Some diets lack sufficient Manganese (Mn), an essential trace element for life. Although increasing Mn in grain by biofortification could prevent Mn deficiency, it may increase levels of the toxic element cadmium (Cd). Recently, researchers from China National Rice Research Institute, Chinese Academy of Agricultural Sciences cloned a major QTL for grain Mn.

Researchers investigated Mn concentration in rice (Oryza sativa L.) grains of recombinant inbred lines (RILs) from the cross of 93-11 (low grain Mn) with PA64s (high grain Mn). Quantitative trait locus (QTL) analysis identified a major QTL for grain Mn, qGMN7.1, on the short arm of chromosome 7. Compared to 93-11, besides enhanced Mn uptake in roots of the CSSL-qGMN7.1, increased Mn and decreased Cd concentrations were found in grains. Fine mapping delimited qGMN7.1 to a 49.3-kb region containing OsNRAMP5, a gene responsible for Mn and Cd uptake. Sequence variation in the OsNRAMP5 promotor caused changes in its transcript level, and thereafter in grain Mn levels. This study not only cloned OsNRAMP5 for grain Mn concentration in rice, but also developed materials for molecular breeding of high Mn and low Cd concentrations in grains.

The work was supported by the National Natural Science Foundation of China (Grant Nos 31521064 and 91535205). The research has been published in Scientific Reports online on 18 December 2017 (DOI: 10.1038/s41598-017-18090-7). More details are available on the link below: https://www.nature.com/articles/s41598-017-18090-7