RESUMO
We present a 6-gene, 420-species maximum-likelihood phylogeny of Ascomycota, the largest phylum of Fungi. This analysis is the most taxonomically complete to date with species sampled from all 15 currently circumscribed classes. A number of superclass-level nodes that have previously evaded resolution and were unnamed in classifications of the Fungi are resolved for the first time. Based on the 6-gene phylogeny we conducted a phylogenetic informativeness analysis of all 6 genes and a series of ancestral character state reconstructions that focused on morphology of sporocarps, ascus dehiscence, and evolution of nutritional modes and ecologies. A gene-by-gene assessment of phylogenetic informativeness yielded higher levels of informativeness for protein genes (RPB1, RPB2, and TEF1) as compared with the ribosomal genes, which have been the standard bearer in fungal systematics. Our reconstruction of sporocarp characters is consistent with 2 origins for multicellular sexual reproductive structures in Ascomycota, once in the common ancestor of Pezizomycotina and once in the common ancestor of Neolectomycetes. This first report of dual origins of ascomycete sporocarps highlights the complicated nature of assessing homology of morphological traits across Fungi. Furthermore, ancestral reconstruction supports an open sporocarp with an exposed hymenium (apothecium) as the primitive morphology for Pezizomycotina with multiple derivations of the partially (perithecia) or completely enclosed (cleistothecia) sporocarps. Ascus dehiscence is most informative at the class level within Pezizomycotina with most superclass nodes reconstructed equivocally. Character-state reconstructions support a terrestrial, saprobic ecology as ancestral. In contrast to previous studies, these analyses support multiple origins of lichenization events with the loss of lichenization as less frequent and limited to terminal, closely related species.
Assuntos
Ascomicetos/genética , Filogenia , Ascomicetos/classificação , Ascomicetos/citologia , Ecossistema , Genes Fúngicos , ReproduçãoRESUMO
Phylogenetic relationships were inferred among several xylariaceous genera with Nodulisporium or nodulisporium-like anamorphs based on the analyses of beta-tubulin and alpha-actin sequences. One hundred nine cultures and three specimens of 83 representatives of these four genera were included in the study. Biscogniauxia taxa formed a well supported clade that was basal to the other taxa, while taxa of Hypoxylon and Daldinia comprised a large monophyletic group that contained two subclades. The first subclade encompassed Hypoxylon sect. Annulata and is accepted here as the new genus Annulohypoxylon. The second subclade contained taxa of Hypoxylon sect. Hypoxylon and Daldinia. Hypoxylon is restricted to include only those taxa in sect. Hypoxylon. Thirty-three epithets are made in Annulohypoxylon. Hypoxylon cohaerens var. microsporum is raised to the species level and accepted as A. minutellum. Hypoxylon polyporoideum is recognized as distinct from H. crocopeplum. Hypoxylon placentiforme is accepted as Daldinia placentiformis.
Assuntos
Filogenia , Xylariales/classificação , Xylariales/genética , Actinas/genética , DNA Fúngico/análise , Dados de Sequência Molecular , Análise de Sequência de DNA , Especificidade da Espécie , Tubulina (Proteína)/genéticaRESUMO
Paramphisphaeria is described as a new genus on the basis of the single species, P. costaricensis. It differs from Amphisphaeria spp. primarily in having bicellular ascospores with a germ slit and in having an ascus apical ring that does not become blue in iodine. It resembles Amphisphaeria in its brown color and lack of constriction at the septum of the ascospore. An anamorph is unknown. It tentatively is placed in the Xylariaceae for reasons discussed. Pachytrype rimosa is described as a new species.