In conclusion, the expression of the six genes in rice endosperm significantly enhanced the riboflavin content by creating a metabolic sink towards I de novo i riboflavin biosynthesis. Riboflavin-fortified rice produced in this study can be used as a health-promoting cereal grain to decrease the prevalence of riboflavin deficiency. Theoretically, riboflavin content in rice endosperm also can be enhanced via the metabolic engineering of enzymes involved in riboflavin biosynthetic pathways. Keywords: riboflavin deficiency; biofortification; crop breeding; biosynthesis pathway EN riboflavin deficiency biofortification crop breeding biosynthesis pathway 1483 1485 3 08/26/21 20210801 NES 210801 Riboflavin (vitamin B SB 2 sb ) is an essential nutrient for human health and body development. [Extracted from the article]