This study is led by Prof. Jie Luo (Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed Laboratory), Dr. Yufei Li (National Key Laboratory of Crop Genetic Improvement and National Center of Plant Gene Research, Huazhong Agricultural University), Dr. Zhuang Yang (Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed Laboratory), Dr. Chenkun Yang (Sanya Nanfan Research Institute of Hainan University, Hainan Yazhou Bay Seed Laboratory).
Rice (Oryza sativa L.) is one of the most important crops worldwide, providing much of the calorific needs for half of the global population. Economic development and rising living standards have led to a gradual shift in the demand for rice from "being full" to "eating well", and tasty with nutritious varieties is essential for the latter. Much research have focused on improving the eating and cooking quality (ECQ) of rice to meet the demand for "tasty", however, effort to improve comprehensive nutrition in rice remains fragmented.
In this study, taking advantage of metabolome genome-wide association study (mGWAS) and metabolome quantitative trait loci (mQTL) analyses, researchers localized and characterized a rice grain nutrients locus, NET (nutrition, eating, taste). This locus controls both rice ECQ and multiple nutrients accumulation, including vitamins, lipids, amino acids and polyphenols, further, the regulatory mechanism of NET was elucidated based on bioinformatics analysis and molecular biology experiments.
The domestication routes results showed that the NET regions in indica and japonica originated from two different wild rice groups, Wild-1 and Wild-2, respectively. The NET of indica may be evolved from Wild-1, which retains high nutrition but poor tasty due to high amylose ratio and low content of fatty acids. The Wild-2 NET inherited by japonica improves its eating and taste quality by reducing the proportion of amylose and increasing the fatty acids content, but this process comes at the expense of multiple nutrients. This indicates that the taste quality and nutrition quality have not been effectively balanced in the rice breeding process. Therefore, in order to meet people's goal of "eating well", it is necessary to take into account the changes of nutrients in the breeding process for taste, achieve the best of both worlds, and the NET locus appears to be one of the most important genetic loci to achieve this goal.
In summary, this study clarifies the genetic mechanism of changes in nutrient metabolites during rice domestication, and provides a breeding scheme for obtaining ideal high eating quality and nutritional varieties.
