Abstract：
In this study, we determined the sensitivity of 148 Phytophthora litchii isolates to cyazofamid, yielding a mean EC50 value of 0.0091 ± 0.0028 μg/mL. Through fungicide adaptation, resistant mutants (RMs) carrying the F220L substitution in PlCyt b were derived from wild-type isolates. Notably, these RMs exhibited a lower fitness compared with the parental isolates. Molecular docking analysis further revealed that the F220L change contributed to a decrease in the binding energy between cyazofamid and PlCyt b. The total phenol and flavonoid contents in the litchi pericarp treated with cyazofamid on day 5 were significantly higher than in other treatments. Overall, the laboratory assessment indicated a moderate risk of cyazofamid resistance in P. litchii, but the emergence of the F220L change could lead to a high level of resistance. Thus, cyazofamid represents a promising agrochemical for controlling postharvest litchi downy blight and extending the shelf life of litchi fruits.
摘要：
在这项研究中,我们确定了148个李氏疫霉分离株对氰唑的敏感性，平均EC50值为0.0091±0.0028μg/mL。通过杀菌剂的适应，在PlCytb中携带F220L取代的抗性突变体（RM）来自野生型分离株。值得注意的是,与亲本分离株相比,这些RM的适应度较低.分子对接分析进一步表明，F220L的变化导致了氰并聚酰胺与PlCytb之间结合能的降低。在第5天，用氰并聚酰胺处理的荔枝果皮中的总酚和黄酮含量显着高于其他处理。总的来说,实验室评估表明，利奇疟原虫中氰唑虫耐药的风险中等，但F220L变化的出现可能导致高水平的抗性。因此，cyazofamid代表了一种有前途的农用化学品，可用于控制采后荔枝枯萎病和延长荔枝果实的保质期。
