fer, ost2-1D, and det3 are affected in flg22-induced ROS production and MAPK activity. A–D, oxidative burst in response to 100 nm flg22 in fer (A), ost2-1D (B), det3 (C) and respective wild types was indirectly measured as relative light units (RLU). D, oxidative burst in response to 100 nm flg22 in Col-0 seedlings treated with either 5 μm concanamycin A or with respective amounts of DMSO (Control). Note the different levels of ROS production in wild-type seedlings. Relative changes were similar in all experiments. Error bars represent standard deviation of six (A), ten (B), eleven (C), and six (D) independent samples measured in a single experiment. The experiment was performed four (A) or five (B–D) times with similar results. E, MAPK activity in seedlings in response to 100 nm flg22 was determined in a time course experiment by immunoblot analysis. Ponceau staining served as a loading control. The experiment was repeated once yielding similar results.