Abstract：
Amisulbrom is a novel quinone inside inhibitor, which exhibits excellent inhibitory activity against phytopathogenic oomycetes. However, the resistance risk and mechanism of amisulbrom in Phytophthora litchii are rarely reported. In this study, the sensitivity of 147 P. litchii isolates to amisulbrom was determined, with an average EC50 of 0.24 ± 0.11 μg/mL. The fitness of resistant mutants, obtained by fungicide adaption, was significantly lower than that of the parental isolates in vitro. Cross-resistance was detected between amisulbrom and cyazofamid. Amisulbrom could not inhibit the cytochrome bc1 complex activity with H15Y and G30E + F220L point mutations in cytochrome b (Cyt b) in vitro. Molecular docking indicated that the H15Y or G30E point mutation can decrease the binding energy between amisulbrom and P. litchii Cyt b. In conclusion, P. litchii might have a medium resistance risk to amisulbrom, and a novel point mutation H15Y or G30E in Cyt b could cause high amisulbrom resistance in P. litchii.
摘要：
Amisulbrom是一种新型的醌内抑制剂，对植物病原卵菌表现出优异的抑制活性。然而,关于李氏疫霉抗菌药的耐药风险和耐药机制的报道很少。在这项研究中,测定了147株李氏疟原虫分离株对氨磺菌的敏感性，平均EC50为0.24±0.11μg/mL。抗性突变体的适应性，通过杀菌剂适应获得，显著低于亲代分离株。在氨磺溴和氰氨苄之间检测到交叉抗性。Amisulbrom不能在体外抑制细胞色素b（Cytb）中H15Y和G30EF220L点突变的细胞色素bc1复合物活性。分子对接表明，H15Y或G30E点突变可以降低氨磺菌和P.litchiiCytb之间的结合能。P.litchii可能对氨sulbrom有中等的抗性风险，Cytb中的一个新的点突变H15Y或G30E可能导致利奇疟原虫的高氨磺抗性。
