CRISPR-enhanced iron accumulation in TBR225 rice via OsNRAMP7 overexpression

Rice is a staple food for over half of the world’s population; hence, its nutritional quality is crucial for global health. Iron deficiency anemia affects billions of people worldwide and is particularly prevalent in rice-consuming regions. Accordingly, the biofortification of rice through genetic enhancement offers a sustainable solution to this widespread nutritional challenge. Suitably, the elite Vietnamese rice cultivar TBR225, known for its high yield and superior quality, presents an ideal candidate for iron biofortification. Therefore, this study builds upon previous research that used CRISPR/Cas9 technology to overexpress a key iron transporter gene (OsNRAMP7) in TBR225. The genotype and phenotype of these previously developed OsNRAMP7- overexpressing TBR225 lines were evaluated. Molecular analysis confirmed the successful insertion of the 35S promoter upstream of OsNRAMP7 and the resulting increase in OsNRAMP7 expression. Under greenhouse conditions, the edited lines exhibited substantially higher iron accumulation in the roots, shoots, and grains than in wild-type plants, with grain iron content increasing by 18-72%. Importantly, OsNRAMP7 overexpression did not affect the accumulation of other metals, such as zinc and cadmium, thereby demonstrating its specificity for iron transport. Moreover, key agronomic traits, including growth duration, plant height, yield, and grain quality, remained unaffected in the edited lines. Overall, these findings validate the promising potential of OsNRAMP7 overexpression as a strategy to develop ironbiofortified rice varieties without compromising essential agronomic qualities. This approach will effectively address iron deficiency in rice-consuming populations while maintaining agricultural productivity.