Wild ancestors may hold the key to more nutritious rice grains

By Rhowell Tiozon and Glenn Concepcion [Link] For the nearly 9,000 years since its domestication, rice has been selectively bred to feed a growing global population, becoming a staple food source that provides essential calories for billions. However, this long history of artificial selection has come at a cost. In prioritizing traits like higher yield and easier processing, humans have inadvertently stripped rice of many vital nutrients, leading to "hidden hunger," a deficiency of vitamins and minerals affecting over three billion people worldwide. A new scientific review from researchers at the International Rice Research Institute (IRRI) and their collaborators reveals how the wild ancestors of rice could hold the key to restoring this lost nutritional value. The review, co-authored by Rhowell Tiozon Jr., Sung-Ryul Kim, and Nese Sreenivasulu from IRRI's Consumer-Driven Grain Quality and Nutrition unit, alongside Changquan Zhang and Qiaoquan Liu from Yangzhou University, and Alisdair Fernie from the Max Planck Institute of Molecular Plant Physiology, outlines how domestication altered rice's genetic makeup. This evolutionary shift resulted in modern cultivated rice having a significantly higher starch content-up to 64% of its dry weight compared to 38% in wild varieties-but with reductions in essential proteins, fiber, minerals, and beneficial secondary metabolites like flavonoids. For example, the Rc gene, which governs red pericarp pigmentation and is associated with elevated antioxidant called catechin in wild rice, has been lost in most modern cultivated varieties. This loss has not only diminished the antioxidant and potential anti-cancer properties of the grain but also reduced its capacity to modulate glycemic index. [Link]Overview of genetic, geographic, and evolutionary insights into rice domestication and nutritional traits (A) Geographic distribution of wild Oryza species and dispersal patterns of domesticated alleles common to japonica and indica varieties. (B) Key mutations, functional classifications, and origins of variation in domestication-related genes. (C) Domestication and post-domestication genes that influence nutritional traits in rice. (D) Timeline of rice domestication, including inferred changes in grain quality and pigmentation (E) Expression levels of major starch-related genes during rice grain development. (F) Evolutionary relationships among Wx alleles, showing four Wxlv haplotypes (Wxlv-Ito Wxlv-IV) in O. Sativa. (G) Global distribution of Wx alleles in O. sativa, with pie charts indicating allele proportions by region. Pie chart reflects sample count. The team of scientists proposes two main strategies to reclaim these lost nutritional benefits by drawing on the rich genetic diversity of wild rice, much of which is preserved in genebanks like the International Rice Genebank stewarded by IRRI in its Los Baños, Philippines headquarters. The first approach, called "rewilding," aims to reintroduce beneficial genes from wild rice into modern elite cultivars. Using accelerated breeding techniques, such as chromosome segment substitution lines, researchers can transfer specific genetic regions from wild relatives that are linked to higher protein content, increased mineral accumulation, or other desirable nutritional properties. This process may also potentially be used to confer greater resilience to biotic and abiotic stresses, as many wild relatives naturally possess gene traits such as enhanced drought tolerance, salinity tolerance, and pest resistance. A second, more revolutionary strategy is de novo domestication, which essentially domesticates wild rice from scratch using advanced gene-editing tools like CRISPR-Cas9. Instead of breeding wild traits into cultivated rice, this method directly modifies the genes of wild rice to improve its agronomic performance (such as preventing seed shattering and increasing grain size) while preserving its superior nutritional profile. The authors of the study highlight that these advanced genomic and breeding tools can help develop new, "super-nutritious" rice varieties to ensure both food and nutritional security for future generations. Read the full study here: Unlocking the potential of wild rice to bring missing nutrition to elite grains Rhowell Tiozon, Changquan Zhang, Sung-Ryul Kim, Qiaoquan Liu, Alisdair R. Fernie, Nese Sreenivasulu Plant Communications Volume 6, Issue 6 https://doi.org/10.1016/j.xplc.2025.101344