北京、山东和湖南地区烟粉虱抗药性及CYP4v2和CYP6CX1 mRNA水平表达量分析

于2011年采集北京、山东和湖南三地的烟粉虱，进行B、Q隐种鉴定，并测定4种杀虫剂的抗药性，同时通过荧光定量PCR分析CYP4v2和CYP6CX1两个基因的mRNA水平的表达量。结果表明，北京、湖南和长沙烟粉虱均为Q隐种。抗药性监测表明，北京和湖南种群对阿维菌素敏感，山东种群抗性水平较低，而对烟碱类药剂噻虫嗪出现不同程度的抗药性，其中湖南地区烟粉虱对噻虫嗪的抗药性达到49.08倍的高抗水平，北京和山东地区也达到中抗水平。另外，这3个地区的种群对毒死蜱和联苯菊酯抗性水平都较低。通过qRT-PCR分析三地的CYP4v2和CYP6CX1基因表达量，发现相对于敏感种群CYP4v2基因在北京、山东和湖南3个地理种群中分别过量表达3.85倍、19.57倍和10.78倍，而CYP6CX1基因在北京种群中过量表达20.55倍。结果提示田间烟粉虱的细胞色素P450基因CYP4v2和CYP6CX1过量表达可能会是烟粉虱抗药性的形成机制之一。

Resistance status of the whitefly, Bemisia tabaci, in Beijing, Shandong and Hunan areas and relative levels of CYP4v2 and CYP6CX1 mRNA expression

The sibling species of Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) and their resistance levels to four insecticides were studied in three different regions, including Haidian in Beijing, Jiyang in Shangdong, and Changsha in Hunan. The results showed that the sibling species of B. tabaci in the three areas was Q sibling species. B. tabaci populations in Beijing and Hunan were susceptible to abamectin, but Shandong population had low resistance level to abamectin. However, the populations showed moderate to high resistance to neonicotinoid insecticides and thiamethoxam; the highest resistance to thiamethoxam (49.08 fold) was observed in Hunan population. The populations had low resistance degree to chlorpyrifos and bifenthrin in the three areas. Expression analysis by qRT-PCR found that the gene CYP4v2 was over expressed in Beijing population (3.85 fold), Shandong population (19.57 fold) and Hunan population (10.78 fold). The gene CYP6CX1 was over expressed in Beijing populations (20.55 fold), compared with susceptible populations. The results indicated that the enhanced CYP4v2 and CYP6CX1 gene expression might be involved in the resistance mechanisms of B. tabaci in the field.