论文部分内容阅读
本研究明确了kdr突变和解毒代谢在B型烟粉虱Bemisia tabaci对高效氯氰菊酯抗性中的作用。B型烟粉虱NJ品系相对于烟粉虱敏感品系(SUD-S,非B型)对高效氯氰菊酯有266倍的抗性。对NJ品系用高效氯氰菊酯进行群体筛选获得抗性为811倍的NJ-R1品系,对NJ品系进行单对交配筛选获得抗性达2634倍的NJ-R2品系。在NJ,NJ-R1和NJ-R2品系间,酯酶、多功能氧化酶和谷胱甘肽S-转移酶活性无显著差异,说明在筛选过程中解毒代谢没有发生变化。PASA检测结果表明,NJ-R2品系钠离子通道基因L925I突变(kdr突变)频率为100%,NJ-R1品系为80.6%,NJ品系为55%。由此可见,kdr突变频率的增加是B型烟粉虱种群对高效氯氰菊酯抗性上升的主要原因。在NJ,NJ-R1和NJ-R2品系中,增效醚(PBO)对高效氯氰菊酯的增效作用均为20倍左右,而PBO对SUD-S品系没有任何增效作用。PBO能同时抑制烟粉虱的多功能氧化酶和酯酶,通过与TPP增效作用进行对比表明,在B型烟粉虱中PBO所产生的增效作用主要来源于对酯酶的抑制。因此,B型烟粉虱品系(NJ-R2,NJ-R1和NJ)与非B型SUD-S品系相比存在20倍左右的先天抗性,该先天抗性主要与B型烟粉虱的特有酯酶有关。在B型烟粉虱品系对高效氯氰菊酯的抗性中,抗性水平完全由kdr突变频率高低所决定。
This study identified the role of kdr mutation and detoxification metabolism in the resistance of Bemisia tabaci to alpha-cypermethrin. The NJ strain of B. tabaci B-type was 266-fold more resistant to beta-cypermethrin than the susceptible strain of B. tabaci (SUD-S, non-B). NJ-R1 strain NJ-R1 with 811-fold resistance was screened by beta-cypermethrin in NJ strain. NJ-R2 strain with 2634-fold resistance was obtained by single-pair mating screening of NJ strain. There were no significant differences in the activities of esterase, polyoxygenase and glutathione S-transferase between NJ, NJ-R1 and NJ-R2 lines, indicating no change in detoxification metabolism during the screening process. PASA test results showed that the frequency of L925I mutation (kdr mutation) in NJ-R2 strain was 100%, NJ-R1 strain was 80.6%, and NJ strain was 55%. Thus, the increase of kdr mutation frequency is the main reason for the increase of beta-cypermethrin resistance in B. tabaci B population. In the NJ, NJ-R1 and NJ-R2 lines, synergistic effect of PBO on beta-cypermethrin was about 20-fold, whereas PBO had no synergistic effect on the SUD-S line. PBO can simultaneously inhibit the multi-functional oxidase and esterase of B. tabaci. Compared with the synergism of TPP, the synergistic effect of PBO in B. tabaci B-biotype mainly comes from the inhibition of esterase. Therefore, the B-biotype B. tabaci strains (NJ-R2, NJ-R1 and NJ) had about 20-fold innate resistance compared with the non-B-type SUD-S strain, Esterase-specific. In B. tabaci strain resistance to beta-cypermethrin, the level of resistance is completely determined by the kdr mutation frequency.