Identification of low phytic acid and high Zn bioavailable rice (Oryza sativa L.) from 69 accessions of the world rice core collection

Improving the micronutrient content and reducing the phytic acid (PA) in major staple food crops through plant breeding techniques are considered sustainable strategies to increase micronutrient bioavailability. This study documents the variation in PA and zinc (Zn) contents within the natural genetic variation of rice using the World Rice Core collection (WRC) and identifies useful genetic determinants in the Zn biofortification process. Some WRC accessions were observed having a low PA content and high Zn bioavailability and some others with a high PA content and low calculated Zn absorption. No significant differences were observed in the mineral or heavy metal contents among low and high PA lines examined suggesting that different mechanisms are controlling these traits, so that manipulating the PA content could be achieved without affecting the concentration of these elements. A genome-wide association study revealed that a chromosomal region near several significant SNPs determines the natural variation in rice PA content. Furthermore, a low PA trait in rice, rather than a high Zn content should be the key target for increasing Zn bioavailability.