ABSTRACT

This study aimed to detect mutations associated with pyrethroid resistance mechanism in different populations of Varroa destructor from Uruguay and Argentina with different degree of susceptibility to this family of acaricides. Bioassays were performed to evaluate the degree of susceptibility to flumethrin and tau-fuvalinate; then mites were studied in order to determine the presence or absence of the resistance-associated mutations by sequencing a region of the sodium channel gene. In the mites studied from Colonia, which showed resistance to flumethrin and susceptibility to tau-fluvalinate in the bioassays, L925V mutation was observed in heterozygous and homozygous state. The presence of the wild-type allele in homozygous state was identified in all mites from Treinta y Tres, in which acaricides have never been used. The mite population from Mar del Plata through bioassays were determined as susceptible to both pyrethroids, however, genotyping results showed the presence of heterozygous individuals (925 V/L) as well as homozygous wild type (925L), while homozygous resistant individuals (925V) were present at low frequency. This would suggest that this population presents a great potential to give a generalized resistance to pyrethroids. This study represents the first report of a L925V mutation in resistant mites to flumethrin from South America.

摘要

本研究旨在检测与在不同的种群拟除虫菊酯抗性机理相关的基因突变狄斯瓦来自乌拉圭和阿根廷不同程度的敏感性的这个家庭杀螨剂。进行生物测定以评估对氟氯菊酯和tau的敏感性程度- 富马酸；然后通过对钠通道基因的一个区域进行测序来研究螨虫，以确定是否存在与抗性相关的突变。在来自 Colonia 研究的螨虫中，在生物测定中显示出对氟氯氰菊酯的抗性和对 tau-fluvalinate 的敏感性，在杂合子和纯合子状态下观察到 L925V 突变。在来自 Treinta y Tres 的所有螨虫中都发现了纯合状态的野生型等位基因的存在，其中从未使用过杀螨剂。马德普拉塔的螨种群通过生物测定被确定为对两种拟除虫菊酯敏感，然而，基因分型结果显示存在杂合个体 (925 V/L) 以及纯合野生型 (925L)，而纯合抗性个体 (925V)以低频出现。这表明该种群具有对拟除虫菊酯产生普遍抗性的巨大潜力。这项研究代表了南美洲对氟氯菊酯耐药螨的 L925V 突变的首次报告。