![]() ![]() Although prey capture and consumption of the Venus flytrap has been known since Darwin’s time ( 2), the molecular mechanisms of fluid phase secretion underlying animal consumption have remained unknown ( 14). Haptoelectric signaling and touch hormone activation turn the closed trap into a “green stomach,” flooding the entrapped prey with an acidic digestive fluid ( 3, 6, 13). When mechanostimulation is replaced by application of coronatine (COR), a mimic of the biologically active JA hormone JA-Ile, it can substitute for the mechanoelectric stimulation of the flytrap ( 7). From the fifth strike on, glands raise their expression levels of hydrolase and nutrient transporter genes. In case an insect is trapped and struggles to escape, two and more haptoelectric stimuli activate jasmonate (JA) signaling and biosynthesis ( 3, 6, 7). If a second one fires within 20 s, it triggers rapid trap closure. With the first AP, the trap stays open, but memorizes the initial strike. ![]() Each trigger-hair bending elicits the firing of an action potential (AP). Closure of the bilobed snap trap is initiated by mechanical stimulation of trigger hairs located at the inner trap surface. Growing on mineral-deficient soils, the carnivorous Venus flytrap ( Dionaea muscipula) lures, captures, and digests small arthropods ( 3– 8) to feed on the nutrients extracted from their flesh ( 9– 12). Hence, when glands perceive the haptoelectrical stimulation, secretory vesicles are tailored to be released in a sequence that optimizes digestion of the captured animal.Ĭertain plants have turned the sword they capture and consume animals, including potential herbivores ( 1, 2). Early vesicles loaded with H + and Cl − fuse with the plasma membrane, hyperacidifying the “green stomach”-like digestive organ, whereas subsequent ones carry hydrolases and nutrient transporters, together with a glutathione redox moiety, which is likely to act as the major detected compound in amperometry. Gland cells translate APs into touch-inducible JA signaling that promotes the formation of secretory vesicles. Our data indicate that trigger-hair mechanical stimulation evokes APs. Spikes reminiscent of exocytotic events in secretory animal cells progressively increased in frequency, reaching steady state 1 d after stimulation. Trigger-hair bending or direct application of JA caused a quantal release of oxidizable material from gland cells monitored as distinct amperometric spikes. Using advanced analytical and imaging techniques, such as vibrating ion-selective electrodes, carbon fiber amperometry, and magnetic resonance imaging, we monitored stimulus-coupled glandular secretion into the flytrap. Although postulated since Darwin’s pioneering studies, these secretory events have not been recorded so far. Such prey-induced haptoelectric stimulation activates the touch hormone jasmonate (JA) signaling pathway, which initiates secretion of an acidic hydrolase mixture to decompose the victim and acquire the animal nutrients. These action potentials (APs) cause rapid closure of the trap and activate secretory functions of glands, which cover its inner surface. ![]() Prey contacting touch-sensitive hairs trigger traveling electrical waves. The Venus flytrap Dionaea muscipula captures insects and consumes their flesh. ![]()
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