Mechanosensory Trichome Cells Evoke Mechanical Stimuli-induced Immune Response in Plants

Perception of pathogen-derived ligands by their corresponding host receptors is a pivotal strategy in eukaryotic innate immunity. In plants, this is complemented by circadian anticipation of infection timing, thereby promoting basal resistance even in the absence of pathogen threat. Trichomes, which are hair-like structures on the epidermis, directly sense external mechanical forces caused by raindrops to anticipate waterborne infections. Exposure of leaf surfaces to mechanical stimuli such as raindrops initiates the concentric propagation of intercellular calcium waves away from trichomes to induce defense-related genes. We propose a novel layer of plant immunity in which trichomes function as mechanosensory cells to detect potential risks.