Gamma-Aminobutyric acid profiling (GABA) and standardization of in-vitro regeneration protocol in tomato (Solanum lycopersicum L.) genotypes

This present study focused on assessing Gamma-aminobutyric acid (GABA) levels in seventy kharif tomato genotypes to highlight its importance in neurotransmission. The experiment was performed at ICAR- Indian Agricultural Research Institute, New Delhi, during 2021-2022. Analysis revealed that most genotypes exhibited a decline in GABA content from the green to turning stages. However, the yellow and orange fruited genotypes K-69 and K-70 consistently maintained stable GABA levels throughout ripening, underscoring their potential for biofortification. In this experiment, efforts were also made to use in-vitro regeneration methods, emphasising proper sterilization technique. Among the different sterilization techniques, NaOCl 2 % for 10 min showed less contamination. Treatment T₇ (BAP 2 mg/l, NAA 1.5 mg/l, IBA 0.5 mg/l) was most effective for callus induction, while T₅ (BAP 1 mg/l, NAA 0.5 mg/l, IBA 2 mg/l) showed maximum shoot multiplication rate and average number of roots per shoot. Explant length and precise growth regulator combinations were found to be critical factors influencing successful regeneration outcomes. The study encountered challenges such as genotype-dependent variability in tissue culture response and contamination risks, which limited reproducibility across genotypes. Nevertheless, the identification of GABA-stable tomato genotypes and optimized regeneration protocols provides important insights into the relationship between fruit ripening and GABA metabolism. These findings not only advance tissue culture applications for trait improvement and cultivar development but also highlight the nutritional and health benefits of enhancing GABA content in tomato, thereby linking agricultural biotechnology with human health promotion.