Arsenic (As) is a toxic metal that can harm plants by causing oxidative stress, stunting growth, and disrupting metabolism. This study investigates the potential effect of gamma-aminobutyric acid (GABA) and salicylic acid (SA) in mitigating the toxic effects of As on sunflower plants. The aim is to enhance growth, improve metabolite accumulation, strengthen antioxidant defenses, reduce oxidative stress, enhance nutrient status, and minimize As uptake in sunflower plants. To investigate the effect of GABA and SA on arsenic toxicity, two sunflower genotypes (FH-779 and FH-773) were exposed to arsenic at a concentration of 60 mg kg(-)(1) in the soil. The experimental design followed a completely randomized design with three replications of each treatment arranged in a factorial manner. The sunflower plants were treated with foliar sprays of GABA (200 mg L--(1)), SA (100 mg L--(1)), and a combination of both GABA + SA (200 + 100 mg L--(1)). Both FH-779 and FH-773 genotypes exhibited significant accumulation of As + 5 and As+ 3 in roots and leaves, resulting in reduced nutrient uptake. GABA, SA, and GABA + SA treatments alleviated As-induced oxidative stress by reducing hydrogen peroxide (H2O2) production and malondialdehyde (MDA) levels in both genotypes. These treatments also enhanced osmolyte accumulation, improving osmotic adjustment under As stress. Additionally, GABA and SA spray enhanced the activity of antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD), aiding in scavenging reactive oxygen species (ROS) and preventing oxidative damage. The combination of GABA and SA had a more pronounced effect on the translocation and remediation of As compared to GABA and SA alone. Arsenic removal efficiency reached maximum in the GABA + SA treatment in both FH-779 and FH-773 genotypes, greater than control group, respectively. The findings of this study highlight the beneficial roles of gamma-aminobutyric acid and salicylic acid in mitigating the negative effects of arsenic on growth of sunflower plants. These compounds regulate photosynthetic pigments, osmotic pressure, and antioxidant defense systems, improve nutrient status, and reduce arsenic uptake. Salicylic acid and gamma-aminobutyric acid show potential for alleviating stress in other crops facing abiotic stress. This study highlights the impact of these compounds on plant defense mechanisms in stress conditions, providing a promising approach to reduce arsenic toxicity in crops, thereby improving agricultural productivity in contaminated environments.

Salt stress has become a significant issue affecting crop growth, and China has abundant saline soil resources. Sugar beet, as a salt-tolerant crop, efficiently utilizes limited land resources. However, severe salt stress can harm the normal growth of sugar beet. To investigate how to improve its salt tolerance, we conducted a hydroponic experiment using Shuangfeng 8 with five treatments: GABA addition (G + S), 3-MPA addition (T) under salt stress (S) conditions, nutrient solution only (CK), and GABA addition (G) as controls. The results indicate that exogenous GABA pretreatment can mitigate reactive oxygen species damage to membrane lipids and stabilize membrane structure by enhancing antioxidant enzyme activity. It also increased the activity of key enzymes in GABA metabolism and GABA content, providing essential substrates for the tricarboxylic acid cycle. This enhanced the activity of key enzymes in the tricarboxylic acid cycle, ensuring cellular energy supply. GABA can link the tricarboxylic acid cycle with nitrogen metabolism, increasing the activity of nitrogen metabolism enzymes and promoting the synthesis of essential amino acids like glutamate. Ultimately, this improves gas exchange and fluorescence parameters, stabilizing photosynthesis, maintaining normal growth of sugar beet under salt stress, and increasing dry matter accumulation. Reverse validation using GABA inhibitors resulted in significantly higher MAD and ROS levels in sugar beet. Antioxidant enzyme activity, GABA content, photosynthetic fluorescence parameters, and dry matter accumulation were lower than in the treatment with exogenous GABA, further suggesting that exogenous GABA at 1.5 mM L-1 can effectively alleviate salt stress damage in sugar beet.

Salinity has emerged as a critical abiotic stress factor, significantly limiting the growth, productivity, and quality of many crop species. As the global salinization of agricultural land continues to intensify, it is crucial to explore effective mitigation strategies to sustain crop yields. gamma-Aminobutyric acid (GABA), a non-protein amino acid, is present in a variety of organisms, including plants, where it fulfills diverse roles under both optimal and stress conditions. In plants, GABA is intricately involved in nitrogen metabolism, amino acid biosynthesis, and the regulation of primary and secondary metabolic pathways. Functioning through the GABA shunt, it provides the carbon skeletons and energy required for biosynthetic processes and is vital for the regulation of carbon and nitrogen balance. Under abiotic stress conditions, particularly salinity, GABA rapidly accumulates, facilitating several protective mechanisms that help plants cope with stress. These include enhancing osmotic adjustment through the accumulation of osmolytes, protecting cellular structures such as chloroplasts, and improving chlorophyll fluorescence and photosynthetic efficiency. Moreover, GABA has been shown to boost antioxidant enzyme activity, reducing oxidative stress and mitigating the damage caused by reactive oxygen species (ROS) under salinity conditions. This study explores the multifaceted role of GABA in plants under saline environments, with a focus on its physiological, biochemical, and molecular mechanisms in enhancing plant resilience. By elucidating these mechanisms, we aim to highlight the potential of GABA as a natural biostimulant to improve crop performance and sustainability in saline soils.

Licorice is widespread in arid and semi-arid areas, but high soil salinity has always been a limiting factor for vegetation growth in these areas. Gamma-aminobutyric acid (GABA) is a signaling molecule that can regulate tolerance in plant. However, the mechanism by which exogenous GABA regulates the response of licorice to saline-alkali stress is not yet clear. In this study, we investigated the effects of exogenous GABA on growth parameters, oxidative damage, hormone levels and photosynthetic indices of licorice seedlings under different combinations of saline and alkali stress conditions. The experiment involved eight treatments: CK, distilled water (control); CK + GABA, 0.1 mM GABA; salt stress (SS), 150 mM NaCl; SS + GABA, 150 mM NaCl + 0.1 mM GABA; alkali stress (AS), 10 mM Na2CO3; AS + GABA, 10 mM Na2CO3 + 0.1 mM GABA; mixed saline-alkali stress (MAS), 150 mM NaCl + 10 mM Na2CO3; MAS + GABA, 150 mM NaCl + 10 mM Na2CO3 + 0.1 mM GABA. Our results showed that the inhibitory effects of SS and MAS on the seedling height, root length and root-shoot ratio were significantly alleviated by exogenous GABA. Although soluble sugars, chlorophyll a, total chlorophyll, and superoxide dismutase (SOD) activity were lower in the leaves of the seedlings in the SS treatment compared with the control, these physiological parameters increased significantly after GABA application. Exogenous GABA improved glutathione (GSH) activity in both the leaves and roots of the seedlings during the AS treatment. Additionally, take advantage of GABA led to an increase in ABA, GA and IAA contents in leaves under SS, AS and MAS treatments. Furthermore, the photosynthetic parameters, including Pn, gs, Tr, ETR and qP, significantly increased following the utilization of GABA in both the SS and MAS treatments. Therefore, the application of exogenous GABA can reduce the accumulation of harmful substances, preserve cell morphology, and enhance cell function under saline, alkali, and saline-alkali stress. This enhances the resistance of licorice seedlings to stress conditions and reduces physiological damage.