茉莉酸和乙烯通过MdERF1L调控苹果花青苷合成与果实着色的分子机制

Recently, we found that MdERF1L plays an important role in the process which anthocyanin synthesis and fruit coloration in apples is regulated by jasmonic acid and ethylene. However, the molecular mechanism by which anthocyanin biosynthesis and fruit coloration is regulated by jasmonic acid and ethylene via MdERF1L remains unclear. Therefore, this research aimed to verify the potential upstream and downstream regulator genes of MdERF1L, including MdMYC2, MdMYB1, MdMYB9, and MdMYB11, and to elucidate the regulatory roles and relationships among these genes. In this research, the binding and regulatory effects of MdMYC2 to the MdERF1L promoter and the interactions between the MdERF1L and MdMYB1/9/11 promoters will be detected using CHIP-PCR and luciferase techniques. The protein interactions of MdERF1L and MdMYB1/9/11 will be validated through Y2H, CoIP, pull-down, and BiFC techniques. Lastly, transient expression and transgenic techniques will be used to determine the anthocyanin regulatory functions of MdERF1L. Based on the findings of this study, the following signal transduction and regulation model will be attained: MdMYC2→MdERF1L→MdMYB1/9/11. Furthermore, we finally clarified the molecular mechanism underlying anthocyanin biosynthesis and fruit coloration of apples that is regulated by jasmonic acid and ethylene via MdERF1L.

茉莉酸和乙烯调控苹果花青苷合成，促进果实着色。近期我们发现MdERF1L在这一过程中起重要作用，但茉莉酸和乙烯通过MdERF1L调控苹果花青苷合成和果实着色的分子机制尚不清楚。因此，本项目拟进一步对MdERF1L可能的上下游调节基因MdMYC2、MdMYB1、MdMYB9和MdMYB11进行验证，并解析它们之间的调控关系和作用。即利用CHIP-PCR和荧光素酶技术检测MdMYC2与MdERF1L启动子，MdERF1L与MdMYB1/9/11启动子的调控关系和结合活性，利用H2Y、CoIP、 pull-down、BiFC技术检测MdERF1L与MdMYB1/9/11的蛋白互作，利用瞬时表达和转基因技术鉴定MdERF1L的花青苷调控功能。在此基础上构建MdMYC2→MdERF1L→MdMYB1/9/11信号传导模式，最终揭示茉莉酸和乙烯通过MdERF1L调控苹果花青苷合成和果实着色的分子机制。

乙烯和茉莉酸是促进苹果花青苷合成的两种重要激素。但是，两者在调控苹果花青苷合成反应中的相互作用机制尚不清楚。前期我们发现MdERF1B（MdERF1L）可能在这一过程中起重要作用，在本项目中我们对MdERF1B介导的茉莉酸和乙烯调控苹果花青苷合成途径进行了解析，主要研究结果如下：生理和分子实验表明，MdERF1B为促进花青苷合成正向调控基因。MdERF1B直接结合MdMYC2启动子上调其表达。另外，MdERF1B与茉莉酸信号途径抑制因子MdJAZ5和MdJAZ10蛋白互作，MdERF1B-MdJAZ5/10蛋白复合体降低了MdERF1B对MdMYC2启动子的激活活性。另外，乙烯信号途径基因MdEIL1直接结合MdERF1B启动子上调其表达。综上，我们的结果表明MdERF1B作为核心基因，与 MdMYC2、MdEIL1、MdJAZ5和MdJAZ10 共同参与响应茉莉酸和乙烯调控苹果花青苷合成反应。我们的结果为茉莉酸和乙烯协同调控苹果花青苷合成提供了新见解。