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Vaz de Sousa D, Greve M, Oberlander KC. Friends without benefits: Extensive cytotype sympatry and polyploid persistence in an African geophyte. AMERICAN JOURNAL OF BOTANY 2024:e16291. [PMID: 38439133 DOI: 10.1002/ajb2.16291] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 12/08/2023] [Accepted: 12/08/2023] [Indexed: 03/06/2024]
Abstract
PREMISE Polyploidy is a major factor in plant adaptation and speciation. Multiple mechanisms contribute to autopolyploid frequency within populations, but uncertainties remain regarding mechanisms that facilitate polyploid establishment and persistence. Here we aimed to document and predict cytotype distributions of Oxalis obliquifolia Steud. ex A. Rich. across Gauteng, South Africa, and test for evidence of possible mechanisms, including morphological, phenological, and reproductive traits, that may potentially facilitate polyploid persistence. METHODS Over 320 O. obliquifolia plants from 25 sites were cytotyped using flow cytometry, and DNA ploidy was confirmed using meiotic chromosome squashes. Cytotypes were mapped and correlations with abiotic variables assessed using ordinations. To assess morphological and phenological associations with cytotype, we grew multiple cytotypes in a common garden, measured phenotypic traits and compared them using linear models and discriminant analyses. Intercytotype reproductive isolation was assessed using crossing experiments, and AMOVAs based on ITS DNA sequences tested for cytogeographic structure. RESULTS Six cytotypes were identified, and most sites had multiple cytotypes. Abiotic variables were not predictive of cytotype distribution. A clear gigas effect was present. Differences in flower size and phenology suggested pollinator interactions could play a role in polyploid persistence. Intercytotype crosses produced seed at low frequency. DNA data suggested diploids and polyploids were largely reproductively isolated in situ, and polyploidization events were not frequent enough to explain high cytotype sympatry. CONCLUSIONS Diploids and polyploids are behaving as separate species, despite little observable niche differentiation and non-zero potential intercytotype seed set. Tests on biotic interactions and intercytotype F1 fitness may provide insights into diploid and polyploid coexistence.
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Affiliation(s)
- Damian Vaz de Sousa
- Department of Plant and Soil Science, University of Pretoria, Private Bag X20, Hatfield, 0028, Pretoria, South Africa
- H.G.W.J. Schweickerdt Herbarium, Department of Plant and Soil Science, University of Pretoria, Pretoria, South Africa
| | - Michelle Greve
- Department of Plant and Soil Science, University of Pretoria, Private Bag X20, Hatfield, 0028, Pretoria, South Africa
| | - Kenneth C Oberlander
- H.G.W.J. Schweickerdt Herbarium, Department of Plant and Soil Science, University of Pretoria, Pretoria, South Africa
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Weinstein AM, Bohman B, Linde CC, Phillips RD. Conservation assessment of the Drakaea livida (Orchidaceae) ecotypes and an evaluation of methods for their identification. Front Ecol Evol 2022. [DOI: 10.3389/fevo.2022.1004177] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Morphologically cryptic taxa must be accounted for when quantifying biodiversity and implementing effective conservation measures. Some orchids pollinated by sexual deception of male insects contain morphologically cryptic ecotypes, such as the warty hammer orchid Drakaea livida (Orchidaceae). This species is comprised of three cryptic pollination ecotypes, which can be distinguished based on differences in pollinator species and floral volatiles. The present study aims were: (a) to investigate the geographic range of the three D. livida ecotypes, enabling assessment of their conservation status; and (b) to test the efficacy of different methods of identifying the D. livida ecotypes. Three methods of ecotype identification were assessed: morphometric analysis, genome size comparison, and analysis of chemical volatile composition of labellum extracts from pollinated flowers. MaxEnt species distribution models revealed that each ecotype has a different predicted geographic range, with small areas of overlap at the range margins. One ecotype is known from just ten populations over a limited geographic area, the majority of which has been cleared for agriculture, and urban development. While there was broad overlap between the ecotypes in individual morphological traits, multivariate analysis of morphological traits provided correct assignment to ecotype in 87% of individuals. Using the labellum of pollinated flowers, screening for volatile chemical compounds associated with particular ecotypes returned an even higher correct assignment rate, of 96.5%. As such, we advocate that the use of volatiles from the labellum of recently pollinated flowers is an effective way to determine the ecotype of unknown individuals of D. livida, with minimal impact on the flowering plant.
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Mráz P, Španiel S, Skokanová K, Šingliarová B. Temporal stability of spatial cytotype structure in mixed-ploidy populations of Centaurea stoebe. AOB PLANTS 2022; 14:plac052. [PMID: 36439406 PMCID: PMC9683110 DOI: 10.1093/aobpla/plac052] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 10/21/2022] [Indexed: 06/16/2023]
Abstract
Spatial segregation of cytotypes reduces the negative effect of frequency-dependent mating on the fitness of minority cytotype(s) and thus allows its establishment and coexistence with the majority cytotype in mixed-ploidy populations. Despite its evolutionary importance, the stability of spatial segregation is largely unknown. Furthermore, closely related sympatric cytotypes that differ in their life histories might exhibit contrasting spatial dynamics over time. We studied the temporal stability of spatial structure at a secondary contact zone of co-occurring monocarpic diploids and polycarpic tetraploids of Centaurea stoebe, whose tetraploid cytotype has undergone a rapid range expansion in Europe and became invasive in North America. Eleven years after the initial screening, we re-assessed the microspatial distribution of diploids and tetraploids and their affinities to varying vegetation-cover density in three mixed-ploidy populations in Central Europe. We found that overall, spatial patterns and frequencies of both cytotypes in all sites were very similar over time, with one exception. At one site, in one previously purely 2x patch, diploids completely disappeared due to intensive succession by shrubby vegetation. The remaining spatial patterns, however, showed the same cytotype clumping and higher frequency of 2x despite subtle changes in vegetation-cover densities. In contrast to the expected expansion of polycarpic tetraploids having higher colonization ability when compared to diploids, the tetraploids remained confined to their former microsites and showed no spatial expansion. Spatial patterns of coexisting diploids and tetraploids, which exhibit contrasting life histories, did not change over more than a decade. Such temporal stability is likely caused by relatively stable habitat conditions and very limited seed dispersal. Our results thus imply that in the absence of a disturbance regime connected with frequent human- or animal-mediated seed dispersal, spatial patterns may be very stable over time, thus contributing to the long-term coexistence of cytotypes.
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Affiliation(s)
- Patrik Mráz
- Herbarium Collections & Department of Botany, Faculty of Sciences, Charles University, Benátská 2, CZ-128 01 Prague, Czechia
| | | | - Katarína Skokanová
- Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 23 Bratislava, Slovakia
| | - Barbora Šingliarová
- Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 23 Bratislava, Slovakia
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Becker FW, Oberlander KC, Trávníček P, Dreyer LL. Inconsistent expression of the gigas effect in polyploid Oxalis. AMERICAN JOURNAL OF BOTANY 2022; 109:1607-1621. [PMID: 36193941 DOI: 10.1002/ajb2.16077] [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: 03/31/2022] [Revised: 09/02/2022] [Accepted: 09/02/2022] [Indexed: 06/16/2023]
Abstract
PREMISE It is well-known that whole genome duplication (WGD) has played a significant role in the evolution of plants. The best-known phenotypic effect of WGD is the gigas effect, or the enlargement of polyploid plant traits. WGD is often linked with increased weediness, which could be a result of fitness advantages conferred by the gigas effect. As a result, the gigas effect could potentially explain polyploid persistence and abundance. We test whether a gigas effect is present in the polyploid-rich geophyte Oxalis, at both organ and cellular scales. METHODS We measured traits in conspecific diploid and polyploid accessions of 24 species across the genus. In addition, we measured the same and additional traits in 20 populations of the weedy and highly ploidy-variable species Oxalis purpurea L., including measures of clonality and selfing as a proxy for weediness. Ploidy level was determined using flow cytometry. RESULTS We found substantial variation and no consistent ploidy-related size difference, both between and within species, and across traits. Oxalis purpurea polyploids did, however, produce significantly more underground biomass and more bulbils than diploids, consistent with a potential role of WGD in the weediness of this species. CONCLUSIONS Our results suggest a more nuanced role for the gigas effect, at least in Oxalis. It may be temporary, short-lived, and inconsistently expressed and retained on evolutionary time scales, but in the short term can contribute to lineage success via increased vegetative reproduction.
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Affiliation(s)
- Frederik W Becker
- Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Kenneth C Oberlander
- H. G. W. J. Schweickerdt Herbarium, Department of Plant and Soil Sciences, Plant Sciences Complex, University of Pretoria, Private Bag X20, Hatfield, 0028, South Africa
| | - Pavel Trávníček
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice, Czech Republic, and Department of Botany, Charles University, Praha, Czech Republic
| | - Léanne L Dreyer
- Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
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Fernández P, Hidalgo O, Juan A, Leitch IJ, Leitch AR, Palazzesi L, Pegoraro L, Viruel J, Pellicer J. Genome Insights into Autopolyploid Evolution: A Case Study in Senecio doronicum (Asteraceae) from the Southern Alps. PLANTS 2022; 11:plants11091235. [PMID: 35567236 PMCID: PMC9099586 DOI: 10.3390/plants11091235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Revised: 04/27/2022] [Accepted: 04/29/2022] [Indexed: 11/16/2022]
Abstract
Polyploidy is a widespread phenomenon across angiosperms, and one of the main drivers of diversification. Whilst it frequently involves hybridisation, autopolyploidy is also an important feature of plant evolution. Minority cytotypes are frequently overlooked due to their lower frequency in populations, but the development of techniques such as flow cytometry, which enable the rapid screening of cytotype diversity across large numbers of individuals, is now providing a more comprehensive understanding of cytotype diversity within species. Senecio doronicum is a relatively common daisy found throughout European mountain grasslands from subalpine to almost nival elevations. We have carried out a population-level cytotype screening of 500 individuals from Tête Grosse (Alpes-de-Haute-Provence, France), confirming the coexistence of tetraploid (28.2%) and octoploid cytotypes (71.2%), but also uncovering a small number of hexaploid individuals (0.6%). The analysis of repetitive elements from short-read genome-skimming data combined with nuclear (ITS) and whole plastid DNA sequences support an autopolyploid origin of the polyploid S. doronicum individuals and provide molecular evidence regarding the sole contribution of tetraploids in the formation of hexaploid individuals. The evolutionary impact and resilience of the new cytotype have yet to be determined, although the coexistence of different cytotypes may indicate nascent speciation.
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Affiliation(s)
- Pol Fernández
- Institut Botànic de Barcelona (IBB, CSIC-Ajuntament de Barcelona), Passeig del Migdia s.n., Parc de Montjuïc, 08038 Barcelona, Spain;
- Correspondence: (P.F.); (J.P.); Tel.: +34-932890611 (P.F. & J.P.)
| | - Oriane Hidalgo
- Institut Botànic de Barcelona (IBB, CSIC-Ajuntament de Barcelona), Passeig del Migdia s.n., Parc de Montjuïc, 08038 Barcelona, Spain;
- Royal Botanic Gardens, Kew, Kew Green, Richmond TW9 3AE, UK; (I.J.L.); (J.V.)
| | - Ana Juan
- Departamento de Ciencias Ambientales y Recursos Naturales, Universidad de Alicante, 03080 Alicante, Spain;
| | - Ilia J. Leitch
- Royal Botanic Gardens, Kew, Kew Green, Richmond TW9 3AE, UK; (I.J.L.); (J.V.)
| | - Andrew R. Leitch
- School of Biological and Chemical Sciences, Queen Mary University of London, London E1 4NS, UK;
| | - Luis Palazzesi
- Museo Argentino de Ciencias Naturales, CONICET, División Paleobotánica, Buenos Aires C1405DJR, Argentina;
| | - Luca Pegoraro
- Biodiversity and Conservation Biology Research Unit, Swiss Federal Institute for Forest, Snow and Landscape Research WSL, 8903 Bimensdorf, Switzerland;
| | - Juan Viruel
- Royal Botanic Gardens, Kew, Kew Green, Richmond TW9 3AE, UK; (I.J.L.); (J.V.)
| | - Jaume Pellicer
- Institut Botànic de Barcelona (IBB, CSIC-Ajuntament de Barcelona), Passeig del Migdia s.n., Parc de Montjuïc, 08038 Barcelona, Spain;
- Royal Botanic Gardens, Kew, Kew Green, Richmond TW9 3AE, UK; (I.J.L.); (J.V.)
- Correspondence: (P.F.); (J.P.); Tel.: +34-932890611 (P.F. & J.P.)
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Bateman RM, Rudall PJ, Denholm I. In situ morphometric survey elucidates the evolutionary systematics of the orchid genus Gymnadenia in the British Isles. SYST BIODIVERS 2021. [DOI: 10.1080/14772000.2021.1877848] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Richard M. Bateman
- Jodrell Laboratory, Royal Botanic Gardens Kew, Richmond TW9 3DS, Surrey, UK
| | - Paula J. Rudall
- Jodrell Laboratory, Royal Botanic Gardens Kew, Richmond TW9 3DS, Surrey, UK
| | - Ian Denholm
- Department of Biological and Environmental Sciences, University of Hertfordshire, Hatfield AL10 9AB, Hertfordshire, UK
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Trávníček P, Chumová Z, Záveská E, Hanzlíčková J, Kupková (Jankolová) L, Kučera J, Gbúrová Štubňová E, Rejlová L, Mandáková T, Ponert J. Integrative Study of Genotypic and Phenotypic Diversity in the Eurasian Orchid Genus Neotinea. FRONTIERS IN PLANT SCIENCE 2021; 12:734240. [PMID: 34745168 PMCID: PMC8570840 DOI: 10.3389/fpls.2021.734240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 09/20/2021] [Indexed: 05/04/2023]
Abstract
Knowledge of population variation across species' ranges is a prerequisite for correctly assessing the overall variability of any group of organisms and provides an invaluable basis for unraveling evolutionary history, optimizing taxonomy and devising effective conservation strategies. Here, we examine the genus Neotinea, which represents a relatively recently delimited monophyletic genus of orchids, for which a detailed study of its overall variability was lacking. We applied a suite of biosystematic methods, consisting of flow cytometry, multivariate and geometric morphometrics, and analysis of genomic SNP data, to identify phylogenetic lineages within the genus, to delineate phenotypic variation relevant to these lineages, and to identify potential cryptic taxa within lineages. We found clear differentiation into four major lineages corresponding to the groups usually recognized within the genus: Neotinea maculata as a distinct and separate taxon, the Neotinea lactea group comprising two Mediterranean taxa N. lactea and Neotinea conica, the Neotinea ustulata group comprising two phenologically distinct varieties, and the rather complex Neotinea tridentata group comprising two major lineages and various minor lineages of unclear taxonomic value. N. conica constitutes both a monophyletic group within N. lactea and a distinct phenotype within the genus and merits its proposed subspecies-level recognition. By contrast, the spring and summer flowering forms of N. ustulata (var. ustulata and var. aestivalis) were confirmed to be distinct only morphologically, not phylogenetically. The most complex pattern emerged in the N. tridentata group, which splits into two main clades, one containing lineages from the Balkans and eastern Mediterranean and the other consisting of plants from Central Europe and the central Mediterranean. These individual lineages differ in genome size and show moderate degrees of morphological divergence. The tetraploid Neotinea commutata is closely related to the N. tridentata group, but our evidence points to an auto- rather than an allopolyploid origin. Our broad methodological approach proved effective in recognizing cryptic lineages among the orchids, and we propose the joint analysis of flow cytometric data on genome size and endopolyploidy as a useful and beneficial marker for delineating orchid species with partial endoreplication.
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Affiliation(s)
- Pavel Trávníček
- Institute of Botany, Czech Academy of Sciences, Průhonice, Czechia
- *Correspondence: Pavel Trávníček,
| | - Zuzana Chumová
- Institute of Botany, Czech Academy of Sciences, Průhonice, Czechia
- Department of Botany, Faculty of Science, Charles University, Prague, Czechia
- Zuzana Chumová,
| | - Eliška Záveská
- Institute of Botany, Czech Academy of Sciences, Průhonice, Czechia
| | - Johana Hanzlíčková
- Institute of Botany, Czech Academy of Sciences, Průhonice, Czechia
- Department of Botany, Faculty of Science, Charles University, Prague, Czechia
| | | | - Jaromír Kučera
- Institute of Botany, Plant Science and Biodiversity Center, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Eliška Gbúrová Štubňová
- Institute of Botany, Plant Science and Biodiversity Center, Slovak Academy of Sciences, Bratislava, Slovakia
- Slovak National Museum, Bratislava, Slovakia
| | - Ludmila Rejlová
- Institute of Botany, Czech Academy of Sciences, Průhonice, Czechia
- Department of Botany, Faculty of Science, Charles University, Prague, Czechia
| | - Terezie Mandáková
- Central European Institute of Technology (CEITEC), Masaryk University, Brno, Czechia
- Department of Experimental Biology, Faculty of Science, Masaryk University, Brno, Czechia
| | - Jan Ponert
- Institute of Botany, Czech Academy of Sciences, Průhonice, Czechia
- Department of Experimental Plant Biology, Faculty of Science, Charles University, Prague, Czechia
- Prague Botanical Garden, Prague, Czechia
- Jan Ponert,
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Nabieva A, Zaytseva Y, Shakarishili N. Genome size variability of the population of Gymnadenia conopsea (Orchidaceae) in the Novosibirsk Region (Russia). BIO WEB OF CONFERENCES 2021. [DOI: 10.1051/bioconf/20213800084] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Gymnadenia conopsea (Fragrant orchid) is a widespread model species for the study of polymorphism in the European part of Russia and abroad. Flow cytometry refers to rapid methods effective for assessing the structure of a population by DNA size estimation. However, this method is only available in habitats with close proximity to the place of the experiment, because this indicator is determined only in fresh leaves. A small population of G. conopsea in the industrial area adjacent to the Novosibirsk urban agglomeration in the Novosibirsk Region (NR) was studied. Only diploids were detected in the G. conopsea cenopopulation occurred in the industrial zone of the NR. In this study we pointed on significance of genome size variation, which correlates with the adaptive evolution of the G. conopsea in West Siberia. The revealed absence of minor cytotypes (individuals with a higher level of ploidy) in G. conopsea population reduces intraspecific and intrapopulation diversity of the species.
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Duchoslav M, Jandová M, Kobrlová L, Šafářová L, Brus J, Vojtěchová K. Intricate Distribution Patterns of Six Cytotypes of Allium oleraceum at a Continental Scale: Niche Expansion and Innovation Followed by Niche Contraction With Increasing Ploidy Level. FRONTIERS IN PLANT SCIENCE 2020; 11:591137. [PMID: 33362819 PMCID: PMC7755979 DOI: 10.3389/fpls.2020.591137] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 11/06/2020] [Indexed: 05/23/2023]
Abstract
The establishment and success of polyploids are thought to often be facilitated by ecological niche differentiation from diploids. Unfortunately, most studies compared diploids and polyploids, ignoring variation in ploidy level in polyploids. To fill this gap, we performed a large-scale study of 11,163 samples from 1,283 populations of the polyploid perennial geophyte Allium oleraceum with reported mixed-ploidy populations, revealed distribution ranges of cytotypes, assessed their niches and explored the pattern of niche change with increasing ploidy level. Altogether, six ploidy levels (3x-8x) were identified. The most common were pentaploids (53.6%) followed by hexaploids (22.7%) and tetraploids (21.6%). Higher cytotype diversity was found at lower latitudes than at higher latitudes (>52° N), where only tetraploids and pentaploids occurred. We detected 17.4% of mixed-ploidy populations, usually as a combination of two, rarely of three, cytotypes. The majority of mixed-ploidy populations were found in zones of sympatry of the participating cytotypes, suggesting they have arisen through migration (secondary contact zone). Using coarse-grained variables (climate, soil), we found evidence of both niche expansion and innovation in tetraploids related to triploids, whereas higher ploidy levels showed almost zero niche expansion, but a trend of increased niche unfilling of tetraploids. Niche unfilling in higher ploidy levels was caused by a contraction of niche envelopes toward lower continentality of the climate and resulted in a gradual decrease of niche breadth and a gradual shift in niche optima. Field-recorded data indicated wide habitat breadth of tetraploids and pentaploids, but also a pattern of increasing synanthropy in higher ploidy levels. Wide niche breadth of tetra- and pentaploids might be related to their multiple origins from different environmental conditions, higher "age", and retained sexuality, which likely preserve their adaptive potential. In contrast, other cytotypes with narrower niches are mostly asexual, probably originating from a limited range of contrasting environments. Persistence of local ploidy mixtures could be enabled by the perenniality of A. oleraceum and its prevalence of vegetative reproduction, facilitating the establishment and decreasing exclusion of minority cytotype due to its reproductive costs. Vegetative reproduction might also significantly accelerate colonization of new areas, including recolonization of previously glaciated areas.
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Affiliation(s)
- Martin Duchoslav
- Plant Biosystematics and Ecology RG, Department of Botany, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Michaela Jandová
- Plant Biosystematics and Ecology RG, Department of Botany, Faculty of Science, Palacký University, Olomouc, Czechia
- Institute of Botany, Czech Academy of Sciences, Pruhonice, Czechia
| | - Lucie Kobrlová
- Plant Biosystematics and Ecology RG, Department of Botany, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Lenka Šafářová
- Plant Biosystematics and Ecology RG, Department of Botany, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Jan Brus
- Department of Geoinformatics, Faculty of Science, Palacký University, Olomouc, Czechia
| | - Kateřina Vojtěchová
- Plant Biosystematics and Ecology RG, Department of Botany, Faculty of Science, Palacký University, Olomouc, Czechia
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Morgan EJ, Čertner M, Lučanová M, Kubíková K, Marhold K, Kolář F. Niche similarity in diploid-autotetraploid contact zones of Arabidopsis arenosa across spatial scales. AMERICAN JOURNAL OF BOTANY 2020; 107:1375-1388. [PMID: 32974906 DOI: 10.1002/ajb2.1534] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 06/21/2020] [Indexed: 06/11/2023]
Abstract
PREMISE Whole genome duplication is a major evolutionary event, but its role in ecological divergence remains equivocal. When populations of different ploidy (cytotypes) overlap in space, "contact zones" are formed, allowing the study of evolutionary mechanisms contributing toward ploidy divergence. Multiple contact zones per species' range are often described but rarely leveraged as natural replicates. We explored whether the strength of niche differentiation of diploid and autotetraploid Arabidopsis arenosa varies over distinct contact zones and if the frequency of triploids decreases from seedling to adult stage. METHODS We characterized ploidy composition and habitat preferences in 264 populations across three contact zones using climatic niche modeling. Ecological differences of cytotypes were also assessed using local vegetation surveys at 110 populations within two contact zones, and at the finer scale within five mixed-ploidy sites. This was complemented by flow cytometry of seedlings. RESULTS We found no niche differences between diploid and tetraploid populations within contact zones for either climatic or local environmental variables. Comparisons of cytotypes within mixed-ploidy sites found weak niche differences that were inconsistent in direction. Triploid individuals were virtually absent (0.14%) in the field, and they were at a similarly low frequency (0.2%) in ex situ germinated seedlings. CONCLUSIONS This study demonstrates the strength in investigating different spatial scales across several contact zones when addressing ecological niche differentiation between ploidies. The lack of consistent habitat differentiation of ploidies across the scales and locations supports the recently emerging picture that processes other than ecological differentiation may underlie ploidy coexistence in diploid-autopolyploid systems.
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Affiliation(s)
- Emma J Morgan
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
| | - Martin Čertner
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
| | - Magdalena Lučanová
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
- Department of Botany, Faculty of Science, University of South Bohemia, Branišovská 31, CZ-370 05, České Budějovice, Czech Republic
| | - Kateřina Kubíková
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
| | - Karol Marhold
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
- Institute of Botany, Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 23, Bratislava, Slovak Republic
| | - Filip Kolář
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 01, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
- Institute of Botany, University of Innsbruck, Sternwartestrasse 15, AT-6020, Innsbruck, Austria
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Chapurlat E, Le Roncé I, Ågren J, Sletvold N. Divergent selection on flowering phenology but not on floral morphology between two closely related orchids. Ecol Evol 2020; 10:5737-5747. [PMID: 32607187 PMCID: PMC7319237 DOI: 10.1002/ece3.6312] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2020] [Revised: 03/09/2020] [Accepted: 03/30/2020] [Indexed: 11/08/2022] Open
Abstract
Closely related species often differ in traits that influence reproductive success, suggesting that divergent selection on such traits contribute to the maintenance of species boundaries. Gymnadenia conopsea ss. and Gymnadenia densiflora are two closely related, perennial orchid species that differ in (a) floral traits important for pollination, including flowering phenology, floral display, and spur length, and (b) dominant pollinators. If plant-pollinator interactions contribute to the maintenance of trait differences between these two taxa, we expect current divergent selection on flowering phenology and floral morphology between the two species. We quantified phenotypic selection via female fitness in one year on flowering start, three floral display traits (plant height, number of flowers, and corolla size) and spur length, in six populations of G. conopsea s.s. and in four populations of G. densiflora. There was indication of divergent selection on flowering start in the expected direction, with selection for earlier flowering in two populations of the early-flowering G. conopsea s.s. and for later flowering in one population of the late-flowering G. densiflora. No divergent selection on floral morphology was detected, and there was no significant stabilizing selection on any trait in the two species. The results suggest ongoing adaptive differentiation of flowering phenology, strengthening this premating reproductive barrier between the two species. Synthesis: This study is among the first to test whether divergent selection on floral traits contribute to the maintenance of species differences between closely related plants. Phenological isolation confers a substantial potential for reproductive isolation, and divergent selection on flowering time can thus greatly influence reproductive isolation and adaptive differentiation.
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Affiliation(s)
- Elodie Chapurlat
- Plant Ecology and EvolutionDepartment of Ecology and GeneticsEvolutionary Biology CentreUppsala UniversityUppsalaSweden
| | - Iris Le Roncé
- Plant Ecology and EvolutionDepartment of Ecology and GeneticsEvolutionary Biology CentreUppsala UniversityUppsalaSweden
- Master BioSciencesÉcole Normale Supérieure de LyonUniversité Claude Bernard Lyon 1Université de LyonLyonFrance
| | - Jon Ågren
- Plant Ecology and EvolutionDepartment of Ecology and GeneticsEvolutionary Biology CentreUppsala UniversityUppsalaSweden
| | - Nina Sletvold
- Plant Ecology and EvolutionDepartment of Ecology and GeneticsEvolutionary Biology CentreUppsala UniversityUppsalaSweden
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12
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Hanušová K, Čertner M, Urfus T, Koutecký P, Košnar J, Rothfels CJ, Jarolímová V, Ptáček J, Ekrt L. Widespread co-occurrence of multiple ploidy levels in fragile ferns (Cystopteris fragilis complex; Cystopteridaceae) probably stems from similar ecology of cytotypes, their efficient dispersal and inter-ploidy hybridization. ANNALS OF BOTANY 2019; 123:845-855. [PMID: 30541055 PMCID: PMC6526313 DOI: 10.1093/aob/mcy219] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2018] [Accepted: 11/09/2018] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Polyploidy has played an important role in the evolution of ferns. However, the dearth of data on cytotype diversity, cytotype distribution patterns and ecology in ferns is striking in comparison with angiosperms and prevents an assessment of whether cytotype coexistence and its mechanisms show similar patterns in both plant groups. Here, an attempt to fill this gap was made using the ploidy-variable and widely distributed Cystopteris fragilis complex. METHODS Flow cytometry was used to assess DNA ploidy level and monoploid genome size (Cx value) of 5518 C. fragilis individuals from 449 populations collected over most of the species' global distributional range, supplemented with data from 405 individuals representing other related species from the complex. Ecological preferences of C. fragilis tetraploids and hexaploids were compared using field-recorded parameters and database-extracted climate data. KEY RESULTS Altogether, five different ploidy levels (2x, 4x, 5x, 6x, 8x) were detected and three species exhibited intraspecific ploidy-level variation: C. fragilis, C. alpina and C. diaphana. Two predominant C. fragilis cytotypes, tetraploids and hexaploids, co-occur over most of Europe in a diffuse, mosaic-like pattern. Within this contact zone, 40 % of populations were mixed-ploidy and most also contained pentaploid hybrids. Environmental conditions had only a limited effect on the distribution of cytotypes. Differences were found in the Cx value of tetraploids and hexaploids: between-cytotype divergence was higher in uniform-ploidy than in mixed-ploidy populations. CONCLUSIONS High ploidy-level diversity and widespread cytotype coexistence in the C. fragilis complex match the well-documented patterns in some angiosperms. While ploidy coexistence in C. fragilis is not driven by environmental factors, it could be facilitated by the perennial life-form of the species, its reproductive modes and efficient wind dispersal of spores. Independent origins of hexaploids and/or inter-ploidy gene flow may be expected in mixed-ploidy populations according to Cx value comparisons.
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Affiliation(s)
- Kristýna Hanušová
- Department of Botany, Faculty of Science, Charles University, Benátská, Praha, Czech Republic
| | - Martin Čertner
- Department of Botany, Faculty of Science, Charles University, Benátská, Praha, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek, Průhonice, Czech Republic
| | - Tomáš Urfus
- Department of Botany, Faculty of Science, Charles University, Benátská, Praha, Czech Republic
| | - Petr Koutecký
- Department of Botany, Faculty of Science, University of South Bohemia, Branišovská, České Budějovice, Czech Republic
| | - Jiří Košnar
- Department of Botany, Faculty of Science, University of South Bohemia, Branišovská, České Budějovice, Czech Republic
| | - Carl J Rothfels
- University Herbarium and Department of Integrative Biology, University of California, Berkeley, CA, USA
| | - Vlasta Jarolímová
- Institute of Botany, The Czech Academy of Sciences, Zámek, Průhonice, Czech Republic
| | - Jan Ptáček
- Department of Botany, Faculty of Science, Charles University, Benátská, Praha, Czech Republic
| | - Libor Ekrt
- Department of Botany, Faculty of Science, University of South Bohemia, Branišovská, České Budějovice, Czech Republic
- For correspondence. E-mail
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13
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Zhong J, Yi S, Ma L, Wang W. Evolution and phylogeography analysis of diploid and polyploid Misgurnus anguillicaudatus populations across China. Proc Biol Sci 2019; 286:20190076. [PMID: 31014220 DOI: 10.1098/rspb.2019.0076] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The origin and evolution of polyploid organisms have been extensively studied in plants, but this topic remains only partially understood in vertebrates, where polyploidy is relatively rare. In this study, we used Misgurnus anguillicaudatus, a fish that comprises five ploidy levels in nature, as a model animal to improve our understanding of biogeographic history and evolution of polyploid vertebrates. After collecting samples from different geographical populations in China, their ploidy levels were determined using flow cytometry. Two mitochondrial markers ( cytochrome b and control region) were then used for phylogeographic analyses to unravel the possible origins of diploids and tetraploids in China. The results showed that diploids have wider geographical distribution than tetraploids and triploids. There was no clear allopatric geographical range or boundary to divide diploid and polyploid populations. Rather, the analysis of mitochondrial DNA sequences indicated that tetraploids were autopolyploids, with lower genetic diversity than diploids. This suggests that tetraploids originated from sympatric diploids via multiple independent polyploidization events. Genetic structure patterns were similar between diploids and tetraploids, whereas complex genetic differentiation was found among different regions. The potential origin of M. anguillicaudatus was deduced to be in the Pearl River basin, which exhibited the highest nucleotide diversity and genetic differentiation. These findings provide insights into the evolution of polyploidy in vertebrates.
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Affiliation(s)
- Jia Zhong
- College of Fisheries, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University , Wuhan 430070 , People's Republic of China
| | - Shaokui Yi
- College of Fisheries, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University , Wuhan 430070 , People's Republic of China
| | - Laiyan Ma
- College of Fisheries, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University , Wuhan 430070 , People's Republic of China
| | - Weimin Wang
- College of Fisheries, Key Laboratory of Agricultural Animal Genetics, Breeding and Reproduction of Ministry of Education/Key Laboratory of Freshwater Animal Breeding, Ministry of Agriculture, Huazhong Agricultural University , Wuhan 430070 , People's Republic of China
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14
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Šingliarová B, Zozomová-Lihová J, Mráz P. Polytopic origin and scale-dependent spatial segregation of cytotypes in primary diploid–autopolyploid contact zones ofPilosella rhodopea(Asteraceae). Biol J Linn Soc Lond 2019. [DOI: 10.1093/biolinnean/bly199] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Affiliation(s)
- Barbora Šingliarová
- Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta, Bratislava, Slovakia
| | - Judita Zozomová-Lihová
- Plant Science and Biodiversity Centre, Slovak Academy of Sciences, Dúbravská cesta, Bratislava, Slovakia
| | - Patrik Mráz
- Herbarium and Department of Botany, Charles University, Benátská,Prague, Czech Republic
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15
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Garmendia A, Merle H, Ruiz P, Ferriol M. Distribution and ecological segregation on regional and microgeographic scales of the diploid Centaurea aspera L., the tetraploid C. seridis L., and their triploid hybrids (Compositae). PeerJ 2018; 6:e5209. [PMID: 30002989 PMCID: PMC6034602 DOI: 10.7717/peerj.5209] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Accepted: 06/20/2018] [Indexed: 11/20/2022] Open
Abstract
Although polyploidy is considered a ubiquitous process in plants, the establishment of new polyploid species may be hindered by ecological competition with parental diploid taxa. In such cases, the adaptive processes that result in the ecological divergence of diploids and polyploids can lead to their co-existence. In contrast, non-adaptive processes can lead to the co-existence of diploids and polyploids or to differentiated distributions, particularly when the minority cytotype disadvantage effect comes into play. Although large-scale studies of cytotype distributions have been widely conducted, the segregation of sympatric cytotypes on fine scales has been poorly studied. We analysed the spatial distribution and ecological requirements of the tetraploid Centaurea seridis and the diploid Centaurea aspera in east Spain on a large scale, and also microspatially in contact zones where both species hybridise and give rise to sterile triploid hybrids. On the fine scale, the position of each Centaurea individual was recorded along with soil parameters, accompanying species cover and plant richness. On the east Spanish coast, a slight latitudinal gradient was found. Tetraploid C. seridis individuals were located northerly and diploid C. aspera individuals southerly. Tetraploids were found only in the habitats with strong anthropogenic disturbance. In disturbed locations with well-developed semi-fixed or fixed dunes, diploids and tetraploids could co-exist and hybridise. However, on a fine scale, although taxa were spatially segregated in contact zones, they were not ecologically differentiated. This finding suggests the existence of non-adaptive processes that have led to their co-existence. Triploid hybrids were closer to diploid allogamous mothers (C. aspera) than to tetraploid autogamous fathers (C. seridis). This may result in a better ability to compete for space in the tetraploid minor cytotype, which might facilitate its long-term persistence.
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Affiliation(s)
- Alfonso Garmendia
- Instituto Agroforestal Mediterráneo, Universitat Politècnica de València, Valencia, Spain
| | - Hugo Merle
- Departamento de Ecosistemas Agroforestales, Universitat Politècnica de València, Valencia, Spain
| | - Pablo Ruiz
- Departamento de Ecosistemas Agroforestales, Universitat Politècnica de València, Valencia, Spain
| | - Maria Ferriol
- Instituto Agroforestal Mediterráneo, Universitat Politècnica de València, Valencia, Spain
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16
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Gaynor ML, Ng J, Laport RG. Phylogenetic Structure of Plant Communities: Are Polyploids Distantly Related to Co-occurring Diploids? Front Ecol Evol 2018. [DOI: 10.3389/fevo.2018.00052] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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17
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Castro M, Castro S, Figueiredo A, Husband B, Loureiro J. Complex cytogeographical patterns reveal a dynamic tetraploid-octoploid contact zone. AOB PLANTS 2018; 10:ply012. [PMID: 29593853 PMCID: PMC5844219 DOI: 10.1093/aobpla/ply012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2017] [Accepted: 02/13/2018] [Indexed: 05/24/2023]
Abstract
The distribution of cytotypes in mixed-ploidy species is crucial for evaluating ecological processes involved in the establishment and evolution of polyploid taxa. Here, we use flow cytometry and chromosome counts to explore cytotype diversity and distributions within a tetraploid-octoploid contact zone. We then use niche modelling and ploidy seed screening to assess the roles of niche differentiation among cytotypes and reproductive interactions, respectively, in promoting cytotype coexistence. Two cytotypes, tetraploids and octoploids, were dominant within the contact zone. They were most often distributed parapatrically or allopatrically, resulting in high geographic isolation. Still, 16.7 % of localities comprised two or more cytotypes, including the intermediate hexaploid cytotype. Tetraploids and octoploids had high environmental niche overlap and associated with similar climatic environments, suggesting they have similar ecological requirements. Given the geographical separation and habitat similarity among cytotypes, mixed-ploidy populations may be transitional and subject to the forces of minority cytotype exclusion which lead to pure-ploidy populations. However, seed ploidy analysis suggests that strong reproductive barriers may enforce assortative mating which favours stable cytotype coexistence. High cytogenetic diversity detected in the field suggests that unreduced gamete formation and hybridization events seem frequent in the studied polyploid complex and might be involved with the recurrent polyploid formation, governing, as well, the gene flow between cytogenetic entities.
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Affiliation(s)
- Mariana Castro
- CFE, Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, Coimbra, Portugal
| | - Sílvia Castro
- CFE, Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, Coimbra, Portugal
- Botanic Garden of the University of Coimbra, Calçada Martim de Freitas, Coimbra, Portugal
| | - Albano Figueiredo
- CEGOT, Departamento de Geografia e Turismo, Faculdade de Letras, Universidade de Coimbra, Largo da Porta Férrea, Coimbra, Portugal
| | - Brian Husband
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
| | - João Loureiro
- CFE, Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Calçada Martim de Freitas, Coimbra, Portugal
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18
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Kolář F, Čertner M, Suda J, Schönswetter P, Husband BC. Mixed-Ploidy Species: Progress and Opportunities in Polyploid Research. TRENDS IN PLANT SCIENCE 2017; 22:1041-1055. [PMID: 29054346 DOI: 10.1016/j.tplants.2017.09.011] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Revised: 09/12/2017] [Accepted: 09/18/2017] [Indexed: 05/07/2023]
Abstract
Mixed-ploidy species harbor a unique form of genomic and phenotypic variation that influences ecological interactions, facilitates genetic divergence, and offers insights into the mechanisms of polyploid evolution. However, there have been few attempts to synthesize this literature. We review here research on the cytotype distribution, diversity, and dynamics of intensively studied mixed-ploidy species and consider the implications for understanding mechanisms of polyploidization such as cytotype formation, establishment, coexistence, and post-polyploid divergence. In general, mixed-ploidy species are unevenly represented among families: they exhibit high cytotype diversity, often within populations, and frequently comprise rare and odd-numbered ploidies. Odd-ploidies often occur in association with asexuality. We highlight research hypotheses and opportunities that take advantage of the unique properties of ploidy variation.
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Affiliation(s)
- Filip Kolář
- Department of Botany, Faculty of Science, Charles University, Benátská 2, Praha, CZ-128 00, Czech Republic; Institute of Botany, The Czech Academy of Sciences, Zámek 1, Průhonice, CZ-252 43, Czech Republic
| | - Martin Čertner
- Department of Botany, Faculty of Science, Charles University, Benátská 2, Praha, CZ-128 00, Czech Republic; Institute of Botany, The Czech Academy of Sciences, Zámek 1, Průhonice, CZ-252 43, Czech Republic
| | - Jan Suda
- Department of Botany, Faculty of Science, Charles University, Benátská 2, Praha, CZ-128 00, Czech Republic; Institute of Botany, The Czech Academy of Sciences, Zámek 1, Průhonice, CZ-252 43, Czech Republic
| | - Peter Schönswetter
- Institute of Botany, University of Innsbruck, Sternwartestraße 15, A-6020 Innsbruck, Austria
| | - Brian C Husband
- Department of Integrative Biology, University of Guelph, Guelph, ON, N0B 2K0 Canada.
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19
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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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20
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Čertner M, Fenclová E, Kúr P, Kolář F, Koutecký P, Krahulcová A, Suda J. Evolutionary dynamics of mixed-ploidy populations in an annual herb: dispersal, local persistence and recurrent origins of polyploids. ANNALS OF BOTANY 2017; 120:303-315. [PMID: 28398545 PMCID: PMC5737363 DOI: 10.1093/aob/mcx032] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 03/08/2017] [Indexed: 05/18/2023]
Abstract
Background and Aims Despite the recent wealth of studies targeted at contact zones of cytotypes in various species, some aspects of polyploid evolution are still poorly understood. This is especially the case for the frequency and success rate of spontaneous neopolyploidization or the temporal dynamics of ploidy coexistence, requiring massive ploidy screening and repeated observations, respectively. To fill this gap, an extensive study of spatio-temporal patterns of ploidy coexistence was initiated in the widespread annual weed Tripleurospermum inodorum (Asteraceae). Methods DNA flow cytometry along with confirmatory chromosome counts was employed to assess ploidy levels of 11 018 adult individuals and 1263 ex situ germinated seedlings from 1209 Central European populations. The ploidy screening was conducted across three spatial scales and supplemented with observations of temporal development of 37 mixed-ploidy populations. Key Results The contact zone between the diploid and tetraploid cytotypes has a diffuse, mosaic-like structure enabling common cytotype coexistence from the within-population to the landscape level. A marked difference in monoploid genome size between the two cytotypes enabled the easy distinction of neotetraploid mutants from long-established tetraploids. Neotetraploids were extremely rare (0·03 %) and occurred solitarily. Altogether five ploidy levels (2 x -6 x ) and several aneuploids were discovered; the diversity in nuclear DNA content was highest in early ontogenetic stages (seedlings) and among individuals from mixed-ploidy populations. In spite of profound temporal oscillations in cytotype frequencies in mixed-ploidy populations, both diploids and tetraploids usually persisted up to the last census. Conclusions Diploids and tetraploids commonly coexist at all spatial scales and exhibit considerable temporal stability in local ploidy mixtures. Mixed-ploidy populations containing fertile triploid hybrids probaby act as effective generators of cytogenetic novelty and may facilitate inter-ploidy gene flow. Neopolyploid mutants were incapable of local establishment.
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Affiliation(s)
- Martin Čertner
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 00 Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43 Průhonice, Czech Republic
| | - Eliška Fenclová
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 00 Prague, Czech Republic
| | - Pavel Kúr
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 00 Prague, Czech Republic
- Department of Botany, Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-370 05 České Budějovice, Czech Republic
| | - Filip Kolář
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 00 Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43 Průhonice, Czech Republic
- National Centre for Biosystematics, Natural History Museum, University of Oslo, NO-0318 Oslo, Norway
| | - Petr Koutecký
- Department of Botany, Faculty of Science, University of South Bohemia, Branišovská 1760, CZ-370 05 České Budějovice, Czech Republic
| | - Anna Krahulcová
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43 Průhonice, Czech Republic
| | - Jan Suda
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 00 Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43 Průhonice, Czech Republic
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Brown SC, Bourge M, Maunoury N, Wong M, Wolfe Bianchi M, Lepers-Andrzejewski S, Besse P, Siljak-Yakovlev S, Dron M, Satiat-Jeunemaître B. DNA Remodeling by Strict Partial Endoreplication in Orchids, an Original Process in the Plant Kingdom. Genome Biol Evol 2017; 9:1051-1071. [PMID: 28419219 PMCID: PMC5546068 DOI: 10.1093/gbe/evx063] [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] [Accepted: 04/11/2017] [Indexed: 12/12/2022] Open
Abstract
DNA remodeling during endoreplication appears to be a strong developmental characteristic in orchids. In this study, we analyzed DNA content and nuclei in 41 species of orchids to further map the genome evolution in this plant family. We demonstrate that the DNA remodeling observed in 36 out of 41 orchids studied corresponds to strict partial endoreplication. Such process is developmentally regulated in each wild species studied. Cytometry data analyses allowed us to propose a model where nuclear states 2C, 4E, 8E, etc. form a series comprising a fixed proportion, the euploid genome 2C, plus 2-32 additional copies of a complementary part of the genome. The fixed proportion ranged from 89% of the genome in Vanilla mexicana down to 19% in V. pompona, the lowest value for all 148 orchids reported. Insterspecific hybridization did not suppress this phenomenon. Interestingly, this process was not observed in mass-produced epiphytes. Nucleolar volumes grow with the number of endocopies present, coherent with high transcription activity in endoreplicated nuclei. Our analyses suggest species-specific chromatin rearrangement. Towards understanding endoreplication, V. planifolia constitutes a tractable system for isolating the genomic sequences that confer an advantage via endoreplication from those that apparently suffice at diploid level.
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Affiliation(s)
- Spencer C. Brown
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université
Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette Cedex, France
| | - Mickaël Bourge
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université
Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette Cedex, France
| | - Nicolas Maunoury
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université
Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette Cedex, France
| | - Maurice Wong
- Service du Développement Rural, Papeete Tahiti, French Polynesia,
France
| | - Michele Wolfe Bianchi
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université
Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette Cedex, France
| | | | - Pascale Besse
- UMR 53, PVBMT Université de la Réunion – Cirad, Pôle de Protection des
Plantes, St Pierre, France
| | - Sonja Siljak-Yakovlev
- Ecologie Systématique Evolution, Université Paris-Sud, CNRS, AgroParisTech,
Université Paris-Saclay, Orsay Cedex, France
| | - Michel Dron
- Institute of Plant Sciences Paris Saclay IPS2, Université Paris-Sud, CNRS,
INRA, Université Evry, Université Paris Diderot, Sorbonne Paris-Cité, Université
Paris-Saclay, Orsay, France
| | - Béatrice Satiat-Jeunemaître
- Institute for Integrative Biology of the Cell (I2BC), CEA, CNRS, Université
Paris‐Sud, Université Paris‐Saclay, Gif‐sur‐Yvette Cedex, France
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22
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Chrtek J, Herben T, Rosenbaumová R, Münzbergová Z, Dočkalová Z, Zahradníček J, Krejčíková J, Trávníček P. Cytotype coexistence in the field cannot be explained by inter-cytotype hybridization alone: linking experiments and computer simulations in the sexual species Pilosella echioides (Asteraceae). BMC Evol Biol 2017; 17:87. [PMID: 28335715 PMCID: PMC5364689 DOI: 10.1186/s12862-017-0934-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Accepted: 03/10/2017] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Processes driving ploidal diversity at the population level are virtually unknown. Their identification should use a combination of large-scale screening of ploidy levels in the field, pairwise crossing experiments and mathematical modelling linking these two types of data. We applied this approach to determine the drivers of frequencies of coexisting cytotypes in mixed-ploidy field populations of the fully sexual plant species Pilosella echioides. We examined fecundity and ploidal diversity in seeds from all possible pairwise crosses among 2x, 3x and 4x plants. Using these data, we simulated the dynamics of theoretical panmictic populations of individuals whose progeny structure is identical to that determined by the hybridization experiment. RESULTS The seed set differed significantly between the crossing treatments, being highest in crosses between diploids and tetraploids and lowest in triploid-triploid crosses. The number of progeny classes (with respect to embryo and endosperm ploidy) ranged from three in the 2x-2x cross to eleven in the 3x-3x cross. Our simulations demonstrate that, provided there is no difference in clonal growth and/or survival between cytotypes, it is a clear case of minority cytotype exclusion depending on the initial conditions with two stable states, neither of which corresponds to the ploidal structure in the field: (i) with prevalent diploids and lower proportions of other ploidies, and (ii) with prevalent tetraploids and 9% of hexaploids. By contrast, if clonal growth differs between cytotypes, minority cytotype exclusion occurs only if the role of sexual reproduction is high; otherwise differences in clonal growth are sufficient to maintain triploid prevalence (as observed in the field) independently of initial conditions. CONCLUSIONS The projections of our model suggest that the ploidal structure observed in the field can only be reached via a relatively high capacity for clonal growth (and proportionally lower sexual reproduction) in all cytotypes combined with higher clonal growth in the prevailing cytotype (3x).
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Affiliation(s)
- Jindřich Chrtek
- Institute of Botany, The Czech Academy of Sciences, CZ-252 43 Průhonice, Czech Republic
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic
| | - Tomáš Herben
- Institute of Botany, The Czech Academy of Sciences, CZ-252 43 Průhonice, Czech Republic
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic
| | - Radka Rosenbaumová
- Department of Botany, Natural History Museum, National Museum, CZ-193 00 Prague – Horní Počernice, Czech Republic
| | - Zuzana Münzbergová
- Institute of Botany, The Czech Academy of Sciences, CZ-252 43 Průhonice, Czech Republic
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic
| | - Zuzana Dočkalová
- Institute of Botany, The Czech Academy of Sciences, CZ-252 43 Průhonice, Czech Republic
| | - Jaroslav Zahradníček
- Institute of Botany, The Czech Academy of Sciences, CZ-252 43 Průhonice, Czech Republic
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic
| | - Jana Krejčíková
- Institute of Botany, The Czech Academy of Sciences, CZ-252 43 Průhonice, Czech Republic
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic
| | - Pavel Trávníček
- Institute of Botany, The Czech Academy of Sciences, CZ-252 43 Průhonice, Czech Republic
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic
- Faculty of Agriculture, University of South Bohemia, CZ-370 05 České Budějovice, Czech Republic
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Pinheiro F, Zanfra de Melo E Gouveia TM, Cozzolino S, Cafasso D, Cardoso-Gustavson P, Suzuki RM, Palma-Silva C. Strong but permeable barriers to gene exchange between sister species of Epidendrum. AMERICAN JOURNAL OF BOTANY 2016; 103:1472-1482. [PMID: 27519428 DOI: 10.3732/ajb.1600064] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Accepted: 06/08/2016] [Indexed: 06/06/2023]
Abstract
PREMISE OF THE STUDY The investigation of reproductive barriers between sister species can provide insights into how new lineages arise, and how species integrity is maintained in the face of interspecific gene flow. Different pre- and postzygotic barriers can limit interspecific gene exchange in sympatric populations, and different sources of evidence are often required to investigate the role of multiple reproductive isolation (RI) mechanisms. METHODS We tested the hypothesis of hybridization and potential introgression between Epidendrum secundum and Epidendrum xanthinum, two Neotropical food-deceptive orchid species, using nuclear and plastid microsatellites, experimental crosses, pollen tube growth observations, and genome size estimates. KEY RESULTS A large number of hybrids between E. secundum and E. xanthinum were detected, suggesting weak premating barriers. The low fertility of hybrid plants and the absence of haplotype sharing between parental species indicated strong postmating barriers, reducing interspecific gene exchange and the development of advanced generation hybrids. Despite the strength of reproductive barriers, fertile seeds were produced in some backcrossing experiments, and the existence of interspecific gene exchange could not be excluded. CONCLUSIONS Strong but permeable barriers were found between E. secundum and E. xanthinum. Indeed, haplotype sharing was not detected between parental species, suggesting that introgression is limited by a combination of genic incompatibilities, including negative cytonuclear interactions. Most taxonomic uncertainties in this group were potentially influenced by incomplete RI barriers between species, which mainly occurred sympatrically.
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Affiliation(s)
- Fábio Pinheiro
- Departamento de Biologia Vegetal, Instituto de Biologia, Universidade Estadual de Campinas 13083-862, Campinas, SP, Brazil Instituto de Botânica, Núcleo de Pesquisa do Orquidário do Estado04301-902, São Paulo, SP, Brazil
| | | | - Salvatore Cozzolino
- Dipartimento di Biologia, Complesso Universitario di Monte S. Ângelo, Università degli Studidi Napoli Federico II 80100 Napoli, Italy Institute for Sustenible Plant Protection, Consiglio Nazionale delle Ricerche, Via Madonna del Piano 10, I-50019 Sesto Fiorentino (FI), Italy
| | - Donata Cafasso
- Dipartimento di Biologia, Complesso Universitario di Monte S. Ângelo, Università degli Studidi Napoli Federico II 80100 Napoli, Italy
| | | | - Rogério Mamoru Suzuki
- Instituto de Botânica, Núcleo de Pesquisa do Orquidário do Estado04301-902, São Paulo, SP, Brazil
| | - Clarisse Palma-Silva
- Departamento de Ecologia, Universidade Estadual Paulista 13506-900, Rio Claro, SP, Brazil
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24
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Hřibová E, Holušová K, Trávníček P, Petrovská B, Ponert J, Šimková H, Kubátová B, Jersáková J, Čurn V, Suda J, Doležel J, Vrána J. The Enigma of Progressively Partial Endoreplication: New Insights Provided by Flow Cytometry and Next-Generation Sequencing. Genome Biol Evol 2016; 8:1996-2005. [PMID: 27324917 PMCID: PMC4943206 DOI: 10.1093/gbe/evw141] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
In many plant species, somatic cell differentiation is accompanied by endoreduplication, a process during which cells undergo one or more rounds of DNA replication cycles in the absence of mitosis, resulting in nuclei with multiples of 2C DNA amounts (4C, 8C, 16C, etc.). In some orchids, a disproportionate increase in nuclear DNA contents has been observed, where successive endoreduplication cycles result in DNA amounts 2C + P, 2C + 3P, 2C + 7P, etc., where P is the DNA content of the replicated part of the 2C nuclear genome. This unique phenomenon was termed "progressively partial endoreplication" (PPE). We investigated processes behind the PPE in Ludisia discolor using flow cytometry (FCM) and Illumina sequencing. In particular, we wanted to determine whether chromatin elimination or incomplete genome duplication was involved, and to identify types of DNA sequences that were affected. Cell cycle analysis of root tip cell nuclei pulse-labeled with EdU revealed two cell cycles, one ending above the population of nuclei with 2C + P content, and the other with a typical "horseshoe" pattern of S-phase nuclei ranging from 2C to 4C DNA contents. The process leading to nuclei with 2C + P amounts therefore involves incomplete genome replication. Subsequent Illumina sequencing of flow-sorted 2C and 2C + P nuclei showed that all types of repetitive DNA sequences were affected during PPE; a complete elimination of any specific type of repetitive DNA was not observed. We hypothesize that PPE is part of a highly controlled transition mechanism from proliferation phase to differentiation phase of plant tissue development.
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Affiliation(s)
- Eva Hřibová
- Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany, Olomouc, Czech Republic
| | - Kateřina Holušová
- Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany, Olomouc, Czech Republic
| | - Pavel Trávníček
- Institute of Botany, the Czech Academy of Sciences, Průhonice, Czech Republic Department of Botany, Faculty of Science, Charles University in Prague, Czech Republic Biotechnological Centre, Faculty of Agriculture, University of South Bohemia in České Budějovice, Czech Republic
| | - Beáta Petrovská
- Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany, Olomouc, Czech Republic
| | - Jan Ponert
- Department of Experimental Plant Biology, Faculty of Science, Charles University in Prague, Czech Republic Prague Botanical Garden, Prague, Czech Republic
| | - Hana Šimková
- Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany, Olomouc, Czech Republic
| | - Barbora Kubátová
- Biotechnological Centre, Faculty of Agriculture, University of South Bohemia in České Budějovice, Czech Republic
| | - Jana Jersáková
- Department of Ecosystem Biology, Faculty of Science, University of South Bohemia in České Budějovice, Czech Republic
| | - Vladislav Čurn
- Biotechnological Centre, Faculty of Agriculture, University of South Bohemia in České Budějovice, Czech Republic
| | - Jan Suda
- Institute of Botany, the Czech Academy of Sciences, Průhonice, Czech Republic Department of Botany, Faculty of Science, Charles University in Prague, Czech Republic
| | - Jaroslav Doležel
- Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany, Olomouc, Czech Republic
| | - Jan Vrána
- Centre of the Region Haná for Biotechnological and Agricultural Research, Institute of Experimental Botany, Olomouc, Czech Republic
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25
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Etterson JR, Toczydlowski RH, Winkler KJ, Kirschbaum JA, McAulay TS. Solidago altissima differs with respect to ploidy frequency and clinal variation across the prairie-forest biome border in Minnesota. AMERICAN JOURNAL OF BOTANY 2016; 103:22-32. [PMID: 26507110 DOI: 10.3732/ajb.1500146] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 06/30/2015] [Indexed: 06/05/2023]
Abstract
PREMISE OF THE STUDY Although our awareness of ploidy diversity has expanded with the application of flow cytometry, we still know little about the extent to which cytotypes within mixed-ploidy populations are genetically differentiated across environmental gradients. METHODS To address this issue, we reared 14 populations of Solidago altissima spanning the prairie-forest ecotone in Minnesota in a common garden with a watering treatment. We assessed ploidy frequencies and measured survival, flowering phenology, and plant architectural traits for 4 years. KEY RESULTS All populations harbored multiple cytotypes; prairie populations were dominated by tetraploids, forest populations by hexaploids. Diploids and polyploids differed significantly for 84% of the traits. Beyond average differences, the slope of trait values covaried with latitude and longitude, but this relationship was stronger for diploids than the other two polyploid cytotypes as indicated by numerous ploidy × latitude and ploidy × longitude interactions. For example, the timing of flowering of the cytotypes overlapped in populations sampled from the northeastern hemiboreal forest but differed significantly between cytotypes sampled from populations in the southwestern prairie. The watering treatments had weak effects, and there were no ploidy differences for phenotypic plasticity. CONCLUSIONS Our data show that diploids have diverged genetically to a greater extent than polyploids along the environmental clines sampled in this study. Moreover, different environments favor phenotypic convergence over divergence among cytotypes for some traits. Differences in ploidy frequency and phenotypic divergence among cytotypes across gradients of temperature and precipitation are important considerations for restoration in an age of climate change.
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Affiliation(s)
- Julie R Etterson
- Department of Biology, University of Minnesota Duluth, 207A Swenson Science Building, Duluth, Minnesota 55812 USA
| | - Rachel H Toczydlowski
- Department of Biology, University of Minnesota Duluth, 207A Swenson Science Building, Duluth, Minnesota 55812 USA
| | - Katharine J Winkler
- Department of Biology, University of Minnesota Duluth, 207A Swenson Science Building, Duluth, Minnesota 55812 USA
| | - Jessica A Kirschbaum
- Department of Biology, University of Minnesota Duluth, 207A Swenson Science Building, Duluth, Minnesota 55812 USA
| | - Tim S McAulay
- Department of Biology, University of Minnesota Duluth, 207A Swenson Science Building, Duluth, Minnesota 55812 USA
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26
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Pinheiro F, Cafasso D, Cozzolino S, Scopece G. Transitions between self-compatibility and self-incompatibility and the evolution of reproductive isolation in the large and diverse tropical genus Dendrobium (Orchidaceae). ANNALS OF BOTANY 2015; 116:457-67. [PMID: 25953040 PMCID: PMC4549954 DOI: 10.1093/aob/mcv057] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Accepted: 03/30/2015] [Indexed: 05/09/2023]
Abstract
BACKGROUND AND AIMS The evolution of interspecific reproductive barriers is crucial to understanding species evolution. This study examines the contribution of transitions between self-compatibility (SC) and self-incompatibility (SI) and genetic divergence in the evolution of reproductive barriers in Dendrobium, one of the largest orchid genera. Specifically, it investigates the evolution of pre- and postzygotic isolation and the effects of transitions between compatibility states on interspecific reproductive isolation within the genus. METHODS The role of SC and SI changes in reproductive compatibility among species was examined using fruit set and seed viability data available in the literature from 86 species and ∼2500 hand pollinations. The evolution of SC and SI in Dendrobium species was investigated within a phylogenetic framework using internal transcribed spacer sequences available in GenBank. KEY RESULTS Based on data from crossing experiments, estimations of genetic distance and the results of a literature survey, it was found that changes in SC and SI significantly influenced the compatibility between species in interspecific crosses. The number of fruits produced was significantly higher in crosses in which self-incompatible species acted as pollen donor for self-compatible species, following the SI × SC rule. Maximum likelihood and Bayesian tests did not reject transitions from SI to SC and from SC to SI across the Dendrobium phylogeny. In addition, postzygotic isolation (embryo mortality) was found to evolve gradually with genetic divergence, in agreement with previous results observed for other plant species, including orchids. CONCLUSIONS Transitions between SC and SI and the gradual accumulation of genetic incompatibilities affecting postzygotic isolation are important mechanisms preventing gene flow among Dendrobium species, and may constitute important evolutionary processes contributing to the high levels of species diversity in this tropical orchid group.
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Affiliation(s)
- Fabio Pinheiro
- Departamento de Botânica, Instituto de Biociências, Universidade Estadual Paulista, 13506-900, Rio Claro, SP, Brazil,
| | - Donata Cafasso
- Università degli Studi di Napoli Federico II, Department of Biology, via Cinthia, I-80126, Naples, Italy and
| | - Salvatore Cozzolino
- Università degli Studi di Napoli Federico II, Department of Biology, via Cinthia, I-80126, Naples, Italy and
| | - Giovanni Scopece
- Università degli Studi di Napoli Federico II, Department of Biology, via Cinthia, I-80126, Naples, Italy and Institute for Plant Protection, Consiglio Nazionale delle Ricerche, Via Madonna del Piano, 10, I-50019, Sesto Fiorentino (FI), Italy
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27
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Chumová Z, Krejčíková J, Mandáková T, Suda J, Trávníček P. Evolutionary and Taxonomic Implications of Variation in Nuclear Genome Size: Lesson from the Grass Genus Anthoxanthum (Poaceae). PLoS One 2015; 10:e0133748. [PMID: 26207824 PMCID: PMC4514812 DOI: 10.1371/journal.pone.0133748] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Accepted: 06/16/2015] [Indexed: 11/19/2022] Open
Abstract
The genus Anthoxanthum (sweet vernal grass, Poaceae) represents a taxonomically intricate polyploid complex with large phenotypic variation and its evolutionary relationships still poorly resolved. In order to get insight into the geographic distribution of ploidy levels and assess the taxonomic value of genome size data, we determined C- and Cx-values in 628 plants representing all currently recognized European species collected from 197 populations in 29 European countries. The flow cytometric estimates were supplemented by conventional chromosome counts. In addition to diploids, we found two low (rare 3x and common 4x) and one high (~16x-18x) polyploid levels. Mean holoploid genome sizes ranged from 5.52 pg in diploid A. alpinum to 44.75 pg in highly polyploid A. amarum, while the size of monoploid genomes ranged from 2.75 pg in tetraploid A. alpinum to 9.19 pg in diploid A. gracile. In contrast to Central and Northern Europe, which harboured only limited cytological variation, a much more complex pattern of genome sizes was revealed in the Mediterranean, particularly in Corsica. Eight taxonomic groups that partly corresponded to traditionally recognized species were delimited based on genome size values and phenotypic variation. Whereas our data supported the merger of A. aristatum and A. ovatum, eastern Mediterranean populations traditionally referred to as diploid A. odoratum were shown to be cytologically distinct, and may represent a new taxon. Autopolyploid origin was suggested for 4x A. alpinum. In contrast, 4x A. odoratum seems to be an allopolyploid, based on the amounts of nuclear DNA. Intraspecific variation in genome size was observed in all recognized species, the most striking example being the A. aristatum/ovatum complex. Altogether, our study showed that genome size can be a useful taxonomic marker in Anthoxathum to not only guide taxonomic decisions but also help resolve evolutionary relationships in this challenging grass genus.
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Affiliation(s)
- Zuzana Chumová
- Department of Botany, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Jana Krejčíková
- Department of Botany, Faculty of Science, Charles University in Prague, Prague, Czech Republic
| | - Terezie Mandáková
- Central-European Institute of Technology, Masaryk University, Brno, Czech Republic
| | - Jan Suda
- Department of Botany, Faculty of Science, Charles University in Prague, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Průhonice, Czech Republic
| | - Pavel Trávníček
- Department of Botany, Faculty of Science, Charles University in Prague, Prague, Czech Republic
- Institute of Botany, The Czech Academy of Sciences, Průhonice, Czech Republic
- Biotechnological Centre, Faculty of Agriculture, University of South Bohemia, České Budějovice, Czech Republic
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28
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Frajman B, Rešetnik I, Weiss-Schneeweiss H, Ehrendorfer F, Schönswetter P. Cytotype diversity and genome size variation in Knautia (Caprifoliaceae, Dipsacoideae). BMC Evol Biol 2015; 15:140. [PMID: 26182989 PMCID: PMC4504173 DOI: 10.1186/s12862-015-0425-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Accepted: 06/26/2015] [Indexed: 11/30/2022] Open
Abstract
BACKGROUND Polyploidisation is one of the most important mechanisms in the evolution of angiosperms. As in many other genera, formation of polyploids has significantly contributed to diversification and radiation of Knautia (Caprifoliaceae, Dipsacoideae). Comprehensive studies of fine- and broad-scale patterns of ploidy and genome size (GS) variation are, however, still limited to relatively few genera and little is known about the geographic distribution of ploidy levels within these genera. Here, we explore ploidy and GS variation in Knautia based on a near-complete taxonomic and comprehensive geographic sampling. RESULTS Genome size is a reliable indicator of ploidy level in Knautia, even if monoploid genome downsizing is observed in the polyploid cytotypes. Twenty-four species studied are diploid, 16 tetraploid and two hexaploid, whereas ten species possess two, and two species possess three ploidy levels. Di- and tetraploids are distributed across most of the distribution area of Knautia, while hexaploids were sampled in the Balkan and Iberian Peninsulas and the Alps. CONCLUSIONS We show that the frequency of polyploidisation is unevenly distributed in Knautia both in a geographic and phylogenetic context. Monoploid GS varies considerably among three evolutionary lineages (sections) of Knautia, but also within sections Trichera and Tricheroides, as well as within some of the species. Although the exact causes of this variation remain elusive, we demonstrate that monoploid GS increases significantly towards the limits of the genus' distribution.
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Affiliation(s)
- Božo Frajman
- Institute of Botany, University of Innsbruck, Sternwartestraße 15, A-6020, Innsbruck, Austria
| | - Ivana Rešetnik
- Faculty of Science, University of Zagreb, Marulićev trg 20/II, HR-10000, Zagreb, Croatia
| | - Hanna Weiss-Schneeweiss
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030, Vienna, Austria.
| | - Friedrich Ehrendorfer
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030, Vienna, Austria
| | - Peter Schönswetter
- Institute of Botany, University of Innsbruck, Sternwartestraße 15, A-6020, Innsbruck, Austria
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Pachschwöll C, Escobar García P, Winkler M, Schneeweiss GM, Schönswetter P. Polyploidisation and geographic differentiation drive diversification in a European High Mountain Plant Group (Doronicum clusii Aggregate, Asteraceae). PLoS One 2015; 10:e0118197. [PMID: 25749621 PMCID: PMC4352020 DOI: 10.1371/journal.pone.0118197] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 01/08/2015] [Indexed: 11/19/2022] Open
Abstract
Range shifts (especially during the Pleistocene), polyploidisation and hybridization are major factors affecting high-mountain biodiversity. A good system to study their role in the European high mountains is the Doronicum clusii aggregate (Asteraceae), whose four taxa (D. clusii s.s., D. stiriacum, D. glaciale subsp. glaciale and D. glaciale subsp. calcareum) are differentiated geographically, ecologically (basiphilous versus silicicolous) and/or via their ploidy levels (diploid versus tetraploid). Here, we use DNA sequences (three plastid and one nuclear spacer) and AFLP fingerprinting data generated for 58 populations to infer phylogenetic relationships, origin of polyploids-whose ploidy level was confirmed by chromosomally calibrated DNA ploidy level estimates-and phylogeographic history. Taxonomic conclusions were informed, among others, by a Gaussian clustering method for species delimitation using dominant multilocus data. Based on molecular data we identified three lineages: (i) silicicolous diploid D. clusii s.s. in the Alps, (ii) silicicolous tetraploid D. stiriacum in the eastern Alps (outside the range of D. clusii s.s.) and the Carpathians and (iii) the basiphilous diploids D. glaciale subsp. glaciale (eastern Alps) and D. glaciale subsp. calcareum (northeastern Alps); each taxon was identified as distinct by the Gaussian clustering, but the separation of D. glaciale subsp. calcareum and D. glaciale subsp. glaciale was not stable, supporting their taxonomic treatment as subspecies. Carpathian and Alpine populations of D. stiriacum were genetically differentiated suggesting phases of vicariance, probably during the Pleistocene. The origin (autopolyploid versus allopolyploid) of D. stiriacum remained unclear. Doronicum glaciale subsp. calcareum was genetically and morphologically weakly separated from D. glaciale subsp. glaciale but exhibited significantly higher genetic diversity and rarity. This suggests that the more widespread D. glaciale subsp. glaciale originated from D. glaciale subsp. calcareum, which is restricted to a prominent Pleistocene refugium previously identified in other alpine plant species.
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Affiliation(s)
- Clemens Pachschwöll
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
| | - Pedro Escobar García
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
- Department of Botany, Natural History Museum, Burgring 7, A-1010 Vienna, Austria
| | - Manuela Winkler
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
- GLORIA co-ordination, University of Natural Resources and Life Sciences Vienna, Center for Global Change and Sustainability & Austrian Academy of Sciences, Institute for Interdisciplinary Mountain Research, Silbergasse 30, A-1190 Vienna, Austria
| | - Gerald M. Schneeweiss
- Department of Botany and Biodiversity Research, University of Vienna, Rennweg 14, A-1030 Vienna, Austria
- * E-mail:
| | - Peter Schönswetter
- Institute of Botany, University of Innsbruck, Sternwartestrasse 15, A-6020 Innsbruck, Austria
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30
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Hülber K, Sonnleitner M, Suda J, Krejčíková J, Schönswetter P, Schneeweiss GM, Winkler M. Ecological differentiation, lack of hybrids involving diploids, and asymmetric gene flow between polyploids in narrow contact zones of Senecio carniolicus (syn. Jacobaea carniolica, Asteraceae). Ecol Evol 2015; 5:1224-34. [PMID: 25859328 PMCID: PMC4377266 DOI: 10.1002/ece3.1430] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2014] [Revised: 01/27/2015] [Accepted: 01/28/2015] [Indexed: 11/09/2022] Open
Abstract
Areas of immediate contact of different cytotypes offer a unique opportunity to study evolutionary dynamics within heteroploid species and to assess isolation mechanisms governing coexistence of cytotypes of different ploidy. The degree of reproductive isolation of cytotypes, that is, the frequency of heteroploid crosses and subsequent formation of viable and (partly) fertile hybrids, plays a crucial role for the long-term integrity of lineages in contact zones. Here, we assessed fine-scale distribution, spatial clustering, and ecological niches as well as patterns of gene flow in parental and hybrid cytotypes in zones of immediate contact of di-, tetra-, and hexaploid Senecio carniolicus (Asteraceae) in the Eastern Alps. Cytotypes were spatially separated also at the investigated microscale; the strongest spatial separation was observed for the fully interfertile tetra- and hexaploids. The three main cytotypes showed highly significant niche differences, which were, however, weaker than across their entire distribution ranges in the Eastern Alps. Individuals with intermediate ploidy levels were found neither in the diploid/tetraploid nor in the diploid/hexaploid contact zones indicating strong reproductive barriers. In contrast, pentaploid individuals were frequent in the tetraploid/hexaploid contact zone, albeit limited to a narrow strip in the immediate contact zone of their parental cytotypes. AFLP fingerprinting data revealed introgressive gene flow mediated by pentaploid hybrids from tetra- to hexaploid individuals, but not vice versa. The ecological niche of pentaploids differed significantly from that of tetraploids but not from hexaploids.
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Affiliation(s)
- Karl Hülber
- Division of Conservation Biology, Vegetation Ecology and Landscape Ecology, Department of Botany and Biodiversity Research, University of ViennaVienna, Austria
- Vienna Institute for Nature Conservation & AnalysesVienna, Austria
| | - Michaela Sonnleitner
- Division of Conservation Biology, Vegetation Ecology and Landscape Ecology, Department of Botany and Biodiversity Research, University of ViennaVienna, Austria
| | - Jan Suda
- Department of Botany, Faculty of Science, Charles University in PraguePrague, Czech Republic
- Institute of Botany, The Czech Academy of SciencesPrůhonice, Czech Republic
| | - Jana Krejčíková
- Department of Botany, Faculty of Science, Charles University in PraguePrague, Czech Republic
| | | | - Gerald M Schneeweiss
- Division of Systematics and Evolutionary Botany, Department of Botany and Biodiversity Research, University of ViennaVienna, Austria
| | - Manuela Winkler
- Division of Systematics and Evolutionary Botany, Department of Botany and Biodiversity Research, University of ViennaVienna, Austria
- GLORIA co-ordination, Center for Global Change and Sustainability, University of Natural Resources and Life Sciences ViennaVienna, Austria
- Institute for Interdisciplinary Mountain Research, Austrian Academy of SciencesInnsbruck, Austria
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Kolář F, Lučanová M, Záveská E, Fuxová G, Mandáková T, Španiel S, Senko D, Svitok M, Kolník M, Gudžinskas Z, Marhold K. Ecological segregation does not drive the intricate parapatric distribution of diploid and tetraploid cytotypes of theArabidopsis arenosagroup (Brassicaceae). Biol J Linn Soc Lond 2015. [DOI: 10.1111/bij.12479] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Filip Kolář
- Department of Botany; Faculty of Science; Charles University in Prague; Benátská 2 CZ-128 01 Prague Czech Republic
- Institute of Botany; Academy of Sciences of the Czech Republic; Zámek 1 CZ-252 43 Průhonice Czech Republic
| | - Magdalena Lučanová
- Institute of Botany; Academy of Sciences of the Czech Republic; Zámek 1 CZ-252 43 Průhonice Czech Republic
- Department of Botany; Faculty of Science; Charles University in Prague; Benátská 2 CZ-128 01 Prague Czech Republic
| | - Eliška Záveská
- Department of Botany; Faculty of Science; Charles University in Prague; Benátská 2 CZ-128 01 Prague Czech Republic
| | - Gabriela Fuxová
- Department of Botany; Faculty of Science; Charles University in Prague; Benátská 2 CZ-128 01 Prague Czech Republic
| | - Terezie Mandáková
- Plant Cytogenomics Research Group; Central European Institute of Technology (CEITEC); Masaryk University; Kamenice 5 CZ-62500 Brno Czech Republic
| | - Stanislav Španiel
- Department of Botany; Faculty of Science; Charles University in Prague; Benátská 2 CZ-128 01 Prague Czech Republic
| | - Dušan Senko
- Institute of Botany; Slovak Academy of Sciences; Dúbravská cesta 9 SK-845 23 Bratislava Slovak Republic
| | - Marek Svitok
- Department of Biology and General Ecology; Faculty of Ecology and Environmental Sciences; Technical University in Zvolen; T. G. Masaryka 24 SK-960 53 Zvolen Slovak Republic
- Eawag Swiss Federal Institute of Aquatic Science and Technology; Department of Aquatic Ecology, Centre of Ecology; Evolution and Biogeochemistry; Seestrasse 79 CH-6047 Kastanienbaum Switzerland
| | - Martin Kolník
- Tematínska 4 SK-91501 Nové Mesto nad Váhom Slovak Republic
| | - Zigmantas Gudžinskas
- Nature Research Centre; Institute of Botany; Laboratory of Flora and Geobotany; Žaliųjų Ežerų Str. 49 LT-08406 Vilnius Lithuania
| | - Karol Marhold
- Department of Botany; Faculty of Science; Charles University in Prague; Benátská 2 CZ-128 01 Prague Czech Republic
- Institute of Botany; Slovak Academy of Sciences; Dúbravská cesta 9 SK-845 23 Bratislava Slovak Republic
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32
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Liu Y, Li D, Yan L, Huang H. The microgeographical patterns of morphological and molecular variation of a mixed ploidy population in the species complex Actinidia chinensis. PLoS One 2015; 10:e0117596. [PMID: 25658107 PMCID: PMC4319829 DOI: 10.1371/journal.pone.0117596] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 12/29/2014] [Indexed: 11/19/2022] Open
Abstract
Polyploidy and hybridization are thought to have significant impacts on both the evolution and diversification of the genus Actinidia, but the structure and patterns of morphology and molecular diversity relating to ploidy variation of wild Actinidia plants remain much less understood. Here, we examine the distribution of morphological variation and ploidy levels along geographic and environmental variables of a large mixed-ploidy population of the A. chinensis species complex. We then characterize the extent of both genetic and epigenetic diversity and differentiation exhibited between individuals of different ploidy levels. Our results showed that while there are three ploidy levels in this population, hexaploids were constituted the majority (70.3%). Individuals with different ploidy levels were microgeographically structured in relation to elevation and extent of niche disturbance. The morphological characters examined revealed clear difference between diploids and hexaploids, however tetraploids exhibited intermediate forms. Both genetic and epigenetic diversity were high but the differentiation among cytotypes was weak, suggesting extensive gene flow and/or shared ancestral variation occurred in this population even across ploidy levels. Epigenetic variation was clearly correlated with changes in altitudes, a trend of continuous genetic variation and gradual increase of epigenomic heterogeneities of individuals was also observed. Our results show that complex interactions between the locally microgeographical environment, ploidy and gene flow impact A. chinensis genetic and epigenetic variation. We posit that an increase in ploidy does not broaden the species habitat range, but rather permits A. chinensis adaptation to specific niches.
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Affiliation(s)
- Yifei Liu
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, the Chinese Academy of Sciences, Guangzhou, Guangdong, P. R. China
| | - Dawei Li
- Key Laboratory of Plant Germplasm Enhancement and Specially Agriculture, Wuhan Botanical Garden, the Chinese Academy of Sciences, Wuhan, Hubei, P. R. China
| | - Ling Yan
- Key Laboratory of Plant Germplasm Enhancement and Specially Agriculture, Wuhan Botanical Garden, the Chinese Academy of Sciences, Wuhan, Hubei, P. R. China
| | - Hongwen Huang
- Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, the Chinese Academy of Sciences, Guangzhou, Guangdong, P. R. China
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Gross K, Schiestl FP. Are tetraploids more successful? Floral signals, reproductive success and floral isolation in mixed-ploidy populations of a terrestrial orchid. ANNALS OF BOTANY 2015; 115:263-73. [PMID: 25652914 PMCID: PMC4551083 DOI: 10.1093/aob/mcu244] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 10/07/2014] [Accepted: 10/22/2014] [Indexed: 05/11/2023]
Abstract
BACKGROUND AND AIMS Polyploidization, the doubling of chromosome sets, is common in angiosperms and has a range of evolutionary consequences. Newly formed polyploid lineages are reproductively isolated from their diploid progenitors due to triploid sterility, but also prone to extinction because compatible mating partners are rare. Models have suggested that assortative mating and increased reproductive fitness play a key role in the successful establishment and persistence of polyploids. However, little is known about these factors in natural mixed-ploidy populations. This study investigated floral traits that can affect pollinator attraction and efficiency, as well as reproductive success in diploid and tetraploid Gymnadenia conopsea (Orchidaceae) plants in two natural, mixed-ploidy populations. METHODS Ploidy levels were determined using flow cytometry, and flowering phenology and herbivory were also assessed. Reproductive success was determined by counting fruits and viable seeds of marked plants. Pollinator-mediated floral isolation was measured using experimental arrays, with pollen flow tracked by means of staining pollinia with histological dye. KEY RESULTS Tetraploids had larger floral displays and different floral scent bouquets than diploids, but cytotypes differed only slightly in floral colour. Significant floral isolation was found between the two cytotypes. Flowering phenology of the two cytotypes greatly overlapped, and herbivory did not differ between cytotypes or was lower in tetraploids. In addition, tetraploids had higher reproductive success compared with diploids. CONCLUSIONS The results suggest that floral isolation and increased reproductive success of polyploids may help to explain their successful persistence in mixed-ploidy populations. These factors might even initiate transformation of populations from pure diploid to pure tetraploid.
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Affiliation(s)
- Karin Gross
- Institute of Systematic Botany, University of Zurich, Zollikerstrasse 107, CH-8008 Zurich, Switzerland
| | - Florian P Schiestl
- Institute of Systematic Botany, University of Zurich, Zollikerstrasse 107, CH-8008 Zurich, Switzerland
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34
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Eugenol synthase genes in floral scent variation in Gymnadenia species. Funct Integr Genomics 2014; 14:779-88. [PMID: 25239559 DOI: 10.1007/s10142-014-0397-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 08/07/2014] [Accepted: 08/31/2014] [Indexed: 02/05/2023]
Abstract
Floral signaling, especially through floral scent, is often highly complex, and little is known about the molecular mechanisms and evolutionary causes of this complexity. In this study, we focused on the evolution of "floral scent genes" and the associated changes in their functions in three closely related orchid species of the genus Gymnadenia. We developed a benchmark repertoire of 2,571 expressed sequence tags (ESTs) in Gymnadenia odoratissima. For the functional characterization and evolutionary analysis, we focused on eugenol synthase, as eugenol is a widespread and important scent compound. We obtained complete coding complementary DNAs (cDNAs) of two copies of putative eugenol synthase genes in each of the three species. The proteins encoded by these cDNAs were characterized by expression and testing for activity in Escherichia coli. While G. odoratissima and Gymnadenia conopsea enzymes were found to catalyze the formation of eugenol only, the Gymnadenia densiflora proteins synthesize eugenol, as well as a smaller amount of isoeugenol. Finally, we showed that the eugenol and isoeugenol producing gene copies of G. densiflora are evolutionarily derived from the ancestral genes of the other species producing only eugenol. The evolutionary switch from production of one to two compounds evolved under relaxed purifying selection. In conclusion, our study shows the molecular bases of eugenol and isoeugenol production and suggests that an evolutionary transition in a single gene can lead to an increased complexity in floral scent emitted by plants.
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35
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Prančl J, Kaplan Z, Trávníček P, Jarolímová V. Genome size as a key to evolutionary complex aquatic plants: polyploidy and hybridization in Callitriche (Plantaginaceae). PLoS One 2014; 9:e105997. [PMID: 25211149 PMCID: PMC4161354 DOI: 10.1371/journal.pone.0105997] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2014] [Accepted: 07/26/2014] [Indexed: 01/31/2023] Open
Abstract
Despite their complex evolutionary histories, aquatic plants are highly underrepresented in contemporary biosystematic studies. Of them, the genus Callitriche is particularly interesting because of such evolutionary features as wide variation in chromosome numbers and pollination systems. However, taxonomic difficulties have prevented broader investigation of this genus. In this study we applied flow cytometry to Callitriche for the first time in order to gain an insight into evolutionary processes and genome size differentiation in the genus. Flow cytometry complemented by confirmation of chromosome counts was applied to an extensive dataset of 1077 Callitriche individuals from 495 localities in 11 European countries and the USA. Genome size was determined for 12 taxa. The results suggest that many important processes have interacted in the evolution of the genus, including polyploidization and hybridization. Incongruence between genome size and ploidy level, intraspecific variation in genome size, formation of autotriploid and hybridization between species with different pollination systems were also detected. Hybridization takes place particularly in the diploid-tetraploid complex C. cophocarpa-C. platycarpa, for which the triploid hybrids were frequently recorded in the area of co-occurrence of its parents. A hitherto unknown hybrid (probably C. hamulata × C. cophocarpa) with a unique chromosome number was discovered in the Czech Republic. However, hybridization occurs very rarely among most of the studied species. The main ecological preferences were also compared among the taxa collected. Although Callitriche taxa often grow in mixed populations, the ecological preferences of individual species are distinctly different in some cases. Anyway, flow cytometry is a very efficient method for taxonomic delimitation, determination and investigation of Callitriche species, and is even able to distinguish homoploid taxa and identify introduced species.
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Affiliation(s)
- Jan Prančl
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice, Czech Republic
- Department of Botany, Charles University, Praha, Czech Republic
| | - Zdeněk Kaplan
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice, Czech Republic
| | - Pavel Trávníček
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice, Czech Republic
- Department of Botany, Charles University, Praha, Czech Republic
| | - Vlasta Jarolímová
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice, Czech Republic
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36
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Kumar P, Rana PK, Singhal VK, Gupta RC. Chromosome numbers, characterization of chromosomal pairing during meiosis, origin and natural propagation in polyploid cytotypes (4x, 5x and 6x) of Agrimonia eupatoria L. (Rosaceae) in northwest Himalayas (India). PROTOPLASMA 2014; 251:781-795. [PMID: 24318674 DOI: 10.1007/s00709-013-0581-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 10/29/2013] [Indexed: 06/02/2023]
Abstract
Despite the presence of intraspecific polyploidy (2x, 4x, 5x and 6x) in Agrimonia eupatoria, origin of these cytotypes has never been addressed adequately. The aim of the present study was to record the original chromosome counts and characterize chromosomal pairing during meiosis and microsporogenesis in the 5x cytotype, and discussing the hypothesis regarding the possible origin of polyploid cytotypes (4x, 5x and 6x) in the species. The geographical distribution pattern of cytotypes in the Indian Himalayas and elsewhere has also been analyzed. The present meiotic analysis revealed three chromosomes counts, the tetraploid (2n = 4x = 56), the pentaploid (2n = 5x = 70) and the hexaploid (2n = 6x = 84) cytotypes based on x = 14. Meiotic course was perfectly normal in the 4x and 6x cytotypes resulting into high pollen fertility (94-100 %). Meiotic course in the imbalanced 5x cytotype has been found to be irregular characterized by the presence of high frequency of univalents at diakinesis and metaphase-I. Abnormal meiotic course contributed towards high pollen sterility (74-88 %). Even the apparently fertile/stained pollen grains were of irregular shape and of heterogeneous sizes. Meiotic behaviour of the 5x cytotype is like typical of allopolyploid. Individuals of 5x cytotype did not produce seeds and propagate vegetatively (root suckers) while 4x and 6x cytotypes exploited sexual (seeds) as well as vegetative means for propagation. Chromosomal pairing in pentaploid cytotype is like typical of an allopolyploid and we assume that it might have originated owing to natural inter-cytotype hybridization between 4x and 6x cytotypes in a mixed population. Analysis of geographical distribution pattern of cytotypes shows that Indian Himalayas represent the most cytotype-diverse region for A. eupatoria with the existence of all the four cytotypes (2x, 4x, 5x, 6x). This shows the dynamic nature of the species at chromosomal level in this part of the world.
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Affiliation(s)
- Puneet Kumar
- Department of Botany, Punjabi University, Patiala, 147002, Punjab, India,
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Hanzl M, Kolář F, Nováková D, Suda J. Nonadaptive processes governing early stages of polyploid evolution: Insights from a primary contact zone of relict serpentine Knautia arvensis (Caprifoliaceae). AMERICAN JOURNAL OF BOTANY 2014; 101:935-945. [PMID: 24920762 DOI: 10.3732/ajb.1400005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
• Premise of the study: Contact zones between polyploids and their diploid progenitors may provide important insights into the mechanisms of sympatric speciation and local adaptation. However, most published studies investigated secondary contact zones where the effects of genome duplication can be confounded by previous independent evolution of currently sympatric cytotypes. We compared genetically close diploid and autotetraploid serpentine cytotypes of Knautia arvensis (Caprifoliaceae) in a primary contact zone and evaluated the role of adaptive and nonadaptive processes for cytotype coexistence.• Methods: DNA flow cytometry was used to determine ploidy distribution at various spatial scales (from across the entire contact zone to microgeographic). Habitat preferences of diploids and polyploids were assessed by comparing vegetation composition of nearby ploidy-uniform sites and by recording plant species immediately surrounding both cytotypes in mixed-ploidy plots.• Key results: Tetraploids considerably outnumbered their diploid progenitors in the contact zone. Both cytotypes were segregated at all investigated spatial scales. This pattern was not driven by ecological shifts, because both diploids and tetraploids inhabited sites with nearly identical vegetation cover. Certain interploidy niche differentiation was indicated only at the smallest spatial scale; ecologically nonadaptive processes were most likely responsible for this difference.• Conclusions: We conclude that a shift in ecological preferences (i.e., the adaptive scenario) is not necessary for the establishment and evolutionary success of autopolyploid derivatives in primary contact zones. Spatial segregation that would support ploidy coexistence can also be achieved by ecologically nonadaptive processes, including the founder effect, limited dispersal ability, intense clonal growth, and triploid block.
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Affiliation(s)
- Martin Hanzl
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, CZ-128 01 Prague, Czech Republic Institute of Botany, Academy of Sciences of the Czech Republic, Zámek 1, CZ-252 43 Průhonice, Czech Republic
| | - Filip Kolář
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, CZ-128 01 Prague, Czech Republic Institute of Botany, Academy of Sciences of the Czech Republic, Zámek 1, CZ-252 43 Průhonice, Czech Republic
| | - Dora Nováková
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, CZ-128 01 Prague, Czech Republic
| | - Jan Suda
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, CZ-128 01 Prague, Czech Republic Institute of Botany, Academy of Sciences of the Czech Republic, Zámek 1, CZ-252 43 Průhonice, Czech Republic
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Eliášová A, Trávníček P, Mandák B, Münzbergová Z. Autotetraploids of Vicia cracca show a higher allelic richness in natural populations and a higher seed set after artificial selfing than diploids. ANNALS OF BOTANY 2014; 113:159-70. [PMID: 24232383 PMCID: PMC3864723 DOI: 10.1093/aob/mct252] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2012] [Accepted: 09/11/2013] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS Despite the great importance of autopolyploidy in the evolution of angiosperms, relatively little attention has been devoted to autopolyploids in natural polyploid systems. Several hypotheses have been proposed to explain why autopolyploids are so common and successful, for example increased genetic diversity and heterozygosity and the transition towards selfing. However, case studies on patterns of genetic diversity and on mating systems in autopolyploids are scarce. In this study allozymes were employed to investigate the origin, population genetic diversity and mating system in the contact zone between diploid and assumed autotetraploid cytotypes of Vicia cracca in Central Europe. METHODS Four enzyme systems resolved in six putative loci were investigated in ten diploid, ten tetraploid and five mixed-ploidy populations. Genetic diversity and heterozygosity, partitioning of genetic diversity among populations and cytotypes, spatial genetic structure and fixed heterozygosity were analysed. These studies were supplemented by a pollination experiment and meiotic chromosome observation. KEY RESULTS AND CONCLUSIONS Weak evidence of fixed heterozygosity, a low proportion of unique alleles and genetic variation between cytotypes similar to the variation among populations within cytotypes supported the autopolyploid origin of tetraploids, although no multivalent formation was observed. Tetraploids possessed more alleles than diploids and showed higher observed zygotic heterozygosity than diploids, but the observed gametic heterozygosity was similar to the value observed in diploids and smaller than expected under panmixis. Values of the inbreeding coefficient and differentiation among populations (ρST) suggested that the breeding system in both cytotypes of V. cracca is mixed mating with prevailing outcrossing. The reduction in seed production of tetraploids after selfing was less than that in diploids. An absence of correlation between genetic and geographic distances and high differentiation among neighbouring tetraploid populations supports the secondary contact hypothesis with tetraploids of several independent origins in Central Europe. Nevertheless, the possibility of a recent in situ origin of tetraploids through a triploid bridge in some regions is also discussed.
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Affiliation(s)
- Anežka Eliášová
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, CZ-128 01 Prague, Czech Republic
| | - Pavel Trávníček
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, CZ-128 01 Prague, Czech Republic
- Institute of Botany, Academy of Sciences of the Czech Republic, Zámek 1, CZ-252 43 Průhonice, Czech Republic
| | - Bohumil Mandák
- Institute of Botany, Academy of Sciences of the Czech Republic, Zámek 1, CZ-252 43 Průhonice, Czech Republic
| | - Zuzana Münzbergová
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, CZ-128 01 Prague, Czech Republic
- Institute of Botany, Academy of Sciences of the Czech Republic, Zámek 1, CZ-252 43 Průhonice, Czech Republic
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Těšitelová T, Jersáková J, Roy M, Kubátová B, Těšitel J, Urfus T, Trávníček P, Suda J. Ploidy-specific symbiotic interactions: divergence of mycorrhizal fungi between cytotypes of the Gymnadenia conopsea group (Orchidaceae). THE NEW PHYTOLOGIST 2013; 199:1022-1033. [PMID: 23731358 DOI: 10.1111/nph.12348] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2013] [Accepted: 04/28/2013] [Indexed: 05/03/2023]
Abstract
Polyploidy is widely recognized as a major mechanism of sympatric speciation in plants, yet little is known about its effects on interactions with other organisms. Mycorrhizal fungi are among the most common plant symbionts and play an important role in plant nutrient supply. It remains to be understood whether mycorrhizal associations of ploidy-variable plants can be ploidy-specific. We examined mycorrhizal associations in three cytotypes (2x, 3x, 4x) of the Gymnadenia conopsea group (Orchidaceae), involving G. conopsea s.s. and G. densiflora, at different spatial scales and during different ontogenetic stages. We analysed: adults from mixed- and single-ploidy populations at a regional scale; closely spaced adults within a mixed-ploidy site; and mycorrhizal seedlings. All Gymnadenia cytotypes associated mainly with saprotrophic Tulasnellaceae (Basidiomycota). Nonetheless, both adults and seedlings of diploids and their autotetraploid derivatives significantly differed in the identity of their mycorrhizal symbionts. Interploidy segregation of mycorrhizal symbionts was most pronounced within a site with closely spaced adults. This study provides the first evidence that polyploidization of a plant species can be associated with a shift in mycorrhizal symbionts. This divergence may contribute to niche partitioning and facilitate establishment and co-existence of different cytotypes.
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Affiliation(s)
- Tamara Těšitelová
- Faculty of Science, University of South Bohemia, Branišovská 31, České Budějovice, 370 05, Czech Republic
| | - Jana Jersáková
- Faculty of Science, University of South Bohemia, Branišovská 31, České Budějovice, 370 05, Czech Republic
| | - Mélanie Roy
- Laboratoire Evolution et Diversité Biologique, Université de Toulouse, 3 Paul Sabatier, ENFA, CNRS, UMR 5174, 118 route de Narbonne, Toulouse Cedex, 31062, France
| | - Barbora Kubátová
- Faculty of Agriculture, University of South Bohemia, Studentská 13, České Budějovice, 370 05, Czech Republic
| | - Jakub Těšitel
- Faculty of Science, University of South Bohemia, Branišovská 31, České Budějovice, 370 05, Czech Republic
| | - Tomáš Urfus
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, 128 01, Czech Republic
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice 1, 252 43, Czech Republic
| | - Pavel Trávníček
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, 128 01, Czech Republic
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice 1, 252 43, Czech Republic
| | - Jan Suda
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, 128 01, Czech Republic
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice 1, 252 43, Czech Republic
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Krejčíková J, Sudová R, Lučanová M, Trávníček P, Urfus T, Vít P, Weiss-Schneeweiss H, Kolano B, Oberlander K, Dreyer LL, Suda J. High ploidy diversity and distinct patterns of cytotype distribution in a widespread species of Oxalis in the Greater Cape Floristic Region. ANNALS OF BOTANY 2013; 111:641-9. [PMID: 23425783 PMCID: PMC3605962 DOI: 10.1093/aob/mct030] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Genome duplication is widely acknowledged as a major force in the evolution of angiosperms, although the incidence of polyploidy in different floras may differ dramatically. The Greater Cape Floristic Region of southern Africa is one of the world's biodiversity hotspots and is considered depauperate in polyploids. To test this assumption, ploidy variation was assessed in a widespread member of the largest geophytic genus in the Cape flora: Oxalis obtusa. METHODS DNA flow cytometry complemented by confirmatory chromosome counts was used to determine ploidy levels in 355 populations of O. obtusa (1014 individuals) across its entire distribution range. Ecological differentiation among cytotypes was tested by comparing sets of vegetation and climatic variables extracted for each locality. KEY RESULTS Three majority (2x, 4x, 6x) and three minority (3x, 5x, 8x) cytotypes were detected in situ, in addition to a heptaploid individual originating from a botanical garden. While single-cytotype populations predominate, 12 mixed-ploidy populations were also found. The overall pattern of ploidy level distribution is quite complex, but some ecological segregation was observed. Hexaploids are the most common cytotype and prevail in the Fynbos biome. In contrast, tetraploids dominate in the Succulent Karoo biome. Precipitation parameters were identified as the most important climatic variables associated with cytotype distribution. CONCLUSIONS Although it would be premature to make generalizations regarding the role of genome duplication in the genesis of hyperdiversity of the Cape flora, the substantial and unexpected ploidy diversity in Oxalis obtusa is unparalleled in comparison with any other cytologically known native Cape plant species. The results suggest that ploidy variation in the Greater Cape Floristic Region may be much greater than currently assumed, which, given the documented role of polyploidy in speciation, has direct implications for radiation hypotheses in this biodiversity hotspot.
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Affiliation(s)
- Jana Krejčíková
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01 Czech Republic
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice 1, CZ-252 43 Czech Republic
| | - Radka Sudová
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice 1, CZ-252 43 Czech Republic
| | - Magdalena Lučanová
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01 Czech Republic
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice 1, CZ-252 43 Czech Republic
| | - Pavel Trávníček
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01 Czech Republic
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice 1, CZ-252 43 Czech Republic
| | - Tomáš Urfus
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01 Czech Republic
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice 1, CZ-252 43 Czech Republic
| | - Petr Vít
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01 Czech Republic
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice 1, CZ-252 43 Czech Republic
| | - Hanna Weiss-Schneeweiss
- Department of Systematic and Evolutionary Botany, Faculty Centre Botany, University of Vienna, Rennweg 14, Vienna, A-1030 Austria
| | - Bożena Kolano
- Department of Plant Anatomy and Cytology, Silesian University, Jagiellonska 28, 40-032 Katowice, Poland
| | | | - Leanne L. Dreyer
- Department of Botany and Zoology, Stellenbosch University, Private Bag X1, Matieland, 7602, South Africa
| | - Jan Suda
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01 Czech Republic
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice 1, CZ-252 43 Czech Republic
- For correspondence. E-mail:
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Efimov PG. Sibling species of fragrant orchids (Gymnadenia: Orchidaceae, Magnoliophyta) in Russia. RUSS J GENET+ 2013. [DOI: 10.1134/s102279541302004x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Pellicer J, Clermont S, Houston L, Rich TCG, Fay MF. Cytotype diversity in the Sorbus complex (Rosaceae) in Britain: sorting out the puzzle. ANNALS OF BOTANY 2012; 110:1185-93. [PMID: 22922587 PMCID: PMC3478048 DOI: 10.1093/aob/mcs185] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2012] [Accepted: 07/09/2012] [Indexed: 05/25/2023]
Abstract
BACKGROUND AND AIMS Large-scale ploidy surveys using flow cytometry have become an essential tool to study plant genome dynamics and to gain insight into the mechanisms and genetic barriers framing ploidy diversity. As an ideal complement to traditional techniques such as chromosome counting, the analysis of cytotype diversity in plant systems such as Sorbus provides primary investigation into the potential patterns and evolutionary implications of hybrid speciation. METHODS Ploidy was assessed by means of relative nuclear DNA content using propidium iodide flow cytometry in 474 Sorbus samples collected from 65 populations in southern Wales and South-West England. Statistical tests were applied to evaluate the utility of this technique to confidently discriminate ploidy in the genus. KEY RESULTS Flow cytometric profiles revealed the presence of four cytotypes (2x, 3x, 4x and 5x), confirming in many cases chromosome counts previously reported and demonstrating cytotype heterogeneity within specific Sorbus aggregates. Diploid cytotypes were restricted to the potential parental species and homoploid hybrids. Most of the samples processed were polyploid. The occurrence of the pentaploid cytotype had previously only been reported from a single specimen; it is now confirmed for two taxa occurring at different sites. CONCLUSIONS Flow cytometry results obtained have proved useful in shedding light on the taxonomy of several controversial taxa and in confirming the presence of cytoypes which occur at very low frequencies. Notably, the coexistence of several cytotypes in Sorbus populations has probably been facilitated by the overlapping distribution of many of the species studied, which might also explain the high incidence of potential hybrid apomictic polyploids. These results will provide a solid baseline for molecular research aiming to better understand the genetic pathways controlling the formation and establishment of polyploid Sorbus.
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Affiliation(s)
- Jaume Pellicer
- Jodrell Laboratory, Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK.
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Castro S, Loureiro J, Procházka T, Münzbergová Z. Cytotype distribution at a diploid-hexaploid contact zone in Aster amellus (Asteraceae). ANNALS OF BOTANY 2012; 110:1047-55. [PMID: 22887024 PMCID: PMC3448430 DOI: 10.1093/aob/mcs177] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 06/26/2012] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS The present study aims to assess the diversity and distribution of cytotypes of Aster amellus in central and eastern Europe, contributing with data to improve understanding of the evolutionary dynamics of the contact zone between diploids and hexaploids of this polyploid complex. METHODS Large-scale cytotype screening of 4720 individuals collected in 229 populations was performed using 4',6-diamidino-2-phenylindole (DAPI) flow cytometry. Fine-scale cytotype screening was performed in the mixed-ploidy population. Reproductive variables, such as number of florets per flower head, seed set and seedling emergence, as well as ploidy level of seeds and seedlings were recorded in this population. KEY RESULTS The diploid-hexaploid contact zone is large and complex, reaching the Czech Republic in the west, Austria in the south, Poland in the north-east and Romania in the extreme east of the surveyed areas. Most populations presented only one cytotype, either diploid or hexaploid. In several areas of the contact zone both cytotypes were found to grow in parapatry. One mixed-ploidy population of diploids and hexaploids was detected for the first time, but no signs of hybridization were detected. In this population, diploids had a significantly lower reproductive success, and significantly higher production of intercytotype offspring, being in reproductive disadvantage in comparison with hexaploids. CONCLUSIONS The contact zone of diploid and hexaploid A. amellus in central and eastern Europe seems to be highly dynamic and diffuse, with both primary and secondary contacts being possible. The obtained results suggest the origin of hexaploids through diploids, overall supporting previous hypotheses that this species is autopolyploid. Data from the only mixed-ploidy population detected so far suggest that the minority cytotype exclusion is an important evolutionary mechanisms driving the prevalence of single-cytotype populations, and thus contributing to the current distributional patterns of the cytotypes of A. amellus.
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Affiliation(s)
- S Castro
- CFE, Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal.
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Trávníček P, Jersáková J, Kubátová B, Krejčíková J, Bateman RM, Lučanová M, Krajníková E, Těšitelová T, Štípková Z, Amardeilh JP, Brzosko E, Jermakowicz E, Cabanne O, Durka W, Efimov P, Hedrén M, Hermosilla CE, Kreutz K, Kull T, Tali K, Marchand O, Rey M, Schiestl FP, Čurn V, Suda J. Minority cytotypes in European populations of the Gymnadenia conopsea complex (Orchidaceae) greatly increase intraspecific and intrapopulation diversity. ANNALS OF BOTANY 2012; 110:977-86. [PMID: 23002267 PMCID: PMC3448425 DOI: 10.1093/aob/mcs171] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 06/11/2012] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Patterns of ploidy variation among and within populations can provide valuable insights into the evolutionary mechanisms shaping the dynamics of plant systems showing ploidy diversity. Whereas data on majority ploidies are, by definition, often sufficiently extensive, much less is known about the incidence and evolutionary role of minority cytotypes. METHODS Ploidy and proportions of endoreplicated genome were determined using DAPI (4',6-diamidino-2-phenylindole) flow cytometry in 6150 Gymnadenia plants (fragrant orchids) collected from 141 populations in 17 European countries. All widely recognized European species, and several taxa of less certain taxonomic status were sampled within Gymnadenia conopsea sensu lato. KEY RESULTS Most Gymnadenia populations were taxonomically and/or ploidy heterogeneous. Two majority (2x and 4x) and three minority (3x, 5x and 6x) cytotypes were identified. Evolution largely proceeded at the diploid level, whereas tetraploids were much more geographically and taxonomically restricted. Although minority ploidies constituted <2 % of the individuals sampled, they were found in 35 % of populations across the entire area investigated. The amount of nuclear DNA, together with the level of progressively partial endoreplication, separated all Gymnadenia species currently widely recognized in Europe. CONCLUSIONS Despite their low frequency, minority cytotypes substantially increase intraspecific and intrapopulation ploidy diversity estimates for fragrant orchids. The cytogenetic structure of Gymnadenia populations is remarkably dynamic and shaped by multiple evolutionary mechanisms, including both the ongoing production of unreduced gametes and heteroploid hybridization. Overall, it is likely that the level of ploidy heterogeneity experienced by most plant species/populations is currently underestimated; intensive sampling is necessary to obtain a holistic picture.
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Affiliation(s)
- Pavel Trávníček
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic and Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
| | - Jana Jersáková
- Faculty of Science, University of South Bohemia in České Budějovice, CZ-370 05 České Budějovice, Czech Republic
| | - Barbora Kubátová
- Biotechnological Centre, Faculty of Agriculture, University of South Bohemia in České Budějovice, CZ-370 05 České Budějovice, Czech Republic
| | - Jana Krejčíková
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic and Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
| | | | - Magdalena Lučanová
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic and Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
| | - Eva Krajníková
- Biotechnological Centre, Faculty of Agriculture, University of South Bohemia in České Budějovice, CZ-370 05 České Budějovice, Czech Republic
| | - Tamara Těšitelová
- Faculty of Science, University of South Bohemia in České Budějovice, CZ-370 05 České Budějovice, Czech Republic
| | - Zuzana Štípková
- Faculty of Science, University of South Bohemia in České Budějovice, CZ-370 05 České Budějovice, Czech Republic
| | | | - Emilia Brzosko
- Institute of Biology, University of Bialystok, Świerkowa 20B, PL-15-950 Bialystok, Poland
| | - Edyta Jermakowicz
- Institute of Biology, University of Bialystok, Świerkowa 20B, PL-15-950 Bialystok, Poland
| | | | - Walter Durka
- Helmholtz Centre for Environmental Research–UFZ, Department of Community Ecology, Theodor-Lieser-Str. 4, D-06120 Halle, Germany
| | - Peter Efimov
- Herbarium, Komarov Botanical Institute of Russian Academy of Sciences, Prof. Popov str. 2, 197376 Saint-Petersburg, Russia
| | - Mikael Hedrén
- Department of Biology, University of Lund, Solvegatan 37, SE-22362 Lund, Sweden
| | | | - Karel Kreutz
- Oude Landgraaf 35a, NL-6373 Landgraaf, The Netherlands
| | - Tiiu Kull
- Department of Botany, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 5, EE-51014 Tartu, Estonia
| | - Kadri Tali
- Department of Botany, Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Kreutzwaldi 5, EE-51014 Tartu, Estonia
| | | | - Manel Rey
- Institute of Systematic Botany, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
| | - Florian P. Schiestl
- Institute of Systematic Botany, University of Zürich, Zollikerstrasse 107, CH-8008 Zürich, Switzerland
| | - Vladislav Čurn
- Biotechnological Centre, Faculty of Agriculture, University of South Bohemia in České Budějovice, CZ-370 05 České Budějovice, Czech Republic
| | - Jan Suda
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic and Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
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Mráz P, Španiel S, Keller A, Bowmann G, Farkas A, Šingliarová B, Rohr RP, Broennimann O, Müller-Schärer H. Anthropogenic disturbance as a driver of microspatial and microhabitat segregation of cytotypes of Centaurea stoebe and cytotype interactions in secondary contact zones. ANNALS OF BOTANY 2012; 110:615-27. [PMID: 22730023 PMCID: PMC3400448 DOI: 10.1093/aob/mcs120] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Accepted: 04/13/2012] [Indexed: 05/23/2023]
Abstract
BACKGROUND AND AIMS In a mixed-ploidy population, strong frequency-dependent mating will lead to the elimination of the less common cytotype, unless prezygotic barriers enhance assortative mating. However, such barriers favouring cytotype coexistence have only rarely been explored. Here, an assessment is made of the mechanisms involved in formation of mixed-ploidy populations and coexistence of diploid plants and their closely related allotetraploid derivates from the Centaurea stoebe complex (Asteraceae). METHODS An investigation was made of microspatial and microhabitat distribution, life-history and fitness traits, flowering phenology, genetic relatedness of cytotypes and intercytotype gene flow (cpDNA and microsatellites) in six mixed-ploidy populations in Central Europe. KEY RESULTS Diploids and tetraploids were genetically differentiated, thus corroborating the secondary origin of contact zones. The cytotypes were spatially segregated at all sites studied, with tetraploids colonizing preferentially drier and open microhabitats created by human-induced disturbances. Conversely, they were rare in more natural microsites and microsites with denser vegetation despite their superior persistence ability (polycarpic life cycle). The seed set of tetraploid plants was strongly influenced by their frequency in mixed-ploidy populations. Triploid hybrids originated from bidirectional hybridizations were extremely rare and almost completely sterile, indicating a strong postzygotic barrier between cytotypes. CONCLUSIONS The findings suggest that tetraploids are later immigrants into already established diploid populations and that anthropogenic activities creating open niches favouring propagule introductions were the major factor shaping the non-random distribution and habitat segregation of cytotypes at fine spatial scale. Establishment and spread of tetraploids was further facilitated by their superior persistence through the perennial life cycle. The results highlight the importance of non-adaptive spatio-temporal processes in explaining microhabitat and microspatial segregation of cytotypes.
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Affiliation(s)
- Patrik Mráz
- Department of Biology, Unit of Ecology and Evolution, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland.
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Trávníček P, Dočkalová Z, Rosenbaumová R, Kubátová B, Szeląg Z, Chrtek J. Bridging global and microregional scales: ploidy distribution in Pilosella echioides (Asteraceae) in central Europe. ANNALS OF BOTANY 2011; 107:443-54. [PMID: 21208933 PMCID: PMC3043935 DOI: 10.1093/aob/mcq260] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 11/02/2010] [Accepted: 11/24/2010] [Indexed: 05/10/2023]
Abstract
BACKGROUND AND AIMS A detailed knowledge of cytotype distribution can provide important insights into the evolutionary history of polyploid systems. This study aims to explore the spatial distribution of different cytotypes in Pilosella echioides at various spatial scales (from the whole distributional range to the population level) and to outline possible evolutionary scenarios for the observed geographic pattern. METHODS DNA-ploidy levels were estimated using DAPI flow cytometry in 4410 individuals of P. echioides from 46 populations spread over the entire distribution range in central Europe. Special attention was paid to the cytotype structure in the most ploidy-diverse population in south-west Moravia. KEY RESULTS Five different cytotypes (2x, 3x, 4x, 5x and 6x) were found, the last being recorded for the first time. Although ploidy-uniform (di- or tetraploid) sites clearly prevailed, nearly one-quarter of the populations investigated harboured more (up to all five) cytotypes. Whereas penta- and hexaploids constituted only a minority of the samples, a striking predominance of the triploid cytotype was observed in several populations. CONCLUSIONS The representative sampling confirmed previous data on cytotype distribution, i.e. the spatial aggregation of mixed-ploidy populations in south-west Moravia and Lower Austria and the predominance of ploidy-uniform populations in other parts of the area investigated. Recurrent origin of polyploids from diploid progenitors via unreduced gametes and their successful establishment are considered the key factors promoting intrapopulational ploidy mixture ('primary hybrid zones'). As an alternative to the generally accepted theory of cytotype co-existence based on the development of different means of inter-ploidy reproductive isolation, it is suggested that a long-term ploidy mixture can also be maintained in free-mating populations provided that the polyploids originate with a sufficient frequency. In addition, the prevalence (or subdominance) of the triploid cytotype in several mixed-ploidy populations represents the first evidence of such a phenomenon in plant systems with exclusively sexual reproduction.
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Affiliation(s)
- Pavel Trávníček
- Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic
| | - Zuzana Dočkalová
- Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
| | - Radka Rosenbaumová
- Department of Botany, Natural History Museum, National Museum, CZ-193 00 Prague - Horní Počernice, Czech Republic
| | - Barbora Kubátová
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic
- Biotechnological Centre, Faculty of Agriculture, University of South Bohemia, CZ-370 05 České Budějovice, Czech Republic
| | - Zbigniew Szeląg
- Institute of Botany, Jagiellonian University, Kopernika 31, PL-315 01 Kraków, Poland
| | - Jindřich Chrtek
- Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
- Department of Botany, Faculty of Science, Charles University in Prague, CZ-128 01 Prague, Czech Republic
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