Plant Actin Cytoskeleton Dynamics in Salt Stress Tolerance: From Structural Remodeling to Regulatory Networks

Soil salinization causes osmotic stress and ionic toxicity in plant cells and severely restricts crop growth and global agricultural productivity. The actin cytoskeleton functions as a rapidly responsive structural module and core signal integrator, with fast structural remodeling triggered upon salt exposure. This review systematically characterizes salt-induced actin rearrangement profiles and dissects the regulatory functions of key actin-binding proteins (ABPs) in governing actin nucleation, severing, bundling and steady-state turnover under saline conditions. Cross-talk among interconnected signaling cascades, including Ca2+ signals, the salt overly sensitive (SOS) pathway, reactive oxygen species (ROS) and abscisic acid (ABA) signaling, that orchestrate actin dynamics is synthesized. Key findings highlight that actin-binding proteins act as central molecular hubs linking upstream stress signaling to downstream adaptive outputs, and that actin remodeling underpins multiple salt-tolerance-related physiological events, such as cellular ion homeostasis, plastic root growth, vesicle trafficking, and the modulation of salt-triggered premature programmed cell death. Beyond actin-specific pathways, reciprocal functional interplays between actin filaments and microtubules jointly fine-tune plant salt acclimation. Unresolved questions are discussed and future research directions are proposed to bridge the gap between cytoskeletal dynamics and practical strategies for developing salt-tolerant crops. Overall, the novelty of this review lies in its salt stress-centered, multi-faceted integration of actin dynamics, from actin itself and its remodeling regulators to signaling crosstalk, physiological outputs, and actin–microtubule interplay. This review constructs a comprehensive theoretical framework linking cytoskeletal dynamics to plant salt adaptation and outlines research directions that may inform future strategies for developing salt-tolerant crops.