State Key Laboratory of Rice Biology, Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Institute of Biotechnology Zhejiang University, Hangzhou, China.
Key Laboratory of Pesticide, College of Plant Protection, Nanjing Agricultural University, Nanjing, China.
Pest Manag Sci. 2024 Oct;80(10):4959-4966. doi: 10.1002/ps.8226. Epub 2024 Jun 6.
Fusarium head blight (FHB) caused by Fusarium graminearum species complex (FGSG) remains a major challenge to cereal crops and resistance to key fungicides by the pathogen threatens control efficacy. Pydiflumetofen, a succinate dehydrogenase inhibitor, and phenamacril, a cyanoacrylate fungicide targeting myosin I, have been applied to combat this disease. Nonetheless, emergence of pydiflumetofen resistance in a subset of field isolates alongside laboratory-induced facile generation of phenamacril-resistant isolates signals a critical danger of resistance proliferation.
Our study investigates the development of dual resistance to these fungicides in F. graminearum. Utilizing pydiflumetofen-resistant (Py) and -sensitive (Py) isolates, we obtained dual-resistant (PyPh) and phenamacril-resistant (PyPh) mutants on potato sucrose agar containing phenamacril. Mutation rates for phenamacril resistance were comparable between pydiflumetofen-resistant and -sensitive isolates, implying independent pathways for resistance development. The mutants compromised in fungal growth, competitive viability and deoxynivalenol production, suggesting fitness penalties for the dual-resistant mutants. However, no cross-resistance was found with tebuconazole or fludioxonil. In addition, we characterized four critical amino acid changes (S217L, C423R, K537T, E420G) in the Myo1 that were verified to confer phenamacril resistance in F. graminearum.
This research indicates the possibility of resistance development for both pydiflumetofen and phenamacril in F. graminearum and emphasizes the need for fungicide resistance management for FHB. © 2024 Society of Chemical Industry.
镰刀菌禾谷孢腔菌（Fusarium graminearum species complex，FGSG）引起的赤霉病仍然是谷物作物的主要挑战，病原菌对关键杀菌剂的抗性威胁着防治效果。琥珀酸脱氢酶抑制剂吡氟酰草胺和肌球蛋白 I 靶向氰基丙烯酸酯杀菌剂苯霜灵已被应用于防治该病害。然而，田间分离物中部分亚群对吡氟酰草胺的抗性以及实验室诱导的苯霜灵抗性分离物的轻易产生表明了抗性扩散的严重危险。
本研究调查了镰刀菌禾谷孢对这两种杀菌剂的双重抗性的发展。利用吡氟酰草胺抗性（Py）和敏感（Py）分离物，我们在含有苯霜灵的土豆蔗糖琼脂上获得了对吡氟酰草胺和苯霜灵都具有抗性的（PyPh）和苯霜灵抗性（PyPh）突变体。吡氟酰草胺抗性的突变率在抗性和敏感分离物之间相当，这表明了抗性发展的独立途径。突变体在真菌生长、竞争活力和脱氧雪腐镰刀菌烯醇（deoxynivalenol，DON）产生方面受到损害，表明双重抗性突变体存在适应性代价。然而，与戊唑醇或氟唑菌酰胺没有发现交叉抗性。此外，我们还鉴定了 Myo1 中的四个关键氨基酸变化（S217L、C423R、K537T、E420G），这些变化被证实赋予了镰刀菌禾谷孢对苯霜灵的抗性。
本研究表明了镰刀菌禾谷孢对吡氟酰草胺和苯霜灵都可能产生抗性，并强调了对赤霉病进行杀菌剂抗性管理的必要性。 © 2024 化学工业协会。
