针对植物病毒病给园艺作物生产造成严重损失的问题，开展其抗病毒机制研究有重要意义。RNA沉默介导的抵御途径是植物中最有效的抗病毒机制之一。已探明DCL4通过参与small RNA合成从而在RNA沉默中起作用，但DCL4在番茄等园艺作物中的抗病毒研究进展缓慢。申请人前期研究发现，SlDCL4可能参与番茄抵抗病毒侵染，但具体机制不清。本项目拟对SlDCL4开展研究，对SlDCL4基因编辑植株进行转录组分析，确定SlDCL4影响的抗病相关基因；利用small RNA测序鉴定受到SlDCL4调控的small RNA和次级小干扰RNA (sec-siRNA)；利用生物信息学方法预测sec-siRNA的靶基因并用试验手段鉴定，初步确立SlDCL4—sec-siRNA—抗病基因的调控网络，并通过病毒诱导的基因沉默技术验证上述基因抵抗病毒的功能。综合上述研究结果，建立SlDCL4调控番茄抵抗病毒的分子机制。

Due to serious losses of fruits caused by plant viruses, it is important to launch the research on the mechanism of horticultural crops defense against virus. The RNA silencing pathway is one of the most effective antiviral defense mechanisms in plants. DCL4 is proved to play a role in RNA silencing through the production of small RNA, but the research progress of DCL4’s involvement in antiviral defense in tomato and other horticultural crops is slow. Previous studies showed that SlDCL4 might participate in tomato antiviral defense, but the mechanism was unclear. This project aims to carry out research on SlDCL4. Based on the SlDCL4 gene editing materials and RNA-seq, the genes of disease resistance pathway influenced by SlDCL4 will be determined. Small RNA-seq can be used to identify the small RNA and secondary siRNA (sec-siRNA) that regulated by SlDCL4. SlDCL4 & sec-siRNA & resistance gene regulatory network can be established by bioinformatics analysis and 5’ RACE as well as virus-induced gene silencing (VIGS). Based on the above results, the molecular mechanism of SlDCL4 regulating virus defense in tomato will be built.