MicroRNA（miRNA)是一类非编码RNA，其作用是调控转录后基因表达。申请人在前期工作中以海水经济鱼种牙鲆为宿主，研究了鱼类重要病毒肿大细胞病毒感染时宿主miRNA的表达，由此获得了121个病毒诱导的牙鲆miRNA，并且发现某些病毒诱导的miRNA也能被鱼类致病性细菌所诱导。由于细菌和病毒是鱼类所面对的主要病原体系，其种类复杂性制约了相关病害的理论研究和防控技术发展，因此同时针对病毒和细菌的研究方式具有重要理论和应用意义。基于此，申请人拟在本项目中利用前期研究所发现的百余个病毒诱导的牙鲆miRNA，从中筛选不仅被病毒诱导而且也被病原菌诱导的miRNA，获得对病毒和细菌具有共靶向作用的多效型miRNA，解析其功能和调控机制，探索其在病毒和细菌病共防治中的应用性。项目不仅在设计上具有创新性，而且其结果将为“一箭双/多雕”式的鱼类病害防控模式提供新的思路和靶点。

MicroRNA (miRNA) is a type of non-coding RNA that plays an important role in post-transcriptional regulation. In previous work, we studied the expression of Japanese flounder miRNA during the infection process of megalocytivirus, a severe fish virus. As a result, we identified 121 virus-induced flounder miRNA and found that some virus-induced miRNA could also be induced by the infection of fish bacterial pathogens. Since virus and bacteria are the main pathogenic organisms faced by cultured fish and the complexity of the pathogen species poses difficulties for the research of fish disease and the development of disease control techniques, the study that aims simultaneously at multiple viral and bacterial pathogens would be valuable. Based on this rationale, we in this proposal plan to screen from the 121 megalocytivirus-induced miRNA the ones that can be induced by one or multiple bacteria commonly pathogenic to cultured fish, whereby obtaining miRNA with multi-effect against both viral and bacterial pathogens. We will then examine the function and regulation mechanism of the selected miRNA and explore the potentials of applying these miRNA to the prevention of diseases associated with viral and bacterial infection. The design of our study is novel, and the results will provide guidance and targets for fish disease control that aims at multiple pathogens by one shot.