Background: Defense-related anti-oxidative response is a vital defense mechanism of plant against pathogen invasion. Ralstonia solanacearum is an important phytopathogen. Bacterial wilt caused by R. solanacearum is the most destructive disease and causes severe losses in patchouli, an important aromatic and medicinal plant in Southeast Asia. The present study evaluated the defense response of patchouli inoculated with virulent R. solanacearum.

Results: Results showed that the basic enzymatic activities differed not only between the leaves and stems, but also between the upper and lower parts of the same organ of patchouli. POD, SOD, PPO and PAL enzymatic activities were significantly elevated in leaves and stems from patchouli inoculated with R. solanacearum as compared to control. The variation magnitude and rate of POD, PPO and PAL activities were more obvious than SOD in patchouli inoculated with R. solanacearum. PAGE isoenzymatic analysis showed that there were one new POD band and two new SOD bands elicited, and at least two isoformic POD bands and two SOD bands were observably intensified as compared to the corresponding control.

Conclusion: Our results suggest that not only the defensive enzymatic activities were elevated, but also the new isoenzymatic isoforms were induced in patchouli inoculated with R. solanacearum.