Journal of Integrative Agriculture ›› 2025, Vol. 24 ›› Issue (7): 2670-2685.DOI: 10.1016/j.jia.2024.08.017

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琥珀酸脱氢酶复合物的氨基酸位点突变介导玉米小斑病菌对SDHI类杀菌剂氟唑菌酰羟胺的抗药性机制研究

  

  • 收稿日期:2024-06-01 修回日期:2024-08-22 接受日期:2024-07-04 出版日期:2025-07-20 发布日期:2025-06-17

Amino acid substitutions in succinate dehydrogenase complex conferring resistance to the SDHI fungicide pydiflumetofen in Cochliobolus heterostrophus causing southern corn leaf blight

Jiazhi Sun1, 3, 4, Bingyun Yang1, 3, 4, Lingmin Xia1, 3, 4, Rui Yang1, 3, 4, Chaoyang Ding1, 3, 4, Yang Sun1, 3, 4, Xing Chen1, 3, 4, Chunyan Gu2, Xue Yang2#, Yu Chen1, 3, 4#   

  1. 1 School of Plant Protection, Anhui Agricultural University, Hefei 230036, China

    2 Anhui Province Key Laboratory of Pesticide Resistance Management on Grain and Vegetable Pests, Institute of Plant Protection and Agro-products Safety, Anhui Academy of Agricultural Sciences, Hefei 230031, China

    3 Key Laboratory of Agri-products Quality and Biosafety (Anhui Agricultural University), Ministry of Education, Hefei 230036, China

    4 Anhui Province Engineering Laboratory for Green Pesticide Development and Application, School of Plant Protection, Anhui Agricultural University, Hefei 230036, China

  • Received:2024-06-01 Revised:2024-08-22 Accepted:2024-07-04 Online:2025-07-20 Published:2025-06-17
  • About author:#Correspondence Xue Yang, E-mail: yangxue2121@163.com; Yu Chen, E-mail: chenyu66891@sina.com
  • Supported by:
    This study was supported by the National Key Research and Development Program of China (2023YFD1401504), the Open Project of Anhui Province Key Laboratory of Pesticide Resistance Management on Grain and Vegetable Pests, China (PKLPRMGVP202402), the Programs for the Scientific Research Activities of Academic and Technical Leaders of Anhui Province, China (2020D251), the Development Fund for Talent Personnel of Anhui Agricultural University, China (rc342006), the University Synergy Innovation Program of Anhui Province, China (GXXT-2021-059) and Anhui Province Agricultural Eco-Environmental Protection and Quality Safety Industry Technology System, China.

摘要:

玉米作为重要的粮、饲、工兼用作物,是重要的战略资源,对我国经济发展具有举足轻重的作用与意义。在实际生产过程中,玉米受多种病虫害的威胁,其中由异旋孢腔菌(Cochlibolus heterostrophus)侵染引起的玉米小斑病严重影响玉米产量与品质,是制约玉米高产与稳产的重要因素之一。氟唑菌酰羟胺作为一种新型的琥珀酸脱氢酶抑制剂类杀菌剂(Succinate dehydrogenase inhibitor, SDHI),已被证实对玉米小斑病具有良好的防效,然而关于玉米小斑病菌氟唑菌酰羟胺的抗药性机制研究较少。本研究通过室内药剂驯化的方法获得了5株抗氟唑菌酰羟胺的突变体。序列比对分析表明,所有抗药性突变体的琥珀酸脱氢酶ChSdhB/D亚基上发生氨基酸位点突变(ChSdhBH277YChSdhBI279TChSdhDH133Y);根据抗性倍数(Resistance factor, RF)抗药性突变体可分为2种抗性水平:中抗(4株,10<RF<100)和高抗(1株,RF>100);生物适合度结果表明,与亲本菌株相比抗药性突变体在菌丝生长速率、产孢量及菌丝干重均有所降低而致病性增强说明玉米小斑病菌对氟唑菌酰羟胺产生抗药性突变后,其生物适合度会有一定程度降低;交互抗性研究结果表明,抗药性突变体对同类药剂三氟吡啶胺存在正交互抗性,与其他种类药剂咪鲜胺、咯菌腈、异菌脲和吡唑醚菌酯之间无交互抗性;采用同源建模及分子对接技术,模拟了抗药性突变体及其亲本菌株ChSdhB/D亚基与氟唑菌酰羟胺的结合模式,并分析了“药-靶”结合能与抗药性之间的关联性,结果表明,ChSdhBH277YChSdhBI279TChSdhDH133Y的突变均降低了氟唑菌酰羟胺ChSdhB/D亚基之间的结合能,分别-74.07-74.07-152.52 kcal/mol降至-3.90-4.95-9.93 kcal/mol,说明ChSdhB/D亚基的氨基酸位点突变介导了玉米小斑病菌氟唑菌酰羟胺抗药性的产生。本研究结果将为SDHI类杀菌剂合理用于玉米小斑病的科学防控及抗药性管控措施的制定提供理论依据,抗药性机制的解析将为SDHI类药剂的改良优化提供参考

Abstract:

Southern corn leaf blight (SCLB) caused by Cochliobolus heterostrophus, is a widespread foliar disease that has a substantial impact on maize yield in the Huang-Huai-Hai Region of China.  Pydiflumetofen (Pyd), a new succinate dehydrogenase inhibitor (SDHI), has been found as a promising fungicide for the efficient control of SCLB, however, resistance of Cheterostrophus to Pyd has not been studied well.  Here, five Pyd-resistant mutants were generated through fungicide adaptation.  Sequence alignment analysis revealed that these mutants primarily mutated in ChSdhB and ChSdhD, with three genotypes: ChSdhBH277Y, ChSdhBI279T and ChSdhDH133Y, exhibiting two distinct categories of resistance: high resistance (HR) and moderate resistance (MR), among which the resistance factors were 214.22 and 44.33–53.67, respectively.  These mutants were more pathogenic than the wild-type parental strains, but there was a significant reduction in mycelial growth rate and sporulation in the resistant mutants, indicating a significant fitness cost associated with resistance to Pyd.  In addition, this study revealed a positive cross-resistance between Pyd and another SDHI fungicide cyclobutrifluram.  However, no cross-resistance was found between Pyd and other classes of fungicides, including prochloraz, fludioxonil, iprodione or pyraclostrobin.  Homology modeling and molecular docking further confirmed that point mutations of ChSdhBH277Y, ChSdhBI279T, and ChSdhDH133Y could reduce binding affinity between Pyd and its target subunits from –74.07, –74.07, –152.52 kcal mol–1 to –3.90, –4.95, –9.93 kcal mol–1, respectively.  These findings not only provided valuable insights for managing SCLB caused by Cheterostrophus, but also enhanced our understanding of molecular mechanism underlying plant pathogen resistance to Pyd.

Key words: Cochliobolus heterostrophus ,  pydiflumetofen , SDHI resistance , resistance mechanism , point mutation