Aspergillus oryzae shares approximately 99.5% of its genome sequence with its closest relative species Aspergillus flavus, which produces harmful aflatoxins. To distinguish the two species, we first constructed two high-quality completed genomes of A. oryzae and then performed comparative genomics on a total of 30 genomes of A. oryzae and three other section Flavi species including A. flavus. Through whole genome and pan- and core-genome analyses, we constructed three phylogenetic trees that successfully distinguished A. oryzae and A. flavus as two distinct species. We focused on the analysis of the aflatoxin biosynthesis gene cluster and divided the 30 genomes into four groups based on gene presence and deletions. Based on the results, we designed four sets of primers that can identify the aflatoxigenic strains within two fungal species isolated from fermented foods. This study provides insight on the genetic diversity and evolution of the aflatoxin pathway in A. oryzae, and the importance of performing comparative genomics on large scales, at the whole genome level. Our two strains will provide useful genomic information on this fungal species, and act as good genomic resources for those working in the food and biotechnology industries.
Full conference title:
- Fungal Genetics Conference 30th (2019)