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【目的】二斑叶螨Tetranychus urticae Koch是为害多种农作物的世界性重大害螨。本研究旨在明确二斑叶螨不同田间种群对阿维菌素的抗药性、抗性相关基因的突变频率及其表达量变化。【方法】采用药管浸叶法测定了我国二斑叶螨8个地理种群对阿维菌素的抗药性并检测其抗性基因突变频率,结合荧光定量PCR技术分析了高抗种群中抗性相关基因表达量变化。【结果】测试的二斑叶螨8个田间种群均对阿维菌素具有抗药性。北京密云、山东潍坊、海南三亚和湖南长沙种群均对阿维菌素产生了极高水平的抗性,抗性倍数分别为1 526.75,481.00,315.25和160.75倍,而北京通县、北京海淀、山西运城和山东泰安种群对阿维菌素的抗性倍数达54.38~136.38倍,处于高抗性水平。二斑叶螨对阿维菌素抗性相关的谷氨酸氯离子通道基因Glu Cl的突变频率在各个田间种群中存在差异。北京密云种群中Glu Cl的突变频率最高(91.7%),其次是山东潍坊(66.7%)和海南三亚(63.3%)种群;山西运城种群最低(13.3%),且点突变频率与抗性倍数之间呈显著的正相关(P<0.05)。与相对敏感种群相比,高抗性二斑叶螨种群中Glu Cl和γ-氨基丁酸受体基因GABAR表达量显著下降。【结论】二斑叶螨田间种群普遍对阿维菌素产生了高水平抗性,抗性相关基因Glu Cl的点突变及其表达量的降低可能与田间抗药性产生相关;田间防治二斑叶螨应避免使用阿维菌素。
【Objective】 Tetranychus urticae Koch is a worldwide pest of many kinds of crops. The aim of this study was to determine the resistance of abamectin to different field populations of two-spotted spider mites, the frequency of mutation and the expression of resistance-related genes. 【Method】 The drug resistance of eight geographical populations of Tetranychus urticae to avermectin was measured and the frequency of mutation of the resistance gene was detected by the method of tube-immersion leaf digestion. The resistance to high-resistant populations was analyzed by fluorescence quantitative PCR Related gene expression changes. 【Result】 Eight field spider mites tested were resistant to abamectin. Miyun of Beijing, Weifang of Shandong, Sanya of Hainan and Changsha of Hunan all had extremely high levels of resistance to avermectin with resistance times of 1 526.75, 481.00, 315.25 and 160.75 times, respectively, whereas Beijing Tongxian, Beijing Haidian, The resistance multiple of avermectins in Yuncheng, Shanxi Province and Tai'an, Shandong province was 54.38-136.38 times, which was at a high resistance level. The frequency of mutation of Glu Cl, a glutamate chloride ion channel gene related to abamectin resistance in two-spotted spider mites, differed in each field population. The mutation frequency of Glu Cl in Miyun population in Beijing was the highest (91.7%), followed by Weifang in Shandong (66.7%) and Hainan (63.3%) in Sanya, and the lowest (13.3%) in Shanxi Yuncheng with the frequency of mutation and the multiple of resistance There was a significant positive correlation (P <0.05). Compared with the relatively sensitive populations, the expression levels of GABAR and Glu Cl and GABA receptor genes in the highly resistant two-spotted spider mite population were significantly decreased. 【Conclusion】 The field population of two-spotted spider mite generally had a high level of resistance to abamectin. The point mutation of Glu Cl and the decrease of its expression level may be related to the emergence of resistance in field. Mites should avoid using avermectins.