Comparative Genomics ofH. pyloriand Non-PyloriHelicobacterSpecies to Identify New Regions Associated with Its Pathogenicity and Adaptability

Abstract

The genusHelicobacteris a group of Gram-negative, helical-shaped pathogens consisting of at least 36 bacterial species.Helicobacter pylori(H. pylori), infecting more than 50% of the human population, is considered as the major cause of gastritis, peptic ulcer, and gastric cancer. However, the genetic underpinnings ofH. pylorithat are responsible for its large scale epidemic and gastrointestinal environment adaption within human beings remain unclear. Core-pan genome analysis was performed among 75 representativeH. pyloriand 24 non-pylori Helicobactergenomes. There were 1173 conserved protein families ofH. pyloriand 673 of all 99Helicobactergenus strains. We found 79 genome unique regions, a total of 202,359bp, shared by at least 80% of theH. pyloribut lacked in non-pylori Helicobacterspecies. The operons, genes, and sRNAs within theH. pyloriunique regions were considered as potential ones associated with its pathogenicity and adaptability, and the relativity among them has been partially confirmed by functional annotation analysis. However, functions of at least 54 genes and 10 sRNAs were still unclear. Our analysis of protein-protein interaction showed that 30 genes within them may have the cooperation relationship.