本项目前期工作发现多株稻曲病菌对三唑类杀菌剂的田间抗药性菌株，且田间适合度较高，表明稻曲病菌对三唑类杀菌剂可能存在抗药性风险。初步研究发现其药剂作用靶标CYP51蛋白的基因启动子区发生了两个碱基“CC”的插入突变，同时Cyp51基因表达量显著上调。JASPAR数据库预测发现“CC”插入突变位置正好位于预测出的转录因子结合位点。DNA pull-down实验数据也表明含“CC”插入突变的核酸序列能够结合更多的稻曲病菌蛋白。因此，我们推测“CC”插入突变可能通过影响基因启动子结合转录因子的能力从而调控药剂靶标CYP51蛋白的表达水平。本项目拟以稻曲病菌对丙环唑的田间抗药性菌株为研究材料，系统筛选鉴定与Cyp51基因启动子互作的转录因子，并深入研究Cyp51基因启动子区插入突变调控其表达的分子机制，揭示稻曲病菌对三唑类杀菌剂的抗药性分子机理，为指导田间科学使用三唑类杀菌剂防治稻曲病提供理论依据。

Previous study found the fitness of propiconazole-resistant isolates of Ustilaginoidea virens (Cooke) Takah in the field were high, which suggested that there may be a potential resistance risk to triazole fungicides for U. virens. In addtion, “CC”insertional mutagenesis was identified in the upstream promoter of the gene coding region in propiconazole-resistant isolates, and the gene expression of Cyp51 was significantly increased. We propose that the changed transcription factor binding ability of promoter may affect the gene expression of Cyp51. The results of JASPAR prediction and DNA pull-down experiment indicated that the promoter of Cyp51 which containing “CC” insertional mutagenesis could bind more proteins in U. virens. Based on the results above, this project aims to identify the transcription factors which interact with the promoter of Cyp51 by DNA pull-down and yeast one-hybrid screen, and further analyze their functions in regulating gene expression of Cyp51. The results are expected to reveal the resistance mechanism of U. virens to triazole fungicides, and then provide guidance for scientific use of triazole fungicides in the control of rice false smut.