Smyth K A, Boyce T M, Russell R J, Oakeshott J G
CSIRO Division of Entomology, GPO Box 1700, Canberra, ACT 2601, Australia.
Heredity (Edinb). 2000 Jan;84 ( Pt 1):63-72. doi: 10.1046/j.1365-2540.2000.00641.x.
Malathion resistance has been shown to be the result of a single point mutation in the LcalphaE7 gene in four independently isolated chromosomes of Lucilia cuprina. The resultant amino acid substitution specifies high malathion carboxylesterase (MCE) activity. We have assayed MCE activities and resistance to malathion in three sets of field-derived samples, two sets of isogenic lines and five mass populations, and show that resistance to malathion in these samples is associated with high MCE activity in both sets of isogenic lines and four of the five mass populations. Additional mechanisms contributing to MCE activity or malathion resistance may be present in one of the mass populations. A second point mutation in LcalphaE7 is responsible for conferring diazinon resistance by encoding an increased organophosphate (OP) hydrolase activity. We also assayed diazinon resistances from the same three samples and show that diazinon and malathion resistances were in complete disequilibrium, with two exceptions. One exception involves the mass population with additional resistance mechanism(s) and the other involves three isogenic lines that are resistant to both insecticides. The molecular data for these lines suggest that they carry a duplication of the LcalphaE7 gene.
在绿蝇（Lucilia cuprina）的四条独立分离的染色体中，马拉硫磷抗性已被证明是LcalphaE7基因中单个点突变的结果。由此产生的氨基酸取代决定了高马拉硫磷羧酸酯酶（MCE）活性。我们测定了三组田间采集样本、两组近交系和五个群体中的MCE活性以及对马拉硫磷的抗性，结果表明，这些样本中对马拉硫磷的抗性与两组近交系以及五个群体中的四个群体的高MCE活性相关。在其中一个群体中可能存在导致MCE活性或马拉硫磷抗性的其他机制。LcalphaE7基因中的第二个点突变通过编码增强的有机磷（OP）水解酶活性赋予了对二嗪农的抗性。我们还测定了来自相同三个样本的二嗪农抗性，结果表明，除两个例外情况外，二嗪农抗性和马拉硫磷抗性完全不平衡。一个例外涉及具有额外抗性机制的群体，另一个例外涉及对两种杀虫剂均有抗性的三个近交系。这些品系的分子数据表明它们携带LcalphaE7基因的重复。
