Comparative genome analyses of Aspergillus oryzae and Aspergillus flavus originated from a Korean fermentation starter, nuruk

초록

Aspergillus oryzae is an industrially important fungus used to produce traditional fermented foods and beverages in Korea and other East Asian countries. Conversely, A. flavus, which exhibits approximately 99.5 % of genomic similarity to A. oryzae, is a species that endangers food safety due to aflatoxin production. This study involved the genome sequences of A. oryzae KBP3 and KSS2 isolated from nuruk, a traditional Korean fermentation starter, assembled at the chromosomal level. To investigate differences among closely related species concerning food safety, compartive genome analysis was conducted on 30 strains of Aspergillus section Flavi, including nuruk strains and 28 genome sequences sourced from additional sequencing and the GenBank database. A detailed interspecific diversity was compared by examining the composition and chromosomal locations of annotated genes across 30 strains. A phylogenetic tree based on whole genome sequences, orthologous genes, and single nucleotide polymorphisms of core genes across 30 strains divided A. oryzae and A. flavus into two separate clades with some exceptions. This study presents two high-quality whole genome sequences of A. oryzae, providing significant genetic insights for this species and its closely related species. Our study confirmed the wide range of enzyme-related genes in A. oryzae isolated from nuruk, and its intraspecific genomic diversity. Our findings also systematically organize the pangenome analysis data of closely related species within Aspergillus section Flavi at the chromosomal level, enhancing the understanding of the genetic information relevant to food safety-related species.

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