Structural and functional genomic analysis of thesalmonella entericahost-restricted serotype abortusovis

Salmonellae cause diseases both in cold-blooded and in warm-blooded. To date, thousands of serotypes have been identified belonging to Salmonella enterica and each of these shows different host range and pathogenicity. Therefore, it is of primary importance to understand the molecular (genetic) basis of host-specificity within serotypes of this species. In this work, we have performed a structural and functional analysis of the genome of one of such Salmonella enterica host-restricted serotypes: serotype Abortusovis (strain SS44). The structural analysis was accomplished throughout the whole genome sequencing using the 454 sequencing technology. We obtained the sequence, analysed it, and compared it with other sequenced genomes. Also, using physical maps and macro-restrictions, we described genome plasticity and structural variation among strains. Plasticity was shown to be high in strains harbouring the IS1414 insertion sequence. Furthermore, two groups of strains displayed large rearrangements within Salmonella Pathogenicity Islands, that are loci otherwise conserved. Finally, functional aspects have been also valuated in this work. The role of plasmidencoded effectors has been observed using an experimental model of infection in lambs, and, in vitro, in phagocytic cells (THP-1). This allowed to identify and characterise a fragment of the SS44 strain virulence plasmid (pSS44) which seems to encode genes with a role in dampering the inflammatory host response.