title: Diversity of 16S-23S rDNA internal transcribed spacer (ITS) reveals phylogenetic relationships in Burkholderia pseudomallei and its near-neighbors.
abstract: Length polymorphisms within the 16S-23S ribosomal DNA internal transcribed spacer (ITS) have been described as stable genetic markers for studying bacterial phylogenetics. In this study, we used these genetic markers to investigate phylogenetic relationships in Burkholderia pseudomallei and its near-relative species. B. pseudomallei is known as one of the most genetically recombined bacterial species. In silico analysis of multiple B. pseudomallei genomes revealed approximately four homologous rRNA operons and ITS length polymorphisms therein. We characterized ITS distribution using PCR and analyzed via a high-throughput capillary electrophoresis in 1,191 B. pseudomallei strains. Three major ITS types were identified, two of which were commonly found in most B. pseudomallei strains from the endemic areas, whereas the third one was significantly correlated with worldwide sporadic strains. Interestingly, mixtures of the two common ITS types were observed within the same strains, and at a greater incidence in Thailand than Australia suggesting that genetic recombination causes the ITS variation within species, with greater recombination frequency in Thailand. In addition, the B. mallei ITS type was common to B. pseudomallei, providing further support that B. mallei is a clone of B. pseudomallei. Other B. pseudomallei near-neighbors possessed unique and monomorphic ITS types. Our data shed light on evolutionary patterns of B. pseudomallei and its near relative species.
authors.affiliation: Department of Biological Sciences, Center for Microbial Genetics and Genomics, Northern Arizona University, Flagstaff, Arizona, United States of America.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Liguori
authors.forename: Stephanie D
authors.initials: SD
authors.lastname: Warrington
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Ginther
authors.forename: Talima
authors.initials: T
authors.lastname: Pearson
authors.forename: Jolene
authors.initials: J
authors.lastname: Bowers
authors.forename: Mindy B
authors.initials: MB
authors.lastname: Glass
authors.forename: Mark
authors.initials: M
authors.lastname: Mayo
authors.forename: Vanaporn
authors.initials: V
authors.lastname: Wuthiekanun
authors.forename: David
authors.initials: D
authors.lastname: Engelthaler
authors.forename: Sharon J
authors.initials: SJ
authors.lastname: Peacock
authors.forename: Bart J
authors.initials: BJ
authors.lastname: Currie
authors.forename: David M
authors.initials: DM
authors.lastname: Wagner
authors.forename: Paul
authors.initials: P
authors.lastname: Keim
authors.forename: Apichai
authors.initials: A
authors.lastname: Tuanyok
mesh_terms: D001483:Base Sequence; D016957:Burkholderia pseudomallei / Q000235:genetics*; D019295:Computational Biology; D004269:DNA, Bacterial / Q000235:genetics*; D004275:DNA, Ribosomal / Q000235:genetics*; D021903:DNA, Ribosomal Spacer / Q000235:genetics*; D019143:Evolution, Molecular; D014644:Genetic Variation; D016680:Genome, Bacterial / Q000235:genetics; D005843:Geography; D008969:Molecular Sequence Data; D009876:Operon / Q000235:genetics; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D021903:DNA, Ribosomal Spacer