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Greaves E, Kron P, Husband BC. Demographic and reproductive impacts of hybridization unrelated to hybrid viability in a native plant. AMERICAN JOURNAL OF BOTANY 2023; 110:e16208. [PMID: 37409880 DOI: 10.1002/ajb2.16208] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2022] [Revised: 04/28/2023] [Accepted: 05/03/2023] [Indexed: 07/07/2023]
Abstract
PREMISE Introduced species can influence native congeners through production of hybrids and introgression, but impacts not involving viable hybrids, such as reduced conspecific offspring and increased asexual seed production, are rarely examined. Here we tested for these demographic and reproductive consequences of hybridization between introduced, domesticated apple (Malus domestica) and native crabapple (M. coronaria) in southern Canada. METHODS We applied four pollination treatments (open, M. coronaria, M. domestica, open + M. coronaria) to focal M. coronaria trees across multiple years and assessed the number and reproductive origins of resulting seeds (hybrid or conspecific endosperm and, for each, sexual or asexual embryo) using flow cytometry. RESULTS In open-pollinated fruit, 27% of seeds had hybrid endosperm; 52% of embryos were asexual. The number of conspecific embryos (sexual or asexual) per fruit did not decline significantly with increasing hybridization, indicating no seed discounting, but hand pollinations using only domestic apple or crabapple pollen reduced the number of conspecific embryos significantly. Hybridization was not associated with a change in percentage asexual embryos, overall, but there was an increase in asexual embryos in tetraploid seeds, the maternal and most common offspring ploidy. CONCLUSIONS We conclude that hybridization can influence native Malus in ways beyond the production of viable hybrids, with significant implications for population dynamics and genetic structure.
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Affiliation(s)
- Elaina Greaves
- Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada
| | - Paul Kron
- Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada
| | - Brian C Husband
- Department of Integrative Biology, University of Guelph, 50 Stone Road E., Guelph, Ontario, N1G 2W1, Canada
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Kolarčik V, Kocová V, Mikoláš V, Mártonfiová L, Hajdučeková N, Mártonfi P. Variability of Reproduction Pathways in the Central-European Populations of Hawthorns with Emphasis on Triploids. PLANTS (BASEL, SWITZERLAND) 2022; 11:3497. [PMID: 36559608 PMCID: PMC9786806 DOI: 10.3390/plants11243497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 11/21/2022] [Accepted: 12/06/2022] [Indexed: 06/17/2023]
Abstract
The role of apomeiosis, parthenogenesis, and pseudogamy in the asexual reproduction of some plant groups has not been fully elucidated in relation to species diversification. Quantitative analyses of seed origin may help in gaining better understanding of intercytotypic interactions. Asexual reproduction associated with polyploidy and frequent hybridization plays a crucial role in the evolutionary history of the genus Crataegus in North America. In Europe, the genus represents a taxonomically complex and very difficult species group not often studied using a modern biosystematic approach. We investigated the reproduction pathways in mixed-cytotype populations of selected taxa of Crataegus in eastern Slovakia, Central Europe. The investigated accessions were characterized by seed production data and the ploidy level of mature plants as well as the embryo and endosperm tissues of their seeds determined via flow cytometry. Diploid and polyploid hawthorns reproduce successfully; they also produce high numbers of seeds. An exception is represented by an almost sterile triploid. Diploids reproduce sexually. Polyploids shift to asexual reproduction, but pseudogamy seems to be essential for regular seed development. In rare cases, fertilization of unreduced gametes occurs, which offers opportunity for the establishment of new polyploid cytotypes between diploid sexuals and polyploid asexuals. Opposite to sexual diploids, triploids are obligate, and tetraploids almost obligate apomicts. Apomixis is considered to help stabilize individual weakly differentiated polyploid microspecies. Pseudogamy is a common feature and usually leads to unbalanced maternal to paternal contribution in the endosperm of triploid accessions. Parental contribution to endosperm gene dosage is somehow relaxed in triploids. Our Crataegus plant system resembles reproduction in the diploids and polyploids of North American hawthorns. Our data provide support for the hypothesis that polyploidization, shifts in reproduction modes, and hybridization shape the genus diversity also in Central Europe.
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Affiliation(s)
- Vladislav Kolarčik
- Institute of Biology and Ecology, Faculty of Science, Pavol Jozef Šafárik University, Mánesova 23, SK-041 54 Košice, Slovakia
| | - Valéria Kocová
- Botanical Garden, Pavol Jozef Šafárik University, Mánesova 23, SK-043 52 Košice, Slovakia
| | | | - Lenka Mártonfiová
- Botanical Garden, Pavol Jozef Šafárik University, Mánesova 23, SK-043 52 Košice, Slovakia
| | | | - Pavol Mártonfi
- Institute of Biology and Ecology, Faculty of Science, Pavol Jozef Šafárik University, Mánesova 23, SK-041 54 Košice, Slovakia
- Botanical Garden, Pavol Jozef Šafárik University, Mánesova 23, SK-043 52 Košice, Slovakia
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3
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Karunarathne P, Reutemann AV, Schedler M, Glücksberg A, Martínez EJ, Honfi AI, Hojsgaard DH. Sexual modulation in a polyploid grass: a reproductive contest between environmentally inducible sexual and genetically dominant apomictic pathways. Sci Rep 2020; 10:8319. [PMID: 32433575 PMCID: PMC7239852 DOI: 10.1038/s41598-020-64982-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Accepted: 04/25/2020] [Indexed: 12/24/2022] Open
Abstract
In systems alternating between sexual and asexual reproduction, sex increases under unfavorable environmental conditions. In plants producing sexual and asexual (apomictic) seeds, studies on the influence of environmental factors on sex are equivocal. We used Paspalum intermedium to study environmental effects on the expression of sexual and apomictic developments, and on resulting reproductive fitness variables. Flow cytometric and embryological analyses were performed to characterize ploidy and reproductive modes, and effects of local climatic conditions on sexual and apomictic ovule and seed frequencies were determined. Seed set and germination data were collected and used to estimate reproductive fitness. Frequencies of sexual and apomictic ovules and seeds were highly variable within and among populations. Apomictic development exhibited higher competitive ability but lower overall fitness. Frequencies of sexual reproduction in facultative apomictic plants increased at lower temperatures and wider mean diurnal temperature ranges. We identified a two-fold higher fitness advantage of sexuality and a Tug of War between factors intrinsic to apomixis and environmental stressors promoting sexuality which influence the distribution of sex in apomictic populations. This points toward a crucial role of local ecological conditions in promoting a reshuffling of genetic variability that may be shaping the adaptative landscape in apomictic P. intermedium plants.
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Affiliation(s)
- Piyal Karunarathne
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Untere Karspuele 2, 37073, Goettingen, Germany.
- Georg-August University School of Science, University of Goettingen, Goettingen, Germany.
| | - Anna V Reutemann
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Untere Karspuele 2, 37073, Goettingen, Germany
- Instituto de Botánica del Nordeste (IBONE), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), CC209, 3400, Corrientes, Argentina
| | - Mara Schedler
- Instituto de Botánica del Nordeste (IBONE), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), CC209, 3400, Corrientes, Argentina
| | - Adriana Glücksberg
- Instituto de Botánica del Nordeste (IBONE), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), CC209, 3400, Corrientes, Argentina
| | - Eric J Martínez
- Instituto de Botánica del Nordeste (IBONE), Facultad de Ciencias Agrarias, Universidad Nacional del Nordeste (FCA-UNNE), CC209, 3400, Corrientes, Argentina
| | - Ana I Honfi
- Programa de Estudios Florísticos y Genética Vegetal, Instituto de Biología Subtropical (CONICET-UNaM), Facultad de Ciencias Exactas, Químicas y Naturales, Universidad Nacional de Misiones, Rivadavia 2370, 3300, Posadas, Misiones, Argentina
| | - Diego H Hojsgaard
- Department of Systematics, Biodiversity and Evolution of Plants, Albrecht-von-Haller Institute for Plant Sciences, University of Goettingen, Untere Karspuele 2, 37073, Goettingen, Germany.
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Brukhin V, Osadtchiy JV, Florez-Rueda AM, Smetanin D, Bakin E, Nobre MS, Grossniklaus U. The Boechera Genus as a Resource for Apomixis Research. FRONTIERS IN PLANT SCIENCE 2019; 10:392. [PMID: 31001306 PMCID: PMC6454215 DOI: 10.3389/fpls.2019.00392] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 03/14/2019] [Indexed: 05/03/2023]
Abstract
The genera Boechera (A. Löve et D. Löve) and Arabidopsis, the latter containing the model plant Arabidopsis thaliana, belong to the same clade within the Brassicaceae family. Boechera is the only among the more than 370 genera in the Brassicaceae where apomixis is well documented. Apomixis refers to the asexual reproduction through seed, and a better understanding of the underlying mechanisms has great potential for applications in agriculture. The Boechera genus currently includes 110 species (of which 38 are reported to be triploid and thus apomictic), which are distributed mostly in the North America. The apomictic lineages of Boechera occur at both the diploid and triploid level and show signs of a hybridogenic origin, resulting in a modification of their chromosome structure, as reflected by alloploidy, aneuploidy, substitutions of homeologous chromosomes, and the presence of aberrant chromosomes. In this review, we discuss the advantages of the Boechera genus to study apomixis, consider its modes of reproduction as well as the inheritance and possible mechanisms controlling apomixis. We also consider population genetic aspects and a possible role of hybridization at the origin of apomixis in Boechera. The molecular tools available to study Boechera, such as transformation techniques, laser capture microdissection, analysis of transcriptomes etc. are also discussed. We survey available genome assemblies of Boechera spp. and point out the challenges to assemble the highly heterozygous genomes of apomictic species. Due to these challenges, we argue for the application of an alternative reference-free method for the comparative analysis of such genomes, provide an overview of genomic sequencing data in the genus Boechera suitable for such analysis, and provide examples of its application.
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Affiliation(s)
- Vladimir Brukhin
- Theodosius Dobzhansky Center for Genome Bioinformatics, St. Petersburg State University, Saint Petersburg, Russia
- Department of Plant Embryology and Reproductive Biology, Komarov Botanical Institute RAS, Saint Petersburg, Russia
| | - Jaroslaw V. Osadtchiy
- Department of Plant Embryology and Reproductive Biology, Komarov Botanical Institute RAS, Saint Petersburg, Russia
| | - Ana Marcela Florez-Rueda
- Department of Plant and Microbial Biology, Zürich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Dmitry Smetanin
- Department of Plant and Microbial Biology, Zürich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Evgeny Bakin
- Theodosius Dobzhansky Center for Genome Bioinformatics, St. Petersburg State University, Saint Petersburg, Russia
- Bioinformatics Institute, Saint Petersburg, Russia
| | - Margarida Sofia Nobre
- Department of Plant and Microbial Biology, Zürich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
| | - Ueli Grossniklaus
- Department of Plant and Microbial Biology, Zürich-Basel Plant Science Center, University of Zurich, Zurich, Switzerland
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Kaushal P, Dwivedi KK, Radhakrishna A, Srivastava MK, Kumar V, Roy AK, Malaviya DR. Partitioning Apomixis Components to Understand and Utilize Gametophytic Apomixis. FRONTIERS IN PLANT SCIENCE 2019; 10:256. [PMID: 30906306 PMCID: PMC6418048 DOI: 10.3389/fpls.2019.00256] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 02/18/2019] [Indexed: 05/07/2023]
Abstract
Apomixis is a method of reproduction to generate clonal seeds and offers tremendous potential to fix heterozygosity and hybrid vigor. The process of apomictic seed development is complex and comprises three distinct components, viz., apomeiosis (leading to formation of unreduced egg cell), parthenogenesis (development of embryo without fertilization) and functional endosperm development. Recently, in many crops, these three components are reported to be uncoupled leading to their partitioning. This review provides insight into the recent status of our understanding surrounding partitioning apomixis components in gametophytic apomictic plants and research avenues that it offers to help understand the biology of apomixis. Possible consequences leading to diversity in seed developmental pathways, resources to understand apomixis, inheritance and identification of candidate gene(s) for partitioned components, as well as contribution towards creation of variability are all discussed. The potential of Panicum maximum, an aposporous crop, is also discussed as a model crop to study partitioning principle and effects. Modifications in cytogenetic status, as well as endosperm imprinting effects arising due to partitioning effects, opens up new opportunities to understand and utilize apomixis components, especially towards synthesizing apomixis in crops.
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Affiliation(s)
- Pankaj Kaushal
- ICAR-National Institute of Biotic Stress Management, Raipur, India
| | | | | | | | - Vinay Kumar
- ICAR-National Institute of Biotic Stress Management, Raipur, India
| | - Ajoy Kumar Roy
- ICAR-Indian Grassland and Fodder Research Institute, Jhansi, India
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Dobeš C, Scheffknecht S, Fenko Y, Prohaska D, Sykora C, Hülber K. Asymmetric reproductive interference: The consequences of cross-pollination on reproductive success in sexual-apomictic populations of Potentilla puberula (Rosaceae). Ecol Evol 2017; 8:365-381. [PMID: 29321878 PMCID: PMC5756837 DOI: 10.1002/ece3.3684] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Revised: 10/03/2017] [Accepted: 11/08/2017] [Indexed: 11/16/2022] Open
Abstract
Apomixis evolves from a sexual background and usually is linked to polyploidization. Pseudogamous gametophytic apomicts, which require a fertilization to initiate seed development, of various ploidy levels frequently co‐occur with their lower‐ploid sexual ancestors, but the stability of such mixed populations is affected by reproductive interferences mediated by cross‐pollination. Thereby, reproductive success of crosses depends on the difference in ploidy levels of mating partners, that is, on tolerance of deviation from the balanced ratio of maternal versus paternal genomes. Quality of pollen can further affect reproductive success in intercytotype pollinations. Cross‐fertilization, however, can be avoided by selfing which may be induced upon pollination with mixtures of self‐ and cross‐pollen (i.e., mentor effects). We tested for reproductive compatibility of naturally co‐occurring tetraploid sexuals and penta‐ to octoploid apomicts in the rosaceous species Potentilla puberula by means of controlled crosses. We estimated the role of selfing as a crossing barrier and effects of self‐ and cross‐pollen quality as well as maternal: paternal genomic ratios in the endosperm on reproductive success. Cross‐fertilization of sexuals by apomicts was not blocked by selfing, and seed set was reduced in hetero‐ compared to homoploid crosses. Thereby, seed set was negatively related to deviations from balanced parental genomic ratios in the endosperm. In contrast, seed set in the apomictic cytotypes was not reduced in hetero‐ compared to homoploid crosses. Thus, apomictic cytotypes either avoided intercytotype cross‐fertilization through selfing, tolerated intercytotype cross‐fertilizations without negative effects on reproductive success, or even benefitted from higher pollen quality in intercytotype pollinations. Our experiment provides evidence for asymmetric reproductive interference, in favor of the apomicts, with significantly reduced seed set of sexuals in cytologically mixed populations, whereas seed set in apomicts was not affected. Incompleteness of crossing barriers further indicated at least partial losses of a parental genomic endosperm balance requirement.
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Affiliation(s)
- Christoph Dobeš
- Department of Forest Genetics Austrian Research Centre for Forests Vienna Austria
| | - Susanne Scheffknecht
- Department of Pharmacognosy and Pharmacobotany University of Vienna Vienna Austria
| | - Yulia Fenko
- Department of Pharmacognosy and Pharmacobotany University of Vienna Vienna Austria
| | - Dagmar Prohaska
- Department of Pharmacognosy and Pharmacobotany University of Vienna Vienna Austria
| | - Christina Sykora
- Department of Pharmacognosy and Pharmacobotany University of Vienna Vienna Austria
| | - Karl Hülber
- Division of Conservation Biology, Vegetation Ecology and Landscape Ecology Department of Botany and Biodiversity Research University of Vienna Vienna Austria.,Vienna Institute for Nature Conservation and Analyses Vienna Austria
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7
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Evolutionary Dynamics of Unreduced Gametes. Trends Genet 2017; 33:583-593. [PMID: 28732599 DOI: 10.1016/j.tig.2017.06.009] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 06/23/2017] [Accepted: 06/27/2017] [Indexed: 11/20/2022]
Abstract
Unreduced gametes, which have the somatic (2n) chromosome number, are an important precursor to polyploid formation and apomixis. The product of irregularities in meiosis, 2n gametes are expected to be rare and deleterious in most natural populations, contrary to their wide taxonomic distribution and the prevalence of polyploidy. To better understand this discrepancy, we review contemporary evidence related to four aspects of 2n gamete dynamics in natural populations: (i) estimates of their frequency; (ii) their environmental and genetic determinants; (iii) adaptive and nonadaptive processes regulating their evolution; and (iv) factors regulating their union and production of polyploids in diploid populations. Aided by high-throughput methods of detection, these foci will advance our understanding of variation in 2n gametes within and among species, and their role in polyploid evolution.
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9
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Zarrei M, Stefanović S, Dickinson TA. Reticulate evolution in North American black-fruited hawthorns (Crataegus section Douglasia; Rosaceae): evidence from nuclear ITS2 and plastid sequences. ANNALS OF BOTANY 2014; 114:253-69. [PMID: 24984714 PMCID: PMC4111394 DOI: 10.1093/aob/mcu116] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2013] [Accepted: 05/07/2014] [Indexed: 05/19/2023]
Abstract
BACKGROUND AND AIMS The taxonomic complexity of Crataegus (hawthorn; Rosaceae, Maleae), especially in North America, has been attributed by some to hybridization in combination with gametophytic apomixis and polyploidization, whereas others have considered the roles of hybridization and apomixis to be minimal. Study of the chemical composition and therapeutic value of hawthorn extracts requires reproducible differentiation of entities that may be difficult to distinguish by morphology alone. This study sought to address this by using the nuclear ribosomal spacer region ITS2 as a supplementary DNA barcode; however, a lack of success prompted an investigation to discover why this locus gave unsatisfactory results. METHODS ITS2 was extensively cloned so as to document inter- and intraindividual variation in this locus, using hawthorns of western North America where the genus Crataegus is represented by only two widely divergent groups, the red-fruited section Coccineae and the black-fruited section Douglasia. Additional sequence data from selected loci on the plastid genome were obtained to enhance further the interpretation of the ITS2 results. KEY RESULTS In the ITS2 gene tree, ribotypes from western North American hawthorns are found in two clades. Ribotypes from diploid members of section Douglasia occur in one clade (with representatives of the east-Asian section Sanguineae). The other clade comprises those from diploid and polyploid members of section Coccineae. Both clades contribute ribotypes to polyploid Douglasia. Data from four plastid-derived intergenic spacers demonstrate the maternal parentage of these allopolyploids. CONCLUSIONS Repeated hybridization between species of section Douglasia and western North American members of section Coccineae involving the fertilization of unreduced female gametes explains the observed distribution of ribotypes and accounts for the phenetic intermediacy of many members of section Douglasia.
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Affiliation(s)
- M Zarrei
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto ON, Canada M5S 3B2 Department of Natural History, Royal Ontario Museum, 100 Queen's Park, Toronto ON, Canada M5S 2C6
| | - S Stefanović
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto ON, Canada M5S 3B2 Department of Biology, University of Toronto Mississauga, 3359 Mississauga Rd, Mississauga ON, Canada L5L 1C6
| | - T A Dickinson
- Department of Ecology and Evolutionary Biology, University of Toronto, 25 Willcocks Street, Toronto ON, Canada M5S 3B2 Department of Natural History, Royal Ontario Museum, 100 Queen's Park, Toronto ON, Canada M5S 2C6
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10
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Burgess MB, Cushman KR, Doucette ET, Talent N, Frye CT, Campbell CS. Effects of apomixis and polyploidy on diversification and geographic distribution in Amelanchier (Rosaceae). AMERICAN JOURNAL OF BOTANY 2014; 101:1375-87. [PMID: 25156985 DOI: 10.3732/ajb.1400113] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
UNLABELLED • PREMISE OF THE STUDY Amelanchier polyploid apomicts differ from sexual diploids in their more complex diversification, greater species problems, and geographic distribution. To understand these differences, we investigated the occurrence of polyploidy and frequency of apomixis. This research helps clarify species delimitation in an evolutionarily complex genus.• METHODS We used flow cytometry to estimate genome size of 1355 plants. We estimated the frequency of apomixis from flow-cytometrically determined ploidy levels of embryo and endosperm and from a progeny study using RAPD markers. We explored relationships of triploids to other ploidy levels and of ploidy levels to latitude plus elevation.• KEY RESULTS Diploids (32% of sample) and tetraploids (62%) were widespread. Triploids (6%) mostly occurred in small numbers with diploids from two or more species or with diploids and tetraploids. Seeds from diploids were 2% apomictic, the first report of apomixis in Amelanchier diploids. Seeds from triploids were 75% apomictic. We documented potential triploid bridge and triploid block from unbalanced endosperm and low pollen viability. Seeds from tetraploids were 97% apomictic, and tetraploids often formed microspecies. We did not find strong evidence for geographical parthenogenesis in North American Amelanchier. Most currently recognized species contained multiple ploidy levels that were morphologically semicryptic.• CONCLUSIONS Documentation of numerous transitions from diploidy to polyploidy helps clarify diversification, geographic distribution, and the species problem in Amelanchier. Despite the infrequent occurrence of triploids, their retention of 25% sexuality and capacity for triploid bridge may be important steps between sexual diploids and predominantly apomictic tetraploids.
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Affiliation(s)
- Michael B Burgess
- Department of Biological Sciences, State University of New York, Plattsburgh, Plattsburgh, New York 12901 USA
| | - Kevin R Cushman
- School of Biology and Ecology, University of Maine, Orono, Maine 04469 USA
| | - Eric T Doucette
- School of Biology and Ecology, University of Maine, Orono, Maine 04469 USA
| | - Nadia Talent
- Royal Ontario Museum, Department of Natural History, 100 Queen's Park, Toronto, M5S 2C6, Canada
| | - Christopher T Frye
- Maryland Department of Natural Resources, Natural Heritage Program, 909 Wye Mills Road, Wye Mills, Maryland 21679 USA
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Lombello RA, Pinto-maglio CAF. Cytogenetics and Reproductive Biology of Bixa orellana L. (Bixaceae). CYTOLOGIA 2014. [DOI: 10.1508/cytologia.79.379] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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12
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Šarhanová P, Vašut RJ, Dančák M, Bureš P, Trávníček B. New insights into the variability of reproduction modes in European populations of Rubus subgen. Rubus: how sexual are polyploid brambles? ACTA ACUST UNITED AC 2012; 25:319-35. [PMID: 23114637 DOI: 10.1007/s00497-012-0200-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Accepted: 10/19/2012] [Indexed: 11/30/2022]
Abstract
Rubus subgen. Rubus includes common European species with highly complicated taxonomy, ongoing hybridisation and facultative apomixis. Out of approximately 750 species recognised in Europe, only 3 diploid sexual species are known, along with numerous apomictic brambles that are highly connected to polyploidy. One exception of a tetraploid taxon is R. ser. Glandulosi, which is known for prevalent sexuality. This taxon highly hybridises with tetraploid members of R. ser. Discolores and leads to the origin of many hybridogenous populations and individuals. In this study, we verify reproduction modes in different diploid, triploid and tetraploid species of subgen. Rubus, with focus on taxa putatively involved in such hybridisation by applying flow cytometric seed screen analysis. We found 100 % sexuality of diploid species, whereas triploid species had obligate unreduced embryo sac development. In contrast, tetraploid plants had varying degrees of sexuality. Additionally, we discovered that R. bifrons has the ability to undergo a reproduction mode switch as a reaction to environmental conditions. These results provide insight into reproductive modes of European brambles and shed light on their reticulate evolution and speciation.
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Affiliation(s)
- Petra Šarhanová
- Department of Botany, Palacký University in Olomouc, Šlechtitelů 11, 78371 Olomouc, Czech Republic.
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Edwards JE, Brown PN, Talent N, Dickinson TA, Shipley PR. A review of the chemistry of the genus Crataegus. PHYTOCHEMISTRY 2012; 79:5-26. [PMID: 22608128 DOI: 10.1016/j.phytochem.2012.04.006] [Citation(s) in RCA: 121] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Revised: 12/09/2011] [Accepted: 04/17/2012] [Indexed: 05/07/2023]
Abstract
Since the 1800s, natural health products that contain hawthorn (Crataegus spp.) have been used in North America for the treatment of heart problems such as hypertension, angina, arrhythmia, and congestive heart failure. Traditionally, Native American tribes used hawthorn (Crataegus spp.) to treat gastrointestinal ailments and heart problems, and consumed the fruit as food. Hawthorn also has a long history of use in Europe and China for food, and in traditional medicine. Investigations of Crataegus spp. typically focus on the identification and quantification of flavonoids and anthocyanins, which have been shown to have pharmacological activity. The main flavonoids found in Crataegus spp. are hyperoside, vitexin, and additional glycosylated derivatives of these compounds. Reviewed herein are the botany, ethnobotany, and traditional use of hawthorn while focusing on the phytochemicals that have been reported in Crataegus species, and the variation in the described chemistry between individual species.
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Affiliation(s)
- Jennifer E Edwards
- Chemistry, University of British Columbia Okanagan, 3333 University Way, Kelowna, British Columbia V1V 1V7, Canada
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THURLBY KATIEAG, WILSON PETERG, SHERWIN WILLIAMB, CONNELLY CAROLYN, ROSSETTO MAURIZIO. Reproductive bet-hedging in a rare yet widespread rainforest tree,Syzygium paniculatum(Myrtaceae). AUSTRAL ECOL 2012. [DOI: 10.1111/j.1442-9993.2011.02353.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Lo EYY, Stefanovic S, Ritland K, Dickinson TA. Fine-scale comparisons of genetic variability in seed families of asexually and sexually reproducing Crataegus (hawthorn; Rosaceae). AMERICAN JOURNAL OF BOTANY 2010; 97:1014-24. [PMID: 21622471 DOI: 10.3732/ajb.0900091] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
The reproductive system is one of the key mechanisms that determine genetic diversity at different biological levels. However, few attempts have been made to assess the consequences of asexual reproduction by comparing genetic structure and fecundity of seed families in asexually and sexually reproducing individuals. We have examined two similar hawthorn species, Crataegus crus-galli and C. punctata, that differ in ploidy level and breeding system. Fecundity (per-fruit seed set) and microsatellite genotypes for five loci were determined in 18 and 26 seed families of C. crus-galli and C. punctata (totals of 83 and 118 embryos), respectively. Compared with the sexual diploid C. punctata, tetraploid C. crus-galli shows similar fecundity, but lower genotypic diversity within and between seed families. Reproduction in the tetraploid, while predominantly apomictic, is nevertheless accompanied by outcrossing and selfing. We conclude that in C. crus-galli pollen flow between conspecific individuals is limited, and the combination of pollen fertility, self-compatibility, and pseudogamous apomixis provides reproductive assurance in these tetraploids. Reproductive assurance, in turn, may explain the derived floral architecture seen in most North American tetraploid hawthorns. We also discuss analytical approaches for inferring mating-system parameters in tetraploids and for comparing microsatellite variation across ploidy levels.
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Affiliation(s)
- Eugenia Y Y Lo
- Department of Ecology and Evolutionary Biology, Yale University, 21 Sachem Street, New Haven, Connecticut 06511 USA
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Hörandl E. The evolution of self-fertility in apomictic plants. SEXUAL PLANT REPRODUCTION 2010; 23:73-86. [PMID: 20165965 PMCID: PMC2854795 DOI: 10.1007/s00497-009-0122-3] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Accepted: 11/03/2009] [Indexed: 11/28/2022]
Abstract
Self-fertilization and apomixis have often been seen as alternative evolutionary strategies of flowering plants that are advantageous for colonization scenarios and in bottleneck situations. Both traits have multiple origins, but different genetic control mechanisms; possible connections between the two phenomena have long been overlooked. Most apomictic plants, however, need a fertilization of polar nuclei for normal seed development (pseudogamy). If self-pollen is used for this purpose, self-compatibility is a requirement for successful pollen tube growth. Apomictic lineages usually evolve from sexual self-incompatible outcrossing plants, but pseudogamous apomicts frequently show a breakdown of self-incompatibility. Two possible pathways may explain the evolution of SC: (1) Polyploidy not only may trigger gametophytic apomixis, but also may result in a partial breakdown of SI systems. (2) Alternatively, frequent pseudo self-compatibility (PSC) via aborted pollen may induce selfing of pseudogamous apomicts (mentor effects). Self-fertile pseudogamous genotypes will be selected for within mixed sexual-apomictic populations because of avoidance of interploidal crosses; in founder situations, SC provides reproductive assurance independent from pollinators and mating partners. SI pseudogamous genotypes will be selected against in mixed populations because of minority cytotype problems and high pollen discounting; in founder populations, SI reactions among clone mates will reduce seed set. Selection for SC genotypes will eliminate SI unless the apomict maintains a high genotypic diversity and thus a diversity of S-alleles within a population, or shifts to pollen-independent autonomous apomixis. The implications of a breakdown of SI in apomictic plants for evolutionary questions and for agricultural sciences are being discussed.
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Affiliation(s)
- Elvira Hörandl
- Department of Systematic and Evolutionary Botany, Faculty of Life Sciences, University of Vienna, Rennweg 14, 1030, Vienna, Austria.
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Cosendai AC, Hörandl E. Cytotype stability, facultative apomixis and geographical parthenogenesis in Ranunculus kuepferi (Ranunculaceae). ANNALS OF BOTANY 2010; 105:457-70. [PMID: 20100695 PMCID: PMC2826254 DOI: 10.1093/aob/mcp304] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2009] [Revised: 10/12/2009] [Accepted: 11/23/2009] [Indexed: 05/18/2023]
Abstract
BACKGROUND AND AIMS Asexual organisms are more widespread in previously glaciated areas than their sexual relatives ('geographical parthenogenesis'). In plants, this pattern is probably dependent on reproductive isolation and stability of cytotypes within their respective distribution areas. Both partial apomixis and introgressive hybridization potentially destabilize the spatial separation of sexual and apomictic populations. The wide distribution of apomicts may be further enhanced by uniparental reproduction which is advantageous for colonization. These factors are studied in the alpine species Ranunculus kuepferi. METHODS Geographical distribution, diversity and mode of reproduction of cytotypes were assessed using flow cytometry and flow cytometric seed screening on samples from 59 natural populations of Ranunculus kuepferi. Seed set of cytotypes was compared in the wild. KEY RESULTS Diploid sexuals are confined to the south-western parts of the Alps, while tetraploid apomicts dominate in previously glaciated and in geographically isolated areas despite a significantly lower fertility. Other cytotypes (3x, 5x and 6x) occur mainly in the sympatric zone, but without establishing populations. The tetraploids are predominantly apomictic, but also show a partial apomixis via an uncoupling of apomeiosis and parthenogenesis in the seed material. Both pseudogamy and autonomous endosperm formation are observed which may enhance uniparental reproduction. CONCLUSIONS Diploids occupy a glacial relic area and resist introgression of apomixis, probably because of a significantly higher seed set. Among the polyploids, only apomictic tetraploids form stable populations; the other cytotypes arising from partial apomixis fail to establish, probably because of minority cytotype disadvantages. Tetraploid apomicts colonize previously devastated and also distant areas via long-distance dispersal, confirming Baker's law of an advantage of uniparental reproduction. It is concluded that stability of cytotypes and of modes of reproduction are important factors for establishing a pattern of geographical parthenogenesis.
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Affiliation(s)
| | - Elvira Hörandl
- Department of Systematic and Evolutionary Botany, Faculty Centre for Biodiversity, University of Vienna, Rennweg 14, 1030 Vienna, Austria
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