Evolutionary origin and population diversity of a cryptic hybrid pathogen

Area of Science:

• Mycology
• Genomics
• Evolutionary Biology

Background:

• Cryptic fungal pathogens are difficult to manage due to morphological similarities with known species.
• Accurate identification of fungal pathogens is crucial for effective disease control and patient treatment.

Purpose of the Study:

• To investigate the genomic and phenotypic characteristics of Aspergillus section Nidulantes fungi.
• To identify the origin and evolutionary history of the cryptic pathogen Aspergillus latus.
• To understand the genetic diversity and phenotypic traits of A. latus, including drug resistance and stress response.

Main Methods:

• Genome sequencing and phylogenetic analysis of 53 fungal isolates.
• Phenotypic characterization, including drug resistance and growth under oxidative stress.
• Transcriptome profiling of a clinical A. latus isolate.

Main Results:

• Thirty clinical isolates, including four from COVID-19 patients, were identified as Aspergillus latus, a cryptic pathogen previously misidentified.
• A. latus originated from a single allodiploid hybridization event during the Miocene, possessing substantial genetic diversity.
• Transcriptome analysis showed active expression from both parental subgenomes in A. latus.
• Distinct phenotypic profiles, including drug resistance and oxidative stress tolerance, were observed in A. latus compared to related species.
• Four taxonomic features for identifying A. latus were identified.

Conclusions:

• Aspergillus latus is a cryptic pathogen resulting from ancient hybridization, contributing to diagnostic challenges.
• Understanding the origin and genetic diversity of A. latus is essential for improving disease management strategies.
• The distinct phenotypic traits of A. latus warrant further investigation for clinical implications.