Recently, the research group of China National Rice Research Germplasm Innovation Group found a major QTL for controlling manganese accumulation in rice grains, and created excellent breeding materials for high-manganese and low-cadmium rice.
Manganese, as an important mineral element, is often deficient in the daily diet. Though the biocontrol effect can increase the manganese content of rice grain, the content of harmful heavy metal cadmium also increases at the same time. Using recombinant inbred lines with low manganese indica variety 93-11 and high-manganese cultivar Pei-dai 64s as their parents, a major QTL for controlling manganese content was detected on the short arm of rice chromosome 7 using a high-density genetic map – qGMN7.1.93-11 Background Chromosomal segment substitution of qGMN7.1 significantly increased the Mn concentration in grain, significantly decreased the concentration of cadmium, and enhanced the manganese absorption capacity in roots. qGMN7.1 finally confirmed that OsNRAMP5 is a gene regulating the absorption of manganese and cadmium. The sequence variation of the gene promoter caused the transcriptional level difference, leading to the change of manganese concentration in grains. This study shows that OsNRAMP5 plays an important role in the regulation of manganese content in rice grain.