Increasing the species diversity in Aspergillus section Nidulantes: six novel species mainly from the indoor environment

Authors: SKLENAR, F - Charles University, Czech Republic; JURJEVIC, Z - Emsl Analytical, Inc; PETERSON, STEPHEN - Retired ARS Employee; KOLARIK, M - Charles University, Czech Republic; NOVAKOVA, A - Charles University, Czech Republic; KUBATOVA, A - Charles University, Czech Republic; HUBKA, V - Charles University, Czech Republic

Submitted to: Mycologia
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/26/2019
Publication Date: 2/19/2020
Citation: Sklenar, F., Jurjevic, Z., Peterson, S.W., Kolarik, M., Novakova, A., Flieger, M., Stodulkova, E., Kubatova, A., Hubka, V. 2020. Increasing the species diversity in Aspergillus section Nidulantes: six novel species mainly from the indoor environment. Mycologia. 112(2):342-370. https://doi.org/10.1080/00275514.2019.1698923.
DOI: https://doi.org/10.1080/00275514.2019.1698923

Interpretive Summary: Nearly 80 species of molds have been described from Aspergillus section Nidulantes, which includes species associated with human infections and the production of mycotoxins that can pose a threat to human and animal health. As larger numbers of these molds have been examined over the years, previously unrecognized diversity has been discovered that create challenges for existing species definitions and tools for species identification. To address this problem, we used a combination of genetic and microbiological analyses to reevaluate species boundaries within this group of molds. We discovered and formally described six new mold species, providing mycologists, clinicians, and other scientists with a clear taxonomic framework and diagnostic tools to accurately identify molds within section Nidulantes.

Technical Abstract: Aspergillus section Nidulantes encompasses almost 80 homothallic and anamorphic species mostly occurring in soil, plant material or indoor environment. Some of them are clinically relevant or produce mycotoxins. The objective of this study was to reevaluate the species boundaries within several clades of the section Nidulantes using the available strains from culture collections as well as newly isolated strains. We assembled five datasets containing the new isolates and their closest relatives and performed phylogenetic and phenotypic analysis. We tested the hypotheses if the newly isolated or re-examined strains constitute separate species (splitting approach) or should be treated as part of broadly defined species (lumping approach). Four DNA sequence loci were amplified, i.e. ITS and LSU region of the rDNA and partial sequences of the benA, CaM and RPB2 genes. The latter three loci were used for the phylogenetic analysis and served as the input for single-locus (GMYC, bGMYC, PTP and bPTP) and multi-locus (STACEY and BP&P) species delimitation methods. The phenotypic analysis comprised macro- and micromorphology (including scanning electron microscopy) and comparison of maximum growth temperature. The phylogenetic analysis supported the splitting hypothesis in all cases and based on the combined approach, we propose six new species, three of which are homothallic and three anamorphic. Four from the six newly described species were isolated from the indoor environment (Jamaica, Trinidad & Tobago, USA), one originated from soil (Australia), and one from the Kangaroo rat (USA).