水稻类胡萝卜素和维生素E生物合成途径上游的三个重要基因家族成员的功能鉴定

Plant carotenoids and vitamin E have a very important role on humans, animals and plants themselves. It has been demonstrated that breaking the bottlenecks of upstream pathway in the biosynthesis of carotenoids and vitamin E is essential for increasing the accumulation of carotenoids and vitamin E in plants. The proposed project will use rice (Oryza sativa L.), one of the most important cereal crops worldwide, as the research material to carry out in-depth research in the expression characteristics of each member of the 1-deoxy-D-xylulose 5-phosphate synthase (DXS), 4-hydroxy-3-methylbut-2-enyl diphosphate reductase (HDR) and isopentenyl diphosphate isomerases (IPPI) gene families, and the subcellular localization of the encoded enzyme protein for each gene. We will knockout each member of rice DXS, HDR and IPPI gene families by using CRISPR/Cas9 (Clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9) system, and obtain Loss-of-Function mutants in each gene or two genes. The contribution of each member of rice DXS, HDR and IPPI gene families to the carotenoids and vitamin E biosynthesis in endosperm and embryo, as well in leaves and roots will be investigated using these Loss-of-Function mutants. The results obtained in this study are not only important for improving the quality of the carotenoids and vitamin E of rice seeds but also very important for the functional characterization of these orthologous gene family members in other gramineous crops such as wheat, barley and maize.

植物类胡萝卜素和维生素E对于人类、动物和植物自身都具有十分重要的作用。研究表明突破类胡萝卜素和维生素E合成中的上游途径瓶颈限制，对提高植物体内类胡萝卜素和维生素E的积累是非常必要的。本课题拟以世界上重要的粮食作物水稻为研究材料，深入研究水稻1-脱氧-D-木酮糖-5-磷酸合酶（DXS）、4-羟基-3-甲基-2-丁烯基-4-焦磷酸还原酶(HDR)和异戊二烯焦磷酸异构酶（IPPI）基因家族每个成员的表达特性和编码的酶蛋白在亚细胞内的定位。利用CRISPR/Cas9定向敲除技术创制水稻DXS、HDR和IPPI家族每个成员基因功能丧失突变体，探明DXS、HDR和IPPI家族各成员对种子胚乳和胚以及叶片和根等各组织器官中的类胡萝卜素和维生素E生物合成的贡献。该研究获得的成果不仅对水稻种子类胡萝卜素和维生素E品质改良具有重要意义，而且对其他禾本科作物中的这些直向同源基因家族成员的功能鉴定也具有重要意义。

植物类胡萝卜素和维生素E对于人类、动物和植物自身都具有十分重要的作用。本课题以世界上重要的粮食作物水稻为研究材料，深入研究了水稻1-脱氧-D-木酮糖-5-磷酸合酶（DXS）、4-羟基-3-甲基-2-丁烯基-4-焦磷酸还原酶(HDR)和异戊二烯焦磷酸异构酶（IPPI）基因家族每个成员的表达特性和编码的酶蛋白在亚细胞内的定位。利用CRISPR/Cas9定向敲除技术创制水稻DXS、HDR和IPPI家族每个成员基因功能丧失突变体，探明了DXS、HDR和IPPI家族各成员对种子胚乳和胚以及叶片和根等各组织器官中的类胡萝卜素和维生素E生物合成的贡献。我们发现了水稻种子中gusA的高水平表达需要5'-UTR区域。只要启动子近端存在醇溶蛋白盒和AACA基序，ZmBCH2基因启动子的截短变体基本启动子即可保留其种子优先的表达模式。本课题的成果不仅对水稻种子类胡萝卜素和维生素E品质改良具有重要意义，而且对其他禾本科作物中的这些直向同源基因家族成员的功能鉴定也具有重要意义。