RESUMO
Species of the genus Russula are key components of ectomycorrhizal ecosystems worldwide. Nevertheless, their diversity in the tropics is still poorly known. This study aims to contribute to the knowledge of the diversity of Russula species classified in subsection Roseinae based on specimens recently collected in tropical montane rainforests in western Panama. A five gene multilocus phylogeny based on the nuclear markers ITS nrDNA, MCM7, RPB1, RPB2 and TEF-1α was constructed to identify the systematic position of 22 collections from Panama. Four new species, Russula cornicolor, Russula cynorhodon, Russula oreomunneae and Russula zephyrovelutipes are formally described and illustrated. None of the four species are sister species and they are more closely related to North American or Asian species. Two of the newly described species were associated with the ectomycorrhizal tree species Oreomunnea mexicana, while the other two species were associated with Quercus species. All four species are so far only known from mountains in western Panama.
Assuntos
Basidiomycota/classificação , Micorrizas/classificação , Basidiomycota/genética , Biodiversidade , DNA Fúngico/genética , Florestas , Micorrizas/genética , Panamá , Filogenia , Especificidade da Espécie , Clima TropicalRESUMO
Species of Russula are ubiquitous members of ectomycorrhizal fungal communities in tropical ecosystems. However, an important part of the total tropical diversity of this genus and its biogeographic patterns is unknown due to the lack of studies on Russula in tropical ecosystems. We combined molecular, morphological, ecological, and biogeographic data to elaborate concepts for two new subspecies of R. floriformis (subsection Substriatinae). Russula floriformis subsp. floriformis and R. floriformis subsp. symphoniae are described as new from montane forest dominated by Quercus and/or Oreomunnea (Fagales) from Colombia and Panama, respectively. Phylogenies were constructed using nuc rDNA internal transcribed spacer region ITS1-5.8S-ITS2 (ITS), D1-D2 domains of nuc 28S rDNA (28S), and partial regions of the second largest subunit of RNA polymerase II (rpb2) and translation elongation factor 1-alpha (tef1). Similar environmental conditions, similar morphology, and an ITS sequence similarity higher than 99% with only three different positions indicate that these two subspecies are closely related. Detailed observations of microscopic structures and analyses of further DNA loci, however, revealed morphological and molecular characteristics that allow distinguishing the two subspecies of R. floriformis. Spatial distribution and phylogenetic proximity of the two Russula subspecies and their ectomycorrhizal hosts, i.e., species of Quercus, suggest that their diversification is a result of comigration, adaptation, and geographic isolation along the Isthmus of Panama during the Pliocene and Pleistocene.
Assuntos
Ecossistema , Análise por Conglomerados , DNA Fúngico/genética , DNA Ribossômico/genética , DNA Espaçador Ribossômico/genética , Filogenia , RNA Ribossômico 28S/genética , RNA Ribossômico 5,8S , Análise de Sequência de DNARESUMO
Soil degradation can have an impact on the soil microbiota, but its specific effects on soil fungal communities are poorly understood. In this work, we studied the impact of soil degradation on the richness and diversity of communities of soil fungi, including three different degrees of degradation in Germany and Panama. Soil fungi were isolated monthly using the soil-sprinkling method for 8 months in Germany and 3 months in Panama, and characterized by morphological and molecular data. Soil physico-chemical properties were measured and correlated with the observed values of fungal diversity. We isolated a total of 71 fungal species, 47 from Germany, and 32 from Panama. Soil properties were not associated with fungal richness, diversity, or composition in soils, with the exception of soil compaction in Germany. The geographic location was a strong determinant of the soil fungal species composition although in both countries there was dominance by members of the orders Eurotiales and Hypocreales. In conclusion, the results of this work do not show any evident influence of soil degradation on communities of soil fungi in Germany or Panama.
RESUMO
Species of tropical tar spot fungi (Phyllachorales, Ascomycota) are obligate biotrophic plant parasitic fungi associated with living leaves of a wide range of families of host plants, mainly in tropical and subtropical regions. In this study, samples of tropical tar spot fungi were collected in forests in Costa Rica and Panamá. To identify taxa, we used morphology and information on host plants and combined multigene phylogeny of four genes: the large subunit nuclear ribosomal DNA (28S rDNA), the small subunit nuclear ribosomal DNA (18S rDNA), the complete internal transcribed spacer region of ribosomal DNA (nuc rDNA ITS1-5.8S-ITS2; ITS), and the translation elongation factor 1-α (tef1). Here we propose one new species in the genus Camarotella and eight new species in Telimena with their morphological descriptions, illustrations, and sequence data. The newly described species are Camarotella licaniae on Licania arborea (Chrysobalanaceae) and in the genus Telimena: T. billiae on Billia rosea (Sapindaceae), T. drymoniae on Drymonia multiflora (Gesneriaceae), T. hydrangeae on Hydrangea sp. (Hydrangeaceae), T. miravallensis on Symplocos panamensis (Symplocaceae), T. protii on Protium sp. (Burseraceae), T. rinoreae on Rinorea sp. (Violaceae), T. semialarii on Semialarium mexicanum (Celastraceae), and T. triseptata on Tapirira mexicana (Anacardiaceae). The new name Telimena nitens on Schlegelia brachyanta (Schlegeliaceae) is presented and 10 species of Phyllachora are transferred to Telimena, leading to the new combinations T. canarii, T. galavisii, T. insueta, T. ruelliae, T. scutiformis, T. serjaniicola, T. spicatae, T. subrepens, T. symploci, and T. symplocicola. Additionally, revisions of tar spot fungi on host families Burseraceae, Sapindaceae, and Symplocaceae are provided, and four new synonyms are proposed.
Assuntos
Carpóforos/crescimento & desenvolvimento , Phyllachorales/classificação , Phyllachorales/isolamento & purificação , Filogenia , Análise por Conglomerados , Costa Rica , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Microscopia , Microscopia de Contraste de Fase , Panamá , Fator 1 de Elongação de Peptídeos/genética , Phyllachorales/genética , Doenças das Plantas/microbiologia , RNA Ribossômico 18S/genética , RNA Ribossômico 28S/genética , Análise de Sequência de DNARESUMO
Five new species belonging to Hermatomyces (Hermatomycetaceae, Pleosporales) are described based on morphological investigations of specimens collected on rotten twigs and stems of various plants in Panama as well as phylogenetic analyses of sequence data of nuclear ribosomal and protein coding genes (EF1-α, RPB2, ß-TUB). The new species are described as: Hermatomyces bifurcatus, H. constrictus, H. megasporus, H. sphaericoides, and H. verrucosus spp. nov. Previously described species such as H. sphaericus and H. tucumanensis were identified among the studied specimens. The new combination, H. reticulatus, is made for Subicularium reticulatum based on examination of the holotype and fresh collections. Hermatomyces subiculosus, originally described from Thailand, is reduced to synonymy with H. reticulatus; H. tectonae is synonymized under H. sphaericus based on morphological and molecular evidence; and H. chiangmaiensis and H. thailandicus are considered later synonyms of H. krabiensis and H. indicus, respectively. The type material of Scyphostroma mirum was found to be conspecific with H. tucumanensis and, therefore, the generic name Hermatomyces should be conserved or protected against the older name Scyphostroma and the binomial H. tucumanensis against S. mirum. Sixteen species of Hermatomyces are recognized, their distinctive characteristics are highlighted in line drawings and a key is provided for their identification. The peculiar morphology and consistent phylogeny of new and previously known Hermatomyces species supports the recognition of the recently introduced monotypic family Hermatomycetaceae as a well delimited monophyletic taxon within the order Pleosporales.
RESUMO
Background and Aims: Sugarcane smut is caused by the fungus Sporisorium scitamineum (Ustilaginales/Ustilaginomycotina/Basidiomycota), which is responsible for losses in sugarcane production worldwide. Infected plants show a profound metabolic modification resulting in the development of a whip-shaped structure (sorus) composed of a mixture of plant tissues and fungal hyphae. Within this structure, ustilospores develop and disseminate the disease. Despite the importance of this disease, a detailed histopathological analysis of the plant-pathogen interaction is lacking. Methods: The whip-shaped sorus was investigated using light microscopy, scanning and transmission electron microscopy, histochemical tests and epifluorescence microscopy coupled with deconvolution. Key Results: Sorus growth is mediated by intercalary meristem activity at the base of the sorus, where the fungus causes partial host cell wall degradation and formation of intercellular spaces. Sporogenesis in S. scitamineum is thallic, with ustilospore initials in intercalary or terminal positions, and mostly restricted to the base of the sorus. Ustilospore maturation is centrifugal in relation to the ground parenchyma and occurs throughout the sorus median region. At the apex of the sorus, the fungus produces sterile cells and promotes host cell detachment. Hyphae are present throughout the central axis of the sorus (columella). The plant cell produces callose around the intracellular hyphae as well as inside the papillae at the infection site. Conclusions: The ontogeny of the whip-shaped sorus suggests that the fungus can cause the acropetal growth in the intercalary meristem. The sporogenesis of S. scitamineum was described in detail, demonstrating that the spores are formed exclusively at the base of the whip. Light was also shed on the nature of the sterile cells. The presence of the fungus alters the host cell wall composition, promotes its degradation and causes the release of some peripheral cells of the sorus. Finally, callose was observed around fungal hyphae in infected cells, suggesting that deposition of callose by the host may act as a structural response to fungal infection.
Assuntos
Doenças das Plantas/microbiologia , Saccharum/microbiologia , Ustilaginales/fisiologia , Interações Hospedeiro-Patógeno , Hifas/fisiologia , Hifas/ultraestrutura , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Esporos Fúngicos/crescimento & desenvolvimento , Esporos Fúngicos/fisiologia , Esporos Fúngicos/ultraestrutura , Ustilaginales/crescimento & desenvolvimento , Ustilaginales/ultraestruturaRESUMO
Delimitation of species and the search for a proper threshold for defining phylogenetic species in fungi are under discussion. In this study, morphological and molecular data are correlated to delimit species of Tulasnella, the most important mycobionts of Orchidaceae, which suffer from poor taxonomy. Resupinate basidiomata of Tulasnella species were collected in Ecuador and Germany, and 11 specimens (seven from Ecuador, four from Germany) were assigned to traditional species concepts by use of morphological keys. The specimens were compared by micro-anatomical examination with 75 specimens of Tulasnella borrowed from fungaria to obtain better insights on variation of characters. Sequences of the ITS region (127) were obtained after cloning from the fresh basidiomata and from pure cultures. Proportional variability of ITS sequences was analyzed within and among the cultures and the specimens designated to different morphospecies. Results suggested an intragenomic variation of less than 2%, an intraspecific variation of up to 4% and an interspecific divergence of more than 9% in Tulasnella. Cryptic species in Tulasnella, mostly from Ecuador, were revealed by phylogenetic analyses with 4% intraspecific divergence as a minimum threshold for delimiting species. Conventional diagnostic morphological characters appeared insufficient for species characterization. Arguments are presented for molecular delimitation of the established species Tulasnella albida, T. asymmetrica, T. eichleriana, T. cf. pinicola, T. tomaculum and T. violea.
Assuntos
Basidiomycota/genética , Orchidaceae/microbiologia , Sequência de Bases , DNA Fúngico/química , DNA Fúngico/genética , DNA Espaçador Ribossômico/química , DNA Espaçador Ribossômico/genética , Equador , Alemanha , Dados de Sequência Molecular , Filogenia , Análise de Sequência de DNA , Esporos Fúngicos , ÁrvoresRESUMO
Based on opportunistic collections of fungi in Panama, two species of Diatrypaceae (Xylariales) are described and illustrated. One of them, Eutypella semicircularis, found twice on branches probably belonging to Alnus acuminata, is new to science. It differs from known species of Eutypella and Peroneutypa with strongly allantoid or semicircular ascospores, such as E. crustata and P. curvispora, in having larger ascospores that sometimes almost form a circle and broader stromata, among other differences. Molecular data of the ITS rDNA region show that the new species is a sister taxon of Eutypella cerviculata, the type species of the genus Eutypella. Diatrype bermudensis on stems of Guadua angustifolia is reported from Panama for the first time, being known up to now apparently only from Bermuda.
Assuntos
Xylariales/classificação , DNA Fúngico/genética , DNA Ribossômico/genética , Panamá , Filogenia , Xylariales/genética , Xylariales/ultraestruturaRESUMO
In a survey of mycotic human skin and nail lesions in Chiriquí, Western Panama, Talaromyces indigoticus was isolated in one case. This ascomycete is characterised by formation of gymnothecia containing oval, spinose and yellow ascospores, which become blue in mounting fluids, and by short monoverticillate or biverticillate penicilli. It is here reported the first time for Panama and the American continent. Because the strain was isolated from an onychomycosis together with a dermatophyte and other fungal strains, the pathological impact of Talaromyces indigoticus is not evident.
Assuntos
Onicomicose/microbiologia , Talaromyces/isolamento & purificação , Idoso , DNA Fúngico/química , DNA Fúngico/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Genes de RNAr , Humanos , Masculino , Microscopia , Microscopia Eletrônica de Varredura , Dados de Sequência Molecular , Onicomicose/diagnóstico , Panamá , RNA Fúngico/genética , RNA Ribossômico/genética , Análise de Sequência de DNA , Talaromyces/classificação , Talaromyces/citologiaRESUMO
A fungus causing tar spots on leaves of Comarostaphylis arbutoides (Ericaceae) in Panama is described as a new species, Rhytisma panamense. The fungus forms gregarious black stromata on pale yellow spots on the adaxial side of leaves. Its ascomata develop from unilocular or multilocular stromata. An analysis of a combined dataset of DNA sequences from LSU to ITS rDNA supports the placement of the species in the genus Rhytisma.