丙环唑是防治稻曲病的一种三唑类杀菌剂，目前稻曲病菌对该类杀菌剂的抗性分子机制尚不明确。申请人前期筛选获得一株对丙环唑高抗的T-DNA单拷贝插入突变体B857，初步分析其具有多药抗药性。本项目拟在此基础上，克隆突变基因，通过基因敲除及回复突变技术获得突变体，检测突变体对丙环唑和其他不同作用机制杀菌剂的敏感性变化，利用RT-qPCR方法检测突变体与野生型菌株中抗药性相关基因的表达水平，鉴定突变基因在抗药性产生中的功能；借助转录组测序，比较野生型菌株和敲除突变体在有药及无药条件下的转录表达谱，探索突变基因对抗药性产生的调控路径，解析稻曲病菌对丙环唑产生抗性的分子机制，为稻曲病菌对三唑类杀菌剂的抗药性预警及新型杀菌剂的研发提供理论依据。

Propiconazole is a kind of triazole fungicide to control rice false smut, caused by Ustilaginoidea virens. While the resistance molecular mechanism of U. virens to this kind of fungicides is not clear at present. The mutant B857, which showed high resistance to propiconazole was screened from a T-DNA insertional mutant library of U. virens. And a single copy of T-DNA in B857 was confirmed, as well as multidrug-resistance in the preliminary study. Based on this, we intend to clone T-DNA insertional mutated gene of B857. The knockout mutants and the complementary mutants will be obtained by agrobacterium tumefaciens mediated transformation (ATMT) based gene deletion and complementation methods. Sensitivity to propiconazole and other fungicides with different modes of action will be detected. Relative expression values of genes that may contribute to fungicide resistance in the mutants and the wild strain will be tested by Real Time quantitive PCR (RT-qPCR) for validating the function of the mutated gene in fungicide resistance. Moreover, regulatory pathway of the mutated gene on resistance will be explored by transcriptional expression profile comparison between the knockout mutants and the wild strain using transcriptome sequencing. The expected results will clarify resistance molecular mechanism of U. virens to propiconazole. At the meantime, it is useful in providing theoretical basis for resistance warning of U. virens to triazole fungicides and development of new fungicides.