The Burkholderia cenocepacia sensor kinase hybrid AtsR is a global regulator modulating quorum-sensing signalling
Article first published online: 26 JUL 2012
© 2012 Society for Applied Microbiology and Blackwell Publishing Ltd
Special Issue: Environmental Ecology of Pathogens and Resistances
Volume 15, Issue 2, pages 372–385, February 2013
How to Cite
Aubert, D. F., O'Grady, E. P., Hamad, M. A., Sokol, P. A. and Valvano, M. A. (2013), The Burkholderia cenocepacia sensor kinase hybrid AtsR is a global regulator modulating quorum-sensing signalling. Environmental Microbiology, 15: 372–385. doi: 10.1111/j.1462-2920.2012.02828.x
- Issue published online: 28 JAN 2013
- Article first published online: 26 JUL 2012
- Accepted manuscript online: 3 JUL 2012 12:57AM EST
- Received 3 April, 2012; accepted 26 June, 2012.
Burkholderia cenocepacia is commonly found in the environment and also as an important opportunistic pathogen infecting patients with cystic fibrosis. Successful infection by this bacterium requires coordinated expression of virulence factors, which is achieved through different quorum sensing (QS) regulatory systems. Biofilm formation and Type 6 secretion system (T6SS) expression in B. cenocepacia K56-2 are positively regulated by QS and negatively regulated by the sensor kinase hybrid AtsR. This study reveals that in addition to affecting biofilm and T6SS activity, the deletion of atsR in B. cenocepacia leads to overproduction of other QS-regulated virulence determinants including proteases and swarming motility. Expression of the QS genes, cepIR and cciIR, was upregulated in the ΔatsR mutant and resulted in early and increased N-acylhomoserine lactone (AHL) production, suggesting that AtsR plays a role in controlling the timing and fine-tuning of virulence gene expression by modulating QS signalling. Furthermore, a ΔatsRΔcepIΔcciI mutant could partially upregulate the same virulence determinants indicating that AtsR also modulates the expression of virulence genes by a second mechanism, independently of any AHL production. Together, our results strongly suggest that AtsR is a global virulence regulator in B. cenocepacia.