Antonie van Leeuwenhoek

, Volume 96, Issue 2, pp 205–226

New mobile genetic elements in Cupriavidus metallidurans CH34, their possible roles and occurrence in other bacteria

Authors

  • Rob Van Houdt
    • Unit for MicrobiologySCK•CEN
  • Sébastien Monchy
    • Unit for MicrobiologySCK•CEN
    • Biology Department, Brookhaven National Laboratory
  • Natalie Leys
    • Unit for MicrobiologySCK•CEN
    • Unit for MicrobiologySCK•CEN
Original Paper

DOI: 10.1007/s10482-009-9345-4

Cite this article as:
Van Houdt, R., Monchy, S., Leys, N. et al. Antonie van Leeuwenhoek (2009) 96: 205. doi:10.1007/s10482-009-9345-4

Abstract

Cupriavidus metallidurans strain CH34 is a β-Proteobacterium that thrives in low concentrations of heavy metals. The genetic determinants of resistance to heavy metals are located on its two chromosomes, and are particularly abundant in the two megaplasmids, pMOL28 and pMOL30. We explored the involvement of mobile genetic elements in acquiring these and others traits that might be advantageous in this strain using genome comparison of Cupriavidus/Ralstonia strains and related β-Proteobacteria. At least eleven genomic islands were identified on the main replicon, three on pMOL28 and two on pMOL30. Multiple islands contained genes for heavy metal resistance or other genetic determinants putatively responding to harsh environmental conditions. However, cryptic elements also were noted. New mobile genetic elements (or variations of known ones) were identified through synteny analysis, allowing the detection of mobile genetic elements outside the bias of a selectable marker. Tn4371-like conjugative transposons involved in chemolithotrophy and degradation of aromatic compounds were identified in strain CH34, while similar elements involved in heavy metal resistance were found in Delftia acidovorans SPH-1 and Bordetella petrii DSM12804. We defined new transposons, viz., Tn6048 putatively involved in the response to heavy metals and Tn6050 carrying accessory genes not classically associated with transposons. Syntenic analysis also revealed new transposons carrying metal response genes in Burkholderia xenovorans LB400, and other bacteria. Finally, other putative mobile elements, which were previously unnoticed but apparently common in several bacteria, were also revealed. This was the case for triads of tyrosine-based site-specific recombinases and for an int gene paired with a putative repressor and associated with chromate resistance.

Keywords

Genomic islandsTn4371Tyrosine-based site-specific recombinaseIntegraseHeavy metalsChemolithotrophyTransposonAnnotationSynteny

Copyright information

© Springer Science+Business Media B.V. 2009