Aquaporins as Natural Stress Integrator: Coordinating Transport, Signals, and Tolerance Mechanisms in Plants

Aquaporins (AQPs), key members of the major intrinsic protein (MIP) superfamily, have emerged as pivotal regulators of plant responses to diverse abiotic stresses. Beyond their natural role as water channels, AQPs function as integrators of transport, signaling, and acclimation. This review synthesizes current knowledge on their structural diversity, stress-specific isoform expression, and multilayered regulation by transcription factors, phytohormones, and signaling molecules. We highlight the modulation of AQP activity through post-translational mechanisms such as phosphorylation, gating, and trafficking, and emphasize the central role of plasma membrane intrinsic proteins (PIPs) in hydraulic adjustment under drought, salinity, and temperature stress. By linking AQPs with antioxidant systems, ion channels, and stress signaling pathways, we underscore their function as natural hubs of adaptation. We further evaluate their potential in crop improvement through genetic manipulation, including CRISPR-based strategies, while identifying key knowledge gaps in isoform-specific functions, subcellular dynamics, and interactions with soil microbiota. Taken together, AQPs represent promising targets for enhancing crop resilience in the face of climate change.