Hybrid assembly of Penicilliumrubens genomes unveils high conservation of genome structural organisation and the presence of Numts in nuclear DNA.

Abstract

The search for highly accurate chromosomal reference genomes has become a primary objective for the fungal research communities. Various genomic events, including insertions, deletions, inversions and movement of transposable elements, can modify the genomic architecture, resulting in chromosomal rearrangements. Long sequence reads enhance the accuracy and reliability of the assembly procedure, facilitating the study of these genomic characteristics. Here, we have utilised a combination of PacBio and Illumina sequencing technologies to generate hybrid assemblies of Penicilliumrubens strains 212 (PO212) and S27. These assemblies were then subjected to a comparative analysis in order to elucidate the chromosomal rearrangements that underpin the observed genomic differences, with a particular focus on their implications in the biocontrol phenotype against phytopathogenic fungi. This approach has enabled us to obtain the assembly of both PO212 and S27 genomes, with each organised into 13 scaffolds. The genomic organisation between these two isolates is highly conserved and the presence of transposable elements between the strains does not reveal major differences. Using the hybrid assemblies, we were able to detect, for the first time in the genus Penicillium, the presence of two nuclear mitochondrial DNA segments (Numts) in the genomes of the PO212 and S27 strains. The differences in biocontrol phenotype displayed by PO212 and S27 strains are independent of their genome organisation. These genomes provide new information for the existing database repositories.