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Morphological and Genomic Characterization of Filobasidiella depauperata: A Homothallic Sibling Species of the Pathogenic Cryptococcus Species Complex

The 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 syst...

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Autores principales: Rodriguez-Carres, Marianela, Findley, Keisha, Sun, Sheng, Dietrich, Fred S., Heitman, Joseph
Formato: Texto
Lenguaje:English
Publicado: Public Library of Science 2010
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2835752/
https://www.ncbi.nlm.nih.gov/pubmed/20224779
http://dx.doi.org/10.1371/journal.pone.0009620
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author Rodriguez-Carres, Marianela
Findley, Keisha
Sun, Sheng
Dietrich, Fred S.
Heitman, Joseph
author_facet Rodriguez-Carres, Marianela
Findley, Keisha
Sun, Sheng
Dietrich, Fred S.
Heitman, Joseph
author_sort Rodriguez-Carres, Marianela
collection PubMed
description The 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 MAT a 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 MAT a locus may have undergone accelerated evolution prior to the divergence of the pathogenic Cryptococcus species since several of the genes linked to the MAT a locus appear to have a higher number of changes and substitutions than their MATα 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.
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spelling pubmed-28357522010-03-12 Morphological and Genomic Characterization of Filobasidiella depauperata: A Homothallic Sibling Species of the Pathogenic Cryptococcus Species Complex Rodriguez-Carres, Marianela Findley, Keisha Sun, Sheng Dietrich, Fred S. Heitman, Joseph PLoS One Research Article The 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 MAT a 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 MAT a locus may have undergone accelerated evolution prior to the divergence of the pathogenic Cryptococcus species since several of the genes linked to the MAT a locus appear to have a higher number of changes and substitutions than their MATα 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. Public Library of Science 2010-03-10 /pmc/articles/PMC2835752/ /pubmed/20224779 http://dx.doi.org/10.1371/journal.pone.0009620 Text en Rodriguez-Carres et al. http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Rodriguez-Carres, Marianela
Findley, Keisha
Sun, Sheng
Dietrich, Fred S.
Heitman, Joseph
Morphological and Genomic Characterization of Filobasidiella depauperata: A Homothallic Sibling Species of the Pathogenic Cryptococcus Species Complex
title Morphological and Genomic Characterization of Filobasidiella depauperata: A Homothallic Sibling Species of the Pathogenic Cryptococcus Species Complex
title_full Morphological and Genomic Characterization of Filobasidiella depauperata: A Homothallic Sibling Species of the Pathogenic Cryptococcus Species Complex
title_fullStr Morphological and Genomic Characterization of Filobasidiella depauperata: A Homothallic Sibling Species of the Pathogenic Cryptococcus Species Complex
title_full_unstemmed Morphological and Genomic Characterization of Filobasidiella depauperata: A Homothallic Sibling Species of the Pathogenic Cryptococcus Species Complex
title_short Morphological and Genomic Characterization of Filobasidiella depauperata: A Homothallic Sibling Species of the Pathogenic Cryptococcus Species Complex
title_sort morphological and genomic characterization of filobasidiella depauperata: a homothallic sibling species of the pathogenic cryptococcus species complex
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2835752/
https://www.ncbi.nlm.nih.gov/pubmed/20224779
http://dx.doi.org/10.1371/journal.pone.0009620
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