State Key Laboratory of Crop Stress Biology for Arid Areas, Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture and Rural Affairs, Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, College of Plant Protection. Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory for Botanical Pesticide R&D of Shaanxi Province, Yangling 712100, Shaanxi, China.
Key Laboratory of Integrated Pest Management on the Loess Plateau of Ministry of Agriculture and Rural Affairs, Key Laboratory of Plant Protection Resources and Pest Management of Ministry of Education, College of Plant Protection. Northwest A&F University, Yangling 712100, Shaanxi, China; Key Laboratory for Botanical Pesticide R&D of Shaanxi Province, Yangling 712100, Shaanxi, China.
Pestic Biochem Physiol. 2024 Aug;203:105991. doi: 10.1016/j.pestbp.2024.105991. Epub 2024 Jun 18.
Indoxacarb is a pivotal insecticide used worldwide to manage Spodoptera exigua, a devastating agricultural pest. This active compound plays a crucial role in resistance management strategies due to its distinctive mode of action. A field population of S. exigua (SH23) from Shanghai, China, exhibited significantly reduced susceptibility to indoxacarb, with a resistance ratio of 113.84-fold in biological assays. Following two rounds of laboratory screening with indoxacarb, the resistance of the new strain (SH23-S2) escalated steeply to 876.15-fold. Genetic analyses of both the SH23 and SH23-S2 strains demonstrated autosomal inheritance and incompletely dominant resistance patterns. Synergist assays indicated a minor role of detoxification enzymes (glutathione s-transferases and cytochrome P450) of SH23-S2 strain in this resistance, implicating target-site resistance as the primary mechanism. To explore the impact of target-site resistance, segment 1-6 of domain IV (IVS1-6) of the sodium channel in S. exigua was cloned, and the sequences from susceptible and indoxacarb-resistant S. exigua were compared. The V1848I mutation, linked to indoxacarb resistance in Plutella xylostella, Tuta absoluta and Liriomyza trifolii, was identified and strongly associated with the indoxacarb-resistant phenotype in the S. exigua SH23-S2 strain, whereas the F1845Y mutation was not detected. Furthermore, a molecular test for the V1848I mutation in field populations was created using an allele-specific PCR (AS-PCR). The discovery of indoxacarb resistance mutation and the creation of diagnostic tool will enable the early detection of indoxacarb resistance, which will facilitate the implementation of targeted resistance management strategies, ultimately delaying the proliferation of resistance.
茚虫威是一种在全球范围内用于防治鳞翅目农业害虫甜菜夜蛾的重要杀虫剂。由于其独特的作用方式，该活性化合物在抗性管理策略中起着关键作用。来自中国上海的甜菜夜蛾（SH23）田间种群对茚虫威表现出明显的低敏感性，生物测定中的抗性比为 113.84 倍。经过两轮茚虫威室内筛选，新种群（SH23-S2）的抗性急剧上升至 876.15 倍。对 SH23 和 SH23-S2 种群的遗传分析表明，存在常染色体遗传和不完全显性抗性模式。增效剂测定表明，SH23-S2 种群解毒酶（谷胱甘肽 S-转移酶和细胞色素 P450）的作用较小，暗示靶标抗性是主要机制。为了探讨靶标抗性的影响，克隆了甜菜夜蛾钠离子通道 IV 域 1-6 节段（IVS1-6），并比较了敏感和茚虫威抗性甜菜夜蛾的序列。鉴定出与小菜蛾、烟粉虱和南美斑潜蝇的茚虫威抗性相关的 V1848I 突变，并与 SH23-S2 种群的茚虫威抗性表型强烈相关，而未检测到 F1845Y 突变。此外，利用等位基因特异性 PCR（AS-PCR）创建了针对田间种群 V1848I 突变的分子检测。该研究发现茚虫威抗性突变并创建了诊断工具，将有助于早期检测茚虫威抗性，从而实施有针对性的抗性管理策略，最终延缓抗性的扩散。
