Browsing by Subject "Basidiomycota"
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Item Restricted Morphological and genomic characterization of Filobasidiella depauperata: a homothallic sibling species of the pathogenic cryptococcus species complex.(PLoS One, 2010-03-10) Rodriguez-Carres, Marianela; Findley, Keisha; Sun, Sheng; Dietrich, Fred S; Heitman, JosephThe fungal species Cryptococcus neoformans and Cryptococcus gattii cause respiratory and neurological disease in animals and humans following inhalation of basidiospores or desiccated yeast cells from the environment. Sexual reproduction in C. neoformans and C. gattii is controlled by a bipolar system in which a single mating type locus (MAT) specifies compatibility. These two species are dimorphic, growing as yeast in the asexual stage, and producing hyphae, basidia, and basidiospores during the sexual stage. In contrast, Filobasidiella depauperata, one of the closest related species, grows exclusively as hyphae and it is found in association with decaying insects. Examination of two available strains of F. depauperata showed that the life cycle of this fungal species shares features associated with the unisexual or same-sex mating cycle in C. neoformans. Therefore, F. depauperata may represent a homothallic and possibly an obligately sexual fungal species. RAPD genotyping of 39 randomly isolated progeny from isolate CBS7855 revealed a new genotype pattern in one of the isolated basidiospores progeny, therefore suggesting that the homothallic cycle in F. depauperata could lead to the emergence of new genotypes. Phylogenetic analyses of genes linked to MAT in C. neoformans indicated that two of these genes in F. depauperata, MYO2 and STE20, appear to form a monophyletic clade with the MATa alleles of C. neoformans and C. gattii, and thus these genes may have been recruited to the MAT locus before F. depauperata diverged. Furthermore, the ancestral MATa locus may have undergone accelerated evolution prior to the divergence of the pathogenic Cryptococcus species since several of the genes linked to the MATa locus appear to have a higher number of changes and substitutions than their MATalpha counterparts. Synteny analyses between C. neoformans and F. depauperata showed that genomic regions on other chromosomes displayed conserved gene order. In contrast, the genes linked to the MAT locus of C. neoformans showed a higher number of chromosomal translocations in the genome of F. depauperata. We therefore propose that chromosomal rearrangements appear to be a major force driving speciation and sexual divergence in these closely related pathogenic and saprobic species.Item Open Access Two new endophytic Atractiellomycetes, Atractidochium hillariae and Proceropycnis hameedii.(Mycologia, 2018-01) Aime, M Catherine; Urbina, Hector; Liber, Julian A; Bonito, Gregory; Oono, RyokoSterile fungal isolates are often recovered in leaf and root endophytic studies, although these seldom play a significant role in downstream analyses. The authors sought to identify and characterize two such endophytes-one representing the most commonly recovered fungal isolate in recent studies of needle endophytes of Pinus taeda and the other representing a rarely isolated root endophyte of Populus trichocarpa. Both are shown by DNA sequencing to be undescribed species of Atractiellomycetes (Pucciniomycotina, Basidiomycota), a poorly characterized class of mostly plant-associated and presumably saprobic microfungi. The authors describe the new genus and species Atractidochium hillariae (Phleogenaceae) and the new species Proceropycnis hameedii (Hoehnelomycetaceae), both in the Atractiellales, to accommodate these unusual isolates. Following incubations of 1-2 mo, A. hillariae produces minute white sporodochia, similar to those produced by several other members of Atractiellales, whereas Pr. hameedii forms conidia singly or in chains in a manner similar to its sister species Pr. pinicola. Additionally, we provide a taxonomic revision of Atractiellomycetes based on multilocus analyses and propose the new genera Neogloea (Helicogloeaceae) and Bourdotigloea (Phleogenaceae) to accommodate ex-Helicogloea species that are not congeneric with the type H. lagerheimii. Atractiellomycetes consists of a single order, Atractiellales, and three families, Hoehnelomycetaceae, Phleogenaceae, and Helicogloeaceae. Accumulated evidence suggests that Atractiellomycetes species are common but infrequently isolated members of plant foliar and root endobiomes.