Phaeomoniella chlamydospora-induced oxidative burst in vitis vinifera cell suspensions : role of NADPH oxidase and Ca2+

Abstract

The biphasic oxidative burst induced by Phaeomoniella chlamydospora extract (Pce) in Vitis vinifera (Vv) cell suspensions was investigated. Treatment of cell suspensions with diphenyleneiodonium chloride, an inhibitor of NADPH oxidase, prevented the Pce-induced biphasic reactive oxygen species (ROS) accumulation, suggesting that NADPH oxidase is the primary ROS source in the oxidative burst induced by Pce elicitation of Vv cells. The role of Ca2+ in the oxidative burst was also investigated using a Ca2+ chelator and several Ca2+ channel blockers. The treatment of Vv cell suspensions with the Ca2+ chelator ethylene glycol-bis(2-aminoethylether)-N, N, N’; N’-tetraacetic acid (EGTA) completely inhibited Pce-induced ROS accumulation, suggesting that Ca2+ availability is necessary for occurrence of the induced oxidative burst. However, only the Ca2+ channel blocker ruthenium red strongly inhibited the Pce-induced ROS accumulation, suggesting that the specific Ca2+ channel types from which Ca2+ influx is originated also play an important role in the Pce-induced oxidative burst. Furthermore, Ca2+ availability seems to be necessary for the Pce-induced activity of NADPH oxidase.