Dynamic calcium signals mediate the feeding response of the carnivorous sundew plant

Some of the most spectacular examples of botanical carnivory-in which predator plants catch and digest animals presumably to supplement the nutrient-poor soils in which they grow-occur within the Droseraceae family. For example, sundews of the genus Drosera have evolved leaf movements and enzyme secretion to facilitate prey digestion. The molecular underpinnings of this behavior remain largely unknown; however, evidence suggests that prey-induced electrical impulses are correlated with movement and production of the defense hormone jasmonic acid (JA), which may alter gene expression. In noncarnivorous plants, JA is linked to electrical activity via changes in cytoplasmic Ca²⁺. Here, we find that dynamic Ca²⁺changes also occur in sundew (Drosera spatulata) leaves responding to prey-associated mechanical and chemical stimuli. Furthermore, inhibition of these Ca²⁺changes reduced expression of JA target genes and leaf movements following chemical feeding. Our results are consistent with the presence of a conserved Ca²⁺-dependent JA signaling pathway in the sundew feeding response and provide further credence to the defensive origin of plant carnivory.