Calcium Signaling in Plant-Insect Interactions.

In plant-insect interactions, calcium (Ca) variations are among the earliest events associated with the plant perception of biotic stress. Upon herbivory, Ca waves travel long distances to transmit and convert the local signal to a systemic defense program. Reactive oxygen species (ROS), Ca and electrical signaling are interlinked to form a network supporting rapid signal transmission, whereas the Ca message is decoded and relayed by Ca-binding proteins (including calmodulin, Ca-dependent protein kinases, annexins and calcineurin B-like proteins). Monitoring the generation of Ca signals at the whole plant or cell level and their long-distance propagation during biotic interactions requires innovative imaging techniques based on sensitive sensors and using genetically encoded indicators. This review summarizes the recent advances in Ca signaling upon herbivory and reviews the most recent Ca imaging techniques and methods.