome mapping. Genome 2003; 46:304-13. [PMID: 12723046 DOI: 10.1139/g03-005] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Linkage analyses increasingly complement cytological and traditional plant breeding techniques by providing valuable information regarding genome organization and transmission genetics of complex polyploid species. This study reports a genome map of buffelgrass (Pennisetum ciliare (L.) Link syn. Cenchrus ciliaris L.). Maternal and paternal maps were constructed with restriction fragment length polymorphisms (RFLPs) segregating in 87 F1 progeny from an intraspecific cross between two heterozygous genotypes. A survey of 862 heterologous cDNAs and gDNAs from across the Poaceae, as well as 443 buffelgrass cDNAs, yielded 100 and 360 polymorphic probes, respectively. The maternal map included 322 RFLPs, 47 linkage groups, and 3464 cM, whereas the paternal map contained 245 RFLPs, 42 linkage groups, and 2757 cM. Approximately 70 to 80% of the buffelgrass genome was covered, and the average marker spacing was 10.8 and 11.3 cM on the respective maps. Preferential pairing was indicated between many linkage groups, which supports cytological reports that buffelgrass is a segmental allotetraploid. More preferential pairing (disomy) was found in the maternal than paternal parent across linkage groups (55 vs. 38%) and loci (48 vs. 15%). Comparison of interval lengths in 15 allelic bridges indicated significantly less meiotic recombination in paternal gametes. Allelic interactions were detected in four regions of the maternal map and were absent in the paternal map.
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Affiliation(s)
- R W Jessup
- Department of Soil and Crop Sciences, Texas A & M University, College Station, TX 77843, U.S.A
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Development and Implementation of Molecular Markers for Forage Crop Improvement. DEVELOPMENTS IN PLANT BREEDING 2001. [DOI: 10.1007/978-94-015-9700-5_6] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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