异丙硫醇(IPT),一种系统性杀菌剂,自1970年代以来一直用于控制稻瘟病。尽管已经观察到对IPT的抗性,抗性机制仍未完全阐明。在这项研究中,在实验室产生的两个IPT抗性突变体之间检测到核苷酸多态性,和他们的亲本野生型分离株使用全基因组测序方法。在两个抗性突变体的基因组中,在编码Zn2Cys6转录因子样蛋白的基因中鉴定出单点突变。值得注意的是,在野生型分离株中敲除基因或用突变等位基因(R343W)替换野生型等位基因导致对IPT的抗性,表明该基因与IPT抗性有关,因此被指定为MoIRR(稻瘟病菌异丙硫醇相关抗性)。随着突变体1a_mut中的点突变R343W,和R345C在1c_mut中,6c_mut中16bp的插入也位于MoIRR的Fungal_TF_MHR域,揭示该域可能是IPT电阻的核心元素。此外,IPT抗性突变体和转化体显示与ipronfos(IBP)的交叉抗性,这与之前的观察结果一致。这些结果表明,MoIRR与胆碱生物合成抑制剂(CBI)的抗性密切相关,进一步的工作应该集中在研究MoIRR的下游效应上。
Isoprothiolane (IPT), a systemic fungicide, has been applied to control rice blast since the 1970s. Although resistance to IPT has been observed, the mechanism of resistance still has not been fully elucidated. In this study, nucleotide polymorphisms were detected between two IPT-resistant mutants generated in the lab, and their parental wild type isolates using a whole-genome sequencing approach. In the genomes of the two resistant mutants, single point mutations were identified in a gene encoding a Zn2Cys6 transcription factor-like protein. Notably, either knocking out the gene or replacing the wild type allele with the mutant allele (R343W) in a wild type isolate resulted in resistance to IPT, indicating that the gene is associated with IPT resistance, and thus was designated as MoIRR (Magnaporthe oryzae isoprothiolane resistance related). Along with point mutations R343W in mutant 1a_mut, and R345C in 1c_mut, a 16 bp insertion in 6c_mut was also located in the Fungal_TF_MHR domain of MoIRR, revealing that this domain may be the core element for IPT resistance. In addition, IPT-resistant mutants and transformants showed cross-resistance with iprobenfos (IBP), which was consistent with previous observations. These results indicated that MoIRR is strongly connected to resistance to choline biosynthesis inhibitor (CBI), and further work should focus on investigating downstream effects of MoIRR.