马铃薯GPX-TRX活性氧清除系统作用机制及进化关系研究

GPX-TRX is an important antioxidant system in plants. GPXs are TRX-dependent peroxidases. There is direct interaction between GPX and TRX protein. In plants, GPX and TRX usually exist as gene family. But plants have much more TRXs than GPXs. Why plants need so many TRXs, what pattern exists between GPX and TRX gene family, and what is the evolutionary relationship between these two families? To answer these questions, we will conduct systematic functional analysis on the GPX and TRX gene family in potato. First, we will identify all the GPX and TRX genes from potato, and then analyse their phylogenetic relationship and selective pressure. Second, RT-PCR will be used to examine the expression pattern of GPXs and TRXs under different growth conditions. Third, by transiently expressing GPX-GFP and TRX-RFP proteins in Nicotiana. benthamiana, the subcellular localization of GPXs and TRXs will be determined. Fourth, the GPX and TRX proteins will be expressed in E. coli, the biochemical characterization of the purified recombinant proteins will be investigated. Protein structures of GPXs and TRXs will also be modeled and analyzed. By integrating sequence data, gene expression, protein subcellular localization, protein biochemical characteristics and protein structure analysis, this study will shed light on the functional mechanism and evolutionary relationship of GPX-TRX antioxidant system in potato.

GPX-TRX系统是植物体内重要的活性氧清除系统，在抵御各种胁迫方面发挥重要作用。GPX依赖TRX作为还原剂进行氧化还原反应，两者之间存在直接的蛋白相互作用。在植物中，GPX和TRX都是以多基因构成的基因家族形式存在，但是TRX基因的数目远远多于GPX基因。为什么植物需要如此多的TRX基因？GPX和TRX基因家族之间存在怎样的互作模式？其进化关系是什么？为了回答这一系列问题，本课题将以完成全基因组测序的重要农作物-马铃薯为研究对象，通过基因表达、蛋白亚细胞定位和蛋白生化功能分析，鉴定马铃薯GPX和TRX基因家族成员的对应关系，解析马铃薯GPX和TRX家族的互作模式，进而阐明马铃薯GPX-TRX抗氧化系统的作用机制，并结合序列特征、选择压力和蛋白结构分析，解析马铃薯GPX和TRX家族的进化关系及其机制，从而逐步揭示马铃薯抗逆系统的作用机制，为利用分子手段对马铃薯进行遗传改良提供一定的依据。