Locust Pathogen Aspergillus oryzae XJ1 Is Different from Aspergillus oryzae and Aspergillus flavus Based on Genomics Comparisons

Fungi play an increasingly important role in the biological control of insect pests. <i>Aspergillus oryzae</i> XJ1 is highly virulent to locust adults and nymphs, which are a destructive economic pest worldwide. Because of its host association with locusts, which is unique in <i>Aspergillus</i>, in this study, we examined the genetic relationships of <i>A. oryzae</i> XJ1 within <i>Aspergillus</i>. We sequenced the genome of <i>A. oryzae</i> XJ1 and compared it with the genomes of other <i>Aspergillus</i> species. The complete genome of <i>A. oryzae</i> XJ1 is 37.9 Mb, comprising 11,720 putative genes, assembled into eight chromosomes. The genome size is similar to that of other <i>A. oryzae</i> strains. Phylogenomic analysis indicated that <i>A. oryzae</i> XJ1 was most closely related to <i>A. flavus</i> NRRL3357, not <i>A. oryzae</i> RIB40. Core/pan-genome analysis of <i>A. oryzae</i> XJ1 and other <i>Aspergillus</i> species revealed that <i>A. oryzae</i> XJ1 had 704 strain-specific genes, whereas <i>A. flavus</i> NRRL3357, <i>A. oryzae</i> KDG 21, and <i>A. parasiticus</i> NRRL 2999 had 646, 955, and 779 unique genes, respectively. The <i>A. oryzae</i> XJ1 genome showed structural differences compared with the genomes of <i>A. oryzae</i> RIB40 and <i>A. flavus</i> NRRL3357 in genomic synteny analysis. These results indicate that <i>A. oryzae</i> XJ1 is genetically distinct at the genome level from other <i>Aspergillus</i> species, including <i>A. oryzae</i> and <i>A. flavus</i>, and may be as a distinct species. This will provide new insight into the classification of <i>Aspergillus</i> based on genomics.