桃单果重性状候选基因PpCYP79B2.1的功能验证及启动子活性分析

Fruit weight is one of the important appearance quality traits in peach, but also an important indicator of fruit yield. In Arabidopsis, rice, tomato, and other popular crops, several related genes which regulated organ development in seeds and fruits have been identified. But the progress is slow in peach, a popular crop in Rosaceae fruit tree. In previous studies, we identified a candidate gene in peach, PpCYP79B2.1, encoding a key enzyme involved in IAA synthesis pathway, using genome-wide association analysis (GWAS), expression analysis and candidate gene association analysis. To further verify the function of this gene and the mechanism of IAA in fruit weight development, we first identified association signal of IAA content in peach fruit by GWAS and analyzed their relationship with that of fruit weight. Then, the spatio-temporal expression pattern of all CYP79B gene were studied. On the basis of this, the overexpression and antisense vectors of PpCYP79B2.1 gene were constructed to verify the function of the gene. Finally, the promoter activity of the gene was analyzed to interpert the reasons for the differential expression of the genes in peach with different fruit weight. The implementation of this project has important theoretical and applied value for breeding new varieties of peach by molecular markers assistant and revealing the molecular regulation mechanism of fruit weight traits in peach.

单果重是桃重要的外观品质性状之一，也是果实产量的重要指标。在拟南芥、水稻和番茄等模式作物中，种子和果实等器官发育的相关基因克隆取得一定进展，但在蔷薇科果树的模式树种桃上，进展缓慢。前期研究中，本团队利用全基因组关联分析（GWAS）、表达分析及候选基因关联分析，鉴定出一个桃单果重关键候选基因PpCYP79B2.1，编码生长素IAA合成途径的关键酶。为了进一步验证该基因功能，解析IAA在单果重形成中的作用，本项目拟首先通过GWAS鉴定桃果实IAA含量的关联位点，分析其与单果重关联区段的关系；同时，研究桃CYP79B基因家族的时空表达特性；在此基础上，构建PpCYP79B2.1基因的超表达和反义载体，验证基因功能；最后，分析PpCYP79B2.1基因启动子活性，解析基因在不同单果重种质差异表达的原因。本项目的实施对通过分子手段培育桃大果新品种、揭示桃单果重性状形成的分子调控机理具有重要意义。

单果重是桃重要的外观品质性状之一，也是果实产量的重要指标。在拟南芥、水稻和番茄等模式作物中，种子和果实等器官发育的相关基因克隆取得一定进展，但在蔷薇科果树的模式树种桃上，进展缓慢。前期研究中，本团队利用全基因组关联分析（GWAS）、表达分析及候选基因关联分析，鉴定出一个桃单果重关键候选基因PpCYP79B2.1，编码生长素IAA合成途径的关键酶。为了进一步验证该基因功能，解析IAA在单果重形成中的作用，本项目首先分析了桃CYP79B基因家族的时空表达特性；在此基础上，构建PpCYP79B2.1基因的超表达和反义载体，转化番茄，发现能引起果实变小，研究同时分析了PpCYP79B2.1基因启动子活性，最后，本研究同时鉴定了另外两个单果重候选基因。