Insights into the genomic characterization and pathogenicity

Abstract

In these studies, genome-wide studies were conducted to have insights into the genomic characterization and pathogenesis. Although many researchers have tried to focus on the pathogenesis interaction with living organisms, little genomic research has been performed into the mechanism of pathogenesis leading to the disease. Therefore, to extend comprehensive understanding at the genomic level, I conducted comparative analysis and genome-wide association study. In chapter 2, I performed a comparative genomic analysis with the complete genomes of B. cereus strains which is well known as a gastrointestinal pathogen that induces food poisoning. Based on the result of comparative analysis, I could identify the virulence factors playing a crucial role in pathogenesis, positively selected genes and strain-specific genes of FORC_013. In chapter 3, pan-genome analysis was conducted using 20 Shigella complete genomes available on the NCBI genome database. I found not only the overall genetic contents in Shigella spp. but also newly obtained genes through horizontal gene transfer. And these species are defined as monophyletic groups using the phylogenetic tree based on the core gene clustering and ANI analysis. Genes under positive selection account for very low rate in the core genome. In chapter 4, genome-wide association studies on fusarium wilt resistance in radish (Raphanus sativus) was conducted to identify the relationship between phenotypic and genotypic data. I found the significant loci responsible for leading fusarium disease. Through these studies, I could not only understand about genetic features in living organisms but also provide a comprehensive insight into further studies regarding pathogenesis mechanism at genomic level.