Kumar Ram, Mazakova Jana, Ali Asad, Sur Vishma Pratap, Sen Madhab Kumar, Bolton Melvin D, Manasova Marie, Rysanek Pavel, Zouhar Miloslav
Department of Plant Protection, Faculty of Agrobiology, Food and Natural Resources, Czech University of Life Sciences Prague, Kamycka 129, 165 00 Prague, Czech Republic.
Laboratory of Reproductive Biology, Institute of Biotechnology of the Czech Academy of Sciences, BIOCEV, Prumyslova 595, 252 50 Vestec, Czech Republic.
J Fungi (Basel). 2021 Dec 11;7(12):1062. doi: 10.3390/jof7121062.
Cercospora leaf spot (CLS), caused by the fungal pathogen , is the most important foliar pathogen of sugar beet worldwide. Extensive reliance on fungicides to manage CLS has resulted in the evolution of fungicide resistance in worldwide, including populations in the Czech Republic. One important class of fungicides used to manage CLS is the sterol demethylation inhibitors (DMI). The aim of our study was to assess DMI resistance in from the Czech Republic and elucidate the molecular basis of DMI resistance in this population. A total of 50 isolates were collected in 2018 and 2019 from the major sugar beet growing regions of the Czech Republic and assessed for in vitro sensitivity to the DMI fungicides propiconazole, prochloraz, and epoxiconazole. These analyses identified three strains that exhibited 50% effective concentration (EC) values > 1.0 μg mL against respective fungicides, which were therefore considered resistant. In contrast, strains that exhibited lowest EC values were considered sensitive. To explore the molecular basis of resistance in these three strains, the cytochrome P450-dependent sterol 14α-demethylase () gene was sequenced. Sequence analysis identified a Y464S mutation in all three resistant strains. To assess whether gene expression may play a role in DMI resistance, selected strains were grown in vitro with and without fungicide treatment. These analyses indicated that gene expression was significantly induced after fungicide treatment. Thus, we conclude that Y464S point mutation along with induced gene overexpression is likely responsible for resistance against DMI fungicides in from the Czech Republic.
由真菌病原体引起的尾孢叶斑病（CLS）是全球甜菜最重要的叶部病原体。在全球范围内，包括捷克共和国的种群，过度依赖杀菌剂来防治CLS已导致杀菌剂抗性的演变。用于防治CLS的一类重要杀菌剂是甾醇脱甲基抑制剂（DMI）。我们研究的目的是评估捷克共和国的尾孢菌对DMI的抗性，并阐明该种群中DMI抗性的分子基础。2018年和2019年从捷克共和国主要甜菜种植区共收集了50个分离株，并评估了它们对DMI杀菌剂丙环唑、咪鲜胺和环氧菌唑的体外敏感性。这些分析确定了三个菌株，它们对各自杀菌剂的50%有效浓度（EC）值>1.0μg/mL，因此被认为具有抗性。相比之下，EC值最低的菌株被认为是敏感的。为了探究这三个菌株抗性的分子基础，对细胞色素P450依赖性甾醇14α-脱甲基酶（）基因进行了测序。序列分析在所有三个抗性菌株中均鉴定出Y464S突变。为了评估基因表达是否可能在DMI抗性中起作用，选择的菌株在有和没有杀菌剂处理的情况下进行体外培养。这些分析表明，杀菌剂处理后基因表达显著诱导。因此，我们得出结论，Y464S点突变以及诱导的基因过表达可能是捷克共和国尾孢菌对DMI杀菌剂产生抗性的原因。
