Decoding the multifunctional role of γ-aminobutyric acid in plant adaptation to drought stress

GABA acts as a central integrator of molecular, physiological, and metabolic responses, enhancing drought tolerance by improving water-use efficiency, osmotic balance, redox homeostasis, and stress signaling. Drought is one of the most severe abiotic stresses, limiting plant growth, yield, and global food security under climate change and resource scarcity. Gamma-aminobutyric acid (GABA), a non-proteinogenic amino acid, acts as a multifunctional regulator of plant drought tolerance by orchestrating physiological, biochemical, and molecular responses. GABA enhances osmotic adjustment, antioxidant defense, and stomatal regulation, promotes proline accumulation, and interacts with polyamines and hormonal pathways such as ABA, collectively improving water-use efficiency and mitigating oxidative stress. Its metabolism and signaling integrate diverse cellular processes, enabling efficient stress perception, adaptation, and maintenance of cellular homeostasis. GABA also coordinates metabolic crosstalk, supporting stress-responsive networks that enhance resilience under water-limited conditions. By modulating these interconnected pathways, GABA contributes to improved plant survival, growth, and productivity during drought. Exploiting GABA-mediated mechanisms offers promising strategies for enhancing crop drought tolerance, sustaining agricultural productivity, and guiding future research toward practical applications. This review synthesizes current knowledge on GABA's multifunctional role in drought adaptation, encompassing metabolic regulation, physiological responses, stomatal control, antioxidant systems, and interactions with polyamines, providing an integrated perspective on its potential to improve plant resilience under increasingly frequent and severe water-deficit conditions.