DETECTION OF THE TOTAL OXIDATIVE BURST DURING THE EARLY STAGE OF PLANT/BACTERIAL INTERACTIONS

Authors: Baker, Con; Mock, Norton

Submitted to: Free Radicals in Biology and Medicine
Publication Type: Abstract Only
Publication Acceptance Date: 4/1/2004
Publication Date: 5/1/2004
Citation: Baker, C.J., Mock, N.M. 2005. Detection of the total oxidative burst during the early stage of plant/bacterial interactions. Free Radicals in Biology and Medicine. 64:255-261.

Interpretive Summary:

Technical Abstract: We have developed an assay that provides a more complete picture of the total oxidative burst that occurs during the interaction of plant cell suspensions and bacterial pathogens. We have found that cell suspensions rapidly produce and maintain considerable levels of extracellular antioxidants when placed in fresh buffer. This extracellular antioxidant pool will attenuate and often mask the detection of hydrogen peroxide produced during an oxidative burst. In our model system, which employs potato and tobacco suspension cells and strains of virulent and avirulent Pseudomonas syringae pathovars, there appears to be no process for redox-recycling of these extracellular antioxidants. Therefore the amount of hydrogen peroxide scavenged appears to be stoichiometrically proportional to the decrease in concentration of the antioxidant. Using a modification of a luminol chemiluminescent assay, changes in the extracellular antioxidant concentration resulting from an oxidative burst in cell suspensions can be monitored over a period of time. The difference in antioxidant concentration between various plant cell/bacterial interactions and control treatments, can be used to determine the amount of H2O2 that has been produced at the time of sampling. In our studies, this technique has provided a better estimation of both the magnitude and timing of the oxidative bursts during cell suspension/bacterial interactions.