Pathogenesis of the human opportunistic pathogen Pseudomonas aeruginosa PA14 in Arabidopsis

The human opportunistic pathogen Pseudomonas aeruginosa strain PA14 is a mu ltihost pathogen that can infect Arabidopsis. We found that PA14 pathogenes is in Arabidopsis involves the following steps: attachment to the leaf surf ace, congregation of bacteria at and invasion through stomata or wounds, co lonization of intercellular spaces, and concomitant disruption of plant cel l wall and membrane structures, basipetal movement along the vascular paren chyma, and maceration and rotting of the petiole and central bud. Distincti ve features of P. aeruginosa pathogenesis are that the surface of mesophyll . cell walls adopt an unusual convoluted or undulated appearance, that PA14 cells orient themselves perpendicularly to the outer surface of mesophyll cell walls, and that PA14 cells make circular perforations, approximately e qual to the diameter of P. aeruginosa, in mesophyll cell walls. Taken toget her, our data show that P, aeruginosa strain PA14 is a facultative pathogen of Arabidopsis that is capable of causing local and systemic infection, wh ich can result in the death of the infected plant.