The extensive set of accessory Pseudomonas aeruginosa genomic components.
Up to 20% of the chromosomal Pseudomonas aeruginosa DNA belong to the so-called accessory genome. Its elements are specific for subgroups or even single strains and are likely acquired by horizontal gene transfer (HGT). Similarities of the accessory genomic elements to DNA from other bacterial species, mainly the DNA of γ- and β-proteobacteria, indicate a role of interspecies HGT. In this study, we analysed the expression of the accessory genome in 150 clinical P. aeruginosa isolates as uncovered by transcriptome sequencing and the presence of accessory genes in eleven additional isolates. Remarkably, despite the large number of P. aeruginosa strains that have been sequenced to date, we found new strain-specific compositions of accessory genomic elements and a high portion (10-20%) of genes without P. aeruginosa homologues. Although some genes were detected to be expressed/present in several isolates, individual patterns regarding the genes, their functions and the possible origin of the DNA were widespread among the tested strains. Our results demonstrate the unaltered potential to discover new traits within the P. aeruginosa population and underline that the P. aeruginosa pangenome is likely to increase with increasing sequence information.
Department of Molecular Bacteriology, Helmholtz Centre for Infection Research, Braunschweig, Germany; Institute for Molecular Bacteriology, TWINCORE GmbH, Centre for Clinical and Experimental Infection Research, a joint venture of the Hannover Medical School and the Helmholtz Centre for Infection Research, Hannover, Germany.
Sarah
S
Pohl
Jens
J
Klockgether
Denitsa
D
Eckweiler
Ariane
A
Khaledi
Monika
M
Schniederjans
Philippe
P
Chouvarine
Burkhard
B
Tümmler
Susanne
S
Häussler
D020869:Gene Expression Profiling; D022761:Gene Transfer, Horizontal; D014644:Genetic Variation; D016680:Genome, Bacterial; D020071:Interspersed Repetitive Sequences; D011552:Pseudomonas Infections / Q000382:microbiology; D011550:Pseudomonas aeruginosa / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification
accessory genome composition; extended gene pool; horizontal gene transfer