赤霉病菌对氰烯菌酯抗性减除RNAi分子的筛选及调控机制研究

Fusarium head blight (FHB) is a devastating disease worldwide. Unfortunately, natural resistance against Fusarium is inadequate, the control of FHB has mainly depended on application of fungicides until now. A new fungicide, phenamacril (experimental code JS399-19), is a Fusarium-specific fungicide that is used to control FHB. However, Fusarium graminearum shows frequently resistance mutants to phenamacril under the selection pressure in laboratory. The study of phenamacril resistance mechanism reveals that mutations in myosin-5 confer resistance to phenamacril in F. graminearum. Our studies eliminate Fusarium resistance to phenamacril by RNA interference technology including HIGS and siRNA in vitro. The sensibility of high phenamacril-resistance strain increased 79%, whose myosin-5 gene was interfered. The results revealed the plan that eliminates Fusarium resistance to phenamacril by RNA interference can be fully carried out.

小麦赤霉病是由镰刀菌引起的世界性真菌病害，由于谷类作物缺乏对赤霉病菌的天然抗源，化学防治一直是小麦赤霉病最有效的防治措施。氰烯菌酯是我国自主研发的新型杀菌剂，已成为赤霉病防治的主要药剂。项目组前期研究发现，氰烯菌酯的靶标肌球蛋白-5基因不仅极易发生变异而产生抗药性，而且其表达水平与抗药性水平及生活力呈正相关，因此，降低肌球蛋白-5基因的表达可减除病菌对氰烯菌酯的抗性，并能降低病菌的适合度。为解决赤霉病菌对氰烯菌酯的抗药性问题，本项目基于RNA干扰的原理，分别采用HIGS和体外siRNA手段降低肌球蛋白-5基因的表达，以减少药剂靶标丰度，增加野生型赤霉病菌对氰烯菌酯的药敏性，解除变异病原菌的抗药性；同时确立靶基因干扰程度与药敏性增加程度的最佳平衡点，研究靶基因mRNA二级结构对RNAi效率的调控机制。本项目研究成果对于小麦赤霉病防控及抗药性治理新技术的研发具有理论指导意义。

小麦赤霉病是由镰刀菌引起的世界性真菌病害，由于谷类作物缺乏对赤霉病菌的天然抗源，化学防治一直是小麦赤霉病最有效的防治措施。氰烯菌酯是我国自主研发的新型杀菌剂，已成为赤霉病防治的主要药剂。项目组研究发现，降低氰烯菌酯的靶标肌球蛋白-5基因的表达可减除病菌对氰烯菌酯的抗性，并能降低病菌的适合度。项目基于RNA干扰的原理，分别采用HIGS和体外siRNA手段降低肌球蛋白-5基因的表达，减少了药剂靶标丰度，增加了野生型赤霉病菌对氰烯菌酯的药敏性，解除了变异病原菌的抗药性；同时发现，赤霉病中RNA干扰的持效期受到RdRP限制，siRNA级联放大效应丧失；植物表皮细胞的完整性对dsRNA向植物的递送有重要作用。本项目研究成果对于小麦赤霉病防控及抗药性治理新技术的研发具有理论指导意义。