Development of Low-Cadmium-Accumulating Rice
Cadmium (Cd) has an important impact on agriculture, and the excessive consumption of Cd from contaminated food crops can lead to toxicity in humans. Rice (Oryza sativa L.) is the greatest source of dietary intake of Cd for populations that consume rice as a staple food. However, there is currently no practical technique designed to substantially reduce the Cd contamination of rice. Here, we report a new rice cultivar, Koshihikari Kan No. 1, which does not accumulate Cd in the grains. Koshihikari Kan No. 1 is a mutant produced from ion-beam irradiation. This cultivar has a single-nucleotide deletion in OsNRAMP5, which encodes a manganese transporter that incidentally transports Cd into rice; this deletion results in a decreased root Cd uptake. In Cd-contaminated paddy fields, Koshihikari Kan No. 1 showed nearly undetectable Cd concentrations in the grains and exhibited no economically adverse traits. A DNA marker, which detects the mutated region of OsNRAMP5, has been developed to facilitate marker-assisted breeding of cultivars with low-Cd traits. Our findings will help to greatly reduce Cd levels in paddy rice.
KeywordsCadmium Ion beam Marker-assisted breeding OsNRAMP5 transporter Rice mutant
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