Abstract：
BACKGROUND: SYP-34773 is a low-toxicity pyrimidine amine compound, which was synthesized by modifying the lead compound diflumetorim. Previous literature has shown that it can strongly inhibit the mycelial growth of several important plant pathogens, including Phytophthora litchii. However, the resistance risk of SYP-34773 has not been reported for P. litchii.
RESULTS: The mean effective concentration (EC50 ) value of SYP-34773 against the mycelial growth of 111 P. litchii isolates was 0.108 ± 0.008 μg mL-1 , which can be used as the baseline sensitivity for SYP-34773 resistance detection in the future. Six mutants were obtained from two parental strain through fungicide induction, whose resistance factors fell between 194- and 687-fold, with stability. Results regarding mycelial growth, sporangial production, sporangial germination, zoospore release, cystspore germination, and pathogenicity showed that the mutants\' compound fitness index values were significantly lower than those of their parental isolate. Furthermore, there was no cross-resistance between SYP-34773 and diflumetorim in P. litchii. Significant inhibition of the mitochondrial complex I enzyme activity in two wild-type P. litchii isolates, but not in mutants, was observed upon treatment with SYP-34773.
CONCLUSIONS: The resistance risk of SYP-34773 in P. litchii is moderate, and resistance management strategies should be adopted in field use. SYP-34773 is a mitochondrial complex I inhibitor, and SYP-34773-resistant P. litchii isolates did not show cross-resistance against diflumetorim. © 2023 Society of Chemical Industry.
RESULTS: The mean effective concentration (EC50 ) value of SYP-34773 against the mycelial growth of 111 P. litchii isolates was 0.108 ± 0.008 μg mL-1 , which can be used as the baseline sensitivity for SYP-34773 resistance detection in the future. Six mutants were obtained from two parental strain through fungicide induction, whose resistance factors fell between 194- and 687-fold, with stability. Results regarding mycelial growth, sporangial production, sporangial germination, zoospore release, cystspore germination, and pathogenicity showed that the mutants\' compound fitness index values were significantly lower than those of their parental isolate. Furthermore, there was no cross-resistance between SYP-34773 and diflumetorim in P. litchii. Significant inhibition of the mitochondrial complex I enzyme activity in two wild-type P. litchii isolates, but not in mutants, was observed upon treatment with SYP-34773.
CONCLUSIONS: The resistance risk of SYP-34773 in P. litchii is moderate, and resistance management strategies should be adopted in field use. SYP-34773 is a mitochondrial complex I inhibitor, and SYP-34773-resistant P. litchii isolates did not show cross-resistance against diflumetorim. © 2023 Society of Chemical Industry.
摘要：
背景：SYP-34773是一种低毒性的嘧啶胺化合物，它是通过修饰铅化合物diflumetorim合成的。以前的文献表明，它可以强烈抑制几种重要植物病原体的菌丝生长，包括Litchii疫霉.然而,SYP-34773的耐药风险尚未报告。
结果：SYP-34773对111个李氏疟原虫菌丝生长的平均EC50值为0.108±0.008μgmL-1，可作为SYP-34773耐药性检测的基线灵敏度。通过杀菌剂诱导从两个亲本菌株中获得了六个突变体，其阻力因子在194到687倍之间，稳定。关于菌丝生长的结果，孢子囊生产，孢子囊萌发,游动孢子释放，孢子萌发,和致病性表明，突变体的复合适应度指数值明显低于其亲本分离株。此外，利奇疟原虫SYP-34773和diflumetorim之间没有交叉抗性。在两个野生型P.litchii分离物中，线粒体复合物I酶活性受到显着抑制，但不是在突变体中，在用SYP-34773治疗时观察到。
结论：SYP-34773在利奇毕赤酵母中的耐药风险中等，在野外使用中应采用抗性管理策略。SYP-34773是一种线粒体复合物I抑制剂，和SYP-34773抗性的利奇疟原虫分离株未显示对二氟多林的交叉抗性。本文受版权保护。保留所有权利。
结果：SYP-34773对111个李氏疟原虫菌丝生长的平均EC50值为0.108±0.008μgmL-1，可作为SYP-34773耐药性检测的基线灵敏度。通过杀菌剂诱导从两个亲本菌株中获得了六个突变体，其阻力因子在194到687倍之间，稳定。关于菌丝生长的结果，孢子囊生产，孢子囊萌发,游动孢子释放，孢子萌发,和致病性表明，突变体的复合适应度指数值明显低于其亲本分离株。此外，利奇疟原虫SYP-34773和diflumetorim之间没有交叉抗性。在两个野生型P.litchii分离物中，线粒体复合物I酶活性受到显着抑制，但不是在突变体中，在用SYP-34773治疗时观察到。
结论：SYP-34773在利奇毕赤酵母中的耐药风险中等，在野外使用中应采用抗性管理策略。SYP-34773是一种线粒体复合物I抑制剂，和SYP-34773抗性的利奇疟原虫分离株未显示对二氟多林的交叉抗性。本文受版权保护。保留所有权利。
