RESUMO
Phylogenetic approaches to macroevolution have provided unique insight into evolutionary relationships, ancestral ranges, and diversification patterns for many taxa. Similar frameworks have also been developed to assess how environmental and/or spatial variables shape species diversity and distribution patterns at different spatial/temporal scales, but studies implementing these are still scarce for many groups, including lichens. Here, we combine phylogeny-based ancestral range reconstruction and diversification analysis with community phylogenetics to reconstruct evolutionary origins and assess patterns of taxonomic and phylogenetic relatedness between island communities of the lichenized fungal genus Sticta in the Caribbean. Sampling was carried out in the Greater Antilles (Cuba, Jamaica, Dominican Republic, and Puerto Rico) and Lesser Antilles (Dominica, Guadeloupe, and Martinique). Data for six molecular loci were obtained for 64 candidate Caribbean species and used to perform both macroevolutionary phylogenetics, which also included worldwide taxa, and phylobetadiversity analyses, which emphasized island-level communities. Our work uncovered high levels of island endemism (â¼59%) in Caribbean Sticta. We estimate initial colonization of the region occurred about 19 Mya from a South American ancestor. Reverse migration events by Caribbean lineages to South America were also inferred. We found no evidence for increased diversification rates associated with range expansion into the Caribbean. Taxonomic and phylogenetic turnover between island-level communities was most strongly correlated with environmental variation rather than with geographic distance. We observed less dissimilarity among communities from the Dominican Republic and Jamaica than between these islands and the Lesser Antilles/Puerto Rico. High levels of hidden diversity and endemism in Caribbean Sticta reaffirm that islands are crucial for the maintenance of global biodiversity of lichenized fungi. Altogether, our findings suggest that strong evolutionary links exist between Caribbean and South American biotas but at regional scales, species assemblages exhibit complex taxonomic and phylogenetic relationships that are determined by local environments and shared evolutionary histories.
Assuntos
Ascomicetos , Evolução Biológica , Filogenia , Região do Caribe , Biodiversidade , Ascomicetos/genéticaRESUMO
Symbioses are evolutionarily pervasive and play fundamental roles in structuring ecosystems, yet our understanding of their macroevolutionary origins, persistence, and consequences is incomplete. We traced the macroevolutionary history of symbiotic and phenotypic diversification in an iconic symbiosis, lichens. By inferring the most comprehensive time-scaled phylogeny of lichen-forming fungi (LFF) to date (over 3,300 species), we identified shifts among symbiont classes that broadly coincided with the convergent evolution of phylogenetically or functionally similar associations in diverse lineages (plants, fungi, bacteria). While a relatively recent loss of lichenization in Lecanoromycetes was previously identified, our work instead suggests lichenization was abandoned far earlier, interrupting what had previously been considered a direct switch between trebouxiophycean and trentepohlialean algal symbionts. Consequently, some of the most diverse clades of LFF are instead derived from nonlichenized ancestors and re-evolved lichenization with Trentepohliales algae, a clade that also facilitated lichenization in unrelated lineages of LFF. Furthermore, while symbiont identity and symbiotic phenotype influence the ecology and physiology of lichens, they are not correlated with rates of lineage birth and death, suggesting more complex dynamics underly lichen diversification. Finally, diversification patterns of LFF differed from those of wood-rotting and ectomycorrhizal taxa, likely reflecting contrasts in their fundamental biological properties. Together, our work provides a timeline for the ecological contributions of lichens, and reshapes our understanding of symbiotic persistence in a classic model of symbiosis.
Assuntos
Líquens/genética , Líquens/metabolismo , Simbiose/genética , Ascomicetos/genética , Evolução Biológica , Clorófitas/genética , Ecossistema , Filogenia , Análise de Sequência de DNA/métodosRESUMO
We present the first broad molecular-phylogenetic revision of the lichenized family Gomphillaceae, based on 408 newly generated sequences of the mitochondrial SSU rDNA and nuclear LSU rDNA, representing 342 OTUs. The phylogenetic analysis of 20 out of the 28 currently accepted genera resulted in 48 clades. Twelve genera were resolved as monophyletic: Actinoplaca, Arthotheliopsis, Bullatina, Caleniopsis, Corticifraga, Gomphillus, Gyalectidium, Gyalidea, Jamesiella, Rolueckia, Rubrotricha, and Taitaia. Two genera resulted paraphyletic, namely Aulaxina (including Caleniopsis) and Asterothyrium (including Linhartia). Six genera were in part highly polyphyletic: Aderkomyces, Calenia, Echinoplaca, Gyalideopsis, Psorotheciopsis, and Tricharia. While ascoma morphology and anatomy has traditionally been considered as main character complex to distinguish genera, our study supported the notion that the characteristic asexual anamorph of Gomphillaceae, the so-called hyphophores, are diagnostic for most of the newly recognized clades. As a result, we recognize 26 new genus-level clades, three of which have names available (Microxyphiomyces, Psathyromyces, Spinomyces) and 23 that will require formal description as new genera. We also tested monophyly for 53 species-level names for which two or more specimens were sequenced: 27 were supported as monophyletic and representing a single species, 13 as monophyletic but with an internal topology suggesting cryptic speciation, four as paraphyletic, and nine as polyphyletic. These data suggest that species richness in the family is higher than indicated by the number of accepted names (currently 425); they also confirm that recently refined species concepts reflect species richness better than the broad concepts applied in Santesson's monograph. A divergence time analysis revealed that foliicolous Gomphillaceae diversified after the K-Pg-boundary and largely during the Miocene, a notion supported by limited data available for other common foliicolous lineages such as Chroodiscus (Graphidaceae), Pilocarpaceae, and Porinaceae. This contradicts recent studies suggesting that only macrofoliose Lecanoromycetes exhibit increased diversification rates in the Cenozoic.
Assuntos
Ascomicetos , Líquens , Ascomicetos/genética , Sequência de Bases , DNA Ribossômico/genética , Líquens/genética , Filogenia , Análise de Sequência de DNARESUMO
Recent studies have uncovered remarkable diversity in Dictyonema s.lat. basidiolichens, here recognized as subtribe Dictyonemateae. This group includes five genera and 148 species, but hundreds more await description. The photobionts of these lichens belong to Rhizonema, a recently resurrected cyanobacterial genus known by a single species. To further investigate photobiont diversity within Dictyonemateae, we generated 765 new cyanobacterial sequences from 635 specimens collected from 18 countries. The ITS barcoding locus supported the recognition of 200 mycobiont (fungal) species among these samples, but the photobiont diversity was comparatively low. Our analyses revealed three main divisions of Rhizonema, with two repeatedly recovered as monophyletic (proposed as new species), and the third mostly paraphyletic. The paraphyletic lineage corresponds to R. interruptum and partnered with mycobionts from all five genera in Dictyonemateae. There was no evidence of photobiont-mycobiont co-speciation, but one of the monophyletic lineages of Rhizonema appears to partner predominantly with one of the two major clades of Cora (mycobiont) with samples collected largely from the northern Andes. Molecular clock estimations indicate the Rhizonema species are much older than the fungal species in the Dictyonemateae, suggesting that these basidiolichens obtained their photobionts from older ascolichen lineages and the photobiont variation in extant lineages of Dictyonemateae is the result of multiple photobiont switches. These results support the hypothesis of lichens representing "fungal farmers," in which diverse mycobiont lineages associate with a substantially lower diversity of photobionts by sharing those photobionts best suited for the lichen symbiosis among multiple and often unrelated mycobiont lineages.
Assuntos
Agaricales , Líquens , Líquens/genética , Filogenia , Simbiose/genéticaRESUMO
Species in the fungal genus Sticta form symbiotic associations primarily with either green algae or cyanobacteria, but tripartite associations or photosymbiodemes involving both types of photobionts occur in some species. Sticta is known to associate with green algae in the genus Symbiochloris. However, previous studies have shown that algae from other genera, such as Heveochlorella, may also be suitable partners for Sticta. We examined the diversity of green algal partners in the genus Sticta and assessed the patterns of association between the host fungus and its algal symbiont. We used multi-locus sequence data from multiple individuals collected in Australia, Cuba, Madagascar, Mauritius, New Zealand, Reunion and South America to infer phylogenies for fungal and algal partners and performed tests of congruence to assess coevolution between the partners. In addition, event-based methods were implemented to examine which cophylogenetic processes have led to the observed association patterns in Sticta and its green algal symbionts. Our results show that in addition to Symbiochloris, Sticta associates with green algae from the genera Chloroidium, Coccomyxa, Elliptochloris and Heveochlorella, the latter being the most common algal symbiont associated with Sticta in this study. Geography plays a strong role in shaping fungal-algal association patterns in Sticta as mycobionts associate with different algal lineages in different geographic locations. While fungal and algal phylogenies were mostly congruent, event-based methods did not find any evidence for cospeciation between the partners. Instead, the association patterns observed in Sticta and associated algae, were largely explained by other cophylogenetic events such as host-switches, losses of symbiont and failure of the symbiont to diverge with its host. Our results also show that tripartite associations with green algae evolved multiple times in Sticta.
Assuntos
Ascomicetos/classificação , Clorófitas/classificação , Ascomicetos/genética , Clorófitas/genética , Tipagem de Sequências Multilocus , Filogenia , RNA Ribossômico 18S/química , RNA Ribossômico 18S/classificação , RNA Ribossômico 18S/genética , SimbioseRESUMO
A major challenge to evolutionary biologists is to understand how biodiversity is distributed through space and time and across the tree of life. Diversification of organisms is influenced by many factors that act at different times and geographic locations but it is still not clear which have a significant impact and how drivers interact. To study diversification, we chose the lichen genus Sticta, by sampling through most of the global range and producing a time tree. We estimate that Sticta originated about 30 million years ago, but biogoegraphic analysis was unclear in estimating the origin of the genus. Furthermore, we investigated the effect of dispersal ability finding that Sticta has a high dispersal rate, as collections from Hawaii showed that divergent lineages colonized the islands at least four times. Symbiont interactions were investigated using BiSSE to understand if green-algal or cyanobacterial symbiont interactions influenced diversification, only to find that the positive results were driven almost completely by Type I error. On the other hand, another BiSSE analysis found that an association with Andean tectonic activity increases the speciation rate of species.
Assuntos
Ascomicetos/classificação , Biodiversidade , Filogenia , Evolução Biológica , Extinção Biológica , Líquens/classificação , Filogeografia , Fatores de TempoRESUMO
The number of Fungi is estimated at between 1.5 and 3 million. Lichenized species are thought to make up a comparatively small portion of this figure, with unrecognized species richness hidden among little-studied, tropical microlichens. Recent findings, however, suggest that some macrolichens contain a large number of unrecognized taxa, increasing known species richness by an order of magnitude or more. Here we report the existence of at least 126 species in what until recently was believed to be a single taxon: the basidiolichen fungus Dictyonema glabratum, also known as Cora pavonia. Notably, these species are not cryptic but morphologically distinct. A predictive model suggests an even larger number, with more than 400 species. These results call into question species concepts in presumably well-known macrolichens and demonstrate the need for accurately documenting such species richness, given the importance of these lichens in endangered ecosystems such as paramos and the alarming potential for species losses throughout the tropics.
Assuntos
Basidiomycota/classificação , Líquens/classificaçãoRESUMO
Foliicolous lichens are formed by diverse, highly specialized fungi that establish themselves and complete their life cycle within the brief duration of their leaf substratum. Over half of these lichen-forming fungi are members of either the Gomphillaceae or Pilocarpaceae, and associate with Trebouxia-like green algae whose identities have never been positively determined. We investigated the phylogenetic affinities of these photobionts to better understand their role in lichen establishment on an ephemeral surface. Thallus samples of Gomphillaceae and Pilocarpaceae were collected from foliicolous communities in southwest Florida and processed for sequencing of photobiont marker genes, algal cultivation and/or TEM. Additional specimens from these families and also from Aspidothelium (Thelenellaceae) were collected from a variety of substrates globally. Sequences from rbcL and nuSSU regions were obtained and subjected to Maximum Likelihood and Bayesian analyses. Analysis of 37 rbcL and 7 nuSSU algal sequences placed all photobionts studied within the provisional trebouxiophycean assemblage known as the Watanabea clade. All but three of the sequences showed affinities within Heveochlorella, a genus recently described from tree trunks in East Asia. The photobiont chloroplast showed multiple thylakoid stacks penetrating the pyrenoid centripetally as tubules lined with pyrenoglobuli, similar to the two described species of Heveochlorella. We conclude that Heveochlorella includes algae of potentially major importance as lichen photobionts, particularly within (but not limited to) foliicolous communities in tropical and subtropical regions worldwide. The ease with which they may be cultivated on minimal media suggests their potential to thrive free-living as well as in lichen symbiosis.
Assuntos
Clorófitas/classificação , Clorófitas/fisiologia , Líquens/fisiologia , Filogenia , Simbiose , Proteínas de Algas/genética , Clorófitas/genética , DNA de Algas/genética , Florida , Análise de Sequência de DNARESUMO
We present a taxonomic revision of the lichenized basidiomycete genus Acantholichen, species of which produce a characteristic blue-gray, microsquamulose thallus with spiny apical hyphal cells known as acanthohyphidia. Since its discovery, the genus was thought to be monospecific, only including the generic type, A. pannarioides. However, a detailed morphological and anatomical study of recently collected specimens from the Galápagos, Costa Rica, Brazil and Colombia, combined with a molecular phylogenetic analysis of the internal transcribed spacer (ITS1-5.8S-ITS2) region and 28S of the nuc rDNA and RPB2 sequences, revealed a much more diverse and widespread species assemblage. Based on the results of these analyses, we describe five new species in the genus: A. albomarginatus, A. campestris, A. galapagoensis, A. sorediatus and A. variabilis. We also provide an identification key to all species, anatomical and morphological descriptions, photographs and a table comparing main characters of each species.
Assuntos
Basidiomycota/classificação , Variação Genética , Líquens/classificação , Sequência de Bases , Basidiomycota/citologia , Basidiomycota/genética , Brasil , Colômbia , Costa Rica , DNA Fúngico/química , DNA Fúngico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Proteínas Fúngicas/genética , Líquens/citologia , Líquens/genética , Dados de Sequência Molecular , Filogenia , Alinhamento de Sequência , Análise de Sequência de DNARESUMO
The internal transcribed spacer region (ITS) of the nuclear rDNA cistron represents the barcoding locus for Fungi. Intragenomic variation of this multicopy gene can interfere with accurate phylogenetic reconstruction of biological entities. We investigated the amount and nature of this variation for the lichenized fungus Cora inversa in the Hygrophoraceae (Basidiomycota: Agaricales), analyzing base call and length variation in ITS1 454 pyrosequencing data of three samples of the target mycobiont, for a total of 16,665 reads obtained from three separate repeats of the same samples under different conditions. Using multiple fixed alignment methods (PaPaRa) and maximum likelihood phylogenetic analysis (RAxML), we assessed phylogenetic relationships of the obtained reads, together with Sanger ITS sequences from the same samples. Phylogenetic analysis showed that all ITS1 reads belonged to a single species, C. inversa. Pyrosequencing data showed 266 insertion sites in addition to the 325 sites expected from Sanger sequences, for a total of 15,654 insertions (0.94 insertions per read). An additional 3,279 substitutions relative to the Sanger sequences were detected in the dataset, out of 5,461,125 bases to be called. Up to 99.3% of the observed indels in the dataset could be interpreted as 454 pyrosequencing errors, approximately 65% corresponding to incorrectly recovered homopolymer segments, and 35% to carry-forward-incomplete-extension errors. Comparison of automated clustering and alignment-based phylogenetic analysis demonstrated that clustering of these reads produced a 35-fold overestimation of biological diversity in the dataset at the 95% similarity threshold level, whereas phylogenetic analysis using a maximum likelihood approach accurately recovered a single biological entity. We conclude that variation detected in 454 pyrosequencing data must be interpreted with great care and that a combination of a sufficiently large number of reads per taxon, a set of Sanger references for the same taxon, and at least two runs under different emulsion PCR and sequencing conditions, are necessary to reliably separate biological variation from 454 sequencing errors. Our study shows that clustering methods are highly sensitive to artifactual sequence variation and inadequate to properly recover biological diversity in a dataset, if sequencing errors are substantial and not removed prior to clustering analysis.
Assuntos
Basidiomycota/genética , DNA Espaçador Ribossômico , Genoma Fúngico , Haplótipos , Basidiomycota/classificação , Biodiversidade , Evolução Molecular , Variação Genética , Mutagênese InsercionalRESUMO
The Lecanoromycetes is the largest class of lichenized Fungi, and one of the most species-rich classes in the kingdom. Here we provide a multigene phylogenetic synthesis (using three ribosomal RNA-coding and two protein-coding genes) of the Lecanoromycetes based on 642 newly generated and 3329 publicly available sequences representing 1139 taxa, 317 genera, 66 families, 17 orders and five subclasses (four currently recognized: Acarosporomycetidae, Lecanoromycetidae, Ostropomycetidae, Umbilicariomycetidae; and one provisionarily recognized, 'Candelariomycetidae'). Maximum likelihood phylogenetic analyses on four multigene datasets assembled using a cumulative supermatrix approach with a progressively higher number of species and missing data (5-gene, 5+4-gene, 5+4+3-gene and 5+4+3+2-gene datasets) show that the current classification includes non-monophyletic taxa at various ranks, which need to be recircumscribed and require revisionary treatments based on denser taxon sampling and more loci. Two newly circumscribed orders (Arctomiales and Hymeneliales in the Ostropomycetidae) and three families (Ramboldiaceae and Psilolechiaceae in the Lecanorales, and Strangosporaceae in the Lecanoromycetes inc. sed.) are introduced. The potential resurrection of the families Eigleraceae and Lopadiaceae is considered here to alleviate phylogenetic and classification disparities. An overview of the photobionts associated with the main fungal lineages in the Lecanoromycetes based on available published records is provided. A revised schematic classification at the family level in the phylogenetic context of widely accepted and newly revealed relationships across Lecanoromycetes is included. The cumulative addition of taxa with an increasing amount of missing data (i.e., a cumulative supermatrix approach, starting with taxa for which sequences were available for all five targeted genes and ending with the addition of taxa for which only two genes have been sequenced) revealed relatively stable relationships for many families and orders. However, the increasing number of taxa without the addition of more loci also resulted in an expected substantial loss of phylogenetic resolving power and support (especially for deep phylogenetic relationships), potentially including the misplacements of several taxa. Future phylogenetic analyses should include additional single copy protein-coding markers in order to improve the tree of the Lecanoromycetes. As part of this study, a new module ("Hypha") of the freely available Mesquite software was developed to compare and display the internodal support values derived from this cumulative supermatrix approach.
Assuntos
Ascomicetos/classificação , Filogenia , Ascomicetos/genética , Núcleo Celular/genética , Genes Fúngicos , Genes Mitocondriais , Funções Verossimilhança , Modelos Genéticos , RNA Ribossômico/genética , Alinhamento de Sequência , Análise de Sequência de DNA , SoftwareRESUMO
Article 59.1, of the International Code of Nomenclature for Algae, Fungi, and Plants (ICN; Melbourne Code), which addresses the nomenclature of pleomorphic fungi, became effective from 30 July 2011. Since that date, each fungal species can have one nomenclaturally correct name in a particular classification. All other previously used names for this species will be considered as synonyms. The older generic epithet takes priority over the younger name. Any widely used younger names proposed for use, must comply with Art. 57.2 and their usage should be approved by the Nomenclature Committee for Fungi (NCF). In this paper, we list all genera currently accepted by us in Dothideomycetes (belonging to 23 orders and 110 families), including pleomorphic and nonpleomorphic genera. In the case of pleomorphic genera, we follow the rulings of the current ICN and propose single generic names for future usage. The taxonomic placements of 1261 genera are listed as an outline. Protected names and suppressed names for 34 pleomorphic genera are listed separately. Notes and justifications are provided for possible proposed names after the list of genera. Notes are also provided on recent advances in our understanding of asexual and sexual morph linkages in Dothideomycetes. A phylogenetic tree based on four gene analyses supported 23 orders and 75 families, while 35 families still lack molecular data.
RESUMO
Colombia is a megadiverse country, but with a substantial gap in the taxonomic and ecological knowledge of fungi and lichens. Thus, the objective of the present study was an ecogeographical analysis of the Sticta species in Colombia. The data included macrodistribution (with respect to mountain ranges and life zones) and microhabitat preferences (light, substrate) and were obtained from field work and herbarium collection labels (completed by comparison with modern geographic and vegetation maps), for 103 species of Sticta currently recognized in Colombia (plus seven additional biotypes with different photobionts or reproductive mode). Using non-metric multidimensional scaling (NMS), correlations between ecogeographical variables and species were established, and ecotypes were delimited. Colombian species of Sticta showed distinct distribution patterns relative to altitude, mountain ranges, life zones, as well as light exposure and substrate, forming several distinct groups. Cyanobacterial species tend to have wider distribution ranges than green algal species. We concluded that the orogeny of the Northern Andes substantially affected speciation of the genus Sticta and its ecogeographical differentiation.
Assuntos
Ascomicetos/classificação , Colômbia , Ecossistema , Geografia , FilogeniaRESUMO
The genus Wetmoreana was studied using quantitative integrative taxonomy methods to resolve the genus delimitation and explore its taxonomy diversity at the species level. As a result, the genus Fulgogasparrea is synonymized with Wetmoreana, and the latter includes 15 formally described species, one subspecies, and three further, thus far undescribed species: W. appressa, W. awasthii comb. nov., W. bahiensis sp. nov., W. brachyloba comb. nov., W. brouardii, W. chapadensis comb. nov., W. circumlobata sp. nov., W. decipioides, W. intensa comb. nov., W. ochraceofulva comb. nov., W. rubra sp. nov., W. sliwae sp. nov., W. sliwae ssp. subparviloba subsp. nov., W. subnitida comb. nov., W. texana, and W. variegata sp. nov. Eleven of 19 examined taxa are newly placed within this genus or confirmed to belong to it. Two species, W. awasthii and W. intensa, are transferred to Wetmoreana without additional analysis but based on previous studies. The W. brouardii and W. ochraceofulva species complexes are discussed in detail. Additionally, Caloplaca muelleri and C. rubina var. evolutior are transferred to Squamulea, and the latter is elevated to the species rank.
RESUMO
Four species of the genus Sticta are described as new from Bolivia, based on morphological examination and phylogenetic analysis of the fungal ITS barcoding marker. Additionally, two species are reported as new to Bolivia (their identification confirmed by molecular data) and one previously reported species is confirmed by molecular data for the first time. Detailed morphological and anatomical descriptions are provided for all new species. Two of the new species, S.isidiolobulata Ossowska, B. Moncada, Lücking & Kukwa and S.madidiensis Ossowska, B. Moncada, Lücking & Kukwa belong to clade I, as defined in previous studies. In contrast, S.montepunkuensis Ossowska, B. Moncada, Lücking & Kukwa and S.macrolobata Ossowska, B. Moncada, Lücking & Kukwa, also described here as new to science, belong to clade III. Stictaisidiolobulata has an irregular to suborbicular thallus of medium size, with isidia developing into spathulate lobules, cyanobacterial photobiont and apothecia with entire to weakly-crenate margins. The large irregular thallus of the cyanobacteria-associated S.macrolobata has broad lobes, apothecia with verrucous to tomentose margins and cyphellae with raised margins, whereas S.madidiensis has a medium-sized, palmate to irregular thallus with a stipe, but without vegetative propagules and apothecia. Stictamontepunkuensis has large and irregular thalli with green algae as photobiont, apothecia with crenate to verrucous margins and urceolate cyphellae with a wide pore and a scabrid basal membrane. Two species, S.beauvoisii Delise and S.riparia Merc.-Díaz are reported as new to Bolivia (the latter also as new to South America) and belong to clade III. Stictatomentosa (Sw.) Ach., species confirmed from Bolivia by molecular data, belongs to clade II. Stictabeauvoisii is characterised by a smooth yellowish-brown upper surface with darker apices and abundant, marginal isidia and a brown lower surface with golden-chocolate brown primary tomentum and sparse, golden-brown rhizines. Stictariparia has a strongly branched thallus, with undulate lobes and abundant, marginal, palmate, grey to dark brown phyllidia and greyish-brown lower surface with the primary tomentum absent towards the margins. Stictatomentosa has palmate, bluish thalli with white cilia and abundant, submarginal apothecia and creamy-white lower surface with a sparse, white primary tomentum.
RESUMO
The nuclear ribosomal internal transcribed spacer (ITS) region is the formal fungal barcode and in most cases the marker of choice for the exploration of fungal diversity in environmental samples. Two problems are particularly acute in the pursuit of satisfactory taxonomic assignment of newly generated ITS sequences: (i) the lack of an inclusive, reliable public reference data set and (ii) the lack of means to refer to fungal species, for which no Latin name is available in a standardized stable way. Here, we report on progress in these regards through further development of the UNITE database (http://unite.ut.ee) for molecular identification of fungi. All fungal species represented by at least two ITS sequences in the international nucleotide sequence databases are now given a unique, stable name of the accession number type (e.g. Hymenoscyphus pseudoalbidus|GU586904|SH133781.05FU), and their taxonomic and ecological annotations were corrected as far as possible through a distributed, third-party annotation effort. We introduce the term 'species hypothesis' (SH) for the taxa discovered in clustering on different similarity thresholds (97-99%). An automatically or manually designated sequence is chosen to represent each such SH. These reference sequences are released (http://unite.ut.ee/repository.php) for use by the scientific community in, for example, local sequence similarity searches and in the QIIME pipeline. The system and the data will be updated automatically as the number of public fungal ITS sequences grows. We invite everybody in the position to improve the annotation or metadata associated with their particular fungal lineages of expertise to do so through the new Web-based sequence management system in UNITE.
Assuntos
Bases de Dados de Ácidos Nucleicos , Fungos/classificação , Filogenia , Código de Barras de DNA Taxonômico , DNA Fúngico/genética , DNA Espaçador Ribossômico/genética , Fungos/genética , InternetRESUMO
PREMISE OF THE STUDY: This study elucidates the phylogenetic position of a unique taxon of Graphidaceae occurring on rock in coastal desert areas, assessing its importance for our understanding of the evolution of the largest family of tropical lichenized fungi. ⢠METHODS: We used maximum likelihood and Bayesian approaches to reconstruct a three-gene phylogeny of Graphidaceae and a Bayesian molecular clock approach to estimate divergence dates for major clades, as well as Bayesian ancestral ecogeography state analysis. ⢠KEY RESULTS: The new genus Redonographa represents a new subfamily, Redonographoideae, sister to subfamily Graphidoideae. Redonographa is exclusively saxicolous and restricted to the American Pacific coast from California to central Chile, including Galapagos. It contains four species: Redonographa chilensis comb. nov., R. saxiseda comb. nov., R. saxorum comb. nov., and R. galapagoensis sp. nov. The genus Gymnographopsis, with a similar ecogeography but differing in excipular carbonization and chemistry, is also included in Redonographoideae, with the species G. chilena from Chile and G. latispora from South Africa. Molecular clock analysis indicates that Redonographoideae diverged from Graphidoideae about 132 million years ago (Ma) in the Early Cretaceous. ⢠CONCLUSIONS: The divergence date for subfamilies Redonographoideae and Graphidoideae coincides with the early breakup of Gondwana and ancient origin of the Atacama Desert. However, the common ancestor of Redonographoideae plus Graphidoideae was reconstructed to be tropical-epiphytic. Thus, even if Redonographoideae is subtropical-saxicolous, the hypothesis that Graphidoideae evolved from a subtropical-saxicolous ancestor is not supported.
Assuntos
Ascomicetos/classificação , Ascomicetos/genética , Evolução Biológica , Demografia , Líquens , Paraparesia Espástica Tropical , Filogenia , Estados UnidosRESUMO
More than 10 years after the establishment of the six core competencies by the Accreditation Council for Graduate Medical Education, systems-based practice remains an elusive subject to teach, measure, and document. A wide variety of methods have been reported that address teaching and assessing performance for the discrete parts of systems-based practice; however, no single approach has been described that encompasses the competency in its entirety. To better understand the current state of this competency, orthopaedic residents and educators from around the country were surveyed to determine which systems-based practice topics were being taught at their institutions, how these topics were being taught, and how resident performance was assessed. Seven focus group sessions were held with members involved in the care of musculoskeletal patients to determine what they believed were essential skills for residents to learn relative to the healthcare system. Using this information, a health systems rotation was created for first-year residents that incorporated several different teaching and assessment methods. This rotation has received positive feedback from residents, patients, and health professionals. Its effect on resident development will be tracked over the next 5 years.
Assuntos
Competência Clínica , Internato e Residência , Ortopedia/educação , Grupos Focais , Humanos , Aprendizagem Baseada em Problemas , Ensino/métodosRESUMO
Using the genus Casearia, we assessed the status of nested singletons: individual specimens corresponding to accepted species but in molecular trees appearing nested within clades of closely related species. Normally, such cases would be left undecided, while on the other hand, timely taxonomic decisions are required. We argue that morphological, chorological, and ecological data can be informative to illuminate patterns of speciation. Their use can provide a first step in testing taxon concepts at species level. We focused on five cases of nested singletons in trees of the genus Casearia. We employed PCA and cluster analysis to assess phenotypic differentiation. Using geocoordinates, we calculated niche space differentiation based on 19 bioclim variables, by means of PCA and niche equivalency and similarity tests and generated dot maps. We found that the singletons were morphologically distinctive in two of the five cases (Casearia selloana and C. manausensis), relatively distinctive in two other cases (C. zizyphoides and C. mariquitensis), and partially overlapping in the last case (C. grandiflora). For two cases (C. mariquitensis and C. selloana), ecological niche space was broadly overlapping, in two cases it was found broadly nested (C. grandiflora and C. zizyphoides), and in one case narrowly nested (C. manausensis), but in no case niche differentiation was observed. Niche overlap, similarity and equivalency showed corresponding patterns. Given these data, one would interpret C. selloana and C. manausensis as presumably well-distinguished taxa, their narrow distribution ranges suggesting recently emerging lineages. The other three cases are not clearcut. Morphological data would suggest particularly C. grandiflora conspecific with C. arborea, but differences in the distribution are intriguing. Our approach would reject the notion of potential synonymy based on nested phylogenetic placement for at least two of the five cases. The other case also shows no complete lack of differentiation which would support synonymy.
RESUMO
We sequenced over 200 recent specimens of Lecanora s.lat. from Brazil, delimiting 28 species in our material. Many seem to represent undescribed species, some of which being morphologically and chemically similar to each other or to already described species. Here, we present a phylogenetic analysis based on ITS, including our specimens and GenBank data. We describe nine new species. The purpose of the paper is to illustrate the diversity of the genus in Brazil, not to focus on segregate genera. However, we found that all Vainionora species cluster together and these will be treated separately. Other Lecanora species with dark hypothecium clustered in several different clades. Species with the morphology of Lecanora caesiorubella, in which currently several subspecies with different chemistry and distribution are recognized, fall apart in different, distantly related clades, so they cannot be regarded as subspecies but should be recognized at species level. A key is given for the Lecanora species from Brazil.