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Chelsea D. Specht - One of the best experts on this subject based on the ideXlab platform.
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Gondwanan Vicariance or Dispersal in the Tropics? The Biogeographic History of the Tropical Monocot Family Costaceae (Zingiberales)
Aliso, 2017Co-Authors: Chelsea D. SpechtAbstract:Costaceae are a pantropical family, distinguished from other families within the order Zingiberales by their spiral phyllotaxy and showy labellum comprised of five fused staminodes. While the majority of Costaceae species are found in the neotropics, the pantropical distribution of the family as a whole could be due to a number of historical biogeographic scenarios, including continental-drift mediated vicariance and long-distance dispersal events. Here, the hypothesis of an ancient Gondwanan distribution followed by vicariance via continental drift as the leading cause of the current pantropical distribution of Costaceae is tested, using molecular dating of cladogenic events combined with phylogeny-based biogeographic analyses. Dispersal-Vicariance Analysis (DIVA) is used to determine ancestral distributions based upon the modern distribution of extant taxa in a phylogenetic context. Diversification ages within Costaceae are estimated using chloroplast DNA data (trnL-F and trnK) analyzed with a local clock procedure. In the absence of fossil evidence, the divergence time between Costaceae and Zingiberaceae, as estimated in an ordinal analysis of Zingiberales, is used as the calibration point for converting relative to absolute ages. The results of the temporal analysis based on extant taxa indicate that the initial diversification within Costaceae occurred approximately 65 million years ago, long after the final break up of the Gondwanan supercontinent. Considering this minimum age of diversification, potential scenarios for the current biogeographic patterns found in Costaceae are presented in a temporal and spatial context. The evolution of specialized floral forms associated with specific pollinators is also discussed within the biogeographic framework.
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speciation dynamics and biogeography of neotropical spiral gingers Costaceae
Molecular Phylogenetics and Evolution, 2016Co-Authors: Thiago Andre, Shayla Salzman, Tânia Wendt, Chelsea D. SpechtAbstract:Species can arise via the divisive effects of allopatry as well as due to ecological and/or reproductive character displacement within sympatric populations. Two separate lineages of Costaceae are native to the Neotropics; an early-diverging clade endemic to South America (consisting of ca. 16 species in the genera Monocostus, Dimerocostus and Chamaecostus); and the Neotropical Costus clade (ca. 50 species), a diverse assemblage of understory herbs comprising nearly half of total familial species richness. We use a robust dated molecular phylogeny containing most of currently known species to inform macroevolutionary reconstructions, enabling us to examine the context of speciation in Neotropical lineages. Analyses of speciation rate revealed a significant variation among clades, with a rate shift at the most recent common ancestor of the Neotropical Costus clade. There is an overall predominance of allopatric speciation in the South American clade, as most species display little range overlap. In contrast, sympatry is much higher within the Neotropical Costus clade, independent of node age. Our results show that speciation dynamics during the history of Costaceae is strongly heterogeneous, and we suggest that the Costus radiation in the Neotropics arose at varied geographic contexts.
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monograph of african Costaceae
Blumea, 2016Co-Authors: Maasvan H De Kamer, Paul J M Maas, J J Wieringa, Chelsea D. SpechtAbstract:A taxonomic revision of the African genera of Costaceae (Costus and Paracostus) is given. Within the genus Costus 24 species are recognized, 8 of which are here described as new and one is given a new name. Included are chapters on the history of the taxonomy of the family, morphology, flower biology, pollination, dispersal, distribution, ecology, phylogeny and molecular studies and conservation. The species treatments include descriptions, full synonymy, geographical and ecological notes and taxonomic notes. For all species distribution maps are provided. A complete identification list with all exsiccatae studied and an index to scientific names is included at the end.
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evolution of species diversity in the genus chamaecostus Costaceae molecular phylogenetics and morphometric approaches
Phytotaxa, 2015Co-Authors: Thiago Andre, Chelsea D. Specht, Shayla Salzman, Clarisse Palmasilva, Tânia WendtAbstract:While most species within the genus Chamaecostus (Costaceae) are well defined, the broad geographic range and long list of synonyms associated with Chamaecostus subsessilis led us to believe there may be some cryptic species within the complex. We thus investigate the phylogenetic relationships of species in the Chamaecostus lineage and specifically test the monophyly and diversity of the Chamaecostus subsessilis species complex from a population perspective by analyzing molecular sequence data and leaf morphometrics. We interpret evolutionary trends across the entire genus based on a molecular character-based phylogenetic hypothesis that includes all currently described species of Chamaecostus . Our results show that while Chamaecostus is strongly monophyletic, C. cuspidatus is found to be sister to a clade of some but not all samples of C. subsessilis , making it necessary to acknowledge more than one species in the C. subsessilis complex. Herbarium specimens of the C. subsessilis complex could be assigned based on geographic proximity to one of the major three clades recovered in the phylogenetic analysis. Leaf morphometric measurements were performed on each of these lineages and traits were tested to detect differences among phylogenetic lineages. We conclude by proposing the recognition of a new combination, Chamaecostus acaulis , which we describe.
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Tracking the development of the petaloid fertile stamen in Canna indica: insights into the origin of androecial petaloidy in the Zingiberales
AoB PLANTS, 2013Co-Authors: Ana Maria Rocha De Almeida, Andrew Brown, Chelsea D. SpechtAbstract:Flowers of the order Zingiberales demonstrate a remarkable trend of reduction in the number of fertile stamens; from five or six fertile, filamentous stamens bearing two thecae each in Musaceae and Strelitziaceae to just a single petaloid stamen bearing a single theca in Cannaceae and Marantaceae. As one progresses from ancestral to derived floral forms, 5–6 fertile stamens are replaced by 4–5 petaloid staminodes. In Cannaceae and Costaceae, all members of the androecial whorls exhibit petaloidy, including the fertile stamen. In Costaceae, a single fertile stamen develops two thecae embedded on a broad petaloid appendage, while in Cannaceae the single fertile stamen is further reduced to a single theca with a prominent, expanded petaloid appendage. Whether petaloidy of the fertile stamen is a synapomorphy of the entire ginger clade (including Cannaceae, Costaceae, Zingiberaceae and Marantaceae), or the result of independent convergent evolution in Cannaceae, Costaceae, and some Zingiberaceae, is unclear. We combine a developmental series of the formation of the petaloid fertile stamen in Canna indica with data on the expression of B- and C-class floral organ identity genes to elucidate the organogenetic identity of the petaloid stamen and staminodes. Our data indicate that the single fertile theca in C. indica and its petaloid appendage are derived from one-half of the primordium of a single stamen, with no contribution from the remaining part of the stamen (i.e. the second theca primordium) which aborts early in development. The petaloid appendage expands later, and develops from the position of the filament/connective of the developing theca. Floral identity gene expression shows that petal identity genes (i.e. B-class genes) are expressed in all floral organs studied while C-class gene AG-1 is expressed in an increasing gradient from sepals to gynoecium, and AG-2 is expressed in all floral organs except the petals. The canonical model for molecular specification of floral organ identity is not sufficient to explain petaloidy in the androecial whorl in Canna sp. Further studies understanding the regulation of gene networks are required.
Douglas W Schemske - One of the best experts on this subject based on the ideXlab platform.
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adaptation to seasonal drought in two closely related species of neotropical costus Costaceae
Biotropica, 2019Co-Authors: Grace F. Chen, Douglas W SchemskeAbstract:Seasonal drought has been shown to greatly influence the distributions and species composition of plants in tropical rain forests. By conducting a series of field, greenhouse, and growth chamber experiments, we examined how Costus villosissimus, a forest edge species, has adapted to drought and differentiated from C. allenii, its closely related species in the understory. We hypothesize that delayed seed germination and high drought tolerance may lead to habitat differentiation and thus reproductive isolation between closely related plant species in the tropics. Abstract in Spanish is available with online material.
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ecological differentiation and local adaptation in two sister species of neotropical costus Costaceae
Ecology, 2015Co-Authors: Grace F. Chen, Douglas W SchemskeAbstract:Reciprocal transplant experiments have often provided evidence of local adaptation in temperate plants, but few such studies have been conducted in the tropics. To enhance our knowledge of local adaptation in tropical plants, we studied natural populations of two recently diverged Neotropical plant species, Costus allenii and C. villosissimus, in central Panama. We found that these species display a parapatric distribution that reflects local environmental differences on a fine geographic scale: C. allenii is found along ravines in the understory of primary forest, while C. villosissimus is found along forest edges. Light availability was lower in C. allenii habitats, while precipitation and soil moisture were lower in C. villosissimus habitats. We carried out reciprocal transplant experiments with seeds and clones of mature plants to test the hypothesis that the parapatric distribution of these species is due to divergent adaptation to their local habitats. We found strong evidence of local adaptation, i...
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rapid speciation and the evolution of hummingbird pollination in neotropical costus subgenus costus Costaceae evidence from nrdna its and ets sequences
American Journal of Botany, 2005Co-Authors: Kathleen M Kay, Douglas W Schemske, Patrick A Reeves, Richard G OlmsteadAbstract:We estimate phylogenetic relationships and the biogeographic and pollination history of Costus subgenus Costus (Costaceae) using sequence data from the internal and external transcribed spacer (ITS and ETS) regions of 18S‐26S nuclear ribosomal DNA. The African members of the subgenus form a series of lineages basal to a monophyletic neotropical species radiation. The neotropical species have large, showy flowers visited by either euglossine bees or hummingbirds. The hummingbird pollination syndrome is supported as a derived character state from the bee pollination syndrome, and we estimate that it has evolved independently seven or more times in the neotropics. A molecular clock approach suggests that diversification of the neotropical clade has been recent and rapid and that it coincides with dramatic climatic and geologic changes, Andean orogeny, and the closing of the Panama isthmus that occurred in the Pliocene and Pleistocene epochs. We propose a scenario for the diversification of Costus, in which rapid floral adaptation in geographic isolation and range shifts in response to environmental changes contribute to reproductive isolation among close relatives. We suggest that these processes may be common in other recently diversified plant lineages centered in Central America or the Northern Andean phytogeographic region.
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pollinator assemblages and visitation rates for 11 species of neotropical costus Costaceae
Biotropica, 2003Co-Authors: Kathleen M Kay, Douglas W SchemskeAbstract:Most plant species in tropical forests are pollinated by animals, and yet the diversity and specificity of pollinator assemblages are poorly documented. Here, we investigated pollinator relationships for 11 species of understory herbs in the genus Costus, with the goal of documenting visitation rates and pollinator assemblages among a variety of habitats. For a subset of species, we documented pollinator visitation for multiple years and/or multiple sites to examine temporal and spatial variation in pollinator relationships. Furthermore, we examined the extent to which specialization in pollination systems can contribute to reproductive isolation for sympatric species. Each species was primarily pollinated by either euglossine bees or hummingbirds. Total visitation rates were generally low, averaging 3.2 visits per flower per hour for bee-pollinated species and 0.5 visits per flower per hour for hummingbird-pollinated species. All of the higher elevation species studied were hummingbird-pollinated, while low elevation species were pollinated either by euglossine bees or hummingbirds. Spatial and temporal variation in visitation rates and pollinator identities was minimal. Pollinator specificity was found to contribute strongly to reproductive isolation for the 11 pairwise combinations of sympatric species differing in pollination syndrome, in some cases functioning as a complete barrier to potential pollen flow.
Raphael Sanzio Pimenta - One of the best experts on this subject based on the ideXlab platform.
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multiloci identification of diaporthe fungi isolated from the medicinal plant costus spiralis jacq roscoe Costaceae
Journal of Applied Microbiology, 2018Co-Authors: Diângeli Soares, D P De Oliveira, T Dos T Santos, P G Marson, Raphael Sanzio PimentaAbstract:AIMS The purpose of this study is to identify species from genus Diaporthe associated with a medicinal plant Costus spiralis by ITS, EF 1-α, TUB and CAL gens. METHODS AND RESULTS The 30 isolates from the genus Diaporthe associated with the medicinal plant Costus spiralis were characterized based on morphological characters and the microculture technique and grouped by DNA fingerprinting with the ISSP gene. Afterwards, a total of 12 isolates were selected for the identification of the species based on the comparative research on the blast through the sequences of the ITS gene. Phylogenetic Tree of Maximum Likelihood were generated with the ITS gene individually and with the genes ITS, TUB, CAL and EF1-α combined with the Diaporthe species recognized and with the additional sequences obtained from GenBank for these species. CONCLUSIONS It was not possible to characterize the 30 isolates microscopically and macromorphologically through the microculture technique and the macromorphological characteristics. The 12 isolates selected based on the DNA fingerprinting profile identified phylogenetically, revealed five distinct species of Diaporthe which are present in C. spiralis. SIGNIFICANCE AND IMPACT OF THE STUDY The molecular analyses used in this study are excellent alternatives for species-level identification of Diaporthe associated with medicinal plants.
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chemical assessment and antimicrobial and antioxidant activities of endophytic fungi extracts isolated from costus spiralis jacq roscoe Costaceae
Evidence-based Complementary and Alternative Medicine, 2014Co-Authors: Poliana Guerino Marson Ascencio, Sergio Donizeti Ascencio, Aline Aires Aguiar, Adriana Fiorini, Raphael Sanzio PimentaAbstract:Costus spiralis (Costaceae) is a species native to the Amazon region and is used in traditional medicine. The endophytic fungi used in this study were obtained from leaves of this plant. 13 strains were selected to obtain hydroethanolic extracts and were submitted to hydroalcoholic extraction and evaluated for antioxidant activity by DPPH (2,2-difenil-1-picrilhidrazil) and FRAP (ferric reducing antioxidant power), and all of the fungi had positive results. The antimicrobial action of crude extracts had a good range of activities. All extracts had inhibitory activities against the yeasts of Candida albicans and C. parapsilosis, with 125 to 500 μg/mL MIC. Eight extracts had antimicrobial activities against Bacillus subtilis (MIC from 62.4 to 125 μg/mL), 5 against Pseudomonas aeruginosa (MIC from 125 to 500 μg/mL), 2 against Salmonella enterica (MIC from 125 to 62.5 μg/mL), and 2 against Enterococcus faecalis (MIC from 500 to 125 μg/mL). The presence of secondary metabolites, including coumarins, was observed during chemical evaluation by thin layer chromatography. Total phenol content was estimated, and a strong positive correlation to antioxidant activity was observed, according to its Pearson coefficient. This is the first report of the bioactive potential of endophytic fungi isolated from the Costaceae family in Brazilian ecosystems.
Grace F. Chen - One of the best experts on this subject based on the ideXlab platform.
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adaptation to seasonal drought in two closely related species of neotropical costus Costaceae
Biotropica, 2019Co-Authors: Grace F. Chen, Douglas W SchemskeAbstract:Seasonal drought has been shown to greatly influence the distributions and species composition of plants in tropical rain forests. By conducting a series of field, greenhouse, and growth chamber experiments, we examined how Costus villosissimus, a forest edge species, has adapted to drought and differentiated from C. allenii, its closely related species in the understory. We hypothesize that delayed seed germination and high drought tolerance may lead to habitat differentiation and thus reproductive isolation between closely related plant species in the tropics. Abstract in Spanish is available with online material.
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ecological differentiation and local adaptation in two sister species of neotropical costus Costaceae
Ecology, 2015Co-Authors: Grace F. Chen, Douglas W SchemskeAbstract:Reciprocal transplant experiments have often provided evidence of local adaptation in temperate plants, but few such studies have been conducted in the tropics. To enhance our knowledge of local adaptation in tropical plants, we studied natural populations of two recently diverged Neotropical plant species, Costus allenii and C. villosissimus, in central Panama. We found that these species display a parapatric distribution that reflects local environmental differences on a fine geographic scale: C. allenii is found along ravines in the understory of primary forest, while C. villosissimus is found along forest edges. Light availability was lower in C. allenii habitats, while precipitation and soil moisture were lower in C. villosissimus habitats. We carried out reciprocal transplant experiments with seeds and clones of mature plants to test the hypothesis that the parapatric distribution of these species is due to divergent adaptation to their local habitats. We found strong evidence of local adaptation, i...
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Sexual isolation in two bee-pollinated Costus (Costaceae)
Plant Reproduction, 2013Co-Authors: Grace F. ChenAbstract:Examining reproductive isolating barriers is essential for understanding processes of speciation. Sexual isolation has been shown to contribute to speciation in many sympatric taxa; however, its role in parapatric taxa with reduced interspecific gene flow is poorly understood. I investigated the extent of sexual isolation in two closely related Neotropical understory species, Costus allenii and C. villosissimus , that occur in adjacent habitats within flight distance of their shared pollinators, euglossine bees. Pollination arrays were used to test whether individual pollinators travel between species, to estimate the proportion of hetero- and conspecific pollen deposited on the stigmas, and to examine the proportion of hybrid progeny. In comparison to C. allenii , C. villosissimus produces flowers with larger labella, longer stamen–labellum distances, and longer styles. Pollinators visited both species but preferred C. villosissimus . This preference caused pollinator isolation in C. villosissimus . In C. allenii , the frequency of heterospecific pollinator transitions was not less common than that of conspecific transitions, but floral mechanical isolation greatly reduced the likelihood of heterospecific pollen deposition. The contribution of gametic isolation was not strong in either species. Based on data for pollinator isolation, floral mechanical isolation, and gametic isolation, it appears that sexual isolation is weak in C. allenii , restricting heterospecific gene flow by 25 %, but moderate in C. villosissimus , where gene flow from C. allenii is reduced by 70 %. Further research will estimate the magnitude of other isolation barriers to determine the relative contribution of sexual isolation to total isolation in this parapatric species pair.
Diângeli Soares - One of the best experts on this subject based on the ideXlab platform.
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multiloci identification of diaporthe fungi isolated from the medicinal plant costus spiralis jacq roscoe Costaceae
Journal of Applied Microbiology, 2018Co-Authors: Diângeli Soares, D P De Oliveira, T Dos T Santos, P G Marson, Raphael Sanzio PimentaAbstract:AIMS The purpose of this study is to identify species from genus Diaporthe associated with a medicinal plant Costus spiralis by ITS, EF 1-α, TUB and CAL gens. METHODS AND RESULTS The 30 isolates from the genus Diaporthe associated with the medicinal plant Costus spiralis were characterized based on morphological characters and the microculture technique and grouped by DNA fingerprinting with the ISSP gene. Afterwards, a total of 12 isolates were selected for the identification of the species based on the comparative research on the blast through the sequences of the ITS gene. Phylogenetic Tree of Maximum Likelihood were generated with the ITS gene individually and with the genes ITS, TUB, CAL and EF1-α combined with the Diaporthe species recognized and with the additional sequences obtained from GenBank for these species. CONCLUSIONS It was not possible to characterize the 30 isolates microscopically and macromorphologically through the microculture technique and the macromorphological characteristics. The 12 isolates selected based on the DNA fingerprinting profile identified phylogenetically, revealed five distinct species of Diaporthe which are present in C. spiralis. SIGNIFICANCE AND IMPACT OF THE STUDY The molecular analyses used in this study are excellent alternatives for species-level identification of Diaporthe associated with medicinal plants.
