Comparison of Cd concentration in rice grain between OsNramp5 knock-out mutants and OsHAM3-overexpressing line

Cadmium (Cd) is a highly toxic element that causes cancer and serious diseases in human beings. Rice is prone to accumulate Cd in its grain, which causes health concerns for rice consumers. OsNramp5 is a major Cd and Mn transporter in rice, whereas OsHMA3 is a tonoplast-localized transporter that is involved in Cd sequestration in vacuoles. We generated an OsNramp5 knock-out mutant in T5105 genetic background by gene editing approach. Cd and Mn concentrations in the grain of OsNramp5 knock-out mutants were measured and compared with those in the grain of an OsHMA3-overexpressing line developed in a previous study. We found that the OsHMA3 overexpression approach worked more efficiently than the OsNramp5 knock-out method in generating low-Cd rice grain without affecting Mn uptake and transport in rice.