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Janet M. Davies - One of the best experts on this subject based on the ideXlab platform.
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biogeographical variation in specific ige recognition of temperate and subtropical grass pollen allergens in allergic rhinitis patients
Clinical And Translational Immunology, 2020Co-Authors: Thina Hareesh Kailaivasan, Victoria L. Timbrell, William B Smith, Pete Smith, John W. Upham, Daman Langguth, Graham O Solley, Andrew Mcleantooke, Sheryl Van Nunen, Janet M. DaviesAbstract:Objective: Globally, grass pollens (GP) are major aeroallergen triggers of allergic rhinitis (AR) and asthma. However, patterns of allergic sensitisation to pollen of temperate (Pooideae: Lolium perenne) and subtropical (Chloridoideae: Cynodon dactylon and Panicoideae: Paspalum notatum) subfamilies in diverse climates remain unclear. This study aims to evaluate the level of allergic sensitisation and IgE specificity for major GP allergens representing the three subfamilies in biogeographically distinct regions. Methods: Participants (GP-allergic with AR, 330; non-atopic, 29; other allergies, 54) were recruited in subtropical: Queensland, and temperate: New South Wales, Western and South Australia, regions. Clinical history, skin prick test (SPT), total and specific IgE to GP and purified allergens (ImmunoCAP) were evaluated. Cross-inhibition of sIgE with Pas n 1, Cyn d 1 and Lol p 1 by GP extracts was investigated. Results: Queensland participants showed higher sensitisation to P. notatum and C. dactylon than L. perenne GP. sIgE was higher to Pas n 1 and Cyn d 1, and sIgE to Pas n 1 and Cyn d 1 was inhibited more by Panicoideae and Chloridoideae, respectively, than Pooideae GP. Conversely, participants from temperate regions showed highest sensitisation levels to L. perenne GP and Lol p 1, and sIgE to Lol p 1 was inhibited more by Pooideae than other GP. Conclusion: Levels and patterns of sensitisation to subtropical and temperate GP in AR patients depended on biogeography. Knowledge of the specificity of sensitisation to local allergens is important for optimal diagnosis and choice of allergen-specific immunotherapy to maximise benefit.
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The molecular allergology of subtropical grass pollen
Molecular Immunology, 2018Co-Authors: Thina Hareesh Kailaivasan, Janet M. DaviesAbstract:Grass pollens are amongst the most important aeroallergen sources world-wide triggering allergic rhinoconjunctivitis and asthma in sensitised patients. Much of what we know about the allergen components of grasses is informed by research on pollen of temperate (Pooideae) species that are abundant in the temperate climate zones. However, climate changes are altering the biogeographical distribution as well as timing and allergenicity of grass pollens. This provides an impetus for better understanding of the contribution of subtropical subfamilies of grasses to pollen allergy globally. Pollen of Chloridoideae (e.g. Cynodon dactylon; Bermuda grass) and Panicoideae (e.g. Paspalum notatum; Bahia grass or Sorghum halepense; Johnson grass) subfamilies are clinically important in subtropical zones of Australia, Asia, India, Africa, and America. These grasses differ ecologically and phylogenetically from temperate grasses and, importantly their allergen composition is qualitatively different. For example, subtropical grass pollens appear to lack the major group 5 grass pollen allergen family. In this review we summarize current knowledge of the epidemiology and immunology of subtropical Chloridoideae and Pancoideae pollen allergens, describe the biochemical characteristics of known isoforms and variants as well as properties and structures of subtropical pollen allergen components. Whilst only one subtropical allergen component; Cyn d 1 of Bermuda grass pollen, is available commercially for diagnostic use, in a natural purified form, a number of allergens of Panicoideae grass pollen; Zea m 1, Zea m 3 and Zea m 13 of maize, Pas n 1 and Pas n 13 of Bahia, as well as Sor h 1, Sor h 2, Sor h 13 and Sor h 23 of Johnson grass, have been discovered. Research effort is directed towards making available subtropical grass pollen allergen components as innovative treatment and diagnostic options that more specifically address the needs of patients from warmer regions of the globe.
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Grass pollen allergens globally: The contribution of subtropical grasses to burden of allergic respiratory diseases
2014Co-Authors: Janet M. DaviesAbstract:Grass pollens of the temperate (Pooideae) subfamily and subtropical subfamilies of grasses are major aeroallergen sources worldwide. The subtropical Chloridoideae (e.g. Cynodon dactylon; Bermuda grass) and Panicoideae (e.g. Paspalum notatum; Bahia grass) species are abundant in parts of Africa, India, Asia, Australia and the Americas, where a large and increasing proportion of the world's population abide. These grasses are phylogenetically and ecologically distinct from temperate grasses. With the advent of global warming, it is conceivable that the geographic distribution of subtropical grasses and the contribution of their pollen to the burden of allergic rhinitis and asthma will increase. This review aims to provide a comprehensive synthesis of the current global knowledge of (i) regional variation in allergic sensitivity to subtropical grass pollens, (ii) molecular allergenic components of subtropical grass pollens and (iii) allergic responses to subtropical grass pollen allergens in relevant populations. Patients from subtropical regions of the world show higher allergic sensitivity to grass pollens of Chloridoideae and Panicoideae grasses, than to temperate grass pollens. The group 1 allergens are amongst the allergen components of subtropical grass pollens, but the group 5 allergens, by which temperate grass pollen extracts are standardized for allergen content, appear to be absent from both subfamilies of subtropical grasses. Whilst there are shared allergenic components and antigenic determinants, there are additional clinically relevant subfamily-specific differences, at T- and B-cell levels, between pollen allergens of subtropical and temperate grasses. Differential immune recognition of subtropical grass pollens is likely to impact upon the efficacy of allergen immunotherapy of patients who are primarily sensitized to subtropical grass pollens. The literature reviewed herein highlights the clinical need to standardize allergen preparations for both types of subtropical grass pollens to achieve optimal diagnosis and treatment of patients with allergic respiratory disease in subtropical regions of the world. © 2014 John Wiley & Sons Ltd.
Thina Hareesh Kailaivasan - One of the best experts on this subject based on the ideXlab platform.
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biogeographical variation in specific ige recognition of temperate and subtropical grass pollen allergens in allergic rhinitis patients
Clinical And Translational Immunology, 2020Co-Authors: Thina Hareesh Kailaivasan, Victoria L. Timbrell, William B Smith, Pete Smith, John W. Upham, Daman Langguth, Graham O Solley, Andrew Mcleantooke, Sheryl Van Nunen, Janet M. DaviesAbstract:Objective: Globally, grass pollens (GP) are major aeroallergen triggers of allergic rhinitis (AR) and asthma. However, patterns of allergic sensitisation to pollen of temperate (Pooideae: Lolium perenne) and subtropical (Chloridoideae: Cynodon dactylon and Panicoideae: Paspalum notatum) subfamilies in diverse climates remain unclear. This study aims to evaluate the level of allergic sensitisation and IgE specificity for major GP allergens representing the three subfamilies in biogeographically distinct regions. Methods: Participants (GP-allergic with AR, 330; non-atopic, 29; other allergies, 54) were recruited in subtropical: Queensland, and temperate: New South Wales, Western and South Australia, regions. Clinical history, skin prick test (SPT), total and specific IgE to GP and purified allergens (ImmunoCAP) were evaluated. Cross-inhibition of sIgE with Pas n 1, Cyn d 1 and Lol p 1 by GP extracts was investigated. Results: Queensland participants showed higher sensitisation to P. notatum and C. dactylon than L. perenne GP. sIgE was higher to Pas n 1 and Cyn d 1, and sIgE to Pas n 1 and Cyn d 1 was inhibited more by Panicoideae and Chloridoideae, respectively, than Pooideae GP. Conversely, participants from temperate regions showed highest sensitisation levels to L. perenne GP and Lol p 1, and sIgE to Lol p 1 was inhibited more by Pooideae than other GP. Conclusion: Levels and patterns of sensitisation to subtropical and temperate GP in AR patients depended on biogeography. Knowledge of the specificity of sensitisation to local allergens is important for optimal diagnosis and choice of allergen-specific immunotherapy to maximise benefit.
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The molecular allergology of subtropical grass pollen
Molecular Immunology, 2018Co-Authors: Thina Hareesh Kailaivasan, Janet M. DaviesAbstract:Grass pollens are amongst the most important aeroallergen sources world-wide triggering allergic rhinoconjunctivitis and asthma in sensitised patients. Much of what we know about the allergen components of grasses is informed by research on pollen of temperate (Pooideae) species that are abundant in the temperate climate zones. However, climate changes are altering the biogeographical distribution as well as timing and allergenicity of grass pollens. This provides an impetus for better understanding of the contribution of subtropical subfamilies of grasses to pollen allergy globally. Pollen of Chloridoideae (e.g. Cynodon dactylon; Bermuda grass) and Panicoideae (e.g. Paspalum notatum; Bahia grass or Sorghum halepense; Johnson grass) subfamilies are clinically important in subtropical zones of Australia, Asia, India, Africa, and America. These grasses differ ecologically and phylogenetically from temperate grasses and, importantly their allergen composition is qualitatively different. For example, subtropical grass pollens appear to lack the major group 5 grass pollen allergen family. In this review we summarize current knowledge of the epidemiology and immunology of subtropical Chloridoideae and Pancoideae pollen allergens, describe the biochemical characteristics of known isoforms and variants as well as properties and structures of subtropical pollen allergen components. Whilst only one subtropical allergen component; Cyn d 1 of Bermuda grass pollen, is available commercially for diagnostic use, in a natural purified form, a number of allergens of Panicoideae grass pollen; Zea m 1, Zea m 3 and Zea m 13 of maize, Pas n 1 and Pas n 13 of Bahia, as well as Sor h 1, Sor h 2, Sor h 13 and Sor h 23 of Johnson grass, have been discovered. Research effort is directed towards making available subtropical grass pollen allergen components as innovative treatment and diagnostic options that more specifically address the needs of patients from warmer regions of the globe.
Fernando O. Zuloaga - One of the best experts on this subject based on the ideXlab platform.
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Evolutionary relationships in Panicoid grasses based on plastome phylogenomics (Panicoideae; Poaceae).
BMC Plant Biology, 2016Co-Authors: Sean V. Burke, Lynn G. Clark, William P. Wysocki, Fernando O. Zuloaga, Joseph M. Craine, J. Chris Pires, Patrick P. Edger, Dustin Mayfield-jones, Scot A. Kelchner, Melvin R. DuvallAbstract:Panicoideae are the second largest subfamily in Poaceae (grass family), with 212 genera and approximately 3316 species. Previous studies have begun to reveal relationships within the subfamily, but largely lack resolution and/or robust support for certain tribal and subtribal groups. This study aims to resolve these relationships, as well as characterize a putative mitochondrial insert in one linage. 35 newly sequenced Panicoideae plastomes were combined in a phylogenomic study with 37 other species: 15 Panicoideae and 22 from outgroups. A robust Panicoideae topology largely congruent with previous studies was obtained, but with some incongruences with previously reported subtribal relationships. A mitochondrial DNA (mtDNA) to plastid DNA (ptDNA) transfer was discovered in the Paspalum lineage. The phylogenomic analysis returned a topology that largely supports previous studies. Five previously recognized subtribes appear on the topology to be non-monophyletic. Additionally, evidence for mtDNA to ptDNA transfer was identified in both Paspalum fimbriatum and P. dilatatum, and suggests a single rare event that took place in a common progenitor. Finally, the framework from this study can guide larger whole plastome sampling to discern the relationships in Cyperochloeae, Steyermarkochloeae, Gynerieae, and other incertae sedis taxa that are weakly supported or unresolved.
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A Peculiar Amphitropical Genus of Paniceae (Poaceae, Panicoideae)
Systematic Botany, 2014Co-Authors: M. Amalia Scataglini, Mabel A. Lizarazu, Fernando O. ZuloagaAbstract:Abstract The genus Louisiella (Poaceae, Paniceae) is reviewed. This African monotypic genus was originally circumscribed on the basis of morphological characters. Recent phylogenetic studies have shown its affinity with an American species of Panicum, P. elephantipes. Molecular, morphological, and anatomical characters of Louisiella fluitans and P. elephantipes were analyzed. Both species share vegetative and reproductive characters, including habit, ligules, blades, inflorescence, and spikelet features, such as a reduced lower glume, lanceolate upper glume and lower lemma both longer than the upper anthecium, lower palea reduced or absent, and lower flower absent, upper anthecium indurate, and a caryopsis with a linear hilum. Anatomically, both taxa are Kranz of the PS-subtype, with specialized chloroplasts on the outer parenchymatous sheath. The molecular phylogenetic analysis also corroborates the relationship between these species, with a 100% bootstrap support. As a result, we conclude that P. elepha...
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Phylogeny of the Paniceae (Poaceae: Panicoideae): integrating plastid DNA sequences and morphology into a new classification.
Cladistics, 2012Co-Authors: Osvaldo Morrone, Elizabeth A. Kellogg, Lone Aagesen, María Amalia Scataglini, Diego L. Salariato, Silvia S. Denham, Maria Amelia Chemisquy, Silvana M. Sede, Liliana M. Giussani, Fernando O. ZuloagaAbstract:Included in the PACMAD clade of the family Poaceae (Panicoideae, Arundinoideae, Chloridoideae, Micrairoideae, Aristidoideae, Danthonioideae), the tribe Paniceae s.l. is one of the largest tribes of the subfamily Panicoideae, with more than 2000 species. This tribe comprises a huge morphological, cytological and physiological diversity represented by different inflorescence types, several basic chromosome numbers, and at least four major photosynthetic pathways. The tribe Paniceae has been the subject of molecular studies that have confirmed its paraphyly: two major clades were recognized based on their basic chromosome numbers (x = 9, x = 10). The x = 10 Paniceae clade is sister to the Andropogoneae–Arundinelleae s.s. clade (x = 10), while the combined x = 10 clade is sister to the x = 9 clade that contains the remaining genera of Paniceae. As a result of a recent realignment within the tribe in terms of the phylogenetic position of minor and major Paniceae genera, a reanalysis of the whole sampling is performed and new underrepresented taxa are discussed. A total of 155 genera, currently considered within subfamily Panicoideae, are represented here by almost all genera of Paniceae s.l., representatives of Andropogoneae and Arundinelleae s.s., and the endemic and small tribe Steyermarkochloeae; we also included specimens of subfamily Micrairoideae, tribes Isachneae and Eriachneae. The sampling includes as outgroups 18 genera of the PACMAD clade (excluding Panicoideae) and four genera from the BEP clade (Bambusoideae, Ehrhartoideae, Pooideae), rooting with Bromus inermis. A matrix with 265 taxa based on the combined evidence from ndhF plastid sequences (2074 bp) and 57 morphological characters was subjected to parsimony analyses. Jackknife resampling was used to calculate group support. Most clades are characterized by morphological, cytological, anatomical, and/or physiological characters. Major tribal changes are based on the basic chromosome number; the pantropical x = 9 clade is here recognized as Paniceae s.s., while the American x = 10 Paniceae s.l. is restricted to the reinstated tribe Paspaleae. The optimization of the photosynthetic pathway for the Paspaleae–Andropogoneae–Arundinelleae s.s. clade, including the monotypic Reynaudia, shows a plesiomorphic C4 state while the ancestral state for Paniceae s.s. is ambiguous. If Reynaudia were not included or placed elsewhere, the ancestral photosynthetic pathway for both the Paspaleae–Andropogoneae–Arundinelleae s.s. clade and the Paniceae s.s. would be unambiguously C3. In order to explore character evolution further, the morphological characters were mapped onto one of the most parsimonious trees. A relationship between photosynthetic pathways and inflorescence morphology is suggested here for the first time. Based on the optimization of morphological characters and additional data, we propose names for almost all inner clades at the rank of subtribe with a few groups as incertae sedis. With this extensive sampling, we resolved the phylogenetic relationships and the assignation of synapomorphies, and improved the support in subtribe sorting; consequently a robust circumscription of the tribe Paniceae s.l. is proposed.
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New Species of Paniceae (Poaceae, Panicoideae) from Brazil
Systematic Botany, 2011Co-Authors: Diego L. Salariato, Osvaldo Morrone, Fernando O. ZuloagaAbstract:Abstract Two new species of Paniceae are here described, one belonging to Dichanthelium (Dichanthelium barbadense) and the other to Panicum sect. Laxa (Panicum harleyi). Both taxa grow in open areas of Central Brazil are described, illustrated, and compared with putative related species.
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CHROMOSOME STUDIES IN AMERICAN PANICEAE (POACEAE, Panicoideae)
Annals of the Missouri Botanical Garden, 2010Co-Authors: Silvana M. Sede, Osvaldo Morrone, Alejandro Escobar, Fernando O. ZuloagaAbstract:Abstract Chromosome numbers and meiotic behavior of 60 individuals of American Paniceae, Poaceae, are provided, including six previously uncounted species: Axonopus andinus G. A. Black (2n = 20), A. iridifolius (Poepp.) G. A. Black (2n = 20), Dichanthelium hebotes (Trin.) Zuloaga (2n = 18), Paspalum geminiflorum Steud. (2n = ca. 20), P. heterotrichon Trin. (2n = 20), and Setaria tenacissima Schrad. ex Schult. (2n = 36). Of the remaining 54 counts, 17 correspond to new ploidy levels in species of Echinochloa P. Beauv., Eriochloa Kunth, Hymenachne P. Beauv., Panicum L., Parodiophyllochloa Zuloaga & Morrone, Paspalum L., and Setaria P. Beauv., and 37 are confirmations of previous reports.
Reyjane Patrícia De Oliveira - One of the best experts on this subject based on the ideXlab platform.
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Lectotypifications in Orthoclada (Poaceae, Panicoideae, Zeugiteae)
Phytotaxa, 2016Co-Authors: Marcos Da Costa Dórea, Reyjane Patrícia De Oliveira, Cassiano Aimberê Dorneles WelkerAbstract:The grass genus Orthoclada Beauvois (1812: 69) is currently placed in the subfamily Panicoideae, tribe Zeugiteae (Soreng et al. 2015), and includes only two species from forests of Tropical America and Africa: O. laxa (Richard 1792: 106) Beauvois (1812: 70) and O. africana Hubbard (1940: 3419) (Kellogg 2015, The Plant List 2016). The genus was formerly included in subfamily Centothecoideae (Clayton & Renvoize 1986), which was recently submerged into the Panicoideae (Sanchez-Ken & Clark 2010, Soreng et al. 2015). Orthoclada is characterized by its bisexual flowers and the unusual fusion of its rachilla internode to the palea keels (Kellogg 2015).
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Panicoideae poaceae em remanescentes florestais do sul da bahia aspectos taxonomicos e ecologicos
Rodriguésia - Instituto de Pesquisas Jardim Botânico do Rio de Janeiro, 2012Co-Authors: Karena Mendes Pimenta, Marcos Da Costa Dórea, Reyjane Patrícia De OliveiraAbstract:Resumo Esse trabalho consiste no levantamento das especies de Panicoideae (Poaceae) em remanescentes de Mata Atlântica no sul do estado da Bahia. As coletas foram realizadas entre os anos de 2007 e 2010, concentrando-se nos bordos e no interior dos tres maiores remanescentes florestais da Reserva Ecologica da Michelin (Mata da Vila 5, Pancada Grande e Pacange). Foram confirmadas 24 especies em 11 generos, sendo Ichnanthus P. Beauv. e Paspalum L. os mais representativos, com cinco e oito especies, respectivamente. Uma chave de identificacao para generos e especies e apresentada, assim como descricoes, ilustracoes e dados ecologicos, contribuindo para o conhecimento das especies florestais de Poaceae do Brasil. Palavras-chave : Gramineae , floristica, Mata Atlântica. Panicoideae (Poaceae) from forest remnants at the Southern Bahia: taxonomic and ecological aspects Abstract We present a floristic survey of Panicoideae (Poaceae) in remnants of Atlantic Forest in Southern Bahia State, Brazil, in the Michelin Ecological Reserve. Collections were made from 2007 to 2010, focusing on the borders and interior of the three major forest fragments (Vila 5, Pancada Grande and Pacange). Twenty four species in 11 genera were found, being Ichnanthus P. Beauv. and Paspalum L. the most representative, with five and eight species, respectively. An identification key to genera and species is presented, as well as descriptions, illustrations and ecological data, increasing the knowledge on Poaceae from Brazilian forests. Key words : Gramineae , floristic survey, Atlantic Forest.
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Ichnanthus longhi-wagnerii (Panicoideae): New Grass from the Atlantic Moist Forest of Bahia, Brazil
Systematic Botany, 2012Co-Authors: Aline Costa Da Mota, Reyjane Patrícia De OliveiraAbstract:Abstract Ichnanthus belongs to the grass subfamily Panicoideae and is characterized by the presence of winged appendages at the base of the upper lemma or by their scars. The genus includes about 30 species that predominate in Neotropical forests, with a great diversity found in Brazil. A new species, Ichnanthus longhi-wagnerii, is herein described, illustrated, and compared with its congeners. We also present geographical and ecological information, as well as SEM micrographs of the upper anthecium. This new species was previously collected in a submontane Atlantic moist forest in Southern Bahia, Brazil, but was not found during recent fieldtrips and is therefore considered endangered.
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Panicoideae (Poaceae) em remanescentes florestais do sul da Bahia: aspectos taxonômicos e ecológicos 1 Panicoideae (Poaceae) from forest remnants at the Southern Bahia: taxonomic and ecological aspects
2012Co-Authors: Karena Mendes Pimenta, Marcos Da Costa Dórea, Reyjane Patrícia De OliveiraAbstract:a floristic survey of Panicoideae (Poaceae) in remnants of Atlantic Forest in Southern Bahia State, Brazil, in the Michelin Ecological Reserve. Collections were made from 2007 to 2010, focusing on the borders and interior of the three major forest fragments (Vila 5, Pancada Grande and Pacange). Twenty four species in 11 genera were found, being Ichnanthus P. Beauv. and Paspalum L. the most representative, with five and eight species, respectively. An identification key to genera and species is presented, as well as descriptions, illustrations and ecological data, increasing the knowledge on Poaceae from Brazilian forests.
Lynn G. Clark - One of the best experts on this subject based on the ideXlab platform.
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Evolutionary relationships in Panicoid grasses based on plastome phylogenomics (Panicoideae; Poaceae).
BMC Plant Biology, 2016Co-Authors: Sean V. Burke, Lynn G. Clark, William P. Wysocki, Fernando O. Zuloaga, Joseph M. Craine, J. Chris Pires, Patrick P. Edger, Dustin Mayfield-jones, Scot A. Kelchner, Melvin R. DuvallAbstract:Panicoideae are the second largest subfamily in Poaceae (grass family), with 212 genera and approximately 3316 species. Previous studies have begun to reveal relationships within the subfamily, but largely lack resolution and/or robust support for certain tribal and subtribal groups. This study aims to resolve these relationships, as well as characterize a putative mitochondrial insert in one linage. 35 newly sequenced Panicoideae plastomes were combined in a phylogenomic study with 37 other species: 15 Panicoideae and 22 from outgroups. A robust Panicoideae topology largely congruent with previous studies was obtained, but with some incongruences with previously reported subtribal relationships. A mitochondrial DNA (mtDNA) to plastid DNA (ptDNA) transfer was discovered in the Paspalum lineage. The phylogenomic analysis returned a topology that largely supports previous studies. Five previously recognized subtribes appear on the topology to be non-monophyletic. Additionally, evidence for mtDNA to ptDNA transfer was identified in both Paspalum fimbriatum and P. dilatatum, and suggests a single rare event that took place in a common progenitor. Finally, the framework from this study can guide larger whole plastome sampling to discern the relationships in Cyperochloeae, Steyermarkochloeae, Gynerieae, and other incertae sedis taxa that are weakly supported or unresolved.
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Resolving deep relationships of PACMAD grasses: a phylogenomic approach
BMC Plant Biology, 2015Co-Authors: Joseph L. Cotton, Lynn G. Clark, William P. Wysocki, J. Chris Pires, Patrick P. Edger, Dustin Mayfield-jones, Scot A. Kelchner, Melvin R. DuvallAbstract:Plastome sequences for 18 species of the PACMAD grasses (subfamilies Panicoideae, Aristidoideae, Chloridoideae, Micrairoideae, Arundinoideae, Danthonioideae) were analyzed phylogenomically. Next generation sequencing methods were used to provide complete plastome sequences for 12 species. Sanger sequencing was performed to determine the plastome of one species, Hakonechloa macra, to provide a reference for annotation. These analyses were conducted to resolve deep subfamilial relationships within the clade. Divergence estimates were assessed to determine potential factors that led to the rapid radiation of this lineage and its dominance of warmer open habitats. New plastomes were completely sequenced and characterized for 13 PACMAD species. An autapomorphic ~1140 bp deletion was found in Hakonechloa macra putatively pseudogenizing rpl14 and eliminating rpl16 from this plastome. Phylogenomic analyses support Panicoideae as the sister group to the ACMAD clade. Complete plastome sequences provide greater support at deep nodes within the PACMAD clade. The initial diversification of PACMAD subfamilies was estimated to occur at 32.4 mya. Phylogenomic analyses of complete plastomes provides resolution for deep relationships of PACMAD grasses. The divergence estimate of 32.4 mya at the crown node of the PACMAD clade coincides with the Eocene-Oligocene Transition (EOT). The Eocene was a period of global cooling and drying, which led to forest fragmentation and the expansion of open habitats now dominated by these grasses. Understanding how these grasses are related and determining a cause for their rapid radiation allows for future predictions of grassland distribution in the face of a changing global climate.
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Phylogeny and a new tribal classification of the Panicoideae s.l. (Poaceae) based on plastid and nuclear sequence data and structural data.
American Journal of Botany, 2010Co-Authors: J. Gabriel Sánchez-ken, Lynn G. ClarkAbstract:UNLABELLED PREMISE OF THE STUDY The subfamily Panicoideae (Poaceae) encompasses nearly one-third of the diversity of grass species, including important crops such as maize and sugarcane. Previous analyses recovered strong support for a Panicoideae+Centothecoideae lineage within the diverse Panicoideae+Arundinoideae+Chloridoideae+Micrairoideae+Aristidoideae+Danthonioideae (PACMAD) clade, although support for internal relationships was inconsistent. The objectives of this research were to (1) further test the monophyly of each subfamily and previously recovered clades within the Panicoideae+Centothecoideae lineage, (2) establish phylogenetic relationships among these groups, and (3) propose a new tribal classification for this lineage based explicitly on the phylogeny. • METHODS Maximum parsimony and Bayesian inference analyses of 37 taxa were based on previously published sequences (ndhF and rpl16 intron) and on new plastid and nuclear (rbcL and granule-bound starch synthase I) sequence data as well as structural data. • Key results. The Panicoideae+Centothecoideae lineage and a majority of the clades identified in previous analyses continue to be robustly supported, but resolution along the backbone of the topology remains elusive. Support for the monophyly of both subfamilies was lacking although support values for some clades increased. The tribes Centotheceae and Arundinelleae were confirmed as polyphyletic. • CONCLUSIONS Subfamily Centothecoideae is formally submerged into the Panicoideae, and a new tribal classification for the expanded Panicoideae is proposed based explicitly on the phylogeny. This classification includes 12 tribes of which Chasmanthieae and Zeugiteae are segretated from the Centotheceae; Tristachyideae is segregated from Arundinelleae, and a new tribe, Cyperochloeae, is validated to accommodate two isolated genera. A key to the tribes is provided.
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Phylogenetic Relationships Within the Centothecoideae + Panicoideae Clade (Poaceae) Based on ndhF and rpl16 Intron Sequences and Structural Data
Aliso, 2007Co-Authors: J. Gabriel Sánchez-ken, Lynn G. ClarkAbstract:The PACCAD clade (Panicoideae, Arundinoideae, Chloridoideae, Centothecoideae, Aristidoideae, Danthonioideae) is well supported in all recent studies of Poaceae. However, phylogenetic relationships within the clade are still unresolved, although several branches are strongly supported. In this study, we focus on the phylogeny of the Centothecoideae + Panicoideae clade, one of the major lineages within the PACCAD clade, and one of the most diverse in the family. Two previously unsampled tribes, Isachneae and Steyermarkochloeae, are included, as are additional taxa of Centothecoideae. Phylogenetic analyses of plastid genome sequences (ndhl gene and rpl16 intron) and structural data show increased support of the centothecoid-panicoid clade, but phylogenetic relationships between the two putative subfamilies remain unresolved. Centothecoideae may be sister to Panicoideae or they may be paraphyletic with respect to Panicoideae, as monophyly of Centothecoideae is weakly supported at best. Polyphyly of Panicoideae is demonstrated as Isachneae and Steyermarkochloeae (only with ndhF) form well-supported clades with Micraira-Eriachne and Chasmanthium, respectively. Polyphyly of Arundinelleae is also confirmed as Danthoniopsis and related genera resolve elsewhere. Centothecoideae, as recently circumscribed, resolve as three strongly supported clades including Danthoniopsis and related genera. Cyperochloa (previously incertae sedis) and arundinoid Spartochloa are sister and fall within the centothecoids with strong support. Centotheceae are polyphyletic and segregate into three major groups. One centothecoid genus, Zeugites, is demonstrably paraphyletic.
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phylogenetic relationships within the centothecoideae Panicoideae clade poaceae based on ndhf and rpl16 intron sequences and structural data
Aliso, 2007Co-Authors: Gabriel J Sanchezken, Lynn G. ClarkAbstract:The PACCAD clade (Panicoideae, Arundinoideae, Chloridoideae, Centothecoideae, Aristidoideae, Danthonioideae) is well supported in all recent studies of Poaceae. However, phylogenetic relationships within the clade are still unresolved, although several branches are strongly supported. In this study, we focus on the phylogeny of the Centothecoideae + Panicoideae clade, one of the major lineages within the PACCAD clade, and one of the most diverse in the family. Two previously unsampled tribes, Isachneae and Steyermarkochloeae, are included, as are additional taxa of Centothecoideae. Phylogenetic analyses of plastid genome sequences (ndhl gene and rpl16 intron) and structural data show increased support of the centothecoid-panicoid clade, but phylogenetic relationships between the two putative subfamilies remain unresolved. Centothecoideae may be sister to Panicoideae or they may be paraphyletic with respect to Panicoideae, as monophyly of Centothecoideae is weakly supported at best. Polyphyly of Panicoideae is demonstrated as Isachneae and Steyermarkochloeae (only with ndhF) form well-supported clades with Micraira-Eriachne and Chasmanthium, respectively. Polyphyly of Arundinelleae is also confirmed as Danthoniopsis and related genera resolve elsewhere. Centothecoideae, as recently circumscribed, resolve as three strongly supported clades including Danthoniopsis and related genera. Cyperochloa (previously incertae sedis) and arundinoid Spartochloa are sister and fall within the centothecoids with strong support. Centotheceae are polyphyletic and segregate into three major groups. One centothecoid genus, Zeugites, is demonstrably paraphyletic.
