Species Identification and Orthologous Allergen Prediction and Expression in the Genus Aspergillus.

Abstract

The genus Aspergillus comprises a diverse group of fungi that can cause a range of health issues, including systemic infections and allergic reactions. In this regard, A. fumigatus has been recognized as the most prevalent allergen-producing species. This genus taxonomic classification has been subject to frequent updates, which has generated considerable difficulties for its classification when traditional identification methodologies are employed. To demonstrate the feasibility of this approach, we sequenced the whole genomes of 81 Aspergillus isolates and evaluated a WGS-based pipeline for precise species identification. This pipeline employed two methodologies: (i) BLASTn web using four barcode genes and (ii) species tree inference by OrthoFinder. Furthermore, we conducted a prediction of allergenic capacity based on a homology analysis across all the isolated species and confirmed by RT-qPCR the expression of three orthologous allergens (Asp f 1, Asp f 3 and Asp f 22) in fifteen different Aspergillus species. The species-level identification rate with the barcoding and the species tree were calculated at 64.2% and 100%, respectively. The results demonstrated that A. fumigatus, A. flavus and A. niger were the most prevalent species. The species A. hortae, A. uvarum, A. spinulosporus, A. sydowii, A. westerdijkiae, A. amoenus and A. rhizopodus identified in this study represent the inaugural report of their presence in our region. The results of the homology analysis indicated the presence of orthologous allergens in a wide range of non-fumigatus species. This study presents a novel approach based on WGS that enables the classification of new species within the genus Aspergillus and reports the genomic sequences of a great diversity of species isolated in our geographic area that had never been reported before. Additionally, this approach enables the prediction of allergens in species other than A. fumigatus and demonstrates their genetic expression, thereby contributing to the understanding of the allergenic potential of different species within this fungal genus.