Abscisic acid plays a pivotal role in stomatal defense at the early infection of Verticillium dahliae in Gossypium hirsutum

Plant leaf stomata serve as primary conduits for gas exchange while simultaneously mediating immune responses against phyllosphere pathogen infection and colonization. However, the contribution of stomatal responses to interactions between plants and the rhizosphere pathogen Verticillium dahliae (V. dahliae) remains poorly understood. Our results show that inoculation of cotton roots with V. dahliae induces rapid stomatal closure preceding pathogen colonization of leaves, which is associated with elevated levels of second messengers including hydrogen peroxide (H2O2), cytosolic calcium (Ca²⁺), and nitric oxide (NO). Transcriptomic analyses reveal that hormone signaling pathways predominantly govern stomatal-mediated immunity. Specifically, accumulation of endogenous salicylic acid (SA) promotes stomatal closure in an abscisic acid (ABA)-dependent manner in response to V. dahliae infection. Live imaging indicates that during early infection stages, stomatal opening facilitates increased V. dahliae colonization and disease progression, highlighting the important function of stomatal dynamics and hydraulic regulation in V. dahliae-cotton interactions. Our findings establish a link between stomata and V. dahliae infection, providing a new understanding of stomatal biology in the context of plant-rhizosphere pathogen interactions. Further understanding of the stomatal response to V. dahliae infection may provide new strategies to enhance Verticillium wilt resistance in cotton.