PEI-G阳离子核酸载体的构建及其递送SYNV P蛋白适配体用于抑制病毒复制的机制研究

植物弹状病毒严重威胁农业生产，亟需有效防治手段。适配体是一类具有蛋白特异性结合功能的核酸分子，在治疗动物病毒疾病中效果显著。由于缺乏合适的递送手段，该技术难以在抗植物病毒领域中应用。近期，我们发现聚乙烯亚胺-葡萄糖（PEI-G）复合体具有向植物细胞递送小分子核酸的潜力，并以苦苣菜黄网病毒(SYNV)为对象，筛选到4组特异结合病毒P蛋白的ssDNA适配体，经鉴定适配体P13.7对SYNV复制有抑制作用。在此基础上，本项目拟通过筛选PEI聚合体类型、优化合成条件等方式，建立高效植物适配体递送平台；通过构建基于P13.7序列的适配体突变体库，筛选结合效率更高、抑制作用更强的第二代核酸适配体；结合反向遗传学体系、分子互作系统等手段，建立目标适配体与P蛋白互作的分子模型，明确目标适配体抑制SYNV复制的分子机制，为“核酸递送+适配体技术”这一新的抗植物病毒策略提供研究基础和理论依据。

Plant rhabdovirus poses a serious threat to agricultural productions, and effective control measures are urgently needed. Aptamer is a kind of nucleic acid molecule with the specific binding function of protein, which has remarkable effect in the treatment of animal virus diseases. Due to the lack of suitable means of delivery, this technology is difficult to be applied in the field of anti-plant virus research. Recently, we found that the polyethylenimine-glucose (PEI-G) complex has the potential to deliver small molecule nucleic acids to plant cells. We obtaind four SSDNA aptamers specifically binding to P protein of sonchus yellow net virus, among which aptamer P13.7 can inhibit the replication of SYNV. On this basis, this project intends to establish an efficient plant aptamers delivery platform by screening PEI polymeric types and optimizing synthesis conditions. A library of aptamer mutants based on P13.7 sequence will be constructed to screen the second-generation aptamer with higher binding efficiency and stronger inhibition. In combination with reverse genetic system and molecular interaction system, the interaction model of target aptamer and P protein will be analyzed, and the molecular mechanism of target aptamer inhibiting SYNV replication will be studied, which could provide the theoretical basis for the new anti-plant virus strategy of "nucleic acid delivery + aptamer technology".