Department of Entomology and BIO5, University of Arizona, Tucson, Arizona 85721, USA.
Environ Toxicol. 2014 May;29(5):526-33. doi: 10.1002/tox.21778. Epub 2012 Apr 4.
Aphis gossypii (Glover) has been found to possess multiple mutations in the acetylcholinesterase (AChE) gene (Ace) that might involve target site insensitivity. In vitro functional expression of AChEs reveals that the resistant Ace1 (Ace1R) and Ace2 (Ace2R) were significantly less inhibited by eserine, omethoate, and malaoxon than the susceptible Ace1 (Ace1S) and Ace2 (Ace2S). Furthermore, in both the mutant and susceptible AChEs, Ace2 was significantly less sensitive to eserine, omethoate, and malaoxon than Ace1. These results suggested that both the mutant Ace1 and Ace2 were responsible for omethoate resistance, while the mutant Ace2 played a major role in insecticide resistance. The DNA copy number and transcription level of Ace2 were 1.52- and 1.88-fold higher in the ORR strain than in the OSS strain. Furthermore, the DNA copy number and transcription level of Ace2 were significantly higher than that of Ace1 in either OSS or ORR strains, demonstrating the involvement of Ace2 gene duplication in resistance. Thus, the authors conclude that omethoate resistance in cotton aphids appears to have evolved through a combination of multiple mutations and extensive Ace2R gene duplication.
棉蚜（Aphis gossypii）被发现其乙酰胆碱酯酶（AChE）基因（Ace）中存在多种突变，这些突变可能涉及靶标不敏感性。体外 AChE 功能表达表明，抗性 Ace1（Ace1R）和 Ace2（Ace2R）对 eserine、氧乐果和马拉氧磷的抑制作用明显低于敏感 Ace1（Ace1S）和 Ace2（Ace2S）。此外，在突变型和敏感型 AChE 中，Ace2 对 eserine、氧乐果和马拉氧磷的敏感性均明显低于 Ace1。这些结果表明，突变型 Ace1 和 Ace2 均与氧乐果抗性有关，而突变型 Ace2 在杀虫剂抗性中起主要作用。ORR 菌株中 Ace2 的 DNA 拷贝数和转录水平分别比 OSS 菌株高 1.52 倍和 1.88 倍。此外，在 OSS 或 ORR 菌株中，Ace2 的 DNA 拷贝数和转录水平均明显高于 Ace1，表明 Ace2 基因重复参与了抗性。因此，作者得出结论，棉蚜对氧乐果的抗性似乎是通过多种突变和广泛的 Ace2R 基因重复相结合而进化的。
