膜定位信号对重复基因BrrICE1.2功能分化的影响

重复基因的功能分化是植物产生新基因的主要来源，其中蛋白本身特征变化对其功能分化贡献更大，但作用机制仍然需要进一步揭示。芜菁是青藏高原传统种植的芸薹属作物，对高原极端环境有较强的适应性。前期研究发现芜菁ICE1基因是重复基因，其中BrrICE1.1保留祖先抗低温的功能，而BrrICE1.2的膜定位信号（GGERV）影响BrrICE1.2的细胞膜定位及与BrrCIPKs的相互作用，暗示膜定位信号可能引起了BrrICE1.1和BrrICE1.2的功能差异。因此，本项目拟通过分析BrrICE1.2的膜定位信号对BrrICE1.2与BrrCIPKs互作的能力、位点磷酸化的差异、转基因株系的抗逆性以及对下游靶基因调控等方面的作用，解析膜定位信号对芜菁重复基因BrrICE1.2功能分化的影响。本项目的结果将揭示由蛋白本身特征变化引起重复基因功能分化的机制，为高原作物适应极端环境提供理论依据。

Functional divergence of duplicated genes is the main source of new genes generation in plants, among which changes in the characteristics of the protein itself contribute more to its functional divergence, but the mechanism still needs to be further revealed. Turnip is a traditional Brassica crop grown on the Qinghai-Tibetan plateau with strong adaptability to the extreme environment of the plateau. Previous studies found that the turnip ICE1 gene is a duplicate gene, in which BrrICE1.1 retains the function of ancestor resistance to low temperature, while the membrane localization signal (GGERV) of BrrICE1.2 affects the cell membrane localization of BrrICE1.2 and the interaction with BrrCIPKs, suggesting that the membrane localization signal may cause the functional differences between BrrICE1.1 and BrrICE1.2. In the present project, we aim to analyze the effects of membrane localization signals of BrrICE1.2 on the ability of BrrICE1.2 to interact with BrrCIPKs, differences in site phosphorylation, resistance of transgenic plants and regulation of downstream target genes, so as to resolve the effects of membrane localization signals on the functional divergence of the turnip duplicated gene BrrICE1.2. Our results will reveal the mechanism of functional divergence of the duplicated gene caused by changes in the characteristics of the protein itself, and provide theoretical basis for the adaptation of plateau crops to extreme environments.