Bt杀虫蛋白对不同品系棉铃虫和中红侧沟茧蜂生长发育的影响

Effect of Bt protein on development of different strains of the cotton bollworm, Helicoverpa armigera (Hbner) and the parasitoid, Microplitis mediator (Haliday)

以棉铃虫Helicoverpaarmigera (H櫣ｂｎｅｒ)室内敏感品系和田间品系为寄主 ,研究了亚致死浓度的Bt杀虫蛋白对中红侧沟茧蜂Microplitismediator (Haliday)生长发育的影响。结果表明 :当寄主一直取食 ,或者在被寄生前 12小时开始取食含Bt杀虫蛋白浓度为 0 ,0 5 ,1 0 ,2 0 ,4 0 ,8 0 μg g的饲料时 ,与对照相比 ,中红侧沟茧蜂的卵_幼虫历期延长 ,茧重和成虫体重降低 ,成虫寿命缩短 ,但对茧期没有明显影响。Bt杀虫蛋白能有效抑制两个棉铃虫品系幼虫的生长 ,显著降低棉铃虫蛹重 ;当Bt蛋白浓度为 4 0 μg g时 ,显著降低棉铃虫化蛹率。用转双基因抗虫棉SGK32 1(表达Cry1A +CpTI蛋白 )饲喂两个棉铃虫品系初孵幼虫 ,室内品系的第 2、3、4和 5天校正死亡率分别为 4 8 5 %、87 8%、96 6 %和 95 8% ,显著高于田间品系 (30 9%、5 9 6 %、80 9%及 86 1% )。本研究表明 ,不论是田间品系还是室内品系 ,棉铃虫取食含Bt杀虫蛋白的饲料后 。

Two strains of the cotton bollworm, Helicoverpa armigera (Hübner), one is a susceptible laboratory strain and the other is collected from Bt cotton fields, were used as the insect hosts to study the effect of Bt insecticidal protein on the development of the parasitoid, Microplitis mediator (Haliday). The results showed that the larval duration of the parasitoid was delayed, and the pupal weight, body weight of the newly emerged adult and adult longevity decreased significantly when the hosts larvae fed on diet containing Bt protoxin Cry1Ac at the concentrations of 0.5-8.0 μg/g in all time or from 12 h before parasitism till pupation of the parasitoid . Compared with the control, the larval weight and pupal weight of H. armigera decreased significantly when the larvae fed on diet containing cry1Ac. Pupation rate of H. armigera decreased significantly in the treatment with diet containing Cry1Ac at 4.0 μg/g. When H. armigera larvae fed on the transgenic cotton leaves expressing both Cry1A and CpTI proteins, the mortality of the laboratory strain was 48.5%-95.8% in 2-5 days after treatment, which was significantly higher than that of the field strain (30.9%-86.1%). It is concluded that feeding on diet containing Bt insecticidal protein, both strains of the cotton bollworm will have significantly negative effects on development of the parasitoid, M.mediator.