Plant-dependent active biological containment system for recombinant rhizobacteria

Summary 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.