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Watanabe K, Yaneshita M, Denda T, Yokota M, Hirota SK, Suyama Y, Tsumura Y. Genetic Structure of the Liriope muscari Polyploid Complex and the Possibility of Its Genetic Disturbance in Japan. PLANTS (BASEL, SWITZERLAND) 2022; 11:3015. [PMID: 36432743 PMCID: PMC9697476 DOI: 10.3390/plants11223015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 10/28/2022] [Accepted: 11/03/2022] [Indexed: 06/16/2023]
Abstract
Anthropogenic activities, such as the movement of plants through greening, can result in genetic disturbance that can interfere with local adaptation in wild populations. Although research is underway to prevent genetic disturbance associated with greening, genetic disturbance of intraspecific polyploidy, which is estimated to be present in 24% of vascular plants, has not been well studied. Liriope muscari is a polyploid complex with known diploid (2n = 36), tetraploid (2n = 72), and hexaploid (2n = 108) forms. The plants of this species tolerate dry and hot conditions and are therefore frequently used for greening and gardening. However, the distribution of this polyploid in Japan, its genetic structure, and genetic disturbance are not known. In this study, we investigated the polyploidy distribution and genetic structure in naturally distributed L. muscari in Japan using chloroplast DNA (cpDNA) haplotypes and nuclear DNA (nDNA). Commercially produced individuals were also studied and compared with natural populations to assess any genetic disturbance of the ploidy complex in this species. Chromosome counts, cpDNA, and nDNA results showed three genetically and cytologically distinct groups in Japan: first, a tetraploid group in mainland Japan; second, a hexaploid group in the Ryukyu Islands; and third, a diploid and tetraploid group in the Ryukyu Islands. Significant isolation by distance was also detected within the three groups (p = 0.001). Genetic disturbance due to greening and gardening should be avoided among the three groups. Genetic disturbance can be reduced by using individuals derived from natural populations that are close to the sites used for greening and gardening. For commercially produced individuals, genetic disturbance is unlikely in the Kanto region, an area of high usage, while genetic disturbance is thought possible in the Ryukyu Islands.
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Affiliation(s)
- Keita Watanabe
- Graduate School of Life and Environmental Science, University of Tsukuba, Tsukuba 305-8572, Japan
- Environment Research Section Urban Engineering Research Department, Taisei Corporation, Yokohama 245-0051, Japan
| | - Makoto Yaneshita
- Environment Research Section Urban Engineering Research Department, Taisei Corporation, Yokohama 245-0051, Japan
| | - Tetsuo Denda
- Laboratory of Ecology and Systematics, Faculty of Science, University of the Ryukyus, Nishihara 903-0213, Japan
| | - Masatsugu Yokota
- Laboratory of Ecology and Systematics, Faculty of Science, University of the Ryukyus, Nishihara 903-0213, Japan
| | - Shun K. Hirota
- Botanical Gardens, Osaka Metropolitan University, Katano 576-0004, Japan
| | - Yoshihisa Suyama
- Field Science Center, Graduate School of Agricultural Science, Tohoku University, Osaki 989-6711, Japan
| | - Yoshihiko Tsumura
- Faculty of Life and Environmental Sciences, University of Tsukuba, Tsukuba 305-8786, Japan
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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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Cheng J, Li J, Zhang Z, Lu H, Chen G, Yao B, Dong Y, Ma L, Yuan X, Xu J, Zhang Y, Dai W, Yang X, Xue L, Zhang Y, Zhang C, Mauricio R, Peng G, Hu S, Valverde BE, Song X, Li Y, Stift M, Qiang S. Autopolyploidy‐driven range expansion of a temperate‐originated plant to pan‐tropic under global change. ECOL MONOGR 2021. [DOI: 10.1002/ecm.1445] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Jiliang Cheng
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Jun Li
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Zheng Zhang
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Huan Lu
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Guoqi Chen
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Beibei Yao
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Yingxue Dong
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Ling Ma
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Xiaoxiao Yuan
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Jingxuan Xu
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Ying Zhang
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Weimin Dai
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Xianghong Yang
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Lifang Xue
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Yu Zhang
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Chaobin Zhang
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Rodney Mauricio
- Department of Genetics University of Georgia Athens Georgia30602USA
| | - Gary Peng
- Agriculture and Agri‐Food Canada 107 Science Place Saskatoon SaskatchewanS7N 0X2Canada
| | - Shuijin Hu
- Department of Entomology and Plant Pathology North Carolina State University Raleigh North Carolina27695USA
- College of Resources and Environmental Sciences Nanjing Agricultural University Nanjing210095China
| | - Bernal E. Valverde
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
- College of Life Sciences University of Copenhagen Taastrup Denmark
| | - Xiaoling Song
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
| | - Yi Li
- Department of Plant Science and Landscape Architecture College of Agriculture and Natural Resources University of Connecticut Storrs Connecticut06269USA
| | - Marc Stift
- Ecology Department of Biology University of Konstanz Konstanz78457Germany
| | - Sheng Qiang
- Weed Research Laboratory Nanjing Agricultural University Nanjing210095China
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Martino M, Semple JC, Beck JB. Two cytotype niche shifts are of different magnitude in Solidago gigantea. AMERICAN JOURNAL OF BOTANY 2020; 107:1567-1576. [PMID: 33150610 DOI: 10.1002/ajb2.1556] [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: 04/29/2020] [Accepted: 07/06/2020] [Indexed: 06/11/2023]
Abstract
PREMISE Polyploidy may serve to contribute to range size if autopolyploid cytotypes are adapted to differing ecological conditions. This study aims to establish the geographic distribution of cytotypes within the giant goldenrod (Solidago gigantea), and to assess whether cytotypes exhibit differing ecological tolerances and morphology. METHODS A range-wide set of 629 Solidago gigantea individuals was obtained through field collecting, sampling from herbarium specimens, and incorporating existing chromosome counts. Cytotype of each unknown sample was estimated by observing allele numbers at twelve microsatellite loci, a strategy that was assessed by comparing estimated to known cytotype in 20 chromosome-counted samples. Abiotic ecological differentiation was assessed for two transitions: diploid-tetraploid and tetraploid-hexaploid. Morphological differentiation among cytotypes was assessed. RESULTS Microsatellite repeat variation accurately estimated cytotype in 85% of samples for which ploidy was known. Applying this approach to samples of unknown ploidy established that the three cytotypes are non-randomly distributed. Although niche modeling and MANOVA approaches identified significant differences in macro-climatic conditions for both cytotype transitions, the tetraploid to hexaploid transition was more substantial. Leaf length and width did not differ among cytotypes. Although leaf vestiture exhibited strong trends, no absolute differences were observed among cytotypes. CONCLUSIONS With the largest such study to date, we established niche transitions among giant goldenrod cytotypes of differing magnitudes. Collectively, this suggests that whole-genome duplication has contributed to Solidago gigantea's large range.
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Affiliation(s)
- Maria Martino
- Department of Biological Sciences, Wichita State University, 537 Hubbard Hall, Wichita, Kansas, 67260, USA
| | - John C Semple
- Department of Biology, University of Waterloo, Waterloo, Ontario, NL2 3G1, Canada
| | - James B Beck
- Department of Biological Sciences, Wichita State University, 537 Hubbard Hall, Wichita, Kansas, 67260, USA
- Botanical Research Institute of Texas, 1700 University Drive, Fort Worth, Texas, 76107, USA
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Castro M, Loureiro J, Husband BC, Castro S. The role of multiple reproductive barriers: strong post-pollination interactions govern cytotype isolation in a tetraploid-octoploid contact zone. ANNALS OF BOTANY 2020; 126:991-1003. [PMID: 32353869 PMCID: PMC7596367 DOI: 10.1093/aob/mcaa084] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/23/2020] [Indexed: 05/13/2023]
Abstract
BACKGROUND AND AIMS Polyploidy is an important contributor to sympatric speciation and assortative mating is a key mechanism driving cytotype interactions in contact zones. While strong reproductive barriers can mediate the coexistence of different cytotypes in sympatry, positive frequency-dependent mating disadvantage ultimately drives the transition to single-ploidy populations. However, comprehensive estimates of reproductive isolation among cytotypes and across multiple barriers are rare. We quantify the strength of isolation across multiple reproductive stages in a tetraploid-octoploid contact zone to understand the potential for coexistence. METHODS Assortative mating due to flowering asynchrony, pollinator behaviour, morphological overlap, self-fertilization and gametic competition between tetraploid and octoploid Gladiolus communis in a contact zone in the Western Iberian Peninsula were assessed in natural and experimental populations to quantify reproductive isolation (RI) between cytotypes. KEY RESULTS Tetraploids and octoploids have a high degree of overlap in flowering time and similar floral morphology, and are visited by generalist insects without cytotype foraging preferences, resulting in weak pre-pollination RI (from 0.00 to 0.21). In contrast, post-pollination isolation resulting from gametic selection was a strong barrier to inter-cytotype mating, with ploidy composition in stigmatic pollen loads determining the levels of RI (from 0.54 to 1.00). Between-cytotype cross-incompatibility was relatively high (RI from 0.54 to 0.63) as was isolation acquired through self-pollination (RI of 0.59 in tetraploids and 0.39 in octoploids). CONCLUSIONS Total RI was high for both tetraploids (from 0.90 to 1.00) and octoploids (from 0.78 to 0.98). Such high rates of assortative mating will enable cytotype coexistence in mixed-ploidy populations by weakening the impacts of minority cytotype exclusion. This study reveals the key role of gametic selection in cytotype siring success and highlights the importance of comprehensive estimates across multiple reproductive barriers to understand cytotype interactions at contact zones.
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Affiliation(s)
- Mariana Castro
- University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, Calçada Martim de Freitas, Coimbra, Portugal
| | - João Loureiro
- University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, Calçada Martim de Freitas, Coimbra, Portugal
| | - Brian C Husband
- Department of Integrative Biology, University of Guelph, Guelph, Ontario, Canada
| | - Sílvia Castro
- University of Coimbra, Centre for Functional Ecology, Department of Life Sciences, Calçada Martim de Freitas, Coimbra, Portugal
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Christie K, Strauss SY. Frequency-dependent fitness and reproductive dynamics contribute to habitat segregation in sympatric jewelflowers. Proc Biol Sci 2020; 287:20200559. [PMID: 32396796 DOI: 10.1098/rspb.2020.0559] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Coexistence results from a complex suite of past and contemporary processes including biogeographic history, adaptation, ecological interactions and reproductive dynamics. Here we explore drivers of local micro-parapatry in which two closely related and reproductively isolated Streptanthus species (jewelflower, Brassicaceae) inhabit continuous or adjacent habitat patches and occur within seed dispersal range, yet rarely overlap in fine-scale distribution. We find some evidence for abiotic niche partitioning and local adaptation, however differential survival across habitats cannot fully explain the scarcity of coexistence. Competition may also reduce the fitness of individuals migrating into occupied habitats, yet its effects are insufficient to drive competitive exclusion. Experimental migrants suffered reduced seed production and seed viability at sites occupied by heterospecifics, and we infer that heterospecific pollen transfer by shared pollinators contributes to wasted gametes when the two congeners come into contact. A minority disadvantage may reduce effective colonization of patches already occupied by heterospecifics, even when habitat patches are environmentally suitable. Differential adaptation and resource competition have often been evoked as primary drivers of habitat segregation in plants, yet negative reproductive interactions-including reproductive interference and decreased fecundity among low-frequency migrants-may also contribute to non-overlapping distributions of related species along local tension zones.
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Affiliation(s)
- Kyle Christie
- Department of Evolution and Ecology, and Center for Population Biology, University of California Davis, One Shields Avenue, Davis CA 95616-5270, USA
| | - Sharon Y Strauss
- Department of Evolution and Ecology, and Center for Population Biology, University of California Davis, One Shields Avenue, Davis CA 95616-5270, USA
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Castro M, Loureiro J, Figueiredo A, Serrano M, Husband BC, Castro S. Different Patterns of Ecological Divergence Between Two Tetraploids and Their Diploid Counterpart in a Parapatric Linear Coastal Distribution Polyploid Complex. FRONTIERS IN PLANT SCIENCE 2020; 11:315. [PMID: 32265966 PMCID: PMC7098452 DOI: 10.3389/fpls.2020.00315] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Accepted: 03/03/2020] [Indexed: 05/24/2023]
Abstract
Polyploidization is a widespread mechanism of evolutionary divergence in flowering plants. Ecological divergence of polyploid lineages has been proposed as a key process shaping the distribution of cytotypes in nature (niche shift hypothesis); however, evidence for the role of niche separation in replicated diploid-polyploid species pairs is still needed. This study aimed to assess the role of abiotic factors shaping current cytotype distributions. For that, we examined the distribution and environmental niches of two varieties recognized in diploid-tetraploid Jasione maritima across the species range and within a putative contact zone on the Iberian Peninsula. We counted chromosomes, screened for ploidy across Iberian Peninsula and characterized environmental requirements using niche modeling tools. We found that J. maritima var. maritima is composed by diploids with disjunct distribution in the west coast of France and northwest Iberian Peninsula, and by tetraploids in Iberian Peninsula, while var. sabularia is tetraploid. In the Iberian Peninsula, two parapatric contact zones along a linear coastal distribution were detected, one between diploid and tetraploid var. maritima, and the other between tetraploids of the two varieties. Environmental variables of diploid populations from France are distinct from those of southern diploid populations, which are more similar to tetraploids. In general, niche modeling results are congruent with the observed distribution patterns, although the results suggest a wider contact zone between varieties and cytotypes. Tetraploids of both varieties revealed different degrees of environmental divergence in comparison with their diploid counterpart. Tetraploid var. sabularia differed environmentally from diploids suggesting niche divergence. In contrast, tetraploid var. maritima overlapped with diploid environmental niche and currently occupies its entire predicted range, whereas diploids are restricted to northern areas of their suitable environment. Differences in ecological envelopes facilitate the recognition of functional units of biodiversity within polyploid groups, allowing the study of factors related to post-polyploidization divergence. Thus, whereas changes in environmental requirements may have allowed tetraploid var. sabularia to spread in habitats not favorable to diploids, other factors are involved with the distribution of diploid and tetraploid var. maritima.
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Affiliation(s)
- Mariana Castro
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - João Loureiro
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - Albano Figueiredo
- Centre for Studies in Geography and Spatial Planning, Department of Geography and Tourism, Faculty of Arts and Humanities, University of Coimbra, Coimbra, Portugal
| | - Miguel Serrano
- Department of Botany, Faculty of Pharmacy, University of Santiago de Compostela, Santiago de Compostela, Spain
| | - Brian C. Husband
- Department of Integrative Biology, University of Guelph, Guelph, ON, Canada
| | - Sílvia Castro
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
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Decanter L, Colling G, Elvinger N, Heiðmarsson S, Matthies D. Ecological niche differences between two polyploid cytotypes of Saxifraga rosacea. AMERICAN JOURNAL OF BOTANY 2020; 107:423-435. [PMID: 32067225 PMCID: PMC7216898 DOI: 10.1002/ajb2.1431] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 12/04/2019] [Indexed: 05/30/2023]
Abstract
PREMISE Different cytotypes of a species may differ in their morphology, phenology, physiology, and their tolerance of extreme environments. We studied the ecological niches of two subspecies of Saxifraga rosacea with different ploidy levels: the hexaploid Central European endemic subspecies sponhemica and the more widely distributed octoploid subspecies rosacea. METHODS For both cytotypes, we recorded local environmental conditions and mean plant trait values in populations across their areas of distribution, analyzed their distributions by niche modeling, studied their performance at two transplant sites with contrasting conditions, and experimentally tested their cold resistance. RESULTS Mean annual temperature was higher in hexaploid than in octoploid populations and experiments indicated that frost tolerance of the hexaploid is lower than that of the octoploid. Reproduction of octoploids from Central Europe was higher than that of hexaploids at a transplant site in subarctic Iceland, whereas the opposite was true in temperate Luxembourg, indicating adaptation of the octoploids to colder conditions. Temperature variables were also most important in niche models predicting the distribution of the two cytotypes. Genetic differences in survival among populations were larger for the octoploids than for the hexaploids in both field gardens, suggesting that greater genetic variability may contribute to the octoploid's larger distributional range. CONCLUSIONS Our results support the hypotheses that different cytotypes may have different niches leading to spatial segregation, and that higher ploidy levels can result in a broader ecological niche and greater tolerance of more extreme conditions.
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Affiliation(s)
- Lucile Decanter
- Fondation Faune‐Flore c/o Musée national d'histoire naturelle25 rue MünsterL‐2160LuxembourgLuxembourg
- Population Biology and EvolutionMusée national d'histoire naturelle25 rue MunsterL‐2160LuxembourgLuxembourg
- Unit of Plant EcologyDepartment of BiologyUniversity of MarburgKarl‐von‐Frisch‐Straße 8D‐35043MarburgGermany
| | - Guy Colling
- Population Biology and EvolutionMusée national d'histoire naturelle25 rue MunsterL‐2160LuxembourgLuxembourg
| | - Nora Elvinger
- Population Biology and EvolutionMusée national d'histoire naturelle25 rue MunsterL‐2160LuxembourgLuxembourg
| | - Starri Heiðmarsson
- The Icelandic Institute of Natural HistoryBorgir vid Nordurslod600AkureyriIceland
| | - Diethart Matthies
- Unit of Plant EcologyDepartment of BiologyUniversity of MarburgKarl‐von‐Frisch‐Straße 8D‐35043MarburgGermany
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From sympatry to parapatry: a rapid change in the spatial context of incipient allochronic speciation. Evol Ecol 2019. [DOI: 10.1007/s10682-019-10021-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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10
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Christie K, Strauss SY. Reproductive isolation and the maintenance of species boundaries in two serpentine endemic Jewelflowers. Evolution 2019; 73:1375-1391. [PMID: 31152435 DOI: 10.1111/evo.13767] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/28/2019] [Accepted: 05/03/2019] [Indexed: 12/30/2022]
Abstract
Speciation occurs when reproductive barriers substantially reduce gene flow between lineages. Understanding how specific barriers contribute to reproductive isolation offers insight into the initial forces driving divergence and the evolutionary and ecological processes responsible for maintaining diversity. Here, we quantified multiple pre- and post-pollination isolating barriers in a pair of closely related California Jewelflowers (Streptanthus, Brassicaceae) living in an area of sympatry. S. breweri and S. hesperidis are restricted to similar serpentine habitats; however, populations are spatially isolated at fine-scales and rarely co-occur in intermixed stands. Several intrinsic postzygotic barriers were among the strongest we quantified, yet, postzygotic barriers currently contribute little to overall reproductive isolation due to the cumulative strength of earlier-acting extrinsic barriers, including spatial isolation, and flowering time and pollinator differences. Data from multiple years suggest that pre-pollination barriers may have different strengths depending on annual environmental conditions. Similarly, crossing data suggest that the strength of intrinsic isolation may vary among different population pairs. Estimates of total reproductive isolation in S. breweri and S. hesperidis are robust to uncertainty and variability in individual barrier strength estimates, demonstrating how multiple barriers can act redundantly to prevent gene flow between close relatives living in sympatry.
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Affiliation(s)
- Kyle Christie
- UC Davis Department of Evolution and Ecology, and Center for Population Biology, University of California, One Shields Avenue, Davis, California, 95616
| | - Sharon Y Strauss
- UC Davis Department of Evolution and Ecology, and Center for Population Biology, University of California, One Shields Avenue, Davis, California, 95616
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Liu K, Meng W, Zheng L, Wang L, Zhou S. Cytogeography and chromosomal variation of the endemic East Asian herb Lycoris radiata. Ecol Evol 2019; 9:6849-6859. [PMID: 31380020 PMCID: PMC6662380 DOI: 10.1002/ece3.5252] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 12/17/2018] [Accepted: 02/22/2019] [Indexed: 01/16/2023] Open
Abstract
Information on the spatial distribution of cytotypes and karyotype variation in plants is critical for studies of the origin and evolution of polyploid complexes. Here, the spatial distribution of cytological races and intraspecific variation in the karyotype of Lycoris radiata, an endemic species to East Asia, is investigated. Conventional karyotype analysis methods were used to determine ploidy level and karyotypical characteristics in 2,420 individuals from 114 populations of L. radiata nearly covering the whole distribution areas in China. Of 114 populations studied, 52 (45.61%), 58 (50.88%), and 4 (3.51%) are diploid, triploid, and mixoploid populations, respectively, with 1,224, 1,195, and 1 individuals being diploid, triploid, and tetraploid, respectively. The triploid possesses a much wider distribution range than the diploid, with the former almost occupying the entire range of this complex species in East Asia and the latter distributing in the middle and east regions of China. Triploids tend to occur at high altitudes, and the relationship between the ploidy and altitude is significantly positive but low (r 2 = 0.103, p < 0.01). About 98.6% of examined bulbs have a common karyotype consisting of 22 or 33 acrocentric (A) chromosomes. Some aberrant chromosomes which should be generated from A-type chromosome have been found including metacentrics (m), small metacentrics (m'), and B-type chromosome. The results can provide a fundamental cytogeographic data for further studies on the evolutionary origins and adaptive divergences of polyploids, especially the triploid, within L. radiata using molecular and/or ecological methods in the future.
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Affiliation(s)
- Kun Liu
- Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological ResourcesCollege of Life SciencesAnhui Normal UniversityWuhuChina
| | - Weiqi Meng
- Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological ResourcesCollege of Life SciencesAnhui Normal UniversityWuhuChina
| | - Lu Zheng
- Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological ResourcesCollege of Life SciencesAnhui Normal UniversityWuhuChina
| | - Lida Wang
- Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological ResourcesCollege of Life SciencesAnhui Normal UniversityWuhuChina
| | - Shoubiao Zhou
- Anhui Provincial Key Laboratory of the Conservation and Exploitation of Biological ResourcesCollege of Life SciencesAnhui Normal UniversityWuhuChina
- Anhui Provincial Engineering Laboratory of Water and Soil Pollution Control and RemediationCollege of Environmental Science and EngineeringAnhui Normal UniversityWuhuChina
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12
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Bigl K, Paule J, Dobeš C. The morphometrics of autopolyploidy: insignificant differentiation among sexual-apomictic cytotypes. AOB PLANTS 2019; 11:plz028. [PMID: 31198530 PMCID: PMC6548344 DOI: 10.1093/aobpla/plz028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 03/11/2019] [Accepted: 05/22/2019] [Indexed: 06/09/2023]
Abstract
Polyploidization of the plant genome affects the phenotype of individuals including their morphology, i.e. size and form. In autopolyploids, we expect mainly nucleotypic effects, from a number of monoploid genomes (i.e. chromosome sets) or genome size, seen from an increase in size or dimension of the polyploids compared with the diploids (or lower ploids). To identify nucleotypic effects, confounding effects of hybridity (observed in allopolyploids), postpolyploidization processes or environmental effects need to be considered. We morphometrically analysed five ploidy cytotypes of the sexual-apomictic species Potentilla puberula cultivated ex situ under the same experimental conditions. Sexuals are mainly tetraploid, while higher ploidy (penta- to octoploidy) is typically associated with the expression of apomixis. The cytotypes likely arose via autopolyploidization although historic involvement of another species in the origin of apomicts cannot be fully ruled out, suggested by a slight molecular differentiation among reproductive modes. We (i) revisited molecular differentiation using amplified fragment length polymorphisms and performed a morphometric analysis to test (ii) if cytotypes are morphologically differentiated from each other and (iii) if the size of individuals is related to their ploidy. Weak molecular differentiation of sexual versus apomictic individuals was confirmed. Cytotypes and reproductive modes were also morphologically poorly differentiated from each other, i.e. apomicts largely resampled the variation of the sexuals and did not exhibit a unique morphology. Overall size of individuals increased moderately but significantly with ploidy (ca. 14 % in the comparison of octo- with tetraploids). The results support an autopolyploid origin of the P. puberula apomicts and suggest a nucleotypic effect on overall plant size. We discuss taxonomic consequences of the results in the context of data on reproductive relationships among cytotypes and their ecological preferences and evolutionary origin, and conclude that cytotypes are best treated as intraspecific variants within a single species.
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Affiliation(s)
- Karin Bigl
- Department of Pharmacognosy, Pharmacobotany, University of Vienna, Althanstrasse, Vienna, Austria
| | - Juraj Paule
- Department of Botany and Molecular Evolution, Senckenberg Research Institute & Natural History Museum Frankfurt, Senckenberganlage, Frankfurt/Main, Germany
| | - Christoph Dobeš
- Department of Pharmacognosy, Pharmacobotany, University of Vienna, Althanstrasse, Vienna, Austria
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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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Čertner M, Sudová R, Weiser M, Suda J, Kolář F. Ploidy-altered phenotype interacts with local environment and may enhance polyploid establishment in Knautia serpentinicola (Caprifoliaceae). THE NEW PHYTOLOGIST 2019; 221:1117-1127. [PMID: 30221362 DOI: 10.1111/nph.15426] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 07/24/2018] [Indexed: 06/08/2023]
Abstract
Whole genome duplication is a key process in plant evolution and has direct phenotypic consequences. However, it remains unclear whether ploidy-related phenotypic changes can significantly alter the fitness of polyploids in nature and thus contribute to establishment of new polyploid mutants in diploid populations. We addressed this question using a unique natural system encompassing a diploid and its sympatric locally established autotetraploid derivative. By setting a common garden experiment with two manipulated environmental factors (presence/absence of serpentine substrate and competition), we tested whether these two locally important factors differently shape the phenotypic response of the two ploidy levels. Tetraploids attained significantly higher values of both above- and below-ground biomass, and root : shoot ratio compared to their diploid progenitors. Tetraploid superiority in vegetative fitness indicators was most prominent when they were cultivated together with a competitor in nutrient-rich nonserpentine substrate. We show that even genetically very closely related diploids and tetraploids can respond differently to key environmental factors. Provided there are sufficient nutrients, tetraploids can be more successful in tolerating interspecific competition than their diploid progenitors. Such superior performance might have provided an adaptive advantage for the newly established tetraploid promoting colonisation of new (micro-)habitats, which was indeed observed at the natural site.
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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
| | - Radka Sudová
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
| | - Martin Weiser
- Department of Botany, Faculty of Science, Charles University, Benátská 2, CZ-128 00, Prague, 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
| | - 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
- Institute of Botany, University of Innsbruck, AT-6020, Innsbruck, Austria
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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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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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Muñoz-Pajares AJ, Perfectti F, Loureiro J, Abdelaziz M, Biella P, Castro M, Castro S, Gómez JM. Niche differences may explain the geographic distribution of cytotypes in Erysimum mediohispanicum. PLANT BIOLOGY (STUTTGART, GERMANY) 2018; 20 Suppl 1:139-147. [PMID: 28741843 DOI: 10.1111/plb.12605] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2017] [Accepted: 07/18/2017] [Indexed: 05/26/2023]
Abstract
Polyploidisation has played an important role in plant diversification, and variation in ploidy level may be found not only between species of the same genus, but also within a single species. Although establishing the adaptive significance of polyploidy to explain the geographic distribution of cytotypes is challenging, the occurrence of different cytotypes in different ecological niches may suggest an adaptive role of genome duplication. We studied the adaptive significance of the geographic distribution of cytotypes across the entire distribution range of the endemic Erysimum mediohispanicum (Brassicaceae). For that, we have used climate variables, population elevation and soil properties to model ecological niches for the different cytotypes. In addition, we analysed the effect that ploidy level has on the floral phenotype. We found a clear geographic pattern in the distribution of cytotypes, with diploid individuals occurring in the southernmost part of the distribution range, while tetraploids were found in the northern area. A contact (mosaic) zone between both cytotypes was identified, but diploids and tetraploids occur in sympatry in only one population (although in a highly unbalanced proportion). Gene flow between different cytotypes seems to be negligible, as evident from an almost complete absence of triploids and other minority cytotypes. Niches occupied by both cytotypes showed subtle, but significant differences, even in the contact zone. Precipitation was higher in regions occupied by tetraploid individuals, which present wider corolla tubes and thinner but taller stalks than diploids. Our findings highlight the potential role of polyploidy in the ecological adaptation of E. mediohispanicum to both abiotic factors and biotic interactions.
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Affiliation(s)
- A J Muñoz-Pajares
- Plant Biology, CIBIO/InBio, Centro de Investigação em Biodiversidade e Recursos Genéticos, Laboratório Associado, Universidade do Porto, Vairão, Portugal
- Departamento de Genetica, Universidad de Granada, Granada, Spain
| | - F Perfectti
- Departamento de Genetica, Universidad de Granada, Granada, Spain
| | - J Loureiro
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - M Abdelaziz
- Departamento de Genetica, Universidad de Granada, Granada, Spain
| | - P Biella
- Departamento de Ecologıa, Universidad de Granada, Granada, Spain
- Department of Zoology, Faculty of Science, University of South Bohemia, České Budějovice, Czech Republic
- Institute of Entomology, Biology Centre of the Academy of Sciences of the Czech Republic, České Budějovice, Czech Republic
| | - M Castro
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - S Castro
- Centre for Functional Ecology, Department of Life Sciences, University of Coimbra, Coimbra, Portugal
| | - J M Gómez
- Departamento de Ecologıa, Universidad de Granada, Granada, Spain
- Estación Experimental de Zonas Aridas (EEZA-CSIC), Almería, Spain
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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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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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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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Casazza G, Boucher FC, Minuto L, Randin CF, Conti E. Do floral and niche shifts favour the establishment and persistence of newly arisen polyploids? A case study in an Alpine primrose. ANNALS OF BOTANY 2017; 119:81-93. [PMID: 28025287 PMCID: PMC5218380 DOI: 10.1093/aob/mcw221] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 07/29/2016] [Accepted: 09/10/2016] [Indexed: 05/31/2023]
Abstract
BACKGROUND AND AIMS Polyploidization plays a key role in plant evolution. Despite the generally accepted 'minority-cytotype exclusion' theory, the specific mechanisms leading to successful establishment and persistence of new polyploids remain controversial. The majority of newly formed polyploids do not become established, because they are less common, have fewer potential mates or may not be able to compete successfully with co-occurring progenitors at lower ploidy levels. Changes in floral traits and ecological niches have been proposed as important mechanisms to overcome this initial frequency-dependent disadvantage. The aim of this study was to determine whether dodecaploids of the heterostylous P. marginata differ from their hexaploid progenitors in P. marginata and P. allionii for selected floral traits and ecological preferences that might be involved in establishment and persistence, providing a possible explanation for the origin of polyploidized populations. METHODS Floral morphological traits and ecological niche preferences among dodecaploids and their hexaploid progenitors in P. marginata and P. allionii ,: all restricted to the south-western Alps, were quantified and compared KEY RESULTS: Differences in floral traits were detected between dodecaploids and their closest relatives, but such differences might be too weak to counter the strength of minority cytotype disadvantage and are unlikely to enable the coexistence of different cytotypes. Furthermore, the results suggest the preservation of full distyly and no transition to selfing in dodecaploids. Finally, dodecaploids occur almost exclusively in environments that are predicted to be suitable also for their closest hexaploid relatives. CONCLUSIONS In light of the results, P. marginata dodecaploids have probably been able to establish and persist by occupying geographical areas not yet filled by their closest relatives without significant evolution in their climatic and pollination niches. Dispersal limitation and minority-cytotype exclusion probably maintain their current range disjunct from those of its close relatives.
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Affiliation(s)
- Gabriele Casazza
- DISTAV, University of Genoa, Corso Europa 26, I-16132 Genoa, Italy
| | - Florian C Boucher
- Department of Systematic and Evolutionary Botany and Botanic Garden, University of Zurich, Zollikerstrasse 107, CH-8008 Zurich, Switzerland
- Department of Botany and Zoology, University of Stellenbosch, Private Bag X1, Matieland 7602, South Africa
| | - Luigi Minuto
- DISTAV, University of Genoa, Corso Europa 26, I-16132 Genoa, Italy
| | - Christophe F Randin
- Department of Ecology & Evolution, University of Lausanne, Biophore, CH-1015 Lausanne, Switzerland
| | - Elena Conti
- Department of Systematic and Evolutionary Botany and Botanic Garden, University of Zurich, Zollikerstrasse 107, CH-8008 Zurich, Switzerland
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Cuba-Díaz M, Cerda G, Rivera C, Gómez A. Genome size comparison in Colobanthus quitensis populations show differences in species ploidy. Polar Biol 2016. [DOI: 10.1007/s00300-016-2058-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Guo W, Yang J, Sun XD, Chen GJ, Yang YP, Duan YW. Divergence in Eco-Physiological Responses to Drought Mirrors the Distinct Distribution of Chamerion angustifolium Cytotypes in the Himalaya-Hengduan Mountains Region. FRONTIERS IN PLANT SCIENCE 2016; 7:1329. [PMID: 27630654 PMCID: PMC5005327 DOI: 10.3389/fpls.2016.01329] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Accepted: 08/18/2016] [Indexed: 05/08/2023]
Abstract
Polyploid species generally occupy harsher habitats (characterized by cold, drought and/or high altitude) than diploids, but the converse was observed for Chamerion angustifolium, in which diploid plants generally inhabit higher altitudes than their polyploid derivatives. Plants at high altitudes may experience cold-induced water stress, and we therefore examined the physiological responses of diploid and hexaploid C. angustifolium to water stress to better understand the ecological differentiation of plants with different ploidy levels. We conducted a common garden experiment by subjecting seedlings of different ploidy levels to low, moderate, and severe water stress. Fourteen indicators of physiological fitness were measured, and the anatomical characteristics of the leaves of each cytotype were determined. Both cytotypes were influenced by drought, and diploids exhibited higher fitness in terms of constant root:shoot ratio (R:S ratio) and maximum quantum yield of PS II (Fv/Fm ), less reduced maximal photosynthetic rate (A max), transpiration rate (E), intercellular CO2 concentration (C i) and stomatal conductance (g s), and higher long-term water use efficiency (WUEL) under severe water stress than did hexaploids. Analysis of leaf anatomy revealed morphological adjustments for tolerating water deficiency in diploids, in the form of closely packed mesophyll cells and small conduits in the midvein. Our results indicate that diploid C. angustifolium is more tolerant of drought than hexaploid plants, ensuring the successful survival of the diploid at high altitudes. This eco-physiological divergence may facilitate the species with different cytotypes to colonize new and large geographic ranges with heterogeneous environmental conditions.
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Affiliation(s)
- Wen Guo
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- University of the Chinese Academy of SciencesBeijing, China
- Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
| | - Jie Yang
- School of Life Sciences, Yunnan Normal UniversityKunming, China
| | - Xu-Dong Sun
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
| | - Guang-Jie Chen
- Key Laboratory of Plateau Lake Ecology and Global Change, School of Tourism and Geography, Yunnan Normal UniversityKunming, China
| | - Yong-Ping Yang
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
| | - Yuan-Wen Duan
- Key Laboratory for Plant Diversity and Biogeography of East Asia, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
- Institute of Tibetan Plateau Research at Kunming, Kunming Institute of Botany, Chinese Academy of SciencesKunming, China
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McAllister CA, Miller AJ. Single nucleotide polymorphism discovery via genotyping by sequencing to assess population genetic structure and recurrent polyploidization in Andropogon gerardii. AMERICAN JOURNAL OF BOTANY 2016; 103:1314-1325. [PMID: 27466055 DOI: 10.3732/ajb.1600146] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Accepted: 06/27/2016] [Indexed: 06/06/2023]
Abstract
PREMISE OF THE STUDY Autopolyploidy, genome duplication within a single lineage, can result in multiple cytotypes within a species. Geographic distributions of cytotypes may reflect the evolutionary history of autopolyploid formation and subsequent population dynamics including stochastic (drift) and deterministic (differential selection among cytotypes) processes. Here, we used a population genomic approach to investigate whether autopolyploidy occurred once or multiple times in Andropogon gerardii, a widespread, North American grass with two predominant cytotypes. METHODS Genotyping by sequencing was used to identify single nucleotide polymorphisms (SNPs) in individuals collected from across the geographic range of A. gerardii. Two independent approaches to SNP calling were used: the reference-free UNEAK pipeline and a reference-guided approach based on the sequenced Sorghum bicolor genome. SNPs generated using these pipelines were analyzed independently with genetic distance and clustering. KEY RESULTS Analyses of the two SNP data sets showed very similar patterns of population-level clustering of A. gerardii individuals: a cluster of A. gerardii individuals from the southern Plains, a northern Plains cluster, and a western cluster. Groupings of individuals corresponded to geographic localities regardless of cytotype: 6x and 9x individuals from the same geographic area clustered together. CONCLUSIONS SNPs generated using reference-guided and reference-free pipelines in A. gerardii yielded unique subsets of genomic data. Both data sets suggest that the 9x cytotype in A. gerardii likely evolved multiple times from 6x progenitors across the range of the species. Genomic approaches like GBS and diverse bioinformatics pipelines used here facilitate evolutionary analyses of complex systems with multiple ploidy levels.
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Affiliation(s)
- Christine A McAllister
- Department of Biology and Natural Resources, Principia College, Elsah, Illinois 62028 USA
| | - Allison J Miller
- Department of Biology, Saint Louis University, St. Louis, Missouri 63130 USA
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Mandák B, Vít P, Krak K, Trávníček P, Havrdová A, Hadincová V, Zákravský P, Jarolímová V, Bacles CFE, Douda J. Flow cytometry, microsatellites and niche models reveal the origins and geographical structure of Alnus glutinosa populations in Europe. ANNALS OF BOTANY 2016; 117:107-20. [PMID: 26467247 PMCID: PMC4701152 DOI: 10.1093/aob/mcv158] [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: 01/08/2015] [Accepted: 09/01/2015] [Indexed: 05/11/2023]
Abstract
BACKGROUND AND AIMS Polyploidy in plants has been studied extensively. In many groups, two or more cytotypes represent separate biological entities with distinct distributions, histories and ecology. This study examines the distribution and origins of cytotypes of Alnus glutinosa in Europe, North Africa and western Asia. METHODS A combined approach was used involving flow cytometry and microsatellite analysis of 12 loci in 2200 plants from 209 populations combined with species distribution modelling using MIROC and CCSM climatic models, in order to analyse (1) ploidy and genetic variation, (2) the origin of tetraploid A. glutinosa, considering A. incana as a putative parent, and (3) past distributions of the species. KEY RESULTS The occurrence of tetraploid populations of A. glutinosa in Europe is determined for the first time. The distribution of tetraploids is far from random, forming two geographically well-delimited clusters located in the Iberian Peninsula and the Dinaric Alps. Based on microsatellite analysis, both tetraploid clusters are probably of autopolyploid origin, with no indication that A. incana was involved in their evolutionary history. A projection of the MIROC distribution model into the Last Glacial Maximum (LGM) showed that (1) populations occurring in the Iberian Peninsula and North Africa were probably interconnected during the LGM and (2) populations occurring in the Dinaric Alps did not exist throughout the last glacial periods, having retreated southwards into lowland areas of the Balkan Peninsula. CONCLUSIONS Newly discovered tetraploid populations are situated in the putative main glacial refugia, and neither of them was likely to have been involved in the colonization of central and northern Europe after glacial withdrawal. This could mean that neither the Iberian Peninsula nor the western part of the Balkan Peninsula served as effective refugial areas for northward post-glacial expansion of A. glutinosa.
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Affiliation(s)
- Bohumil Mandák
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic; Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, Praha 6-Suchdol, CZ-165 21, Czech Republic;
| | - Petr Vít
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic; Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, Praha 6-Suchdol, CZ-165 21, Czech Republic
| | - Karol Krak
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic; Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, Praha 6-Suchdol, CZ-165 21, Czech Republic
| | - Pavel Trávníček
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic; Faculty of Agriculture, University of South Bohemia, Studentská 13, CZ-370 05, České Budějovice, Czech Republic and
| | - Alena Havrdová
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic; Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, Praha 6-Suchdol, CZ-165 21, Czech Republic
| | - Věroslava Hadincová
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
| | - Petr Zákravský
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
| | - Vlasta Jarolímová
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic
| | - Cecile Fanny Emilie Bacles
- University of Pau and Pays Adour, UFR Sciences et Techniques, Departement de Biologie, F-64100 Pau, France
| | - Jan Douda
- Institute of Botany, The Czech Academy of Sciences, Zámek 1, CZ-252 43, Průhonice, Czech Republic; Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Kamýcká 129, Praha 6-Suchdol, CZ-165 21, Czech Republic
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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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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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29
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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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Odee DW, Wilson J, Omondi S, Perry A, Cavers S. Rangewide ploidy variation and evolution in Acacia senegal: a north-south divide? AOB PLANTS 2015; 7:plv011. [PMID: 25680798 PMCID: PMC4363475 DOI: 10.1093/aobpla/plv011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Knowledge of rangewide variation in DNA content and ploidy level may be valuable in understanding the evolutionary history of a species. Recent studies of Acacia senegal report diploids and occasional tetraploids in the Sudano-Sahelian region of sub-Saharan Africa, but nothing is known about the overall extent of DNA ploidy variation within the species. In this study, we determine the DNA content and ploidy level of A. senegal across its native range, and explore whether the variation is related to its evolutionary and colonization history. We used propidium iodide flow cytometry (FCM) to estimate DNA content (2C value) and infer ploidy in 157 individuals from 54 populations on various tissues, using seeds, fresh leaves, dried leaves and twigs and herbarium specimens. The mean 2C DNA (pg ± s.d.) contents detected were 1.47 ± 0.09, 2.12 ± 0.02, 2.89 ± 0.12, and a single individual with 4.51 pg, corresponding to a polyploid series of diploid, triploid, tetraploid and hexaploid individuals. Diploids were confirmed by chromosome counts (2n = 2x = 26). Most populations (90.7 %) were of single ploidy level, while mixed ploidy populations (9.3 %) comprising mostly diploids (2x+3x, 2x+4x and 2x+6x) were restricted to the Sudano-Sahelian and Indian subcontinent regions, its northern range. The species is predominantly diploid, and no mixed ploidy populations were detected in east and southern Africa, its southern range. The geographic pattern of ploidy variation in conjunction with existing phylogeographic and phylogenetic data of the species suggests that polyploids have occurred multiple times in its evolutionary and recent colonization history, including contemporary ecological timescales. The successful use of external tissues of dried twigs in FCM is new, and presents the opportunity to study numerous other dryland woody species.
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Affiliation(s)
- David W Odee
- Kenya Forestry Research Institute, PO Box 20412-00200, Nairobi, Kenya Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB, UK
| | - Julia Wilson
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB, UK
| | - Stephen Omondi
- Kenya Forestry Research Institute, PO Box 20412-00200, Nairobi, Kenya
| | - Annika Perry
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB, UK
| | - Stephen Cavers
- Centre for Ecology and Hydrology, Bush Estate, Penicuik, Midlothian EH26 0QB, UK
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31
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McAllister C, Blaine R, Kron P, Bennett B, Garrett H, Kidson J, Matzenbacher B, Glotzbach A, Miller AJ. Environmental correlates of cytotype distribution in Andropogon gerardii (Poaceae). AMERICAN JOURNAL OF BOTANY 2015; 102:92-102. [PMID: 25587152 DOI: 10.3732/ajb.1400296] [Citation(s) in RCA: 7] [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
UNLABELLED • PREMISE OF THE STUDY Information about geographic distribution of cytotypes can provide insight into the origin and maintenance of autopolyploid complexes and builds a foundation for understanding cytotype differentiation and the dynamics of mixed-ploidy populations. Here, we investigate environmental correlates of the geographic distributions of 6x and 9x individuals in the ecologically dominant grass Andropogon gerardii to examine the role of climate in shaping patterns of cytotype distribution in this species.• METHODS Flow cytometry was used to estimate ploidy level in 352 individuals from 32 populations across North America. Ecological differentiation of cytotypes was tested by relating BIOCLIM variables to cytotype distribution using principal components analysis and partial linear regression.• KEY RESULTS Broad geographic sampling confirmed two primary cytotypes-6x (hexaploid) and 9x (enneaploid)-and revealed that 9x plants are more common than previously thought. Enneaploids occur frequently in the southern portions of the range, with hexaploids dominating in northern regions. Mixed-ploidy populations were common (46.9%). Principal components analysis and partial linear regression indicated that reduced summer precipitation and increased variation in diurnal and seasonal temperature range were significant predictors of the frequency of 9x plants in a population.• CONCLUSIONS Results indicate that (1) geographic distribution of 6x and 9x individuals is nonrandom; (2) environmental variables are associated with cytotype distribution in A. gerardii; and (3) nearly half of populations surveyed include both 6x and 9x individuals. The persistence of mixed-ploidy populations may reflect a combination of recurrent polyploid formation and the prevalence of clonal reproduction.
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Affiliation(s)
- Christine McAllister
- Principia College, Department of Biology and Natural Resources, Elsah, Illinois 62028 USA Saint Louis University, Department of Biology, 3507 Macelwane Hall, St. Louis, Missouri 63103 USA
| | - Russell Blaine
- Southern Illinois University, Edwardsville, 1 Hairpin Drive, Edwardsville, Illinois 62025 USA
| | - Paul Kron
- University of Guelph, Department of Integrative Biology, 50 Stone Road East, Guelph, Ontario, Canada, NIG 2W1
| | - Brent Bennett
- Principia College, Department of Biology and Natural Resources, Elsah, Illinois 62028 USA
| | - Heidi Garrett
- Principia College, Department of Biology and Natural Resources, Elsah, Illinois 62028 USA
| | - Jennifer Kidson
- Principia College, Department of Biology and Natural Resources, Elsah, Illinois 62028 USA
| | - Blanda Matzenbacher
- Principia College, Department of Biology and Natural Resources, Elsah, Illinois 62028 USA
| | - Anna Glotzbach
- Principia College, Department of Biology and Natural Resources, Elsah, Illinois 62028 USA
| | - Allison J Miller
- Saint Louis University, Department of Biology, 3507 Macelwane Hall, St. Louis, Missouri 63103 USA
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32
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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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Geographical separation of diploid and triploid cytotypes of Allium scorodoprasum in Lithuania. Biologia (Bratisl) 2013. [DOI: 10.2478/s11756-013-0186-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Weiss-Schneeweiss H, Emadzade K, Jang TS, Schneeweiss G. Evolutionary consequences, constraints and potential of polyploidy in plants. Cytogenet Genome Res 2013; 140:137-50. [PMID: 23796571 PMCID: PMC3859924 DOI: 10.1159/000351727] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Polyploidy, the possession of more than 2 complete genomes, is a major force in plant evolution known to affect the genetic and genomic constitution and the phenotype of an organism, which will have consequences for its ecology and geography as well as for lineage diversification and speciation. In this review, we discuss phylogenetic patterns in the incidence of polyploidy including possible underlying causes, the role of polyploidy for diversification, the effects of polyploidy on geographical and ecological patterns, and putative underlying mechanisms as well as chromosome evolution and evolution of repetitive DNA following polyploidization. Spurred by technological advances, a lot has been learned about these aspects both in model and increasingly also in nonmodel species. Despite this enormous progress, long-standing questions about polyploidy still cannot be unambiguously answered, due to frequently idiosyncratic outcomes and insufficient integration of different organizational levels (from genes to ecology), but likely this will change in the near future. See also the sister article focusing on animals by Choleva and Janko in this themed issue.
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Affiliation(s)
- H. Weiss-Schneeweiss
- Department of Systematic and Evolutionary Botany University of Vienna, Rennweg 14 AT–1030 Vienna (Austria)
| | - K. Emadzade
- Department of Systematic and Evolutionary Botany University of Vienna, Rennweg 14 AT–1030 Vienna (Austria)
| | - T.-S. Jang
- Department of Systematic and Evolutionary Botany University of Vienna, Rennweg 14 AT–1030 Vienna (Austria)
| | - G.M. Schneeweiss
- Department of Systematic and Evolutionary Botany University of Vienna, Rennweg 14 AT–1030 Vienna (Austria)
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Huang H, Tong Y, Zhang QJ, Gao LZ. Genome size variation among and within Camellia species by using flow cytometric analysis. PLoS One 2013; 8:e64981. [PMID: 23724111 PMCID: PMC3664571 DOI: 10.1371/journal.pone.0064981] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Accepted: 04/19/2013] [Indexed: 02/04/2023] Open
Abstract
BACKGROUND The genus Camellia, belonging to the family Theaceae, is economically important group in flowering plants. Frequent interspecific hybridization together with polyploidization has made them become taxonomically "difficult taxa". The DNA content is often used to measure genome size variation and has largely advanced our understanding of plant evolution and genome variation. The goals of this study were to investigate patterns of interspecific and intraspecific variation of DNA contents and further explore genome size evolution in a phylogenetic context of the genus. METHODOLOGY/PRINCIPAL FINDINGS The DNA amount in the genus was determined by using propidium iodide flow cytometry analysis for a total of 139 individual plants representing almost all sections of the two subgenera, Camellia and Thea. An improved WPB buffer was proven to be suitable for the Camellia species, which was able to counteract the negative effects of secondary metabolite and generated high-quality results with low coefficient of variation values (CV) <5%. Our results showed trivial effects on different tissues of flowers, leaves and buds as well as cytosolic compounds on the estimation of DNA amount. The DNA content of C. sinensis var. assamica was estimated to be 1C = 3.01 pg by flow cytometric analysis, which is equal to a genome size of about 2940 Mb. CONCLUSION Intraspecific and interspecific variations were observed in the genus Camellia, and as expected, the latter was larger than the former. Our study suggests a directional trend of increasing genome size in the genus Camellia probably owing to the frequent polyploidization events.
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Affiliation(s)
- Hui Huang
- Key Laboratory of Biodiversity and Biogeography, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species in Southwest China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
| | - Yan Tong
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species in Southwest China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Qun-Jie Zhang
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species in Southwest China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
- University of the Chinese Academy of Sciences, Beijing, China
| | - Li-Zhi Gao
- Plant Germplasm and Genomics Center, Germplasm Bank of Wild Species in Southwest China, Kunming Institute of Botany, Chinese Academy of Sciences, Kunming, China
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Severns PM, Bradford E, Liston A. Whole genome duplication in a threatened grassland plant and the efficacy of seed transfer zones. DIVERS DISTRIB 2012. [DOI: 10.1111/ddi.12004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
| | - Emma Bradford
- Department of Botany and Plant Pathology; Oregon State University; Corvallis; OR; USA
| | - Aaron Liston
- Department of Botany and Plant Pathology; Oregon State University; Corvallis; OR; USA
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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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Fehlberg SD, Ferguson CJ. Intraspecific cytotypic variation and complicated genetic structure in the Phlox amabilis-P. woodhousei (Polemoniaceae) complex. AMERICAN JOURNAL OF BOTANY 2012; 99:865-874. [PMID: 22523347 DOI: 10.3732/ajb.1100540] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
PREMISE OF THE STUDY Polyploidy is widely recognized as an important process in the evolution of plants, but less attention has been paid to the study of intraspecific polyploidy, including its prevalence, formation, taxonomic implications, and effect on genetic diversity, structure, and gene flow within and among individuals and populations. Here we studied intraspecific ploidy level variation in the Phlox amabilis-P. woodhousei complex to determine the amount and distribution of cytotypic and genetic variation present and measure the extent of gene flow among species, cytotypes, and populations. METHODS Flow cytometry and microsatellite analyses were used to ascertain cytotypic variation, genetic diversity, and population structure within and among eight populations of P. amabilis and 10 populations of P. woodhousei from Arizona and New Mexico. KEY RESULTS Our analyses support the recognition of P. amabilis and P. woodhousei as two distinct species. Both species exhibit cytotypic variation with geographically structured diploid, tetraploid, and hexaploid populations, and genetic analyses suggest a combination of auto- and allopolyploidy in their formation. Diploid, tetraploid, and most hexaploid populations within species share much of their genetic variation, while some hexaploid populations are genetically distinct. All populations maintain moderately high genetic diversity and connectivity, and genetic structure is strongly influenced by geography. CONCLUSIONS This study highlights the potential for complicated patterns of genetic variation relative to cytotypic variation and provides evidence for the role of cytotypic variation and geographic isolation in shaping diversity, differentiation, and potentially speciation in the P. amabilis-P. woodhousei complex.
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Affiliation(s)
- Shannon D Fehlberg
- Desert Botanical Garden, 1201 North Galvin Parkway, Phoenix, Arizona 85008, USA
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Manzaneda AJ, Rey PJ, Bastida JM, Weiss-Lehman C, Raskin E, Mitchell-Olds T. Environmental aridity is associated with cytotype segregation and polyploidy occurrence in Brachypodium distachyon (Poaceae). THE NEW PHYTOLOGIST 2012; 193:797-805. [PMID: 22150799 PMCID: PMC3257369 DOI: 10.1111/j.1469-8137.2011.03988.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
• The ecological and adaptive significance of plant polyploidization is not well understood and no clear pattern of association between polyploid frequency and environment has emerged. Climatic factors are expected to predict cytotype distribution. However, the relationship among climate, cytotype distribution and variation of abiotic stress tolerance traits has rarely been examined. • Here, we use flow cytometry and root-tip squashes to examine the cytotype distribution in the temperate annual grass Brachypodium distachyon in 57 natural populations distributed across an aridity gradient in the Iberian Peninsula. We further investigate the link between environmental aridity, ploidy, and variation of drought tolerance and drought avoidance (flowering time) traits. • Distribution of diploids (2n = 10) and allotetraploids (2n = 30) in this species is geographically structured throughout its range in the Iberian Peninsula, and is associated with aridity gradients. Importantly, after controlling for geographic and altitudinal effects, the link between aridity and polyploidization occurrence persisted. Water-use efficiency varied between ploidy levels, with tetraploids being more efficient in the use of water than diploids under water-restricted growing conditions. • Our results indicate that aridity is an important predictor of polyploid occurrence in B. distachyon, suggesting a possible adaptive origin of the cytotype segregation.
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Affiliation(s)
- Antonio J. Manzaneda
- Departamento Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Paraje las Lagunillas s/n, 23071, Jaén, Spain
- Institute for Genome Sciences and Policy, Department of Biology, Duke University, PO Box 90338, Durham, North Carolina 27708, USA
| | - Pedro J. Rey
- Departamento Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Paraje las Lagunillas s/n, 23071, Jaén, Spain
| | - Jesús M. Bastida
- Departamento Biología Animal, Biología Vegetal y Ecología, Universidad de Jaén, Paraje las Lagunillas s/n, 23071, Jaén, Spain
| | - Christopher Weiss-Lehman
- Institute for Genome Sciences and Policy, Department of Biology, Duke University, PO Box 90338, Durham, North Carolina 27708, USA
| | - Evan Raskin
- Institute for Genome Sciences and Policy, Department of Biology, Duke University, PO Box 90338, Durham, North Carolina 27708, USA
| | - Thomas Mitchell-Olds
- Institute for Genome Sciences and Policy, Department of Biology, Duke University, PO Box 90338, Durham, North Carolina 27708, USA
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Collins AR, Naderi R, Mueller-Schaerer H. Competition between cytotypes changes across a longitudinal gradient in Centaurea stoebe (Asteraceae). AMERICAN JOURNAL OF BOTANY 2011; 98:1935-1942. [PMID: 22081415 DOI: 10.3732/ajb.1100063] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
PREMISE OF THE STUDY Polyploidy resulting from whole genome duplication has contributed to the adaptive evolution of many plant species. However, the conditions necessary for successful polyploid evolution and subsequent establishment and persistence in sympatry with diploid progenitors are often quite limited. One condition thought to be necessary for establishment is a substantial competitive superiority of the polyploid. METHODS We conducted a pairwise competition experiment using diploid and tetraploid cytotypes of Centaurea stoebe L. to determine whether (1) tetraploids have greater competitive ability than diploids, (2) cytotypes from mixed-cytotype populations have more balanced competitive abilities than single-cytotype populations, and (3) competitive abilities change along a longitudinal gradient. KEY RESULTS Across sampling localities, tetraploids did not produce greater aboveground biomass than diploids but suffered from greater intracytotypic competition. Tetraploids allocated greater biomass belowground than diploids, regardless of competition treatment, and had greater performance for traits associated with long-term persistence (bolted more frequently and produced more accessory rosettes). Competitive ability of tetraploids did not differ between single- and mixed-cytotype populations but varied along a longitudinal gradient. Tetraploids were stronger intercytotypic competitors in Western Europe (Switzerland and Germany) than in Eastern Europe (Hungary and Slovakia), which indicates that cytotype coexistence may be more likely in Eastern Europe, the proposed origin of tetraploids, than in Western Europe. CONCLUSIONS Our study addresses the importance of examining competitive interactions between cytotypes across their distributional range, as competitive interactions were not consistent across sampling localities.
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Affiliation(s)
- Alexandra R Collins
- University of Fribourg, Ecology and Evolution Department, Fribourg, Switzerland.
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Ecogeographic isolation: a reproductive barrier between species and between cytotypes in Houstonia (Rubiaceae). Evol Ecol 2011. [DOI: 10.1007/s10682-011-9539-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Abstract
Although verbal theories of speciation consider landscape changes, ecological speciation is usually modelled in a fixed geographical arrangement. Yet landscape changes occur, at different spatio-temporal scales, due to geological, climatic or ecological processes, and these changes result in repeated divisions and reconnections of populations. We examine the effect of such landscape dynamics on speciation. We use a stochastic, sexual population model with polygenic inheritance, embedded in a landscape dynamics model (allopatry-sympatry oscillations). We show that, under stabilizing selection, allopatry easily generates diversity, but species coexistence is evolutionarily unsustainable. Allopatry produces refuges whose persistence depends on the characteristic time scales of the landscape dynamics. Under disruptive selection, assuming that sympatric speciation is impossible due to Mendelian inheritance, allopatry is necessary for ecological differentiation. The completion of reproductive isolation, by reinforcement, then requires several sympatric phases. These results demonstrate that the succession of past, current and future geographical arrangements considerably influence the speciation process.
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Affiliation(s)
- R Aguilée
- Laboratoire Écologie et Évolution, UPMC Univ Paris 06, Ecole Normale Supérieure, CNRS, Paris, France.
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Sanderson SC. Natural Polyploidization within Tetraploid and Hexaploid Populations of the Desert ShrubAtriplex confertifolia. WEST N AM NATURALIST 2011. [DOI: 10.3398/064.071.0201] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Sonnleitner M, Flatscher R, Escobar García P, Rauchová J, Suda J, Schneeweiss GM, Hülber K, Schönswetter P. Distribution and habitat segregation on different spatial scales among diploid, tetraploid and hexaploid cytotypes of Senecio carniolicus (Asteraceae) in the Eastern Alps. ANNALS OF BOTANY 2010; 106:967-77. [PMID: 20880930 PMCID: PMC2990664 DOI: 10.1093/aob/mcq192] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Revised: 07/27/2010] [Accepted: 08/24/2010] [Indexed: 05/08/2023]
Abstract
BACKGROUND AND AIMS The spatial distribution of cytotypes can provide valuable insights into evolutionary patterns of polyploid complexes. In a previous study the macro-scale distribution of the three main cytotypes in Senecio carniolicus (Asteraceae) within the Eastern Alps was characterized. Employing a roughly 12-fold extended sampling, the present study focuses on unravelling patterns of cytotype distribution on the meso- and microscale and on correlating those with ecological properties of the growing sites. METHODS DAPI flow cytometry of dried samples was used to determine DNA ploidy level in 5033 individuals from 100 populations spread over the entire Eastern Alpine distribution area of S. carniolicus. Descriptors of microhabitats as well as spatial data were recorded in the field, and analysed with a mixed-effects ANOVA. KEY RESULTS Extensive variation in DNA ploidy levels (2x, 3x, 4x, 5x, 6x, 7x, 8x, 9x) was detected. Of the main cytotypes, diploids and hexaploids were widespread and had strongly overlapping distributions resulting in the frequent occurrence of cytotype mixtures (half of the investigated populations), whereas tetraploids were disjunctly distributed and occurred in the south-west and the east of the species' distribution area. In spite of the frequent co-occurrence of cytotypes, only 1 % of the samples belonged to secondary cytotypes (3x, 5x, 7x, 8x, 9x). Diploids, tetraploids and hexaploids were altitudinally segregated, but with broad overlap. Similarly, highly significant differences in vegetation and rock cover as well as microhabitat exposure were found between the main cytotypes. CONCLUSIONS Senecio carniolicus shows a remarkable diversity of cytotypes. The distribution of the three main cytotypes (2x, 4x, 6x) has been shaped by Pleistocene glaciations to different extents. Whereas tetraploids are nearly entirely restricted to refugia, hexaploids colonized areas that were extensively glaciated. Diploid and hexaploid individuals often co-occur in mixed populations, where they are spatially and ecologically segregated at both the meso-scale (altitudinal differentiation, exposure of the growing site) and the micro-scale (cover of vegetation and bare rock). With regard to the ecological parameters investigated, the tetraploid cytotype occupies an intermediate position. The rareness of secondary cytotypes suggests the presence of strong pre- or post-zygotic mating barriers.
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Affiliation(s)
- Michaela Sonnleitner
- Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, Vienna 1030, Austria
| | - Ruth Flatscher
- Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, Vienna 1030, Austria
| | - Pedro Escobar García
- Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, Vienna 1030, Austria
| | - Jana Rauchová
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice 1, CZ-252 43, Czech Republic
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01, Czech Republic
| | - Jan Suda
- Institute of Botany, Academy of Sciences of the Czech Republic, Průhonice 1, CZ-252 43, Czech Republic
- Department of Botany, Faculty of Science, Charles University in Prague, Benátská 2, Prague, CZ-128 01, Czech Republic
| | - Gerald M. Schneeweiss
- Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, Vienna 1030, Austria
- Systematic Botany and Mycology, Ludwig-Maximilians-University Munich, Menzingerstrasse 61, D-80638 Munich, Germany
| | - Karl Hülber
- Vienna Institute for Nature Conservation & Analyses, Giessergasse 6/7, Vienna 1090, Austria
- Department of Conservation Biology, Vegetation Ecology and Landscape Ecology, University of Vienna, Rennweg 14, Vienna 1030, Austria
| | - Peter Schönswetter
- Department of Biogeography and Botanical Garden, University of Vienna, Rennweg 14, Vienna 1030, Austria
- Department of Systematics, Palynology and Geobotany, Institute of Botany, University of Innsbruck, Sternwartestrasse 15, 6020 Innsbruck, Austria
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Sudová R, Rydlová J, Münzbergová Z, Suda J. Ploidy-specific interactions of three host plants with arbuscular mycorrhizal fungi: Does genome copy number matter? AMERICAN JOURNAL OF BOTANY 2010; 97:1798-1807. [PMID: 21616819 DOI: 10.3732/ajb.1000114] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
PREMISE OF THE STUDY Polyploidy has been shown to affect different plant traits and modulate interactions between plants and other organisms, such as pollinators and herbivores. However, no information is available on whether it can also shape the functioning of mycorrhizal symbiosis. • METHODS The mycorrhizal growth response was assessed for three angiosperms with intraspecific ploidy variation. Different cytotypes of Aster amellus, Campanula gentilis, and Pimpinella saxifraga were either left uninoculated or were inoculated with arbuscular mycorrhizal (AM) fungi in a pot experiment. After 3 mo of cultivation in a greenhouse, plant growth, phosphorus concentration in the shoot biomass, and development of the AM symbiosis were evaluated. • KEY RESULTS No significant ploidy-specific differences in AM development were recorded. The inoculation led to consistently greater phosphorus uptake; however, the effect on plant growth differed considerably among plant species, populations, ploidy levels, and AM species. A salient ploidy-specific response was observed in A. amellus. Whereas diploid plants benefited from AM inoculation, the hexaploids consistently showed negative or no-growth responses (depending on the AM species). In contrast to A. amellus, no interactions between inoculation and ploidy were observed in C. gentilis and P. saxifraga. • CONCLUSIONS The first evidence is provided of a ploidy-specific response of a mycotrophic plant to AM fungi. Our results demonstrate the complexity of interaction between plants and associated AM fungi, with the ploidy level of the host plant being one component that may modulate the functioning of the symbiosis.
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Affiliation(s)
- Radka Sudová
- Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
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CIRES EDUARDO, CUESTA CANDELA, REVILLA MARÍAÁNGELES, FERNÁNDEZ PRIETO JOSÉANTONIO. Intraspecific genome size variation and morphological differentiation of Ranunculus parnassifolius (Ranunculaceae), an Alpine-Pyrenean-Cantabrian polyploid group. Biol J Linn Soc Lond 2010. [DOI: 10.1111/j.1095-8312.2010.01517.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lo EYY, Stefanović S, Dickinson TA. RECONSTRUCTING RETICULATION HISTORY IN A PHYLOGENETIC FRAMEWORK AND THE POTENTIAL OF ALLOPATRIC SPECIATION DRIVEN BY POLYPLOIDY IN AN AGAMIC COMPLEX IN CRATAEGUS (ROSACEAE). Evolution 2010; 64:3593-608. [DOI: 10.1111/j.1558-5646.2010.01063.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Duchoslav M, Šafářová L, Krahulec F. Complex distribution patterns, ecology and coexistence of ploidy levels of Allium oleraceum (Alliaceae) in the Czech Republic. ANNALS OF BOTANY 2010; 105:719-35. [PMID: 20363760 PMCID: PMC2859911 DOI: 10.1093/aob/mcq035] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2009] [Revised: 10/05/2009] [Accepted: 01/21/2010] [Indexed: 05/19/2023]
Abstract
BACKGROUND AND AIMS Despite extensive study of polyploidy, its origin, and ecogeographical differences between polyploids and their diploid progenitors, few studies have addressed ploidy-level structure and patterns of ecogeographical differentiation at various spatial scales using detailed sampling procedures. The pattern of coexistence of polyploids in the geophyte Allium oleraceum at the landscape and locality scale and their ecology were studied. METHODS Flow cytometry and root-tip squashes were used to identify the ploidy level of 4347 plants from 325 populations sampled from the Czech Republic using a stratified random sampling procedure. Ecological differentiation among ploidy levels was tested by comparing sets of environmental variables recorded at each locality. KEY RESULTS Across the entire sampling area, pentaploids (2n = 5x = 40) predominated, while hexaploids (2n = 6x = 48) and tetraploids (2n = 4x = 32) were less frequent. The distribution of tetra- and hexaploids was partially sympatric (in the eastern part) to parapatric (in the western part of the Czech Republic) whereas pentaploids were sympatric with other cytotypes. Plants of different ploidy levels were found to be ecologically differentiated and the ruderal character of cytotypes increased in the direction 4x --> 5x --> 6x with the largest realized niche differences between tetra- and hexaploids. Most populations contained only one ploidy level (77 %), 22 % had two (all possible combinations) and 1 % were composed of three ploidy levels. The majority of 4x + 5x and 5x + 6x mixed populations occurred in sympatry with uniform populations of the participating cytotypes in sites with ecologically heterogeneous or marginal environment, suggesting secondary contact between cytotypes. Some mixed 4x + 6x populations dominated by tetraploids being sympatric and intermixed with uniform 4x populations might represent primary zones of cytotype contact. Almost no mixed accessions were observed on the fine spatial scale in mixed populations. CONCLUSIONS The results provide evidence for adaptive differences among ploidy levels, which may contribute to their complex distribution pattern. The prevalence of asexual reproduction, limited dispersal and equilibrium-disrupting processes may support local coexistence of cytotypes.
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Affiliation(s)
- Martin Duchoslav
- Department of Botany, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - Lenka Šafářová
- Department of Botany, Faculty of Science, Palacký University, Šlechtitelů 11, CZ-783 71 Olomouc, Czech Republic
| | - František Krahulec
- Institute of Botany, Academy of Sciences of the Czech Republic, CZ-252 43 Průhonice, Czech Republic
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Marhold K, Kudoh H, Pak JH, Watanabe K, Spaniel S, Lihová J. Cytotype diversity and genome size variation in eastern Asian polyploid Cardamine (Brassicaceae) species. ANNALS OF BOTANY 2010; 105:249-64. [PMID: 20007978 PMCID: PMC2814755 DOI: 10.1093/aob/mcp282] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2009] [Revised: 10/05/2009] [Accepted: 10/26/2009] [Indexed: 05/09/2023]
Abstract
BACKGROUND AND AIMS Intraspecific ploidy-level variation is an important aspect of a species' genetic make-up, which may lend insight into its evolutionary history and future potential. The present study explores this phenomenon in a group of eastern Asian Cardamine species. METHODS Plant material was sampled from 59 localities in Japan and Korea, which were used in karyological (chromosome counting) and flow cytometric analyses. The absolute nuclear DNA content (in pg) was measured using propidium iodide and the relative nuclear DNA content (in arbitrary units) was measured using 4,6-diamidino-2-phenylindole fluorochrome. KEY RESULTS Substantial cytotype diversity was found, with strikingly different distribution patterns between the species. Two cytotypes were found in C. torrentis sensu lato (4x and 8x, in C. valida and C. torrentis sensu stricto, respectively), which displays a north-south geographical pattern in Japan. Hypotheses regarding their origin and colonization history in the Japanese archipelago are discussed. In Korean C. amaraeiformis, only tetraploids were found, and these populations may in fact belong to C. valida. C. yezoensis was found to harbour as many as six cytotypes in Japan, ranging from hexa- to dodecaploids. Ploidy levels do not show any obvious geographical pattern; populations with mixed ploidy levels, containing two to four cytotypes, are frequently observed throughout the range. C. schinziana, an endemic of Hokkaido, has hexa- and octoploid populations. Previous chromosome records are also revised, showing that they are largely based on misidentified material or misinterpreted names. CONCLUSIONS Sampling of multiple populations and utilization of the efficient flow cytometric approach allowed the detection of large-scale variation in ploidy levels and genome size variation attributable to aneuploidy. These data will be essential in further phylogenetic and evolutionary studies.
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Affiliation(s)
- Karol Marhold
- Institute of Botany, Slovak Academy of Sciences, Dúbravská cesta 9, SK-845 23 Bratislava, Slovak Republic.
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