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United States Department of Agriculture

Agricultural Research Service

Research Project: Genomic Analyses and Management of Agricultural and Industrial Microbial Genetic Resources and Associated Information

Location: Bacterial Foodborne Pathogens & Mycology Research Unit

Title: Genetic relatedness versus biological compatibility between Aspergillus fumigatus and related species

Authors
item Sugui, Janyce -
item Figat, Abigail -
item Kwon-Chung, Kyung -
item Peterson, Stephen
item Hansen, Bryan -
item Samson, Robert -
item Mellado, Emilia -
item Cuenca-Estrella, Manuel -

Submitted to: Eukaryotic Cell
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 29, 2014
Publication Date: N/A

Interpretive Summary: Molds in the Aspergillus fumigatus group can cause lung infections in weakened or immunocompromised people. Because knowing the identity of the fungus causing the disease guides the choice of antifungal therapy it is important to identify even very similar looking species. We used DNA sequences, mating ability, and macro- and micro- appearance of these molds to discover three new species that we name here. We also tested virulence and susceptibility of the molds to common antifungals. This work will help guide therapy for people suffering infections from these species. This work will be of interest to pharmaceutical researchers, medical technicians and clinicians, and to academic mycologists.

Technical Abstract: Aspergillus section Fumigati contains twelve clinically relevant species. Among them, A. fumigatus is the most frequent agent of invasive aspergillosis followed by A. lentulus and A. viridinutans. Genealogical concordance and mating experiments were performed to examine the relationship between phylogenetic distance and mating success in these three heterothallic species. Phylogenetic and genealogical concordance analyses of 20 clinical strains revealed the presence of three previously unrecognized species within the broadly circumscribed A. viridinutans. For two of the new species, Aspergillus pseudofelis and Aspergillus pseudoviridinutans, a single mating type was found but in the third, Aspergillus parafelis, both mating types were present. Reciprocal inter-specific pairings of all species in the study showed that the only successful crosses occurred with MAT-2 isolate of A. parafelis. This strain was fertile when paired with MAT-1 isolates of A. fumigatus, A. viridinutans, A. felis, and A. pseudoviridinutans, but was not fertile when paired with A. lentulus. The MAT-1 isolate of A. parafelis was not fertile in any interspecific pairings, but it produced complete sexual cycle with the MAT-2 of A. parafelis. The general infertility in the inter-species crossings suggest that genetically unrelated species are also biologically incompatible, with A. parafelis CM-3147 the exception. Our findings underscore the importance of genealogical concordance analysis for species circumscription as well as accurate species identification since misidentification of morphologically similar pathogens with different innate drug resistance may be of grave consequences for disease management.

Last Modified: 12/20/2014
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