Abstract
Reactive oxygen species (ROS) produced by NADPH oxidases have been shown to play many critical roles in stress responses and development in plants. Respiratory burst oxidase homolog (rboh) genes have been identified in various plants as NADPH oxidases. Among 10 rboh genes in Arabidopsis, AtrbohD and AtrbohF are involved in defense responses against pathogens and ABA signal transduction in stomatal guard cells. We have been analyzing the regulatory mechanisms for activation of Atrboh proteins by a heterologous expression system using the HEK293T cells. AtrbohD possessed ROS-producing enzyme activities, which were synergistically activated by phosphorylation and binding of Ca2+ to its EF-hand motifs (Ogasawara et al., JBC, 2008). We have characterized the activation mechanisms for AtrbohF. Similarities and differences of the ROS-producing activity and regulation between AtrbohD and AtrbohF will be discussed.
