Importers drive leaf-to-leaf transmission of jasmonic acid in wound induced systemic immunity.

Abstract The transmission of mobile wound signals along the phloem pathway is essential to activate wound-induced systemic response/resistance (WSR), which requires the upsurge of jasmonic acid (JA) in the distal undamaged leaves. Among these mobile signals, the electrical signal mediated by the glutamate-dependent activation of several clade three GLUTAMATE RECEPTOR-LIKE (GLR3) proteins is involved to stimulate the production of JA in the distal leaves. However, whether JA acts as the mobile wound signal, and if so, the transmitting mode of JA and its interactions with electrical signal remain vague. Here, we showed that JA was translocated from the local to the distal leaves, which was predominantly regulated by two phloem-expressed and plasma membrane-localized jasmonate transporters, AtJAT3 and AtJAT4 in Arabidopsis. Together with a cooperation between AtJAT3/4 and GLR3.3 in regulating long-distance translocation of JA, our findings indicate that importer-mediated cell-cell transport of JA is important for driving the loading, translocation of JA in the phloem pathway by a self-propagation mode.