Metabolic Engineering in Rice for Functional Metabolite Production

To improve the nutritional and functional value of rice, numerous biotechnological approaches have focused on metabolic engineering to address nutritional deficiencies and produce health-beneficial compounds that are either absent or naturally present in low amounts. A prominent example is ‘Golden Rice’, which has been genetically modified to accumulate β-carotene to combat vitamin A deficiency in regions with limited dietary intake. Scientists have been continuously biofortifying rice with various specialized metabolites, including terpenoids, flavonoids, non-flavonoid polyphenols, betalains, vitamins, and amino acids. This review explores the specific pathways and genetic modifications utilized by researchers to enhance the accumulation of targeted metabolites in rice. It comprehensively summarizes key strategies and research trends in rice metabolic engineering, demonstrating how rice can be transformed into a strategic crop for producing industrially valuable compounds beyond its traditional role as a staple food by leveraging its advantages as a versatile host system through its grains, leaves, and cells. Furthermore, we highlight the potential of intergrating metabolic engineering with synthetic biology and big data-driven computational modeling, particularly through artificial intelligence and machine learning, as promising future research directions.