Euphrasia

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Tsengchieng Huang - One of the best experts on this subject based on the ideXlab platform.

  • evolution of the Euphrasia transmorrisonensis complex orobanchaceae in alpine areas of taiwan
    Journal of Biogeography, 2005
    Co-Authors: Tsengchieng Huang, Shingfa Huang, Peife Lee
    Abstract:

    Aims  To unravel isolation and differentiation of the genetic structure of the Euphrasia transmorrisonensis complex, a showy herb, among alpine regions of mountain peaks in subtropical Taiwan and to infer its evolutionary history. Location  Alpine ecosystems of high-montane regions of Taiwan. Methods  Phylogenetic analyses of the trnL intron and the trnL–trnF intergenic spacer of chloroplast (cp) DNA, and the intertranscribed spacer (ITS) of nuclear ribosomal (nr) DNA between 18S and 26S were carried out on 18 populations of the E. transmorrisonensis complex in Taiwan. Results  In total, 10 haplotypes for cpDNA and 14 haplotypes for nrDNA were detected. Three population groups located in the northern, north-eastern, and south-central regions of the Central Mountain Range (CMR) were revealed according to the frequencies of haplotypes and haplotype lineages of nrDNA. Balancing selection might have played a role in the evolution of Euphrasia in Taiwan. Main conclusions  By integrating the spatial-genetic patterns of cpDNA and nrDNA, two possible evolutionary histories of Euphrasia in Taiwan were inferred. The favourable hypotheses for interpreting the data suggest at least three origins of the E. transmorrisonensis complex in Taiwan, corresponding to each nuclear lineage in the northern (II), northern/north-eastern (I), and central/southern regions (III) with subsequent hybridization between lineages I and II and lineages II and III. These lineage boundaries are strengthened by the finding that haplotypes of C derived from cpDNA were found in the geographical region of lineage II of nrDNA, while haplotypes of A derived from cpDNA were found in the region of lineage III of nrDNA. Thus, the origin of chloroplasts exclusive to lineages II and III supports their long-term isolation from one another.

  • taxonomy of the Euphrasia transmorrisonensis orobanchaceae complex in taiwan based on nrits
    Taxon, 2004
    Co-Authors: Tsengchieng Huang
    Abstract:

    Species delineation in Euphrasia has long been a challenge for taxonomists. In this paper, DNA sequences are used to evaluate the morphological taxa of Taiwanese Euphrasia as well as to elucidate the phylogenetic relationship among them. ITS sequences of 147 samples of Euphrasia, one Aeginetia, and one Pedicularis from Taiwan along with nine samples of Euphrasia from abroad were studied. Six non-native species of Section Euphrasia were used as outgroups and 14 haplotypes from four taxa of Taiwanese Euphrasia, E. tarokoana Ohwi, E. nankotaizanensis Yamam., E. transmorrisonensis Hayata, and E. transmorrisonensis var. durietziana (Ohwi) T. C. Huang & M. J. Wu, served as the ingroup to reconstruct a phylogenetic tree according to the criterion of maximum parsimony. Based on the phylogenetic tree, three monophyletic haplotype lineages of the ingroup were obtained, closely correlating with geographical distributions (with some overlap in adjacent regions). However, plants of different taxa are found in the same lineage. Lineage I includes all four Taiwanese taxa, whereas lineage II includes two taxa, E. transmorrisonensis, and E. transmorrisonensis var. durietziana. Lineage III includes three taxa: E. nankotaizanensis, E. transmorrisonensis, and E. transmorrisonensis var. durietziana. Different taxa share a common haplotype. Euphrasia nankotaizanensis, E. transmorrisonensis, and E. transmorrisonensis var. durietziana share haplotype E; E. nankotaizanensis and E. transmorrisonensis share haplotype D; and E. transmorrisonensis and E. transmorrisonensis var. durietziana share haplotypes G and N. The shared haplotypes may reflect retained ancestral polymorphisms at a neutral locus (ITS) through a series of recent speciation events (lineage sorting). The nucleotide additivities are found frequently among taxa. For example, the A+B additivity pattern of E. tarokoana and E. transmorrisonensis var. durietziana could reflect hybridization. Nucleotide additivity also provided insight into reticulate relationships among populations within and between taxa. Lineage sorting and hybridization might be mechanisms driving speciation in Taiwanese Euphrasia, resulting in retention of morphology and adaptation to distinct habitats. According to ITS evidence, we reconfirm four taxa of Euphrasia in Taiwan.

Erns Vitek - One of the best experts on this subject based on the ideXlab platform.

  • book review metherell c rumsey f j eyebrights Euphrasia of the uk and ireland
    Willdenowia, 2020
    Co-Authors: Erns Vitek
    Abstract:

    Metherell C. & Rumsey F. J. [illustrated by Rumsey F. J.; edited by Edmondson J.], Eyebrights (Euphrasia) of the UK and Ireland. – BSBI Handbook No. 18. – Bristol: Botanical Society of Britain and Ireland, 2018. – ISBN 978-0-901158-53-6. – 14.8 × 21 cm, 220 pp., colour photographs & black/white line drawings, softback. – Price: GBP 17.50.

  • kommentare zur neubearbeitung der exkursionsflora von deutschland band 4 kritischer band 4 eine neue unterart von Euphrasia officinalis
    Schlechtendalia, 2013
    Co-Authors: Erns Vitek
    Abstract:

    Zusammenfassung: Vitek, E. 2002: Kommentare zur Neubearbeitung der Exkursionsflora von Deutschland, Band 4 (Kritischer Band). 4. Eine neue Unterart von Euphrasia officinalis. Schlechtendalia 8 : 15-16. Die neue Unterart Euphrasia officinalis L. subsp. versicolor (A. Kern.) Vitek comb. nov. wird in der vorliegenden Arbeit validiert und diskutiert. Abstract: Vitek, E. 2002: Comments to the revised edition of „Exkursionsflora von Deutschland, Band 4 (Kritischer Band)“. 4. A new subspecies of Euphrasia officinalis. Schlechtendalia 8 : 15-16. The new combination Euphrasia officinalis L. subsp. versicolor (A. Kern.) Vitek comb. nov. is validated and discussed in the present paper.

  • molecular phylogeny and biogeography of the bipolar Euphrasia orobanchaceae recent radiations in an old genus
    Molecular Phylogenetics and Evolution, 2008
    Co-Authors: Galina Gussarova, Erns Vitek, Magnus Popp, Christia Ochma
    Abstract:

    Euphrasia includes perennial or annual green parasitic plants, and has a disjunct bipolar distribution except for one transtropical connection across the high mountains of Oceania. The disjunction is coupled with strikingly contrasting patterns of morphological diversity between the southern and northern hemispheres, making it an exciting model to study processes of evolutionary diversification which shaped present floras. We inferred the relationships among 51 species representing 14 of the 15 sections of the genus based on nrDNA ITS and cpDNA trnL intron, trnL-trnF and atpB-rbcL intergenic spacers. Maximum parsimony and Bayesian inference support monophyly of the genus and of several intrageneric groups characterized by morphology, ploidy level, and geographic range. Molecular phylogenetic dating using Bayesian "relaxed" clock methods suggests that the earliest Euphrasia radiations occurred minimum 11-8 Mya with bipolarity being achieved 7-5 Mya. Biogeographic analyses using explicit model-based approach inferred Eurasia as an ancestral area for the genus. The most parsimonious reconstruction found by a dispersal-vicariance analysis requires 17 dispersals to account for the current biogeographic pattern and supports Eurasian origin for Euphrasia. Both long-distance dispersal and across land vicariance can be invoked to explain the diversification in the genus, which experienced rapid radiations driven by new ecological opportunities of the late Pliocene and Pleistocene but also retained a set of local endemic or relict species of an earlier origin.

  • Euphrasia amurensis e hirtella var ramosa and var karoiana orobanchaceae
    Botanical Journal of the Linnean Society, 2007
    Co-Authors: Galina Gussarova, Erns Vitek
    Abstract:

    The lectotype for Euphrasia hirtella var. ramosa is selected. This taxon and E. hirtella var. karoiana are compared with E. amurensis and confirmed as synonyms, corroborating Juzepcuk (1955). © 2007 The Linnean Society of London, Botanical Journal of the Linnean Society, 2007, 154, 215–223.

  • chromosomenzahlungen an Euphrasia rostkoviana scrophuiariaceae und verwandten taxa
    Flora, 1990
    Co-Authors: Erns Vitek, Michael Kieh
    Abstract:

    Summary The chromosome number of Euphrasia rostkoviana H ayne is n = 11 bzw. 2 n = 22. No irregularities in meiosis (as observed in a sterile hybrid plant of E. x trikoviana V itek or in artificial hybrids between E. alpina and E. rostkoviana or E. picta by Y eo ]976) could be found in mixed populations of E. rostkoviana s. str. and the alpine E. picta W immer (sensu Y eo 1979). Therefore it seems to be better to include the alpine „E. picta‟ in E. rostkoviana s. lat. Relationships within the group, ecological positions, and historical changes in distribution are discussed.

Ale D Twyford - One of the best experts on this subject based on the ideXlab platform.

  • maintenance of species differences in closely related tetraploid parasitic Euphrasia orobanchaceae on an isolated island
    Plant Communications, 2020
    Co-Authors: Hannes Eche, Chris Metherell, Ale D Twyford, Gavi Powell, Nick Riddiford
    Abstract:

    Abstract Polyploidy is pervasive in angiosperm evolution and plays important roles in adaptation and speciation. However, polyploid groups are understudied due to complex sequence homology, challenging genome assembly, and taxonomic complexity. Here, we study adaptive divergence in taxonomically complex eyebrights (Euphrasia), where recent divergence, phenotypic plasticity, and hybridization blur species boundaries. We focus on three closely related tetraploid species with contrasting ecological preferences that are sympatric on Fair Isle, a small isolated island in the British Isles. Using a common garden experiment, we show a genetic component to the morphological differences present between these species. Using whole-genome sequencing and a novel k-mer approach we call “Tetmer”, we demonstrate that the species are of allopolyploid origin, with a sub-genome divergence of approximately 5%. Using ∼2 million SNPs, we show sub-genome homology across species, with a very low sequence divergence characteristic of recent speciation. This genetic variation is broadly structured by species, with clear divergence of Fair Isle heathland Euphrasia micrantha, while grassland Euphrasia arctica and coastal Euphrasia foulaensis are more closely related. Overall, we show that tetraploid Euphrasia is a system of allopolyploids of postglacial species divergence, where adaptation to novel environments may be conferred by old variants rearranged into new genetic lineages.

  • maintenance of species differences in closely related tetraploid parasitic Euphrasia orobanchaceae on an isolated island
    bioRxiv, 2020
    Co-Authors: Hannes Eche, Chris Metherell, Gavi Powell, Nick Riddiford, Ale D Twyford
    Abstract:

    Polyploidy is pervasive in angiosperm evolution and plays important roles in adaptation and speciation. However, polyploid groups are understudied due to complex sequence homology, challenging genome assembly, and taxonomic complexity. Here we study adaptive divergence in taxonomically complex eyebrights (Euphrasia), where recent divergence, phenotypic plasticity and hybridisation blur species boundaries. We focus on three closely-related tetraploid species with contrasting ecological preferences, and which are sympatric on Fair Isle, a small isolated island in the British Isles. Using a common garden experiment, we show a genetic component to the morphological differences present between these species. Using whole genome sequencing and a novel k-mer approach, we demonstrate an allopolyploid origin, with sub-genome divergence of approximately 5%. Using ~2 million SNPs we show sub-genome homology across species consistent with a common origin, with very low sequence divergence characteristic of recent speciation. This genetic variation is broadly structured by species, with clear divergence of Fair Isle heathland E. micrantha, while grassland E. arctica and coastal E. foulaensis are more closely related. Overall, we show tetraploid Euphrasia is an allopolyploid system characterised by postglacial species divergence, where adaptation to novel environments may be conferred by old variants rearranged into new genetic lineages.

  • life history evolution species differences and phenotypic plasticity in hemiparasitic eyebrights Euphrasia
    American Journal of Botany, 2020
    Co-Authors: Natacha Fracho, Chris Metherell, Edga L Y Wong, Ale D Twyford
    Abstract:

    PREMISE Species delimitation in parasitic organisms is challenging because traits used to identify species are often plastic and vary depending on the host. Here, we use species from a recent radiation of generalist hemiparasitic Euphrasia to investigate trait variation and trait plasticity. We tested whether Euphrasia species show reliable trait differences, investigated whether these differences correspond to life history trade-offs between growth and reproduction, and quantified plasticity in response to host species. METHODS Common garden experiments were used to evaluate trait differences between 11 Euphrasia taxa grown on a common host, document phenotypic plasticity when a single Euphrasia species is grown on eight different hosts, and relate observations to trait differences recorded in the wild. RESULTS Euphrasia exhibited variation in life history strategies; some individuals transitioned rapidly to flowering at the expense of early season growth, while others invested in vegetative growth and delayed flowering. Life history differences were present between some species, though many related taxa lacked clear trait differences. Species differences were further blurred by phenotypic plasticity-many traits were plastic and changed with host type or between environments. CONCLUSIONS Phenotypic plasticity in response to host and environment confounds species delimitation in Euphrasia. When grown in a common garden environment, some morphologically distinct taxa can be identified, though others represent morphologically similar shallow segregates. Trait differences present between some species and populations demonstrate the rapid evolution of distinct life history strategies in response to local ecological conditions.

  • life history evolution and phenotypic plasticity in parasitic eyebrights Euphrasia orobanchaceae
    bioRxiv, 2018
    Co-Authors: Ale D Twyford, Natacha Fracho, Edga L Y Wong, Chris Metherell
    Abstract:

    Parasite lifetime reproductive success is determined by both genetic variation and phenotypically plastic life history traits that respond to host quality and external environment. In this study we use the generalist parasitic plant genus Euphrasia to test aspects of life history theory. We evaluate species life history strategies when grown on a common host, document phenotypic plasticity when grown on many different hosts, and relate our observations to trait differences recorded in the wild. We find Euphrasia in a common garden and in the field exhibit a range of life history strategies that differ between species that transition rapidly to flower at the expense of early season growth, and those that invest in vegetative growth and delay flowering. However, aspects of life history show extensive phenotypic plasticity in response to host quality, and demonstrate the costs of attaching to a low-quality host. Our experiments suggest life history strategies in a generalist parasitic plant are the product of natural selection on traits related to growth and flowering, while host quality may be a primary determinant of lifetime reproductive success.

  • dna barcoding british Euphrasia reveals deeply divergent polyploids but lack of species level resolution
    bioRxiv, 2017
    Co-Authors: Xumei Wang, Pete M Hollingsworth, Galina Gussarova, Markus Ruhsam, Natasha De Vere, Chris Metherell, Ale D Twyford
    Abstract:

    Background and aims: DNA barcoding is emerging as a useful tool not only for species identification but for studying evolutionary and ecological processes. Although plant DNA barcodes do not always provide species-level resolution, the generation of large DNA barcode datasets can provide insights into the mechanisms underlying the generation of species diversity. Here, we use DNA barcoding to study evolutionary processes in taxonomically complex British Euphrasia, a group with multiple ploidy levels, frequent self-fertilization, young species divergence and widespread hybridisation. Methods: We sequenced the core plant barcoding loci, supplemented with additional nuclear and plastid loci, in representatives of all 19 British Euphrasia species. We analyse these data in a population genetic and phylogenetic framework. We then date the divergence of haplotypes in a global Euphrasia dataset using a time-calibrated Bayesian approach implemented in BEAST. Key results: No Euphrasia species has a consistent diagnostic haplotype. Instead, haplotypes are either widespread across species, or are population specific. Nuclear genetic variation is strongly partitioned by ploidy levels, with diploid and tetraploid British Euphrasia possessing deeply divergent ITS haplotypes (DXY = 5.1%), with haplotype divergence corresponding to the late Miocene. In contrast, plastid data show no clear division by ploidy, and instead reveal weakly supported geographic patterns. Conclusions: Using standard DNA barcoding loci for species identification in Euphrasia will be unsuccessful. However, these loci provide key insights into the maintenance of genetic variation, with divergence of diploids and tetraploids suggesting that ploidy differences act as a barrier to gene exchange in British Euphrasia, with rampant hybridisation within ploidy levels. The scarcity of shared diploid-tetraploid ITS haplotypes supports the polyploids being allotetraploid in origin. Overall, these results show that even when lacking species-level resolution, DNA barcoding can reveal insightful evolutionary patterns in taxonomically complex genera.

G C French - One of the best experts on this subject based on the ideXlab platform.

  • genetics taxonomy and the conservation of british Euphrasia
    Conservation Genetics, 2008
    Co-Authors: A J Silverside, G C French, Pete M Hollingsworth, Richard A Ennos
    Abstract:

    In Britain the genus Euphrasia comprises ca 20 diploid and tetraploid plant species, including several endemics. However, their conservation is impeded by taxonomic uncertainty. Analysis of cpDNA and AFLP variation was used to assess their taxonomic status and establish the extent of barriers to gene exchange among them. Differences in ploidy level constitute a very strong barrier to genetic exchange, although this is not absolute. The diploid endemics E. vigursii and E. rivularis form morphologically and genetically definable units which show some level of reproductive isolation. Within tetraploid Euphrasia, the species showed varying degrees of distinctness. Analysis of geographically paired samples from two widespread outcrossing taxa E. arctica and E. nemorosa provides evidence for extensive genetic exchange between them. However AFLP data indicate that this outbreeding species complex possesses a gene pool distinct from that of the widespread inbreeding tetraploids. The widespread and endemic inbreeding tetraploids contain examples of morphologically and genetically definable taxa, but also species whose distinctness is more equivocal. The conservation implications of this study are that species-based action plans are potentially suitable for conservation of the diploid endemics E. vigursii and E. rivularis. In contrast we contend that a species-based conservation framework, developed with reproductively isolated and genetically distinct groups in mind, requires modification for conservation of the complex and dynamic diversity found within the tetraploids. The adoption of ‘taxonomic’ action plans, designed to protect the evolutionary processes generating Euphrasia diversity, may provide a supplementary solution for conserving this type of variation.

  • the relationship between flower size inbreeding coefficient and inferred selfing rate in british Euphrasia species
    Heredity, 2005
    Co-Authors: A J Silverside, G C French, Richard A Ennos, Pete M Hollingsworth
    Abstract:

    The relationship between flower size, inbreeding coefficient and inferred selfing rate in British Euphrasia species

  • isolation of polymorphic microsatellite markers for british Euphrasia l
    Molecular Ecology Notes, 2003
    Co-Authors: G C French, Pete M Hollingsworth, Richard A Ennos
    Abstract:

    Euphrasia species in Britain attract a large amount of conservation attention due to the recognition of numerous endemic taxa in what is essentially a species-poor flora. To develop a set of research tools to investigate the evolutionary processes underlying this diversification, a membrane enrichment procedure has been used to isolate five polymorphic microsatellite loci from Euphrasia nemorosa (Pers.) Wallr. These loci amplify polymorphic products in several other British Euphrasia species.

Annakari Kolseth - One of the best experts on this subject based on the ideXlab platform.

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