致病疫霉侵染番茄造成的晚疫病是生产中最严重的常发性、流行性病害，目前尚无对其完全免疫的品种，而化学防治导致的农药残留和病原菌的耐药性等问题日益突出，相关的基础研究相当薄弱。本项目在掌握了致病疫霉接种番茄过程中的诱导抗性和发病条件，并挖掘鉴定了番茄中与抗性相关的miRNA以及预测到致病疫霉中存在miRNA的基础上，拟采用小RNA文库构建、高通量测序、生物信息学分析、分子杂交、实时荧光定量PCR等手段，探究番茄与致病疫霉互作中双方体内起关键作用的miRNA；利用过表达及miRNA海绵技术，通过对转基因植株的抗性检测，解析各miRNA的功能；建立它们相互之间的调控网络模型，揭示番茄抗病防御的分子机制；填补miRNA数据库中尚无致病疫霉miRNA的空白；创制出新的番茄资源材料；找到防治晚疫病的靶点。为抗病分子育种和病原菌的生物靶向治理奠定基础；对番茄无公害生产、提高产量和品质具有重要的意义。

Late blight caused by Phytophthora infestans is a kind of devastating disease which is common and epidemic in tomato production. Currently, there are no tomato varieties immune to the disease while the pesticide residue caused by chemical control and the drug resistance of the pathogens are increasingly prominent. This situation is largely due to lack or insufficient of related basic research. We have mastered the induced resistance and the induction condition of tomato inoculated with P. infestans. We have already identified the resistance-related tomato miRNAs and predicted the existence of P. infestans miRNAs. On these bases, small RNA library construction, high throughput sequencing, bioinformatics analysis, molecular hybridization and real-time quantitative PCR are to be used in this project to explore the crucial miRNAs in both tomato and P. infestans during the interactions between the two. The resistance of transgenic tomato plants to P. infestans will be measured to decipher the functions of the key miRNAs by over expression and miRNA sponge. Then, we will construct the regulatory networks model of these miRNAs and reveal the molecular defense mechanism of tomato. Findings of this work will fill the gap for the absence of any P. infestans miRNAs in the current miRBase. In the meantime, both new disease-resistant tomato germplasm and the targets for the prevention of late blight could be obtained. This project is expected to lay a foundation for molecular breeding of late blight resistance in tomato via targeted control of the pathogen, and hence to improve both quality and quantity of tomato production.