Genome-wide association study revealed novel MTAs for gamma-amino butyric acid in germinated brown rice

Psychiatric nutrition underscores the vital connection between diet and mental well-being. Germinated Brown Rice (GBR), serves as one of the richest natural sources of γ-aminobutyric acid (GABA), a neurotransmitter known for alleviating stress-related disorders, anxiety, and other mental health concerns, thus making GBR a healthier alternative to white rice. The current study depicts a maiden effort to systematically characterize rice germplasm accessions for GABA content in GBR at two locations—Aduthurai, Tamil Nadu and New Delhi—revealing broad genetic variation (7.19–75.04 mg/100g and 9.32–35.74 mg/100g, respectively) for the trait. The genotype, OYR128, that showed stable expression across two locations is identified as a potential donor for introgression breeding programs. The panel was genotyped with 50K SNP markers, and genome-wide association analysis using the multi-locus models FarmCPU and BLINK identified six significant MTAs for GABA content, explaining 0.06–4.15 % of the phenotypic variance. In-silico analysis identified 10 putative candidate genes in the MTA regions, including those encoding Proline-rich proteins, Orn/DAP/Arg decarboxylase, and Aldehyde dehydrogenase, which play key roles in GABA biosynthesis. These MTAs and candidate genes can be deployed in breeding strategies for enhancing GABA content in GBR and developing biofortified rice varieties with nutraceutical properties.