title: Phylogenetic analysis of the genus Aeromonas based on two housekeeping genes.
abstract: The phylogenetic relationships of all known species of the genus Aeromonas, and especially Aeromonas bestiarum and Aeromonas salmonicida, were investigated on 70 strains using the rpoD sequence, which encodes the sigma70 factor. This analysis was complemented with the sequence of gyrB, which has already proven useful for determining the phylogenetic relationships in the genus. Nucleotide sequences of rpoD and gyrB showed that both genes had similar substitution rates (< 2 %) and a similar number of variable positions (34 % for rpoD versus 32 % for gyrB). Strain groupings by analysis of rpoD, gyrB and a combination of both genes were consistent with the taxonomic organization of all Aeromonas species described to date. However, the simultaneous analysis of both clocks improved the reliability and the power to differentiate, in particular, closely related taxa. At the inter-species level, gyrB showed a better resolution for differentiating Aeromonas sp. HG11/Aeromonas encheleia and Aeromonas veronii/Aeromonas culicicola/Aeromonas allosaccharophila, while rpoD more clearly differentiated A. salmonicida from A. bestiarum. The analysis of rpoD provided initial evidence for clear phylogenetic divergence between the latter two species.
authors.affiliation: Unidad de Microbiología, Departamento de Ciencias Médicas Básicas, Facultad de Medicina y Ciencias de la Salud, Universidad Rovira y Virgili, Reus, E-43201 Tarragona, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Soler
authors.affiliation: Labaqua, S.A., Alona, 33, E-03007 Alicante, Spain.|Departamento de Microbiología, Universidad Miguel Hernández, Ctra Beniel Km 3, E-03312 Orihuela (Alicante), Spain.
authors.forename: M A
authors.initials: MA
authors.lastname: Yáñez
authors.affiliation: Unidad de Microbiología, Departamento de Ciencias Médicas Básicas, Facultad de Medicina y Ciencias de la Salud, Universidad Rovira y Virgili, Reus, E-43201 Tarragona, Spain.
authors.forename: M R
authors.initials: MR
authors.lastname: Chacon
authors.affiliation: Departamento de Microbiología, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, 11340 México Distrito Federal, Mexico.|Unidad de Microbiología, Departamento de Ciencias Médicas Básicas, Facultad de Medicina y Ciencias de la Salud, Universidad Rovira y Virgili, Reus, E-43201 Tarragona, Spain.
authors.forename: M G
authors.initials: MG
authors.lastname: Aguilera-Arreola
authors.affiliation: Labaqua, S.A., Alona, 33, E-03007 Alicante, Spain.
authors.forename: V
authors.initials: V
authors.lastname: Catalán
authors.affiliation: Unidad de Microbiología, Departamento de Ciencias Médicas Básicas, Facultad de Medicina y Ciencias de la Salud, Universidad Rovira y Virgili, Reus, E-43201 Tarragona, Spain.
authors.forename: M J
authors.initials: MJ
authors.lastname: Figueras
authors.affiliation: Departamento de Microbiología, Universidad Miguel Hernández, Ctra Beniel Km 3, E-03312 Orihuela (Alicante), Spain.|Molecular Diagnostics Center, Ctra Ncnal, 340, Km 29 Aptdo, 169, E-03300 Orihuela (Alicante), Spain.
authors.forename: A J
authors.initials: AJ
authors.lastname: Martínez-Murcia
mesh_terms: D000333:Aeromonas / Q000145:classification* / Q000235:genetics*; D048409:Aeromonas salmonicida / Q000145:classification / Q000235:genetics; D001426:Bacterial Proteins / Q000235:genetics; D027081:DNA Gyrase / Q000235:genetics*; D004269:DNA, Bacterial / Q000737:chemistry / Q000302:isolation & purification; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D005798:Genes, Bacterial; D008969:Molecular Sequence Data; D010802:Phylogeny; D017422:Sequence Analysis, DNA; D017385:Sequence Homology; D012808:Sigma Factor / Q000235:genetics*
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D012808:Sigma Factor; C081775:RNA polymerase sigma 70; D012321:DNA-Directed RNA Polymerases; D027081:DNA Gyrase