Myosin XI coordinates ABA-induced stomatal closure via microtubule stability and ROS synthesis in drought-stressed Arabidopsis.

Abstract

Key message: Myosin XI contributes to ABA-triggered stomatal closure via reactive oxygen species signaling and microtubule remodeling, boosting drought tolerance in Arabidopsis.. ABA is a key hormone induced by drought stress, and it can regulate stomatal closure through the homeostasis of reactive oxygen species (ROS) and microtubule depolymerization in guard cells, which ultimately enhances plant drought resistance. In this study, we found that myosin XI double (2ko) and triple (3ko) mutants not only exhibited reduced drought resistance but also showed a weakened ABA response compared to the wild-type (WT). Through comprehensive phenotypic analysis and cellular observations, our experiments demonstrated that myosin XI plays a role in regulating ABA-induced ROS synthesis and microtubule depolymerization in guard cells, thereby facilitating stomatal closure, which minimizes leaf water loss while enhancing drought tolerance in Arabidopsis. This study provides novel insights into the role of myosin XI in abiotic stress responses by showing connections with fundamental ABA signaling pathways and broadens our understanding of myosin XI function in plants beyond its established roles in cytoplasmic streaming.