Biochemical characterization of oxidative stress in the compatible interaction between Pepper golden mosaic virus and habanero pepper plants

Abstract

<p>In this work, the role of <em>Pepper golden mosaic virus</em>-mosaic strain (PepGMV-Mo) infection on hydrogen peroxide (H2O2), salicylic acid (SA), and the antioxidant enzymes catalase (CAT) and peroxidase (POX) were analyzed <em>in vitro</em> during the compatible interaction between PepGMV-Mo and <em>Capsicum chinense</em> plants. Endogenous H2O2, SA, CAT and POX were monitored over time, and the levels of all four were increased in the PepGMV-Mo-Mo inoculated plants compared to the mock-inoculated (cloning vector) and healthy plants. Three peaks of H2O2 were observed in the inoculated plants during the time course experiment. The first increase was observed at the beginning of the time course experiment, at 30 minutes post inoculation (mpi), and the last at the end of the experiment, at 24 days pos-inoculation (dpi). The SA concentration increased 12 hours post-inoculation (hpi) in inoculated plants relative to mock-inoculated and healthy plants. Due to PepGMV-Mo infection, CAT and POX activity increased. An increase in CAT activity was observed 4 hpi in PepGMV-Mo-infected plants, and a decrease in CAT activity correlated with the increase in SA concentration at 12 hpi in the infected plants. POX activity was higher in the infected plants than in the mock-inoculated and healthy plants for the duration of the time course experiment. Taken together, the findings suggest that oxidative stress is involved in the compatible interaction between PepGMV-Mo-Mo and <em>C. chinense</em>; however, this burst was not sufficient to confer resistance or tolerance to habanero pepper against the virus based on symptom phenotype observed.</p>