Ameliorative impacts of gamma-aminobutyric acid (GABA) on seedling growth, physiological biomarkers, and gene expression in eight wheat (Triticum aestivum L.) cultivars under salt stress.

Highlights: 1. Gamma-aminobutyric acid (GABA) has been proven to promote seedling growth in wheat varieties exposed to salt stress. As a result, there was enhanced root growth, longer shoot length, and improved overall health of the seedlings. 2. GABA has been shown to enhance physiological indicators (chlorophyll levels and enhanced relative water content) in wheat varieties under salt stress conditions and minimize membrane impairment, all of which indicate improved stress resistance and general plant well-being. 3. GABA therapy has been found to increase gene expression in wheat cultivars subjected to salt stress. This includes the upregulation of stress-responsive genes and the downregulation of genes associated with negative stress responses, ultimately leading to improved resilience and adaptation to harsh growing conditions. 4. The impact of GABA on seedling growth, physiological biomarkers, and gene expression can change depending on the unique wheat cultivar. Each wheat variety may show distinct reactions to GABA therapy, emphasizing the need for cultivar-specific studies and customized strategies to optimize the advantages of GABA in reducing salt stress in wheat farming. Plants spontaneously accumulate γ-aminobutyric acid (GABA), a nonprotein amino acid, in response to various stressors. Nevertheless, there is limited knowledge regarding the precise molecular mechanisms that plants employ to cope with salt stress. The objective of this study was to investigate the impact of GABA on the salt tolerance of eight distinct varieties of bread wheat (Triticum aestivum L.) by examining plant growth rates and physiological and molecular response characteristics. The application of salt stress had a detrimental impact on plant growth markers. Nevertheless, the impact was mitigated by the administration of GABA in comparison to the control treatment. When the cultivars Gemmiza 7, Gemmiza 9, and Gemmiza 12 were exposed to GABA at two distinct salt concentrations, there was a substantial increase in both the leaf chlorophyll content and photosynthetic rate. Both the control wheat cultivars and the plants exposed to salt treatment and GABA treatment showed alterations in stress-related biomarkers and antioxidants. This finding demonstrated that GABA plays a pivotal role in mitigating the impact of salt treatments on wheat cultivars. Among the eight examined kinds of wheat, CV. Gemmiza 7 and CV. Gemmiza 11 exhibited the most significant alterations in the expression of their TaSOS1 genes. CV. Misr 2, CV. Sakha 94, and CV. Sakha 95 exhibited the highest degree of variability in the expression of the NHX1, DHN3, and GR genes, respectively. The application of GABA to wheat plants enhances their ability to cope with salt stress by reducing the presence of reactive oxygen species (ROS) and other stress indicators, regulating stomatal aperture, enhancing photosynthesis, activating antioxidant enzymes, and upregulating genes involved in salt stress tolerance. [ABSTRACT FROM AUTHOR]