Figure 1. The good and bad sides of Rhodococcus.

The acquisition of a virulence plasmid (yellow) can transform benign commensal strains of Rhodococcus (blue) into pathogenic strains (blue and yellow) that stunt the growth of the plant and its roots (left) compared with a healthy plant (right). However, this process is reversible, and the loss of the virulence plasmid results in the bacteria becoming commensal again.