Betanin has been widely used as an additive for many centuries, and its use has increased because of its market application as an additive, high free radical scavenging activity, and safety, health-promoting properties. The main source of betanin is red beet, but many factors notably affect the yield of betanin from red beets. Betanin is not produced in cereal grains. Thus, developing biofortified crops with betanin is another alternative to health-promoting food additives. Here, rice endosperm was bioengineered for betanin biosynthesis by introducing three synthetic genes (meloS, BvDODA1S, and BvCYP76AD1S). The overexpression of these genes driven by rice endosperm-specific promoter established the betanin biosynthetic pathways in the endosperm, resulting in new types of germplasm - 'Betanin Rice' (BR). The BR grains were enriched with betanin and had relatively high antioxidant activity. Our results proved that betanin can be biosynthesized de novo in rice endosperm by introducing three genes in the committed betanin biosynthetic pathway. The betanin-fortified rice in this study can be used as a functional grain to promote health and as a raw material to process dietary supplements.

中文翻译：

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水稻胚乳的代谢工程用于生物素的合成。

甜菜碱已经被广泛用作添加剂已有多个世纪了，由于其作为添加剂的市场应用，高自由基清除活性以及安全性，健康促进特性，甜菜碱的使用有所增加。甜菜碱的主要来源是红甜菜，但是许多因素显着影响红甜菜中甜菜碱的产量。谷物中不产生甜菜碱。因此，用甜菜碱开发生物强化农作物是促进健康的食品添加剂的另一种替代方法。在这里，通过导入三个合成基因（meloS，BvDODA1S和BvCYP76AD1S）对稻胚乳进行了生物工程化，以进行甜菜碱的生物合成。水稻胚乳特异性启动子驱动的这些基因的过表达建立了胚乳中的甜菜碱生物合成途径，从而产生了新型种质-'甜菜碱水稻'（BR）。BR晶粒富含甜菜碱，具有相对较高的抗氧化活性。我们的结果证明，可通过在定型的甜菜碱生物合成途径中引入三个基因，从头开始在稻胚乳中生物合成甜菜碱。在这项研究中，经甜菜碱强化的大米可以用作促进健康的功能性谷物，也可以作为加工膳食补充剂的原料。