Systemic stomatal immunity: the beacon of fire and smoke in plant disease resistance

Plant diseases have long been a significant factor hindering agricultural. Current research indicates that most pathogenic bacteria and some fungi, among other pathogenic microorganisms, exploit stomata as key entry points to invade plants and cause diseases, including many globally prevalent ones (Melotto et al. 2008 ). In response, plants have evolved stomatal immune pathways to prevent pathogen invasion, which plays an extremely vital role in protecting plants from pathogen damage. Traditional stomatal immunity refers to the rapid response of local leaves, which close their stomata to block pathogen entry upon invasion. This pathway relies on the classic receptor complex module FLAGELLIN SENSING2 (FLS2)/BRI1-ASSOCIATED RECEPTOR KINASE 1 (BAK1) and the hormone pathways salicylic acid and abscisic acid (Hou et al. 2024 ). Recently, Liu et al. discovered a novel layer of immune coordination, termed systemic stomatal immunity (SSIM), that enables plants to rapidly synchronize stomatal defense across spatially separated leaves (Liu et al. 2026 ).