OsNramp5 is an important gene in the regulation of Cadmium (Cd), Manganese
(Mn), and other metal icons by rice root cells. When this gene is impaired,
it can reduce the buildup of Cd in rice grains, but the effect on yield and
quality is yet to be discovered. Thus, researchers from Hunan Agricultural
University and partners developed three OsNramp5 rice mutants with low
cadmium content using the CRISPR-Cas9 technology.

Mutation analysis revealed that the mutants expressed defective OsNramp5
protein sequences. Metal content and agronomic traits analyses showed that
Cd was reduced and the rice yield and quality were also affected.
Furthermore, it was also found that with the decrease of OsNramp5 mutation
degree, its effects on chlorenchyma Mn accumulation, yield and quality were
also decreased. Increase in Mn concentration in the soil restored the yield
and quality traits.

The results of the study provide new insights on new materials for
developing rice varieties with low Cd concentrations and premium agronomic
qualities when exposed to high Cd environment.

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