Figure 1.

Initiation of early defense signaling mechanisms in response to insect herbivore attack. Schematic diagram showing herbivore M. sexta feeding induced signaling events, which include the perception of HAEs such as OS, frass, and oviposition by specialized receptors on the outer plasma membrane, which trigger modulation of V_m via H⁺-ATPase and Ca²⁺ ion influx into the cell via Ca²⁺ channels, GLR3.3/3.6 and/or CNGC19. The increase in cytosolic Ca²⁺ may trigger the further release of vacuolar Ca²⁺ via the TPC1 channel. The subsequent release of Ca²⁺ may activate nicotinamide adenine dinucleotide phosphate (NADPH oxidase) and respiratory burst oxidase homologues (RBOHDs), leading to ROS generation, and induction of plant defense responses. Illustration by Annette Diaz.