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Fábio Henrique Pinheiro - One of the best experts on this subject based on the ideXlab platform.
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Unidirectional transitions in nectar gain and loss suggest food deception is a stable evolutionary strategy in Epidendrum (Orchidaceae): insights from anatomical and molecular evidence.
BMC plant biology, 2018Co-Authors: Poliana Cardoso-gustavson, Edlley Pessoa, Mariana Naomi Saka, Clarisse Palma-silva, Fábio Henrique PinheiroAbstract:Nectar gain and loss are important flower transitions observed in angiosperms, and are particularly common in orchids. To understand such transitions, the availability of detailed anatomical data and species-level phylogenies are crucial. We investigated the evolution of food deception in Epidendrum, one of the largest orchid genera, using genus phylogeny to map transitions between nectar gain and loss among different clades. Associations between anatomical and histochemical changes and nectar gain and loss were examined using fresh material available from 27 species. The evolution of nectar presence/absence in Epidendrum species was investigated in a phylogenetic framework of 47 species, using one nuclear and five plastid DNA regions available from GenBank and sequenced in this study. The presence or absence of nectar was strongly associated with changes in the inner epidermal tissues of nectaries. Nectar-secreting species have unornamented epidermal tissue, in contrast to the unicellular trichomes found on the epidermis of food deceptive species. Bayesian tests confirmed that transitions occurred preferentially from nectar presence to nectar absence across the Epidendrum phylogeny. In addition, independent nectar loss events were found across the phylogeny, suggesting a lack of constraint for these transitions. Ornamented nectaries may play an important role in the deceptive pollination strategy by secreting volatile organic compounds and providing tactile stimuli to pollinators. The recurrent and apparently irreversible pattern of nectar loss in Epidendrum suggests that food deception may constitute an alternative evolutionarily stable strategy, as observed in other orchid groups.
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Interploidy hybridization in sympatric zones: the formation of Epidendrum fulgens × E. puniceoluteum hybrids (Epidendroideae, Orchidaceae)
Ecology and evolution, 2013Co-Authors: Ana Paula Moraes, Clarisse Palma-silva, Mariana Chinaglia, Fábio Henrique PinheiroAbstract:Interspecific hybridization is a primary cause of extensive morphological and chromosomal variation and plays an important role in plant species diversification. However, the role of interploidal hybridization in the formation of hybrid swarms is less clear. Epidendrum encompasses wide variation in chromosome number and lacks strong premating barriers, making the genus a good model for clarifying the role of chromosomes in postzygotic barriers in interploidal hybrids. In this sense, hybrids from the interploidal sympatric zone between E. fulgens (2n = 2x = 24) and E. puniceoluteum (2n = 4x = 56) were analyzed using cytogenetic techniques to elucidate the formation and establishment of interploidal hybrids. Hybrids were not a uniform group: two chromosome numbers were observed, with the variation being a consequence of severe hybrid meiotic abnormalities and backcrossing with E. puniceoluteum. The hybrids were triploids (2n = 3x = 38 and 40) and despite the occurrence of enormous meiotic problems associated with triploidy, the hybrids were able to backcross, producing successful hybrid individuals with broad ecological distributions. In spite of the nonpolyploidization of the hybrid, its formation is a long-term evolutionary process rather than a product of a recent disturbance, and considering other sympatric zones in Epidendrum, these events could be recurrent.
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Karyology of the genus Epidendrum (Orchidaceae: Laeliinae) with emphasis on subgenus Amphiglottium and chromosome number variability in Epidendrum secundum
Botanical Journal of the Linnean Society, 2013Co-Authors: Felipe Nollet Medeiros De Assis, Bruno Cesar Querino De Souza, Enoque Medeiros-neto, Fábio Henrique Pinheiro, Ana Emília Barros E Silva, Leonardo Pessoa FelixAbstract:Epidendrum is one of the largest Neotropical genera of Orchidaceae and comprises approximately 1500 species. Only 2.8% of these species have been studied cytologically, demonstrating chromosome numbers ranging from n = 12 in E. fulgens to n = 120 in E. cinnabarinum. The present work evaluated the evolution of the karyotypes of Epidendrum spp. based on data gathered from the literature and from analyses of the karyotypes of 16 Brazilian species (nine previously unpublished). The appearance of one karyotype with n = 12 with one larger chromosome pair in subgenus Amphiglottium appears to have occurred at the beginning of the divergence of this lineage, and x = 12 probably represents the basic number of this subgenus. Epidendrum secundum exhibits wide variation in chromosome numbers, with ten different cytotypes found in 22 Brazilian populations, seven of which were new counts: 2n = 30, 42, 50, 54, 56, 58 and 84. Most lineages of Epidendrum seem to have been secondarily derived from one ancestral stock with x = 20, as is seen in the majority of the present-day representatives of the genus. © 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 172, 329–344.
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Epidendrum (Orchidaceae) as a model system for ecological and evolutionary studies in the Neotropics
TAXON, 2012Co-Authors: Fábio Henrique Pinheiro, Salvatore CozzolinoAbstract:The orchid genus Epidendrum, with 1500 species occurring within the Neotropical region, represents a very promising model system for evolutionary and ecological studies offering an expanded repertoire of research opportunities in the breadth of modern plant biology. Epidendrum displays a significant degree of morphological variation, chromosome number diversity and ecological interactions, which challenges widely held views on reproductive barriers and habitat selection. The widespread geographical distribution of many species and populations offers interesting opportunities to investigate how climatic changes and historic demographic processes shaped the current patterns of genetic and species diversity across different biomes and landscapes. Questions involving chromosome barriers to gene exchange and the role of postzygotic genetic barriers in species cohesion (e.g., the contributions of habitat selection and niche divergence on species cohesion) could be easily addressed when using the variety of natural hybrid zones found across Epidendrum. Several key evolutionary questions could be addressed with this model system, such as the identification of the first stages of adaptive radiation, the evolution of pollination strate- gies, the adaptive ecological significance of trait variation and hybridisation, the influence of historical demographic events on lineage diversification and speciation. With the advance of cost-effective molecular techniques and by combining ecologi- cal and phenotypic data, researchers can now tackle these questions and foster significant progress in the field of Neotropical plant diversification and evolution.
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Integrating different tools to disentangle species complexes: A case study in Epidendrum (Orchidaceae)
TAXON, 2012Co-Authors: Edlley Pessoa, Clarisse Palma-silva, Marccus Alves, Anderson Alves-araújo, Fábio Henrique PinheiroAbstract:Species delimitation remains a central problem in systematic, taxonomic and evolutionary studies. However, the precise delimitation of species depends on the criteria used to identify lineages and the specific species concept that is applied. Recently, multidisciplinary studies using different data sources have significantly improved the delimitation of species within complex taxonomic groups, leading to an integrative taxonomy. To investigate the species delimitation within the Atlantic clade of Epidendrum (subg. Amphyglottium), four different species criteria were examined (phenetic differentiation, monophyly, diagnosability, absence of genetic intermediates). Morphometrics, plastid DNA sequences and nuclear microsatellite markers were used to explore the agreement between patterns recovered and species criteria tested. The conflicts among species criteria are discussed in light of pollination ecology, patterns of gene flow, reproductive isolation mechanisms and selective pressures currently acting in deceptive orchid species. Four currently recognized species from the Atlantic clade could be delimitated, including one newly described species, Epidendrum flammeus. Three out of five species satisfied the monophyly criterion, and few diagnostic flower characters were found among species. In contrast, nuclear microsatellite data correctly assigned individuals to their respective species, even in the presence of weak reproductive isolation and extensive hybridization events reported in the literature. One important implication of this finding is that phylogenetic studies in Epidendrum spp. should make use of singleor low-copy nuclear loci instead of plastid markers, which may be true for other plant groups. The results also indicate that the generalized pollination syndrome found among species of the Atlantic clade, the different levels of gene flow observed between nuclear and plastid markers, and hybridization events are commonly observed as the main evolutionary forces within this orchid group. Finally, we discuss evolutionary processes and taxonomic limits among these species, and we highlight the need to increase the inter-disciplinary approach to investigate species limits in complex plant groups.
Clarisse Palma-silva - One of the best experts on this subject based on the ideXlab platform.
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Unidirectional transitions in nectar gain and loss suggest food deception is a stable evolutionary strategy in Epidendrum (Orchidaceae): insights from anatomical and molecular evidence.
BMC plant biology, 2018Co-Authors: Poliana Cardoso-gustavson, Edlley Pessoa, Mariana Naomi Saka, Clarisse Palma-silva, Fábio Henrique PinheiroAbstract:Nectar gain and loss are important flower transitions observed in angiosperms, and are particularly common in orchids. To understand such transitions, the availability of detailed anatomical data and species-level phylogenies are crucial. We investigated the evolution of food deception in Epidendrum, one of the largest orchid genera, using genus phylogeny to map transitions between nectar gain and loss among different clades. Associations between anatomical and histochemical changes and nectar gain and loss were examined using fresh material available from 27 species. The evolution of nectar presence/absence in Epidendrum species was investigated in a phylogenetic framework of 47 species, using one nuclear and five plastid DNA regions available from GenBank and sequenced in this study. The presence or absence of nectar was strongly associated with changes in the inner epidermal tissues of nectaries. Nectar-secreting species have unornamented epidermal tissue, in contrast to the unicellular trichomes found on the epidermis of food deceptive species. Bayesian tests confirmed that transitions occurred preferentially from nectar presence to nectar absence across the Epidendrum phylogeny. In addition, independent nectar loss events were found across the phylogeny, suggesting a lack of constraint for these transitions. Ornamented nectaries may play an important role in the deceptive pollination strategy by secreting volatile organic compounds and providing tactile stimuli to pollinators. The recurrent and apparently irreversible pattern of nectar loss in Epidendrum suggests that food deception may constitute an alternative evolutionarily stable strategy, as observed in other orchid groups.
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Unidirectional transitions in nectar gain and loss suggest food deception is a stable evolutionary strategy in Epidendrum (Orchidaceae): insights from anatomical and molecular evidence
BMC, 2018Co-Authors: Poliana Cardoso-gustavson, Mariana Naomi Saka, Clarisse Palma-silva, Edlley Max Pessoa, Fabio PinheiroAbstract:Abstract Background Nectar gain and loss are important flower transitions observed in angiosperms, and are particularly common in orchids. To understand such transitions, the availability of detailed anatomical data and species-level phylogenies are crucial. We investigated the evolution of food deception in Epidendrum, one of the largest orchid genera, using genus phylogeny to map transitions between nectar gain and loss among different clades. Associations between anatomical and histochemical changes and nectar gain and loss were examined using fresh material available from 27 species. The evolution of nectar presence/absence in Epidendrum species was investigated in a phylogenetic framework of 47 species, using one nuclear and five plastid DNA regions available from GenBank and sequenced in this study. Results The presence or absence of nectar was strongly associated with changes in the inner epidermal tissues of nectaries. Nectar-secreting species have unornamented epidermal tissue, in contrast to the unicellular trichomes found on the epidermis of food deceptive species. Bayesian tests confirmed that transitions occurred preferentially from nectar presence to nectar absence across the Epidendrum phylogeny. In addition, independent nectar loss events were found across the phylogeny, suggesting a lack of constraint for these transitions. Conclusions Ornamented nectaries may play an important role in the deceptive pollination strategy by secreting volatile organic compounds and providing tactile stimuli to pollinators. The recurrent and apparently irreversible pattern of nectar loss in Epidendrum suggests that food deception may constitute an alternative evolutionarily stable strategy, as observed in other orchid groups
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Additional file 4: of Unidirectional transitions in nectar gain and loss suggest food deception is a stable evolutionary strategy in Epidendrum (Orchidaceae): insights from anatomical and molecular evidence
2018Co-Authors: Poliana Cardoso-gustavson, Edlley Pessoa, Clarisse Palma-silva, Mariana Saka, Fabio PinheiroAbstract:Table S1. Epidendrum species and allied genera analyzed in this study, including GenBank access numbers by molecular marker, including the type of analyses performed (PC = primary calibration, SC = secondary calibration, AN = anatomy), and presence or absence of nectar with the corresponding source of information. (DOCX 30 kb
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Additional file 1: of Unidirectional transitions in nectar gain and loss suggest food deception is a stable evolutionary strategy in Epidendrum (Orchidaceae): insights from anatomical and molecular evidence
2018Co-Authors: Poliana Cardoso-gustavson, Edlley Pessoa, Clarisse Palma-silva, Mariana Saka, Fabio PinheiroAbstract:Figure S1. Details of Epidendrum flowers, showing the cuniculi. (A) E. coronatum flower. The red rectangle indicates the pedicel region dissected by longitudinal sections in the remaining pictures (B–D). (B) Detail of the cuniculus of E. cristatum. The dotted line indicates the area from which most samples were taken for anatomical analyses. (C) Unornamented cuniculus of E. orchidiflorum. (D) Ornamented cuniculus of E. fulgens. Scale bars = 1.0 cm. (PDF 6036 kb
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Strong but permeable barriers to gene exchange between sister species of Epidendrum
American journal of botany, 2016Co-Authors: Fabio Pinheiro, Poliana Cardoso-gustavson, Salvatore Cozzolino, Rogério Mamoru Suzuki, Tiago Manuel Zanfra De Melo E Gouveia, Donata Cafasso, Clarisse Palma-silvaAbstract:PREMISE OF THE STUDY The investigation of reproductive barriers between sister species can provide insights into how new lineages arise, and how species integrity is maintained in the face of interspecific gene flow. Different pre- and postzygotic barriers can limit interspecific gene exchange in sympatric populations, and different sources of evidence are often required to investigate the role of multiple reproductive isolation (RI) mechanisms. METHODS We tested the hypothesis of hybridization and potential introgression between Epidendrum secundum and Epidendrum xanthinum, two Neotropical food-deceptive orchid species, using nuclear and plastid microsatellites, experimental crosses, pollen tube growth observations, and genome size estimates. KEY RESULTS A large number of hybrids between E. secundum and E. xanthinum were detected, suggesting weak premating barriers. The low fertility of hybrid plants and the absence of haplotype sharing between parental species indicated strong postmating barriers, reducing interspecific gene exchange and the development of advanced generation hybrids. Despite the strength of reproductive barriers, fertile seeds were produced in some backcrossing experiments, and the existence of interspecific gene exchange could not be excluded. CONCLUSIONS Strong but permeable barriers were found between E. secundum and E. xanthinum. Indeed, haplotype sharing was not detected between parental species, suggesting that introgression is limited by a combination of genic incompatibilities, including negative cytonuclear interactions. Most taxonomic uncertainties in this group were potentially influenced by incomplete RI barriers between species, which mainly occurred sympatrically.
Yoshinori Asakawa - One of the best experts on this subject based on the ideXlab platform.
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acylglycerols from the slime mould lycogala Epidendrum
Phytochemistry, 1996Co-Authors: Malcolm Stewart Buchanan, Toshihiro Hashimoto, Yoshinori AsakawaAbstract:From the slime mould Lycogala Epidendrum, four unusual new acylglycerols, lycogarides D-G, were isolated. Their structures were determined by spectroscopic and chemical methods. Also, the known lycogalic acid dimethyl esters A and B were obtained.
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Three novel dimethyl pyrroledicarboxylate, lycogarubins AC, from the myxomycetes lycogala Epidendrum
Tetrahedron Letters, 1994Co-Authors: Toshihiro Hashimoto, Yasuda Akiyo, Kyoko Akazawa, Shigeru Takaoka, Motoo Tori, Yoshinori AsakawaAbstract:Abstract Three novel dimethyl pyrroledicarboxylate, named lycogarubins AC have been isolated from the Myxomycetes Lycogala Epidendrum. Their structures have been established by a combination of two dimension NMR spectroscopy, X-ray crystallographic analysis and chemical degradation. Lycogarubin C showed moderate anti-HSV-I virus activity.
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THREE NOVEL POLYACETYLENE TRIGLYCERIDES, LYCOGARIDES A-C, FROM THE MYXOMYCETES LYCOGALA Epidendrum
Chemical and Pharmaceutical Bulletin, 1994Co-Authors: Toshihiro Hashimoto, Kyoko Akazawa, Motoo Tori, Yukiko Kan, Takenori Kusumi, Haruko Takahashi, Yoshinori AsakawaAbstract:Three novel polyacetylene triglycerides, named lycogarides A-C (1-3), have been isolated from the Myxomycetes Lycogala Epidendrum. Their relative structures have been established by a combination of two-dimension NMR spectroscopy and chemical degradation. The absolute structures of compounds 1 and 2 were deduced from the modified Mosher's and dibenzoate exiton chirality methods of their derivatives.
Fabio Pinheiro - One of the best experts on this subject based on the ideXlab platform.
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Unidirectional transitions in nectar gain and loss suggest food deception is a stable evolutionary strategy in Epidendrum (Orchidaceae): insights from anatomical and molecular evidence
BMC, 2018Co-Authors: Poliana Cardoso-gustavson, Mariana Naomi Saka, Clarisse Palma-silva, Edlley Max Pessoa, Fabio PinheiroAbstract:Abstract Background Nectar gain and loss are important flower transitions observed in angiosperms, and are particularly common in orchids. To understand such transitions, the availability of detailed anatomical data and species-level phylogenies are crucial. We investigated the evolution of food deception in Epidendrum, one of the largest orchid genera, using genus phylogeny to map transitions between nectar gain and loss among different clades. Associations between anatomical and histochemical changes and nectar gain and loss were examined using fresh material available from 27 species. The evolution of nectar presence/absence in Epidendrum species was investigated in a phylogenetic framework of 47 species, using one nuclear and five plastid DNA regions available from GenBank and sequenced in this study. Results The presence or absence of nectar was strongly associated with changes in the inner epidermal tissues of nectaries. Nectar-secreting species have unornamented epidermal tissue, in contrast to the unicellular trichomes found on the epidermis of food deceptive species. Bayesian tests confirmed that transitions occurred preferentially from nectar presence to nectar absence across the Epidendrum phylogeny. In addition, independent nectar loss events were found across the phylogeny, suggesting a lack of constraint for these transitions. Conclusions Ornamented nectaries may play an important role in the deceptive pollination strategy by secreting volatile organic compounds and providing tactile stimuli to pollinators. The recurrent and apparently irreversible pattern of nectar loss in Epidendrum suggests that food deception may constitute an alternative evolutionarily stable strategy, as observed in other orchid groups
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Additional file 4: of Unidirectional transitions in nectar gain and loss suggest food deception is a stable evolutionary strategy in Epidendrum (Orchidaceae): insights from anatomical and molecular evidence
2018Co-Authors: Poliana Cardoso-gustavson, Edlley Pessoa, Clarisse Palma-silva, Mariana Saka, Fabio PinheiroAbstract:Table S1. Epidendrum species and allied genera analyzed in this study, including GenBank access numbers by molecular marker, including the type of analyses performed (PC = primary calibration, SC = secondary calibration, AN = anatomy), and presence or absence of nectar with the corresponding source of information. (DOCX 30 kb
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Additional file 1: of Unidirectional transitions in nectar gain and loss suggest food deception is a stable evolutionary strategy in Epidendrum (Orchidaceae): insights from anatomical and molecular evidence
2018Co-Authors: Poliana Cardoso-gustavson, Edlley Pessoa, Clarisse Palma-silva, Mariana Saka, Fabio PinheiroAbstract:Figure S1. Details of Epidendrum flowers, showing the cuniculi. (A) E. coronatum flower. The red rectangle indicates the pedicel region dissected by longitudinal sections in the remaining pictures (B–D). (B) Detail of the cuniculus of E. cristatum. The dotted line indicates the area from which most samples were taken for anatomical analyses. (C) Unornamented cuniculus of E. orchidiflorum. (D) Ornamented cuniculus of E. fulgens. Scale bars = 1.0 cm. (PDF 6036 kb
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Strong but permeable barriers to gene exchange between sister species of Epidendrum
American journal of botany, 2016Co-Authors: Fabio Pinheiro, Poliana Cardoso-gustavson, Salvatore Cozzolino, Rogério Mamoru Suzuki, Tiago Manuel Zanfra De Melo E Gouveia, Donata Cafasso, Clarisse Palma-silvaAbstract:PREMISE OF THE STUDY The investigation of reproductive barriers between sister species can provide insights into how new lineages arise, and how species integrity is maintained in the face of interspecific gene flow. Different pre- and postzygotic barriers can limit interspecific gene exchange in sympatric populations, and different sources of evidence are often required to investigate the role of multiple reproductive isolation (RI) mechanisms. METHODS We tested the hypothesis of hybridization and potential introgression between Epidendrum secundum and Epidendrum xanthinum, two Neotropical food-deceptive orchid species, using nuclear and plastid microsatellites, experimental crosses, pollen tube growth observations, and genome size estimates. KEY RESULTS A large number of hybrids between E. secundum and E. xanthinum were detected, suggesting weak premating barriers. The low fertility of hybrid plants and the absence of haplotype sharing between parental species indicated strong postmating barriers, reducing interspecific gene exchange and the development of advanced generation hybrids. Despite the strength of reproductive barriers, fertile seeds were produced in some backcrossing experiments, and the existence of interspecific gene exchange could not be excluded. CONCLUSIONS Strong but permeable barriers were found between E. secundum and E. xanthinum. Indeed, haplotype sharing was not detected between parental species, suggesting that introgression is limited by a combination of genic incompatibilities, including negative cytonuclear interactions. Most taxonomic uncertainties in this group were potentially influenced by incomplete RI barriers between species, which mainly occurred sympatrically.
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interploidy hybridization in sympatric zones the formation of Epidendrum fulgens e puniceoluteum hybrids epidendroideae orchidaceae
Ecology and Evolution, 2013Co-Authors: Mariana Chinaglia, Ana Paula Moraes, Clarisse Palmasilva, Fabio PinheiroAbstract:Interspecific hybridization is a primary cause of extensive morphological and chromosomal variation and plays an important role in plant species diversification. However, the role of interploidal hybridization in the formation of hybrid swarms is less clear. Epidendrum encompasses wide variation in chromosome number and lacks strong premating barriers, making the genus a good model for clarifying the role of chromosomes in postzygotic barriers in interploidal hybrids. In this sense, hybrids from the interploidal sympatric zone between E. fulgens (2n = 2x = 24) and E. puniceoluteum (2n = 4x = 56) were analyzed using cytogenetic techniques to elucidate the formation and establishment of interploidal hybrids. Hybrids were not a uniform group: two chromosome numbers were observed, with the variation being a consequence of severe hybrid meiotic abnormalities and backcrossing with E. puniceoluteum. The hybrids were triploids (2n = 3x = 38 and 40) and despite the occurrence of enormous meiotic problems associated with triploidy, the hybrids were able to backcross, producing successful hybrid individuals with broad ecological distributions. In spite of the nonpolyploidization of the hybrid, its formation is a long-term evolutionary process rather than a product of a recent disturbance, and considering other sympatric zones in Epidendrum, these events could be recurrent.
Salvatore Cozzolino - One of the best experts on this subject based on the ideXlab platform.
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Strong but permeable barriers to gene exchange between sister species of Epidendrum
American journal of botany, 2016Co-Authors: Fabio Pinheiro, Poliana Cardoso-gustavson, Salvatore Cozzolino, Rogério Mamoru Suzuki, Tiago Manuel Zanfra De Melo E Gouveia, Donata Cafasso, Clarisse Palma-silvaAbstract:PREMISE OF THE STUDY The investigation of reproductive barriers between sister species can provide insights into how new lineages arise, and how species integrity is maintained in the face of interspecific gene flow. Different pre- and postzygotic barriers can limit interspecific gene exchange in sympatric populations, and different sources of evidence are often required to investigate the role of multiple reproductive isolation (RI) mechanisms. METHODS We tested the hypothesis of hybridization and potential introgression between Epidendrum secundum and Epidendrum xanthinum, two Neotropical food-deceptive orchid species, using nuclear and plastid microsatellites, experimental crosses, pollen tube growth observations, and genome size estimates. KEY RESULTS A large number of hybrids between E. secundum and E. xanthinum were detected, suggesting weak premating barriers. The low fertility of hybrid plants and the absence of haplotype sharing between parental species indicated strong postmating barriers, reducing interspecific gene exchange and the development of advanced generation hybrids. Despite the strength of reproductive barriers, fertile seeds were produced in some backcrossing experiments, and the existence of interspecific gene exchange could not be excluded. CONCLUSIONS Strong but permeable barriers were found between E. secundum and E. xanthinum. Indeed, haplotype sharing was not detected between parental species, suggesting that introgression is limited by a combination of genic incompatibilities, including negative cytonuclear interactions. Most taxonomic uncertainties in this group were potentially influenced by incomplete RI barriers between species, which mainly occurred sympatrically.
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Epidendrum (Orchidaceae) as a model system for ecological and evolutionary studies in the Neotropics
TAXON, 2012Co-Authors: Fábio Henrique Pinheiro, Salvatore CozzolinoAbstract:The orchid genus Epidendrum, with 1500 species occurring within the Neotropical region, represents a very promising model system for evolutionary and ecological studies offering an expanded repertoire of research opportunities in the breadth of modern plant biology. Epidendrum displays a significant degree of morphological variation, chromosome number diversity and ecological interactions, which challenges widely held views on reproductive barriers and habitat selection. The widespread geographical distribution of many species and populations offers interesting opportunities to investigate how climatic changes and historic demographic processes shaped the current patterns of genetic and species diversity across different biomes and landscapes. Questions involving chromosome barriers to gene exchange and the role of postzygotic genetic barriers in species cohesion (e.g., the contributions of habitat selection and niche divergence on species cohesion) could be easily addressed when using the variety of natural hybrid zones found across Epidendrum. Several key evolutionary questions could be addressed with this model system, such as the identification of the first stages of adaptive radiation, the evolution of pollination strate- gies, the adaptive ecological significance of trait variation and hybridisation, the influence of historical demographic events on lineage diversification and speciation. With the advance of cost-effective molecular techniques and by combining ecologi- cal and phenotypic data, researchers can now tackle these questions and foster significant progress in the field of Neotropical plant diversification and evolution.
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Hybridization and introgression across different ploidy levels in the Neotropical orchids Epidendrum fulgens and E. puniceoluteum (Orchidaceae).
Molecular ecology, 2010Co-Authors: Fábio Henrique Pinheiro, Fábio De Barros, Michael F. Fay, Clarisse Palma-silva, Diogo Meyer, Rogério Mamoru Suzuki, Christian Lexer, Salvatore CozzolinoAbstract:The hypothesis of gene flow between species with large differences in chromosome numbers has rarely been tested in the wild, mainly because species of different ploidy are commonly assumed to be reproductively isolated from each other because of instantaneous and strong postzygotic barriers. In this study, a broad-scale survey of molecular variation was carried out between two orchid species with different ploidy levels: Epidendrum fulgens (2n =2 x = 24 chromosomes) and Epidendrum puniceoluteum (2n =4 x = 52 chromosomes). To test the strength of their reproductive barriers, we investigated the distribution of genetic variation in sympatric and allopatric populations of these two species and conducted crossing experiments. Nuclear and plastid microsatellite loci were used to genotype 463 individuals from eight populations across the geographical range of both species along the Brazilian coastal plain. All six sympatric populations analysed presented hybrid zones, indicating that hybridization between E. fulgens and E. puniceoluteum is a common phenomenon. Bayesian assignment analysis detected the presence of F1 and F2 individuals and also signs of introgression, demonstrating a high potential for interspecific gene flow. Introgression occurs preferentially from E. fulgens to E. puniceoluteum. Pure parental individuals of both species display strong genotype–habitat associations, indicating that environment-dependent selection could be acting in all hybrid zones. This study suggests that hybridization and introgression are evolutionary processes playing a role in the diversification of Epidendrum and indicates the importance of investigations of hybrid zones in understanding reproductive barriers and speciation processes in Neotropical orchid species.
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Cross-amplification and characterization of microsatellite loci for the Neotropical orchid genus Epidendrum
Genetics and molecular biology, 2009Co-Authors: Fábio Henrique Pinheiro, Fábio De Barros, Clarisse Palma-silva, Salvatore CozzolinoAbstract:In this study we tested the cross-amplification of 33 microsatellite loci previously developed for two closely related Neotropical orchid genera (Epidendrum and Laelia). A set of ten loci were polymorphic across five examined species (20 individuals each) with 2 to 15 alleles per locus. The mean expected and observed heterozygosity (average across species) ranged from 0.34 to 0.82 and from 0.27 to 0.85, respectively. In addition we tested all loci in 35 species representative of the genus Epidendrum. Of these, 26 loci showed successful amplification. Cross-application of these loci represent a potential source of co-dominant markers for evolutionary, ecological and conservation studies in this important orchid genus.
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Isolation and characterization of microsatellite loci in Epidendrum puniceoluteum, an endemic orchid from the Atlantic Rainforest.
Molecular ecology resources, 2008Co-Authors: Fábio Henrique Pinheiro, Fábio De Barros, Clarisse Palma-silva, Diogo Meyer, M. O. Santos, Antonio Salatino, Anete Pereira De Souza, Salvatore CozzolinoAbstract:Epidendrum puniceoluteum is an endemic orchid of Atlantic Rainforest, restricted to few populations only due to the destruction and fragmentation of its native habitat. Here, we report on the development of 10 microsatellite markers isolated from this orchid species. Genetic variability was characterized in two distant populations from Brazil coast. The number of alleles observed for each locus ranged from two to 12 and with an average of 6.4 alleles per locus. These microsatellites should be valuable tools for studying both fine-scale genetic structure of scattered E. puniceoluteum population and patterns will be useful genetic markers for other closely related taxa.