组蛋白去乙酰化酶MdHDA6在苹果干旱胁迫中的功能及调控作用研究

The Northwestern apple production area contributes the primary production of apple in China. The unique geographical location of this area gives apples with good quality, but also brings various abiotic stresses, especially drought stress. The drought stress gradually becomes the key issue of the apple industrial development. Genetic engineering would be the most efficient and economic approach for stress-resistance genetic improvement in apple with long period growth cycle. Histone deacetylases (HDACs), as the upstream gene expression regulator, involve in various stress-resistance responses. Previously, we genome-widely identified and analyzed the apple HDA family based on the sequenced genome. Base on the results, the expression levels of histone deacetylase gene MdHDA6 were induced under the abiotic stresses, so we will focus on the MdHDA6 to further study the biologically functions and regulatory mechanism. Firstly, we will isolate the CDS sequence of MdHDA6 and construct over-expression and RNAi vector, and then transfer the vectors into apple explant to obtain transgenic plants. The biological functions of MdHDA6 will be investigated in the over-expression and RNAi plants under drought stress. Furthermore, ChIP-Seq assay will be applied to study the downstream genes regulated by MdHDA6. The yeast two-hybrid system will be used to screen the interaction proteins with MdHDA6. The ChIP-Seq and yeast two-hybrid system are aim to study the regulatory pathway of MdHDA6 in apple drought stress responses. In conclusion, this research will explore the biological functions and regulatory pathway of MdHDA6 in apple drought stress response. The research finds will private the choiceness gene for apple breeding and genetic germplasm improvement and the transgenic plants with enhanced stress resistance will be useful in apple stress-resistant breeding and genetic improvement.

西北地区是我国苹果的优势产区，但干旱问题严重制约了该产区苹果产业的发展，挖掘优良的抗性基因进行苹果遗传改良具有重要意义。组蛋白去乙酰化酶HDACs（Histone deacetylases）作为一种上游基因表达调控因子，广泛参与调控植物逆境胁迫响应过程。本研究前期从全基因组水平对苹果中HDACs进行了系统的分析，筛选得到显著受干旱胁迫诱导表达的组蛋白去乙酰化基因MdHDA6。本研究拟以MdHDA6为对象，在苹果中超量和干涉MdHDA6基因，解析该基因在苹果干旱胁迫中的功能；进一步利用ChIP-seq和酵母双杂筛选MdHDA6的下游靶基因及互作蛋白，探讨MdHDA6的调控机制及参与的逆境调控网络。本项目旨在解析MdHDA6在苹果干旱胁迫中的功能及调控机制，不仅加深了苹果响应干旱胁迫的表观调控机制，同时为苹果抗逆种质的遗传改良提供优良的基因资源和抗性增强的遗传转化材料，具有理论和实际应用价值。

西北地区是我国苹果的优势产区，但干旱问题严重制约了该产区苹果产业的发展，挖掘优良的抗性基因进行苹果遗传改良具有重要意义。本研究基于前期筛选得到可能参与干旱胁迫的组蛋白去乙酰化基因MdHDA6为研究对象，在苹果中超量和干涉MdHDA6基因，同时结合在烟草中超量表达的结果，说明MdHDA6是负调控植物响应干旱胁迫。为了进一步研究MdHDA6在苹果干旱胁迫中的调控机制，本研究利用ChIP-seq分析了MdHDA6蛋白结合的motif和下游靶基因，初步结果显示MdHDA6偏好结合EAR motif。同时利用酵母双杂、Split-Luc等蛋白互作技术鉴定到MdHDA6的互作蛋白MdJAZ3（茉莉酸途径负调控因子）和MdSUVH1/4（组蛋白甲基化酶），推测MdHDA6可能联合组蛋白甲基化修饰通过茉莉酸途径调控植物响应干旱胁迫。通过本项目的研究，明确了苹果MdHDA6在干旱胁迫中的功能，初步解析了MdHDA6在苹果干旱应答网络中的调控角色，为苹果抗逆种质的遗传改良提供优良的基因资源和遗传转化材料，具有理论和实际应用价值。