A metabolomics-guided mutation breeding approach for enhancing agronomic traits and preserving phytochemical properties in gudma pigmented rice

Rice, a staple food worldwide, is rich in beneficial plant compounds. Traditional rice varieties, prioritized for their nutritional and medicinal qualities, are often neglected because of their low yield and other poor agronomic traits. In this study, mutation breeding was used to enhance the agronomic traits of Gudma Dhan, a dark-red Indian traditional rice variety. Radiation-induced mutation breeding improved agro-morphological characteristics by increasing grain yield, productive tillers, and spikelet fertility (%), while reducing plant height and maturity duration. Metabolomic analysis of Gudma Dhan and its mutants revealed an abundance of flavonoids, such as Cianidanol, Catechin, Taxifolin, and 2,3-cis-oligoproanthocyanidin, along with other bioactive compounds. The phenylalanine pathway was over-enriched in the Gudma Dhan parent and its mutant, implying that flavonoid production is higher in pigmented rice genotypes than in non pigmented rice. The methanolic brown rice extract (BRE) of Gudma Dhan exhibited potent antioxidant properties in cell-free and cellular systems. BRE inhibited the secretion of IL-2, IL-4, IL-6, and IFN-γ by lymphocytes and the secretion of nitric oxide, IL-1β, TNF-α, and IL-6 by macrophages, indicating its anti-inflammatory activity. The mutant variety successfully preserved the bioactivity of the parent, indicating that mutation breeding did not compromise the metabolic profile. Thus, global metabolomics can help in accelerating the selection of mutants with desired properties without the need of wet lab experiments.