title: Patterns of large-scale genomic variation in virulent and avirulent Burkholderia species.
abstract: The human diseases melioidosis and glanders are caused by the bacteria Burkholderia pseudomallei and B. mallei respectively, and both species are regarded as potential biowarfare agents. We used B. pseudomallei DNA microarrays to compare the genomes of several clinical and environmental isolates of B. pseudomallei, B. mallei, and B. thailandensis, a closely related but avirulent species. Open reading frames (ORFs) deleted between the three species were associated with diverse cellular functions, including nitrogen and iron metabolism, quorum sensing, and polysaccharide production. Deleted ORFs in B. mallei exhibited significant genomic clustering, whereas deletions in B. thailandensis were more uniformly dispersed, suggesting that B. mallei and B. thailandensis may have diverged from B. pseudomallei and each other via distinct mechanisms. The genomes of independent B. pseudomallei isolates were highly conserved with a large-scale variance of less than 3% between isolates, and at least three distinct molecular subtypes could be defined. An analysis of subtype-specific genomic regions suggests that DNA loss has played an important role in the evolutionary radiation of B. pseudomallei in the natural environment. Our results raise several hypotheses concerning the possible mechanisms underlying the diverse biological properties exhibited by members of the Burkholderia family.
authors.affiliation: Defense Medical and Environmental Research Institute, Singapore 169610, Republic of Singapore.
authors.forename: Catherine
authors.initials: C
authors.lastname: Ong
authors.forename: Chia Huey
authors.initials: CH
authors.lastname: Ooi
authors.forename: Dongling
authors.initials: D
authors.lastname: Wang
authors.forename: Hweeling
authors.initials: H
authors.lastname: Chong
authors.forename: Kim Chong
authors.initials: KC
authors.lastname: Ng
authors.forename: Fiona
authors.initials: F
authors.lastname: Rodrigues
authors.forename: May Ann
authors.initials: MA
authors.lastname: Lee
authors.forename: Patrick
authors.initials: P
authors.lastname: Tan
mesh_terms: D015373:Bacterial Typing Techniques; D005075:Biological Evolution; D001694:Biological Warfare; D019117:Burkholderia / Q000235:genetics* / Q000378:metabolism / Q000472:pathogenicity*; D017353:Gene Deletion; D005798:Genes, Bacterial / Q000235:genetics*; D014644:Genetic Variation; D005896:Glanders / Q000382:microbiology; D007501:Iron / Q000378:metabolism; D008554:Melioidosis / Q000382:microbiology; D008969:Molecular Sequence Data; D009584:Nitrogen / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D016366:Open Reading Frames / Q000235:genetics*; D011135:Polysaccharides, Bacterial / Q000096:biosynthesis; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D014774:Virulence / Q000235:genetics
chemical_list: D011135:Polysaccharides, Bacterial; D007501:Iron; D009584:Nitrogen