Inheritance of avermectin resistance in Haemonchus contortus
Inheritance of avermectin resistance in Haemonchus contortus
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DOI：
10.1016/s0020-7519(99)00172-1
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发表时间：
2000-01-01
影响因子：
4
通讯作者：
Baker, P
中科院分区：
文献类型：
--
作者：
Le Jambre, LF;Gill, JH;Baker, P
采用幼虫发育试验比较捻转血矛线虫奇斯威克阿维菌素抗性株（CAVRS）、阿维菌素敏感株（VRSG）及其杂交后代对阿维菌素的反应。CAVRS与VRSG正反交的F-1和F-2代分别记为CAVRS雄株× VRSG雌株= CXV和VRSG雄株× CAVRS雌株= VXC。CXV和VXC的F-1代幼虫的阿维菌素抗性水平与阿维菌素抗性亲本的抗性水平没有区别，表明抗性性状完全显性。CXV F-1的阿维菌素剂量-反应曲线在低浓度下未显示50%的死亡率，表明阿维菌素抗性不与性别相关。当发现CXV交配的F-1的成年雄性蠕虫在用200 μ g kg（-1）伊维菌素处理宿主后存活时，证实了这一结论。该剂量率（200 μ g kg（-1）伊维菌素）导致CXV和VXC杂交的F-1中成年雄性数量减少50%，但F-1中成年雌性数量仅无显著减少。在幼虫发育试验中获得的F-2代的剂量-反应曲线表明存在25%的阿维菌素敏感个体，这表明一个单一的主基因在很大程度上控制阿维菌素抗性性状。本研究对一株澳大利亚黑腹果蝇的阿维菌素抗性进行了遗传分析。捻转虫分离株表明，阿维菌素抗性基因的表达在幼虫中是常染色体完全显性的;然而，在成虫中，其表达受性别影响，雄性对阿维菌素的抗性低于雌性。(C)2000年澳大利亚寄生虫学会，由爱思唯尔科学有限公司出版。保留所有权利。
A larval development assay was used to compare the responses of the Chiswick Avermectin Resistant (CAVRS) isolate of Haemonchus contortus, an avermectin-susceptible isolate (VRSG) and their crosses to avermectins, The F-1 and F-2 generations of reciprocal crosses between CAVRS and VRSG were denoted as CAVRS males x VRSG females = CXV, and VRSG males x CAVRS females = VXC. The levels of avermectin resistance in the developing larvae of the F-1 of both CXV and VXC were indistinguishable from that in the avermectin-resistant parent, indicating that the resistance trait is completely dominant. Avermectin dose-response curves for the CXV F-1 did not show a 50% mortality rate at low concentrations, indicating that avermectin resistance is not sex-linked. This conclusion was confirmed when adult male worms of the F-1 of the CXV mating were found to have survived treatment of the host with 200 mu g kg(-1) ivermectin. This dose rate (200 mu g kg(-1) ivermectin) caused a 50% reduction in the number of adult males in the F-1 from both CXV and VXC crosses, but only a non-significant reduction in the number of adult females in the F-1. Dose-response curves obtained for the F-2 generations in the larval development assay indicated the presence of 25% of avermectin-susceptible individuals, suggesting that a single major gene largely controls the avermectin-resistance trait. This genetic analysis of avermectin resistance in an Australian H. contortus isolate indicates that the expression of the gene for avermectin resistance is an autosomal complete dominant in the larvae; however, in adults its expression is sex-influenced, with males having a lower resistance to avermectin than females. (C) 2000 Australian Society for Parasitology Inc, Published by Elsevier Science Ltd. All rights reserved.