Plant-dependent active biological containment system for recombinant rhizobacteria.

This work describes the construction of the rhizobacterium Pseudomonas putida strain CS-4, which contains an active biological containment (ABC) system that ensures bacterial suicide in the absence of proline. Maize plants exudate proline, which allows CS-4 to colonize the rhizosphere at a similar level to that of the wild-type strain. However, when the plants are removed, the CS-4 population decreased in bulk soil at a higher rate than the wild-type strain.