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Polyphasic taxonomy of Aspergillus section Aspergillus (formerly Eurotium), and its occurrence in indoor environments and food

Summary

This research provides an updated classification system for an important group of fungi commonly found in our homes and food. These fungi thrive in dry conditions and are frequently found growing on foods with high sugar or salt content, like jams, dried foods, and preserved meats. The study combines modern DNA analysis with traditional methods to better identify and classify these fungi. Impacts on everyday life: – Improved ability to identify fungi that cause food spoilage, helping to better preserve food products – Better understanding of which fungal species commonly occur in our homes and buildings – Discovery that some compounds produced by these fungi may have beneficial antioxidant properties – Enhanced food safety by confirming these fungi do not produce dangerous mycotoxins – More accurate identification methods to help building inspectors and food safety professionals monitor these organisms

Background

Aspergillus section Aspergillus includes xerophilic species with uniseriate conidiophores, globose to subglobose vesicles, green conidia and yellow, thin walled eurotium-like ascomata with hyaline, lenticular ascospores. These fungi are common in indoor environments and food products with high sugar or salt content. Previous taxonomic work was based mainly on morphological characters, which has led to confusion in species identification.

Objective

To provide a comprehensive taxonomic revision of Aspergillus section Aspergillus using a polyphasic approach combining morphological characters, extrolites, physiological characters and phylogeny. Additionally, to investigate the occurrence and identification of these species in indoor environments worldwide.

Results

Based on the polyphasic approach, 31 species are recognized in section Aspergillus, including nine new species. ITS was found to be highly conserved and insufficient for species identification. All species can be differentiated using CaM or RPB2 sequences. For BenA, only A. brunneus and A. niveoglaucus share identical sequences. Ascospores and conidia morphology, along with growth rates at different temperatures were found to be the most useful phenotypic characters for species identification. From indoor environments, 96 strains were isolated from 15 countries, with A. pseudoglaucus (45%), A. montevidensis (21%), and A. chevalieri (13%) being the most common species.

Conclusion

This study provides an updated taxonomy of Aspergillus section Aspergillus using a polyphasic approach, recognizing 31 species including 9 new species. The research demonstrates that molecular methods, particularly CaM and RPB2 sequences, combined with morphological and physiological characters are essential for accurate species identification. The study also shows these fungi are common in indoor environments worldwide, with three species accounting for nearly 80% of indoor isolates.
  • Published in:Studies in Mycology,
  • Study Type:Taxonomic Study,
  • Source: 10.1016/j.simyco.2017.07.001
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