The ability of Xcc to migrate through stomata in isolated epidermis is dependent on a functional rpfF/DSF system. Confocal images of the inner side of detached Arabidopsis epidermis were recorded after floating them for 3 h, with the cuticle side in contact with bacterial suspensions of Xcc, rpfF, or rpfC in the presence or not of extracts of supernatants from Xcc, rpfF, or rpfC cultures. An extract from Xcc, but not from rpfF or rpfC, restored the ability of rpfF and rpfC to migrate through the epidermis. An extract from rpfC, which contains a high concentration of DSF, reduced the ability of Xcc to migrate through stomata. The experiment was repeated with similar results.