Oral Presentation International Plant Molecular Biology Conference 2024

Micronutrient biofortification of rice for human health (#298)

Wilhelm Gruissem 1 , Fei-Han Chang 1 , Navreet Bhullar 2 , Ting-lun Nieh 1 , Shu-Heng Chang 1
  1. National Chung Hsing University, Taichung, TAICHUNG, Taiwan
  2. Intagris Ltd., Watt, Switzerland

Projections show that the world population will grow to more than 9 billion people by 2050. Goals 2 and 3 of the United Nations Sustainable Development Goals embrace the provision of sufficient and nutritious food for the growing population to promote human health and wellbeing. Major crops such as cassava, maize, potato, rice, and wheat are rich in starch and together they provide more than 60% of the carbohydrate calories consumed worldwide, but they have a poor micronutrient content. People for whom these crops are the primary staple food receive enough calories, but they are often malnourished because these staple foods do not contain enough vitamins and minerals such as iron for a healthy diet. To date, 1.6 billion people worldwide suffer reduced productive capacity due to iron-deficiency anemia. Achieving higher micronutrient content for health and nutrition is often not possible with available breeding germplasm, especially in rice. We are employing genetic engineering technologies and CRISPR-Cas9 strategies to increase the iron and vitamin content of rice.  For example, expression of NICOTIANAMINE SYNTHASE and endosperm-specific expression of FERRITIN increases iron and zinc concentrations in polished rice grains. When combined with IRON RESPONSIVE TRANSPORTER 1 for root-specific iron uptake, NATURAL RESISTANCE ASSOCIATED MACROPHAGE PROTEIN 3 for release of vacuolar iron, FERRIC REDUCTASE 3 for citrate-mediated iron transport, or xylem-to-phloem transporters, this increases iron and zinc levels in polished rice grains to dietary sufficient levels.  Multi-year field experiments and Caco-2 cell assays demonstrate that the micronutrient traits are stable and iron is bioavailable.

  1. Van Der Straeten D, Bhullar N, De Steur H, Gruissem W, et al. (2020) Multiplying the efficiency of biofortification through metabolic engineering. Nature Communications, 11, 5203, https://doi.org/10.1038/s41467-020-19020-4
  2. Wu TY, Gruissem W and Bhullar N. (2018) Targeting intra-cellular transport combined with efficient uptake and storage significantly increases grain iron and zinc levels in rice. Plant Biotechnology Journal 17: 9-20 doi: 10.1111/pbi.12943
  3. Kawakami Y, Gruissem W and Bhullar N. (2022) Novel rice iron biofortification approaches using expression of ZmYS1 and OsTOM1 controlled by tissue-specific promoters. Journal of Experimental Botany 73: 5440-5459, https://doi.org/10.1093/jxb/erac214