Leaf-feeding insects trigger high-amplitude, defense-inducing electrical signals called slow wave potentials (SWPs). These signals are thought to be triggered by the long-distance transport of low molecular mass elicitors termed Ricca’s factors. We sought mediators of leaf-to-leaf electrical signaling in Arabidopsis thaliana and identified them as β-THIOGLUCOSIDE GLUCOHYDROLASE 1 and 2 (TGG1 and TGG2). SWP propagation from insect feeding sites was strongly attenuated in tgg1 tgg2 mutants and wound-response cytosolic Ca²⁺ increases were reduced in these plants. Recombinant TGG1 fed into the xylem elicited wild-type-like membrane depolarization and Ca²⁺ transients. Moreover, TGGs catalyze the deglucosidation of glucosinolates. Metabolite profiling revealed rapid wound-induced breakdown of aliphatic glucosinolates in primary veins. Using in vivo chemical trapping, we found evidence for roles of short-lived aglycone intermediates generated by glucosinolate hydrolysis in SWP membrane depolarization. Our findings reveal a mechanism whereby organ-to-organ protein transport plays a major role in electrical signaling.

食叶昆虫触发高振幅、诱导防御的电信号，称为慢波电位 (SWP)。这些信号被认为是由称为 Ricca 因子的低分子量诱导子的长距离传输触发的。我们在拟南芥中寻找叶间电信号转导的介质，并将它们鉴定为 β-硫代葡糖苷葡萄糖水解酶 1 和 2（TGG1 和 TGG2）。来自昆虫取食点的 SWP 传播在tgg1 tgg2突变体中被强烈减弱，并且在这些植物中伤口反应细胞溶质 Ca ²⁺增加减少。重组 TGG1 进入木质部引发野生型样膜去极化和 Ca ²⁺瞬态。此外，TGGs 催化硫代葡萄糖苷的脱糖苷作用。代谢物分析揭示了原发静脉中脂肪族芥子油苷的快速伤口诱导分解。使用体内化学捕获，我们发现了硫代葡萄糖苷水解产生的短寿命糖苷配基中间体在 SWP 膜去极化中的作用的证据。我们的研究结果揭示了一种机制，即器官间蛋白质转运在电信号传导中起主要作用。