MCA1 mechanosensitive channels enable fast communication of wound signals between lateral roots

Although plant roots are hidden in soil, they are vulnerable to damage by insect herbivory, just as like aerial tissues. Yet wound signalling in roots is poorly understood. Here, we examined how damage signals spread locally and over long distances between Arabidopsis lateral roots. Using intracellular membrane potential recordings, calcium imaging, and optogenetics, we show that mechanical injury triggers immediate local membrane depolarization and cytosolic Ca2+ elevations whose magnitude and duration scale with wound severity. Depolarizations were also detected in neighbouring lateral roots within milliseconds, demonstrating the presence of a rapid inter-root signalling pathway. Through mutant analyses, we highlight the roles of glutamate-like receptors and MCA1 mechanosensitive channels in mediating this long-distance communication. Our results demonstrate that a wound-induced decrease in root cell turgor pressure rapidly spreads across the root network, where neighboring roots decode this signal via MCA1. This work underscores fundamental differences between root and shoot wound responses and uncovers a mechanosensory basis for fast communication between lateral roots.