[Bacterial containment system regulated by the concentration of salicylate]

Use of genetically engineered microorganisms (GEMs) for pollution abatement has been limited because of the risks associated with their uncontrolled release in environment. In this study, a pollutant-dependent bacterial containment system was constructed in E. coli JM109. The system consisted of two plasmids containing a killing element and a regulatory element respectively. The survival of strains can be regulated by the concentration of salicylate in environment. In the presence of salicylate, the expression of the suicide gene gef was inhibited with the synthesis of LacI protein, leading to the normal proliferation of the strain. While in the absence of salicylate, the expression of the regulatory element was cancelled, and the expression of the suicide gene gefled to a high rate of cell killing. This containment system can be used as a model during the construction of genetically engineered strains for bioremediation.