γ-Aminobutyric Acid Suppresses Iron Transportation from Roots to Shoots in Rice Seedlings by Inducing Aerenchyma Formation

Exogenous γ-aminobutyric acid and Bacillus pumilus reduce arsenic uptake and toxicity in rice

In this study, the addition of γ-aminobutyric acid (GABA), Bacillus pumilus, or both, was found to enhance rice growth and yield while significantly decreasing arsenic (As) accumulation in Oryza sativa rice tissues. GABA emerged as a regulator of iron (Fe) homeostasis, acting as a signaling modulator that influenced phytosiderophore secretions in the plant. Meanwhile, B. pumilus directly increased Fe levels through siderophore production, promoting the development of Fe-rich rice plants. Subsequently, Fe competed with As uptake at the root surface, leading to decreased As levels and translocation to the grains. Furthermore, the addition of GABA and B. pumilus optimized rice indole-3 acetic acid (IAA) contents, thereby adjusting cell metabolite balance under As stress. This adjustment results in low malondialdehyde (MDA) contents in the leaves and roots during the early and late vegetative phases, effectively reducing oxidative stress. When added to As-contaminated soil, GABA and B. pumilus effectively maintained endogenous GABA levels and exhibited low ROS generation, similar to normal soil. Concurrently, GABA and B. pumilus significantly downregulated the activity of OsLsi1, OsLsi2, and OsABCC1 in roots, reducing As uptake through roots, shoots, and grains, respectively. These findings suggest that GABA and B. pumilus additions impede As translocation through grains, ultimately enhancing rice productivity under As stress.

Recent advances of γ-aminobutyric acid: Physiological and immunity function, enrichment, and metabolic pathway

γ-aminobutyric acid (GABA) is a non-protein amino acid which naturally and widely occurs in animals, plants, and microorganisms. As the chief inhibitory neurotransmitter in the central nervous system of mammals, it has become a popular dietary supplement and has promising application in food industry. The current article reviews the most recent literature regarding the physiological functions, preparation methods, enrichment methods, metabolic pathways, and applications of GABA. This review sheds light on developing GABA-enriched plant varieties and food products, and provides insights for efficient production of GABA through synthetic biology approaches.