This Bangladeshi and Japanese study screened brown rice from 8503 mutagenized plants of the indica cultivar BRRI dhan84 by ICP-MS and isolated 38 mutants with altered grain iron, zinc, arsenic or cadmium. One mutant, in the OsHMA2 transporter gene, had lower grain zinc and cadmium and grew normally in a paddy field. The authors note it was sensitive to zinc-deficient conditions.
Key numbers
- This paper reports no numerical findings relevant to zinc exposure in its text; grain zinc values appear only in figures (Figures 3 and 5).
Methods (brief)
Seeds were mutagenized with ethyl methanesulfonate or gamma rays, and brown rice from M2 plants was analyzed by ICP-MS. Candidate mutants were chosen by robust Z-scores, and causal genes were identified by whole genome sequencing and F2 segregation.
Evidence fitness
The paper supports the point that, in rice, genes that move cadmium into grain also move zinc, so a low-cadmium allele can lower grain zinc. It does not provide market or dietary zinc data.
Limitations
Zinc values are graphical only. Field results come from one Bangladeshi university site with low-zinc soil.
Related evidence
Update history
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