胡萝卜3号染色体P3位点DcMYBs基因簇在花青苷合成中的精细调控机制研究

胡萝卜主要分胡萝卜素型(非紫色胡萝卜)和花青苷型(紫色胡萝卜)，其肉质根中分别积累高水平的类胡萝卜素和花青苷，非紫色胡萝卜由紫色胡萝卜突变产生。不同基因型紫色胡萝卜肉质根、叶花青苷积累差异大。胡萝卜3号染色体P1和P3位点控制着胡萝卜肉质根、叶中花青苷积累。我们证实P1的DcMYB113和P3的DcMYB7是其中的关键基因。P3位点~500kb区域存在6个DcMYBs串联的基因簇，该DcMYBs基因簇如何精确调控胡萝卜花青苷积累还不清楚。本项目以紫色、橙色和野生型胡萝卜为材料，围绕胡萝卜肉质根、叶花青苷积累，运用形态结构观察、花青苷测定、基因和启动子克隆、基因表达、酵母单/双杂交、启动子功能分析、酶活性测定、基因过量表达和敲除等技术，结合组学分析，着重研究P3位点DcMYBs基因簇对胡萝卜花青苷积累的精细调控。结果将解析胡萝卜颜色形成分子机理，为胡萝卜进化、驯化机制及品质改良提供理论依据。

Carrots (Daucus carota L.), one of the most important root vegetables in the Apiaceae family, are cultivated worldwide. Carrots are mainly classified into two groups according to exact botanical determination: the carotene group (variety sativus) and the anthocyanin group (variety atrorubens). Carotene group members, also known as non-purple carrots, accumulate massive amounts of carotenoids in their roots; anthocyanin group members, also known as purple carrots, accumulate high levels of anthocyanins in their roots. Non-purple carrots are considered to have arisen from purple carrots that acquired mutations. Purple carrot root pigmentation extensively varies across different carrot genotypes, ranging from the purple peridermal carrot type (purple periderm but nonpurple phloem and xylem) to the solid purple carrot type (purple periderm, phloem, and xylem). . Two loci, P1 and P3 on chromosome 3, condition and modify the anthocyanin biosynthesis in taproots and leaves of carrot have been identified. We have characterized the functions two candidate genes, DcMYB113 and DcMYB7, which underlie the P1 and P3 loci, respectively. The DcMYB113 and DcMYB7 genes condition and modify the anthocyanin biosynthesis in taproot and leaf of carrot. The P3 locus hosts six different DcMYBs like genes, including DcMYB6 and DcMYB7. The precise regulation mechanism of the DcMYBs gene cluster at P3 locus on chromosome 3 in anthocyanin biosynthesis of carrot is not clear.. In this project, based on the previous results, we used the different genotypes of purple carrots, orange and wild-type carrots as materials. We mainly focus on the gene function of the DcMYBs gene cluster at P3 locus using methods of morphological, physiological, anatomical, gene clone, promoter clone, gene expression profiles, yeast hybrid system, transgenic plants with over-expression and gene stable editing using CRISPR/Cas9 system, OMICS analysis, etc. An extensive picture of the precise regulation mechanism of the DcMYBs gene cluster at P3 locus on chromosome 3 in anthocyanin biosynthesis of carrot shall be attempted. The project shall help to ascertain the function of DcMYBs gene cluster involved in precise regulation mechanism anthocyanin biosynthesis of carrot. The results will further enrich the molecular mechanism of carrot color formation, provide scientific basis for the evolution and domestication of carrot, and also provide basis for the improvement of carrot quality.