The point mutation R343W in MoIRR, a putative Zn2Cys6 transcription factor, introduces isoprothiolane (IPT) resistance in Magnaporthe oryzae. However, the function of MoIRR has not been characterized. In this study, the function of MoIRR was investigated by subcellular localization observation, transcriptional autoactivation test, and transcriptomic analysis. As expected, GFP-tagged MoIRR was translocated in the nucleus, and its C-terminal could autonomously activate the expression of reporter genes HIS3 and α-galactosidase in absence of any prey proteins in Y2HGold, suggesting that MoIRR was a typical transcription factor. Transcriptomic analysis was then performed for resistant mutant 1a_mut (R343W), knockout transformant ΔMoIRR-1, and their parental wild-type isolate H08-1a. Upregulated genes in both 1a_mut and ΔMoIRR-1 were involved in fungicide resistance-related KEGG pathways, including the glycerophospholipid metabolism and Hog1 MAPK pathways. All MoIRR deficiency-related IPT-resistant strains exhibited increased susceptibility to fludioxonil (FLU) that was due to the upregulation of Hog1 MAPK pathway genes. The results indicated a correlation between FLU susceptibility and MoIRR deficiency-related IPT resistance in M. oryzae. Thus, using a mixture of IPT and FLU could be a strategy to manage the IPT-resistant populations of M. oryzae in rice fields.

中文翻译：

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抗性和野生型分离株的转录组学分析表明氟虫腈是控制新出现的抗异丙硫烷的稻瘟病菌种群的候选物。

MoIRR 中的点突变 R343W（一种推定的 Zn2Cys6 转录因子）在稻瘟病菌中引入了异丙硫醇 (IPT) 抗性。然而，MoIRR 的功能尚未得到表征。本研究通过亚细胞定位观察、转录自激活试验和转录组学分析研究了MoIRR的功能。正如预期的那样，GFP标记的MoIRR在细胞核中易位，其C端可以在Y2HGold中没有任何猎物蛋白的情况下自主激活报告基因HIS3和α-半乳糖苷酶的表达，表明MoIRR是典型的转录因子。然后对抗性突变体 1a_mut (R343W)、敲除转化体 ΔMoIRR-1 及其亲本野生型分离株 H08-1a 进行转录组学分析。1a_mut 和 ΔMoIRR-1 中上调的基因都参与了杀菌剂抗性相关的 KEGG 途径，包括甘油磷脂代谢和 Hog1 MAPK 途径。由于 Hog1 MAPK 通路基因的上调，所有与 MoIRR 缺乏相关的 IPT 抗性菌株都表现出对氟虫腈 (FLU) 的敏感性增加。结果表明，米霉中 FLU 易感性与 MoIRR 缺乏相关的 IPT 抗性之间存在相关性。因此，使用 IPT 和 FLU 的混合物可能是管理稻田中 IPT 抗性米菌种群的策略。由于 Hog1 MAPK 通路基因的上调，所有与 MoIRR 缺乏相关的 IPT 抗性菌株都表现出对氟虫腈 (FLU) 的敏感性增加。结果表明，米霉中 FLU 易感性与 MoIRR 缺乏相关的 IPT 抗性之间存在相关性。因此，使用 IPT 和 FLU 的混合物可能是管理稻田中 IPT 抗性米菌种群的策略。由于 Hog1 MAPK 通路基因的上调，所有与 MoIRR 缺乏相关的 IPT 抗性菌株都表现出对氟虫腈 (FLU) 的敏感性增加。结果表明，米霉中 FLU 易感性与 MoIRR 缺乏相关的 IPT 抗性之间存在相关性。因此，使用 IPT 和 FLU 的混合物可能是管理稻田中 IPT 抗性米菌种群的策略。