Natural Transformation Facilitates Transfer of Transposons, Integrons and Gene Cassettes between Bacterial Species

• DOI: 10.1371/journal.ppat.1002837
• Publication Date: 2012-08-02T21:28:17Z
• Authors: Sara Domingues; Klaus Harms; W. Florian Fricke; Pål J. Johnsen; Gabriela J. da Silva; Kaare Magne Nielsen
• Keywords: Horizontal Gene Transfer; Bacterial genome size; Gene cassette

We have investigated to what extent natural transformation acting on free DNA substrates can facilitate transfer of mobile elements including transposons, integrons and/or gene cassettes between bacterial species. Naturally transformable cells Acinetobacter baylyi were exposed from integron-carrying strains the genera Acinetobacter, Citrobacter, Enterobacter, Escherichia, Pseudomonas, and Salmonella determine nature frequency transfer. Exposure various sources resulted in acquisition antibiotic resistance traits as well entire over a 24 h exposure period. incorporation was not solely dependent integrase functions or genetic relatedness sequence analyses revealed that several mechanisms facilitated stable integration recipient genome depending donor DNA; homologous heterologous recombination types transposition (Tn21-like IS26-like). Both transformed isolates extensively characterized by antimicrobial susceptibility testing, integron- cassette-specific PCRs, sequencing, pulsed field gel electrophoreses (PFGE), Southern blot hybridizations, re-transformation assays. Two transformant also genome-sequenced. Our data demonstrate facilitates interspecies elements, suggesting transient presence cytoplasm may be sufficient for genomic occur. study provides plausible explanation why sequence-conserved IS found disseminated among Moreover, integron harboring populations competent bacteria exchange highly efficient, independent recipient. In conclusion, much broader capacity horizontal acquisitions hence, divergent species than previously assumed.