【摘要】 二化螟抗性和敏感品系分别采自浙江和安徽太湖。毒力测定结果表明 ,抗性品系对杀虫单和甲胺磷分别产生了 37 7和 5 2 7倍的抗性。代谢酶活性的测定结果显示 ,抗性品系多功能氧化酶氧脱甲基活性、氮脱甲基活性分别是敏感品系的3 3和 1 34倍 ,而羧酸酯酶活性和谷胱甘肽转移酶活性两个品系之间没有显著差异。说明多功能氧化酶活性提高可能是二化螟对甲胺磷、杀虫单抗性的一个重要机制。为了研究二化螟可能存在的对沙蚕毒素杀虫剂靶标不敏感机制 ,采用RT -PCR等分子生物学技术 ,分别对 5个敏感个体和 4抗性个体中克隆杀虫单作用的靶标烟碱型乙酰胆碱受体α1亚基 (nAChRαsubunit 1)cDNA序列进行了分子克隆。序列比较发现一共存在 33个单核苷酸的多态性 ,其中 14个引起了编码氨基酸的改变。但是没有发现与抗性有关的特有的碱基突变。更多还原

【Abstract】 Bioassay showed that the rice stem borer, Chilo sup pressalis (Walker), collected from Cixi City, Zhejiang Province, possessed 37 .7 and 52 .7-fold resistance against monosultap and methamidophos respectively compared w ith a susceptible population collected from Taihu County, Anhui Province. The ac tivities of microsomal O-demethylase and N-demethylase in the resistant popula tion were 3.3 and 1.34-fold higher than those in the susceptible population. Th ere was, however, little difference in the activities of esterase and glutathion e S-transferase betwe en the resistant and susceptible population. These findings suggest that the inc reased activities of microsomal O-demethylase and N-demethylase may be importa nt mechanisms involved in the resistance of the rice stem borer to methamidophos a nd monosultap. In order to find the hypothesized monosultap-resistant related p o int mutation, cDNA fragments encoding Chilo suppressalis nAChR α1 (Csα1)su buni t were amplified using the RT-PCR technique from susceptible and resistant indi v iduals. Though no unique mutation was found in resistant individuals, the patter n of single nucleotide polymorphisms was described and discussed. There were a t otal of 33 single nucleotides polymorphisms, of which 14 resulted in amino acid polymorphisms. An insertion was also found in two of the nine cDNAs.更多还原