Abstract
The production of reactive oxygen species at the cell surface, called the oxidative burst, is the earliest events detected during incompatible interactions between plants and pathogens. Treatment of potato tubers with the pathogen-derived elicitor caused a rapid and transient accumulation of H2O2, followed by a massive oxidative burst 6 to 9 h after the treatment. StrbohA and StrbohB are thought to contribute to the bursts. Because NADPH-dependent O2--generating activity was located predominantly in plasma membrane fraction, Strboh has been suggested to localize at the plasma membrane. Here we demonstrate that StrbohA and StrbohB were localized in plasma membrane fractions separated by sucrose density gradient centrifugation using their specific antibodies. Additionally, NADPH-dependent O2--generating activities, which were DPI-sensitive and NaN3-insensitive, were also distributed in plasma membrane fractions. These data suggest that StrbohA and StrbohB are localized at plasma membrane and regulate the oxidative burst in the defense responses.
