The roles of these enzymes in innate immunity are well-documented, and in C. elegans the NADPH oxidase BLI-3 produces ROS in response to pathogen infection, leading in turn to activation of NSY-1/ASK1/MAPKKK, SEK-1/MAPKK, PMK-1/p38 MAPK and SKN-1/Nrf (Hoeven et al., 2011). This evidence concerns the gene MAP2K4 and infection.