Key Laboratory of Biology and Sustainable Management of Plant Diseases and Pests of Anhui Higher Education Institutes, Hefei, China.
College of Plant Protection, Anhui Agricultural University, Hefei, China.
Pest Manag Sci. 2022 Oct;78(10):4018-4027. doi: 10.1002/ps.7020. Epub 2022 Jun 17.
Rice (Oryza sativa) is an important cereal crop around the world, and has constantly been threaten by the most destructive fungus Magnaporthe oryzae. Pydiflumetofen, a novel succinate dehydrogenase inhibitor (SDHI), is currently being used for controlling various fungal diseases. However, the potential resistance risk of M. oryzae to pydiflumetofen has remained unclear to date, and finding the resistance mechanism is critical for the usage of this fungicide.
The M. oryzae strain Guy11 is sensitive to pydiflumetofen, with EC value of 1.24 μg mL . 58 pydiflumetofen-resistant (PR) mutants were obtained through pydiflumetofen-induced spontaneous mutation, with a mean EC value >500 μg mL , and the resistance factor (RF) >400. The PR mutants displayed positive cross-resistance to carboxin, but were more sensitive to fluopyram. Sequencing analysis showed that all PR mutants presented a cytosine-to-thymine transition at nucleotide position +1218, resulting in a replacement of histidine 245 by tyrosine (H245Y) on MoSdhB. The mutation of MoSdhB exhibited strong resistant phenotype, but no detectable growth deficits in fungal development, including vegetative growth and pathogenicity of M. oryzae. An allele-specific PCR for rapid detection of the H245Y mutants was established in M. oryzae.
The M. oryzae is sensitive to pydiflumetofen, and shows a medium to high resistance risk to pydiflumetofen. A point mutation of MoSdhB (H245Y) is responsible for the fungal resistance to pydiflumetofen in M. oryzae. © 2022 Society of Chemical Industry.
水稻（Oryza sativa）是全世界重要的谷类作物，但其一直受到破坏性最强的真菌稻瘟病菌（Magnaporthe oryzae）的威胁。吡氟酰草胺，一种新型琥珀酸脱氢酶抑制剂（SDHI），目前被用于防治各种真菌病害。然而，稻瘟病菌对吡氟酰草胺产生抗药性的潜在风险迄今仍不清楚，寻找抗药性机制对于这种杀菌剂的使用至关重要。
稻瘟病菌菌株 Guy11 对吡氟酰草胺敏感，EC 值为 1.24μg mL 。通过吡氟酰草胺诱导自发突变获得 58 株吡氟酰草胺抗性（PR）突变体，平均 EC 值>500μg mL ，抗性因子（RF）>400。PR 突变体对咯菌腈表现出正向交叉抗性，但对氟吡菌酰胺更为敏感。测序分析表明，所有 PR 突变体在核苷酸位置+1218 处均出现胞嘧啶到胸腺嘧啶的转换，导致 MoSdhB 上的组氨酸 245 被酪氨酸（H245Y）取代。MoSdhB 的突变表现出强烈的抗性表型，但在真菌发育过程中没有检测到生长缺陷，包括稻瘟病菌的营养生长和致病性。在稻瘟病菌中建立了用于快速检测 H245Y 突变体的等位基因特异性 PCR。
稻瘟病菌对吡氟酰草胺敏感，对吡氟酰草胺表现出中至高抗药性风险。MoSdhB 的点突变（H245Y）是稻瘟病菌对吡氟酰草胺产生抗药性的原因。© 2022 化学工业协会。
