Equally contributing authors.
The genetic basis of cadmium resistance of Burkholderia cenocepacia
Article first published online: 19 AUG 2012
© 2012 Society for Applied Microbiology and Blackwell Publishing Ltd
Environmental Microbiology Reports
Volume 4, Issue 5, pages 562–568, October 2012
How to Cite
Schwager, S., Lumjiaktase, P., Stöckli, M., Weisskopf, L. and Eberl, L. (2012), The genetic basis of cadmium resistance of Burkholderia cenocepacia. Environmental Microbiology Reports, 4: 562–568. doi: 10.1111/j.1758-2229.2012.00372.x
- Issue published online: 4 OCT 2012
- Article first published online: 19 AUG 2012
- Accepted manuscript online: 24 JUL 2012 07:27AM EST
- Manuscript Accepted: 16 JUL 2012
- Manuscript Revised: 13 JUL 2012
- Manuscript Received: 25 MAY 2012
- Swiss National Science Foundation. Grant Numbers: 31003A-122013, 31003A-130089
Burkholderia species are highly resistant to heavy metals (HMs), yet their resistance mechanisms are largely unknown. In this study we screened 5000 mini-Tn5 transposon insertion mutants of Burkholderia cenocepacia H111 for loss of cadmium tolerance. Of the four genes identified three affected outer membrane biogenesis and integrity or DNA repair. The fourth gene, BCAE0587, encoded a P1-type ATPase belonging to the CadA family of HM exporters. CadA-deficient strains lost the ability to grow in the presence of cadmium, zinc and lead, whereas resistance to nickel, copper and cobalt was not affected. Expression studies using a transcriptional fusion of the cadA promoter to gfp confirmed this specificity, as induction was only observed in presence of cadmium, zinc and lead. The promoter activity was found to be highest at neutral pH with an activation threshold of 30 nM cadmium. Inoculation of the HM-hyperaccumulating plant Arabidopsis halleri with a RFP-marked derivative of B. cenocepacia H111 containing the PcadA–gfp fusion demonstrated the applicability of this biosensor for monitoring cadmium at the single cell level in a natural environment.