茄子花青素合成关键基因SmDFR及调控因子SmMYB作用机制的研究

Anthocyanin is considered as one of natural active substances being richest of potential health. Purple eggplant is rich of anthocyanins as a high-nutrition and health-value vegetable, but research focused on the anthocyanin biosysthesis pathway and its regulation mechanism is lag behind, and domestic research in this area is nearly blank. The key gene of the eggplant anthocyanin biosysthesis SmDFR that has been cloned in our lab is used as the basis of this project. Through genetic transformation over expression and virus induced gene silence in different eggplant germplasm, we will verify the function of SmDFR. The difference of SmDFR coding sequence among different eggplant germplasm will be tested to analyse the evolutionary model. And we will clone the promoter to identify cis-acting elements sequence characteristics, as well as its impact on SmDFR expression among different color eggplant germplasm resources. At the same time,we will clone anthocyanin synthesis regulatory factor SmMYB and analysis the expression of SmMYB, which provides a theoretical basis to clarify the effect of SmMYB in anthocyanin biosynthetic process. Meanwhile，through shading treatment, relationships among gene expression of SmDFR and SmMYB, eggplant anthocyanin accumulation and light will be studied so that we can find out the relationships among SmDFR、SmMYB and anthocyanin accumulation and types of accumulation. And the process will be carried on further to find the root causes of huge different contents of anthocyanin in the greenhouse production, which can provide a theoretical basis for the eggplant germplasm innovation and breeding of new varieties.

花青素被认为是最富有保健潜力的天然植物活性物质之一。目前茄子花青素生物合成及调控机理尚未明确。项目以本实验室克隆的茄子花青素生物合成关键基因SmDFR为基础，拟在不同茄子中通过遗传转化过量表达及病毒诱导基因沉默干扰SmDFR来验证其功能；对不同茄子种质进行SmDFR编码序列差异性比较分析其进化模式；在其基础上进一步克隆SmDFR启动子序列，确定顺式作用元件的序列特征，以及颜色表型差异的种质间顺式作用元件对SmDFR表达差异性的影响；对茄子花青素合成调控因子SmMYB进行克隆和表达分析；同时通过遮光处理研究茄子花青素积累、SmDFR、SmMYB基因表达及与光照之间的关系，以探讨SmDFR、SmMYB基因与茄子花青素积累量和积累类型的关系，找到日光温室生产中造成花青素含量巨大差异的根本原因，这将为阐明SmMYB转录因子在花青素生物合成过程中的调控机制、茄子种质创新和新品种选育工作提供理论基础。

花青素被认为是最富有保健潜力的天然植物活性物质之一。花青素是类黄酮合成途径的分支，光是影响花青素生物合成的最为重要的环境因子。茄子果实营养丰富，富含花青素。在实际生产中会遇到弱光条件下茄子果皮着色不良，品质下降的现象。目前茄子花青素生物合成及调控机理尚未明确。项目以本实验室克隆的茄子花青素生物合成关键基因SmDFR为基础，通过遗传转化实验验证了其功能；进一步克隆了SmDFR启动子序列；对茄子花青素合成调控因子SmMYB进行克隆和表达分析；通过遮光处理研究茄子花青素积累、SmDFR、SmMYB基因表达及与光照之间的关系，探讨了SmDFR、SmMYB基因与茄子花青素积累量和积累类型的关系。同时提供了一个新的关于描述光诱导茄子花青素合成的调控通路：在有光的条件下，光受体蛋白CRY1和CRY2接受光信号后发生激活，进而与COP1结合抑制COP1的泛素化活性，使下游转录因子HY5和MYB1得到了积累，从而与CHS和DFR的启动子结合激活它们的表达，最后合成花青素使茄子果实着色；在黑暗下，COP1通过与HY5和MYB1结合发挥泛素化活性降解HY5和MYB1，从而下游花青素结构基因不能激活表达，也就没有花青素的积累。这将为茄子种质创新和新品种选育工作提供理论基础。