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, such as aerial tissues. However, wound signaling 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 an immediate local membrane depolarization and cytosolic calcium elevations whose magnitude and duration scale with wound severity. Depolarizations were also detected in neighboring lateral roots within milliseconds, demonstrating the presence of a rapid inter-root signaling pathway. Through mutant analyses, we highlight the roles of glutamate-like receptors and mid1-complementing activity 1 (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.