Glutathione induces trap closure for carnivory in Cape sundew

Charles Darwin was profoundly fascinated by Drosera (sundew plants), which have evolved as flesh-eaters with modified leaves, called traps, to catch small animals yet do not respond to transient mechanical stimuli. Despite Darwin's early insights, and recent advances in characterizing these mechanisms, our knowledge of the signaling molecules underlying prey capture responses remains limited. Here, we identify glutathione (GSH) as an important mediator within the signaling cascade of sundew carnivory, implicated in trap closure in a calcium-dependent manner. We show that prey capture promotes GSH accumulation in sundew leaves, while GSH depletion inhibits the movement. Furthermore, application of GSH is sufficient to induce trap closure across the Droseraceae family, including both the snap traps of Venus flytrap and the adhesive traps of sundew species. These findings advance our understanding of the enigmatic mechanisms of plant carnivory, a phenomenon that has intrigued scientists since Darwin's era.