紫心大白菜花青素特异积累的分子机理研究

Anthocyanins play important roles in human nutrition and health. Chinese cabbage (Brassica rapa L. ssp. Pekinensis) is an important vegetable with the first large cultivation area and consumption in China. The creation of new purple anthocyanin-rich Chinese cabbage provides a new insight in quality improvement of Chinese cabbage, which not only has widely applications perspective in our daily life, but also has significant values in people health. However, the molecular mechanism of anthocyanin accumulation in this new germplasm is still unknown, which limits the progress of gerplasm innovation and new cultivar creation..In this project, the purple heading Chinese cabbage pure line (11S91, with independent intellectual property rights), the white heading Chinese cabbage, and the progeny of F2 segregation population obtained by crossing the 11S91 and the white heading Chinese cabbages will be used in this study by using fine mapping, map-based cloning, RNA-Seq, LC-MS technique, real-time quantitative PCR, and so on. The purposes of this research are to develop molecular markers closely linked with purple head phenotype, detect the anthocyanins composition and obtain the critical genes contributed to anthocyanins accumulation in the purple heading Chinese cabbage..Furthermore, the full-length candidate genes will be cloned and transferred into Arabidopsis and Chinese cabbage using agrobacterium-mediated method for the verification of them. These results will lay a solid foundation for uncovering the molecular mechanism of anthocyanin accumulation in purple heading Chinese cabbage, enriching the theory of anthocyanin regulation in plants, providing theoretical basis and technical support for creating new purple germplasm resources, and breeding new cultivars of Chinese cabbage.

花青素对人体有重要的保健价值。大白菜是我国的第一大蔬菜作物，富含花青素的紫心大白菜的创制为大白菜品质提升开辟了新途径，具有广阔的应用前景和重要保健价值，但是紫心大白菜花青素积累的机理尚不清楚，限制了紫心大白菜的改良与新品种创制。本研究拟以具有自主知识产权的紫心大白菜11S91、普通大白菜以及紫心大白菜与普通大白菜杂交的F2分离群体等为材料，通过精细定位、图位克隆技术， 紫心大白菜不同结球期RNA-seq分析，LC-MS技术和花青素合成基因实时定量分析等方法，开发出与紫色性状紧密连锁的分子标记，鉴定出紫心大白菜中的主要花青苷成分，筛选并克隆调控紫心大白菜叶球积累花青素的候选基因。进一步通过农杆菌介导法转化拟南芥和普通白色大白菜，分析候选基因的功能，从而揭示紫心大白菜叶球中花青素积累的分子机理，其结果将丰富植物花青素调控理论，为紫心大白菜种质资源创新和新品种改良提供理论依据和技术支撑。

花青素对人体有重要的保健价值。大白菜是我国主要蔬菜作物，富含花青素的紫心大白菜的创制为功能大白菜品种选育开辟了新途径，具有广阔的应用前景，但是紫心大白菜花青素积累的机理尚不清楚。本研究以自主创新的紫心大白菜11S91纯系及其亲本、普通大白菜等为材料，开展了①紫心大白菜遗传规律和精密遗传图谱构建、②紫心大白菜叶片中花青素组分及含量分析、③紫心大白菜叶球紫色部分与非紫色部分的花青素合成相关基因表达分析、④紫心大白菜紫心基因的克隆、序列分析与功能分子标记开发和功能验证、⑤大白菜紫心大小性状的遗传规律及指标参数、⑥紫心大白菜花青素提取液抗氧化性和稳定性、⑦紫心大白菜杂一代花青苷含量、组分及相关基因的表达分析、⑧紫心大白菜植株生长和叶球发育过程中花青苷积累及相关基因的表达分析、⑨低温条件下紫心大白菜花青苷积累及相关基因的表达分析、⑩紫橙色大白菜新种质的创制等研究。取得在主要研究结果是：①构建了紫心大白菜精密遗传图谱，获得了2个与紫心大白菜紫色性状紧密连锁的分子标记，申请了发明专利。②明确了紫心大白菜积累的主要花青素成分、含量及其动态分布特点。③明确了紫心大白菜花青素提取液抗氧化性和稳定性。④克隆并验证了紫心大白菜关键基因BrMYB2的功能，阐明了紫心大白菜紫色形成的分子机理。⑤发现了BrMYB2短内含子对基因表达的促进作用、长内含子对基因表达的抑制作用的生物现象。⑥明确了大白菜紫心大小性状的遗传规律及衡量参数。⑦明确了紫心大白菜杂一代花青苷含量、组分及相关基因的表达特点。⑧明确了紫心大白菜植株生长和叶球发育过程中花青苷积累及相关基因的表达特点。⑨明确了低温条件下紫心大白菜花青苷积累及相关基因的表达特点。⑩创制了国内外第一个紫橙色大白菜新种质。其科学意义是丰富了植物花青素代谢理论、首次克隆并证实了紫心大白菜关键基因、发现了基因内含子的调控作用、创制了紫橙色大白菜新种质，为紫心大白菜、紫橙色大白菜种质创新奠定了基础。