Circadian Clock Gates <i>Verticillium dahliae</i> Defence in Cotton by Modulating <i>JAZs</i> Expression

ABSTRACT The circadian clock plays critical roles in orchestrating temporal regulation of diverse physiological processes. However, its role in mediating root‐associated immunity against soil‐borne pathogens in crops remains poorly understood. Here, we show that cotton circadian clock gates nighttime resistance to vascular fungal pathogen Verticillium dahliae by shaping rhizosphere microbiome composition and activating jasmonic acid (JA)‐dependent immune signalling. Pathogen infection, in turn, accelerates clock pace and perturbs nighttime microbial community structure. We identify GhLUX, an evening complex component, as a key regulator of this defence program. GhLUX enhances immunity by repressing GhJAZ expression, thereby amplifying JA signalling at night. Overexpression of GhLUX in field trials confers enhanced resistance to V. dahliae while simultaneously improving cotton fibre yield and quality. These findings uncover a mechanistic link between the circadian clock, rhizosphere microbiota and root immunity in cotton and suggest that circadian regulators can be harnessed to optimize both disease resistance and agronomic performance.