低温胁迫是我国北方地区番茄、黄瓜等喜温蔬菜作物保护地生产中的主要障碍因素之一。SUMO化修饰是蛋白质翻译后修饰的一种重要形式，对于植物的低温响应具有重要作用。植物SIZ1是一种SUMO E3连接酶，在SUMO化的过程中起着关键作用。本项目拟在已克隆番茄SUMO E3连接酶基因（SlSIZ1），并获得过表达、RNAi番茄植株的基础上，制备SlSIZ1抗体，Western 杂交检测转基因植株, 通过Co-IP等方法研究VTC1是否被SIZ1介导的SUMO化修饰；利用酵母双杂等方法验证SIZ1与APX及一些光合作用相关蛋白的互作及其SUMO化修饰情况，并揭示该过程对光合作用的影响。研究低温胁迫下番茄SIZ1对Whirly蛋白在叶绿体与细胞核中分布以及转录活性的影响，明确SUMO化修饰在质体信号通路及光合作用的光破坏防御机制中的作用。该研究对于指导喜温蔬菜栽培和抗逆育种具有重要意义。

Low temperature stress is one of the main obstacle factors in the production of the thermophilic vegetable crops such as tomato and cucumber in northern China. SUMOylation is an important form of post-translational modification of proteins and plays an important role in the low temperature response of plants. SIZ1, a SUMO E3 ligase, plays a key role in SUMOylation of plant. On the basis of the cloned tomato SUMO E3 ligase gene (SlSIZ1), obtained overexpression and RNAi tomato plants, we are planning to prepare SlSIZ1 antibody and to reveal protein signals corresponding to SlSIZ1 in transgenic plants. Co-IP will be used to investigate interaction between SUMO and VTC1. The APX and some other photosynthesis-related protein’s SUMOylation and interaction by SlSIZ1 will be verified by yeast two-hybrid method. At the same time, we will explore the impact of the process on photosynthesis. Under low temperature stress, effects of tomato SIZ1 on the distribution and transcriptional activity of Whirly protein in chloropast and cell nucleus will be analyzed. The role of SUMOylation by SlSIZ1 in retrograde singnal and in photoprotection mechanism of photosynthesis will be investigated. These researches are important for the cultivation and breeding of chilling-sensitive vegetable plants for chilling tolerance.