<xhtml:span xmlns:xhtml="http://www.w3.org/1999/xhtml" xml:lang="en">A comparative genomic and phylogenomic study of Nocardia seriolae strains unveils high genetic homogeneity and open nature of the pangenome </xhtml:span>

The pathogen Nocardia seriolae is responsible for causing chronic granulomatous disease, known as fish nocardiosis, which has been observed in more than 40 species of fish cultured in marine and freshwater environments. Therefore, it is imperative to perform research to address and eradicate this substantial threat to the aquaculture industry. However, quantifying the negative impacts associated with this species is difficult because of insufficient data and underreporting. While several genomes are available in online databases, there is still a lack of comparative genomic analyses and studies on effective treatments, which is particularly important for aquaculture. To gain a deeper understanding of the pathogenic mechanisms associated with various Nocardia strains causing disease outbreaks and their virulence components, as well as the functional enrichment and genetic diversity during infection, it is crucial to develop a dependable and replicable pangenomic dataset. This study quantified Nocardia pangenome openness and discovered the biological processes that drive it. The study also found a substantial association between pangenome openness and numerous parameters such as genomic plasticity, gene synteny, single-copy phylogenomics, and pangenome prediction. The results showed genetic similarity across strains, indicating that the pangenome of this species is moving toward completeness. The diversity was supported by the similarity analysis, which revealed a high percentage of genes in the core genome and close association among the strains. Our findings provide valuable information and emphasize the necessity of sequencing novel genomes of N. serioale isolates to gain a deeper understanding of their diversity and patterns of adaptability.