Fig. 6

The proposed work model illustrating how endosperm-specific expression of OsNOMT leads to the accumulation of sakuranetin in the rice seeds. The expression of the sakuranetin biosynthesis gene OsNOMT was driven by the promoter of the endosperm-specific glutelin gene OsGluD-1, and OsNOMT successfully catalyzes naringenin synthesis of sakuranetin in the rice seeds. Sakuranetin content was highest at the filling stage and decreased with seed maturation. During the filling stage, the rapid and massive accumulation of sakuranetin is proposed to improve disease resistance in crop panicles by acting as a phytoalexin. At the mature stage, the lower abundance of sakuranetin confer potential nutritional and health benefits to humans. The dark brown color in the proposed model represents the rice seed embryo, the yellow color represents the cortex (rice bran layer), the beige color represents the endosperm, and the small red dots represent sakuranetin