Lee Joonhee, Lee Jong Hyeok, Lim Youngcheon, Cho Susie, Moon KyungHwan, Kim Sanghyeon, Kim Young Ho, Lee Si Hyeock
Department of Agricultural Biotechnology, Seoul National University, Seoul 08826, Republic of Korea.
Department of Vector Entomology, Kyungpook National University, Sangju 37224, Republic of Korea.
Pestic Biochem Physiol. 2025 May;210:106387. doi: 10.1016/j.pestbp.2025.106387. Epub 2025 Mar 24.
The Varroa mite, Varroa destructor, is an ectoparasitic pest of Western honey bees and poses a significant threat to apiculture. In Korea, widespread fluvalinate resistance has increased reliance on amitraz as an alternative acaricide. This study identified a novel mutation, T115N, in the β2-adrenergic-like octopamine receptor gene (OctβR) and confirmed its role in amitraz resistance. Genotyping of individual mites, based on time-dependent intoxication responses to a diagnostic dose of amitraz, revealed a strong correlation between genotype and resistance phenotype: mites with early intoxication responses were homozygous for the T115 allele, whereas those with delayed responses predominantly carried the homozygous N115 allele. Mites with homozygous N115 genotype exhibited a median lethal time approximately 2.8-fold longer than their T115 counterparts, confirming the resistance conferred by the T115N mutation. Quantitative sequencing was established to track the spread dynamics of T115N mutation in Korean Varroa mite populations over five years (2020-2024). While the mutation was rare from 2020 to 2022, its frequency increased sharply in 2023 and became widespread across Korea by 2024, coinciding with increased amitraz usage. These findings suggest region-specific selection for the T115N mutation driven by amitraz exposure.
狄氏瓦螨（Varroa destructor）是西方蜜蜂的一种体外寄生害虫，对养蜂业构成重大威胁。在韩国，氟胺氰菊酯抗性的广泛存在增加了对双甲脒作为替代杀螨剂的依赖。本研究在β2 - 肾上腺素样章鱼胺受体基因（OctβR）中鉴定出一种新的突变T115N，并证实了其在双甲脒抗性中的作用。基于对诊断剂量双甲脒的时间依赖性中毒反应对单个螨进行基因分型，结果显示基因型与抗性表型之间存在很强的相关性：中毒反应早的螨对T115等位基因为纯合子，而反应延迟的螨主要携带纯合的N115等位基因。具有纯合N115基因型的螨的半数致死时间比其T115对应物长约2.8倍，证实了T115N突变赋予的抗性。建立了定量测序方法来追踪韩国狄氏瓦螨种群中T115N突变在五年（2020 - 2024年）内的传播动态。虽然该突变在2020年至2022年期间很少见，但其频率在2023年急剧增加，并在2024年在韩国广泛传播，这与双甲脒使用量的增加相吻合。这些发现表明，双甲脒暴露驱动了对T115N突变的区域特异性选择。
