title: Identification and characterization of regions of difference between the Salmonella Gallinarum biovar Gallinarum and the Salmonella Gallinarum biovar Pullorum genomes.
abstract: Salmonella Gallinarum is the causative agent of fowl typhoid, a severe septicaemic disease that affects birds of all ages, whereas S. Pullorum causes pullorum disease, a systemic disorder affecting primarily young birds. A proportion of birds with pullorum disease become carriers and are thereby able to transmit S. Pullorum vertically. Although these two pathogens cause distinct diseases, they are otherwise phenotypically and genetically similar. Therefore, the small variations that lead to the differences in virulence must have a genetic basis which currently is unknown. In the present study, we compared the genome sequences of S. Gallinarum (strains: SG287/91 and SG9) and S. Pullorum (strains: SP_CDC, SP_RKS, SP_FCAV, SP_S06) and identified 223 regions of difference (RODs), characterized by indels which were detected by using the software Artemis Comparison Tool. Some of the RODs led to pseudogenes frequently formed by frameshifts and premature stop codons in genes primarily involved in virulence and metabolism. We further verified the presence of some conserved RODs by PCR in 26 isolates of S. Gallinarum and 17 of S. Pullorum in order to extrapolate data analyses from genome comparison to field strains. The variations observed in virulence-related genes of S. Gallinarum and S. Pullorum appear not to be sufficient to explain the differences between the distinct biology of infection of fowl typhoid and pullorum disease. Thus, we suggest that the identified pseudogenes affecting metabolism might play a greater role during infection than previously thought.
authors.affiliation: Departamento de Patologia Veterinária - Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Via de acesso Paulo Donato Castellane, s/n, Jaboticabal, Sao Paulo 14884-900, Brazil. Electronic address: diegofelipe_vet@hotmail.com.
authors.forename: Diego Felipe Alves
authors.initials: DFA
authors.lastname: Batista
authors.affiliation: Departamento de Patologia Veterinária - Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Via de acesso Paulo Donato Castellane, s/n, Jaboticabal, Sao Paulo 14884-900, Brazil; Departamento de Ciências Veterinárias - Centro de Ciências Agrárias, Universidade Federal da Paraíba, Areia, Paraíba 58071-680, Brazil. Electronic address: oliveirocaetano@yahoo.com.
authors.forename: Oliveiro Caetano
authors.initials: OC
authors.lastname: Freitas Neto
authors.affiliation: School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, United Kingdom. Electronic address: paul.barrow@nottingham.ac.uk.
authors.forename: Paul Andrew
authors.initials: PA
authors.lastname: Barrow
authors.affiliation: Departamento de Tecnologia - Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Via de acesso Paulo Donato Castellane, s/n, Jaboticabal, Sao Paulo, 14884-900, Brazil. Electronic address: mtoliveira@fcav.unesp.br.
authors.forename: Marcos Túlio
authors.initials: MT
authors.lastname: de Oliveira
authors.affiliation: Departamento de Patologia Veterinária - Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Via de acesso Paulo Donato Castellane, s/n, Jaboticabal, Sao Paulo 14884-900, Brazil. Electronic address: adrianaalmeida@fcav.unesp.br.
authors.forename: Adriana Maria
authors.initials: AM
authors.lastname: Almeida
authors.affiliation: Departamento de Ciências Exatas - Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Via de acesso Paulo Donato Castellane, s/n, Jaboticabal, Sao Paulo 14884-900, Brazil. Electronic address: fsajago@gmail.com.
authors.forename: Antonio Sergio
authors.initials: AS
authors.lastname: Ferraudo
authors.affiliation: Departamento de Patologia Veterinária - Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Via de acesso Paulo Donato Castellane, s/n, Jaboticabal, Sao Paulo 14884-900, Brazil. Electronic address: berchier@fcav.unesp.br.
authors.forename: Angelo
authors.initials: A
authors.lastname: Berchieri
mesh_terms: D000818:Animals; D016000:Cluster Analysis; D010861:Fimbriae, Bacterial / Q000235:genetics; D016680:Genome, Bacterial / Q000235:genetics*; D044404:Genomic Islands / Q000235:genetics; D005810:Multigene Family / Q000235:genetics; D011200:Poultry; D011201:Poultry Diseases / Q000382:microbiology*; D011544:Pseudogenes / Q000235:genetics; D012475:Salmonella / Q000145:classification* / Q000235:genetics* / Q000472:pathogenicity; D012481:Salmonella Infections, Animal / Q000382:microbiology*
keywords: Genome comparison; Pseudogenes; Region of difference; S. Pullorum; Salmonella Gallinarum