Metabolomics Uncovers\nthe Mechanisms of Nitrogen Response\nto Anthocyanins Synthesis and Grain Quality of Colored Grain Wheat\n(<i>Triticum aestivum</i> L.)

Nitrogen (N) is a key factor for plant growth and affects\nanthocyanin\nsynthesis. This study aimed to clarify the potential mechanisms of\nN levels (LN, 0 kg·ha<sup>–1</sup>; MN, 150 kg·ha<sup>–1</sup>; HN, 225 kg·ha<sup>–1</sup>) in anthocyanin\nsynthesis and grain quality of colored grain wheat. HN increased the\nyield component traits and grain morphology traits in colored grain\nwheat while decreasing the processing and nutrient quality traits.\nMost quality traits were significantly negatively correlated with\nthe yield composition and morphological traits. Anthocyanin was more\naccumulated under LN conditions, but other related yield and morphological\ntraits of colored grain wheat declined. The anthocyanin content was\nthe highest in blue wheat, followed by that in purple wheat. Cyanidin-3-<i>O</i>-(6-<i>O</i>-malonyl-β-d-glucoside)\nand cyanidin-3-<i>O</i>-rutinoside were the predominant\nanthocyanins in blue and purple wheat. The identified anthocyanin-related\nmetabolites were associated with flavonoid biosynthesis, anthocyanin\nbiosynthesis, and secondary metabolite biosynthesis. Therefore, the\nstudy provided information for optimizing nitrogen fertilizer management\nin producing high quality colored wheat and verified the close relationship\nbetween anthocyanin and low N condition.