Department of Plant Pathology, China Agricultural University, Beijing, China.
State Key Laboratory of Discovery and Development of Novel Pesticide, Shenyang Sinochem Agrochemicals R&D Co., Ltd., Shenyang, China.
Pest Manag Sci. 2020 Dec;76(12):4268-4277. doi: 10.1002/ps.5991. Epub 2020 Aug 13.
A series of pyrimidine amine derivatives has been synthesized by modifying the pyrimidine ring group of diflumetorim-a mitochondrial complex I inhibiting fungicide. One derivative, code number SYP-34773, is investigated in this study involving Magnaporthe oryzae, the causal agent of rice blast, which is the most devastating disease in rice. The response, resistance profile and mechanism of M. oryzae to SYP-34773 were investigated, which provides or provide?? important data for the registration and rational use of pyrimidine amines.
SYP-34773 showed greater control efficacy than fungicide isoprothiolane in the field. The baseline sensitivity was established at a mean 50% effective concentration (EC ) of 0.08 μg ml . Four stable SYP-34773-resistant isolates with reduced sensitivity were generated from one (S118) of ten sensitive isolates with a resistance factor of EC ranging from 7.00 to 15.00. Conidia production and pathogenicity were similar to that of S118, although there was a significant decrease in mycelial growth and conidial germination in resistant isolates. Positive cross-resistance was observed between SYP-34773 and diflumetorim; and the SYP-34773-resistant isolates were still sensitive to isoprothiolane, carbendazim, fluazinam, azoxystrobin, or prochloraz. RNA-Seq analyses revealed three cytochrome P450 genes were upregulated in the resistant isolate under the treatment with SYP-34773, as confirmed by quantitative real-time PCR. The SYP-34773 content was significantly reduced in the resistant isolate when compared with the parental isolate.
The study demonstrated that SYP-34773 exhibits high activity against M. oryzae. Overexpression of three cytochrome P450 genes has an important role in the resistance of M. oryzae to novel pyrimidine amines. © 2020 Society of Chemical Industry.
通过对线粒体复合物 I 抑制剂氟嘧菌酯的嘧啶环结构进行修饰，合成了一系列嘧啶胺衍生物。本研究以稻瘟病菌（Magnaporthe oryzae）为对象，对其中一个代号为 SYP-34773 的衍生物进行了研究，稻瘟病是水稻最具破坏性的病害。该研究调查了 M. oryzae 对 SYP-34773 的反应、抗性特征和机制，为嘧啶胺类农药的登记和合理使用提供了重要数据。
SYP-34773 在田间的防治效果优于对照药剂异噻菌胺。基础敏感性测定结果显示，平均有效浓度（EC ）为 0.08μg ml 时，抑制率为 50%。从 10 个敏感菌株中筛选到 1 个（S118）对 SYP-34773 具有较高抗性的菌株，其抗性倍数（EC ）为 7.00～15.00。S118 及其 4 个稳定的抗性突变体的产孢量和致病性与敏感菌株相似，但在抗性菌株中，菌丝生长和孢子萌发显著降低。SYP-34773 与氟嘧菌酯之间存在正交互抗性，SYP-34773 抗性菌株对异噻菌胺、多菌灵、氟环唑、唑菌胺酯和咯菌腈仍保持敏感。RNA-Seq 分析显示，在 SYP-34773 处理下，抗性菌株中有 3 个细胞色素 P450 基因表达上调，实时定量 PCR 验证结果一致。与亲本菌株相比，SYP-34773 在抗性菌株中的含量显著降低。
本研究表明 SYP-34773 对 M. oryzae 具有高活性。3 个细胞色素 P450 基因的过表达在 M. oryzae 对新型嘧啶胺类化合物的抗性中起重要作用。 © 2020 英国化学学会。
