棉铃虫中肠钙粘蛋白、氨肽酶N及碱性磷酸酯酶的抗血清对Cry1Ac和Cry2Aa毒力的影响

【目的】Cry1A和Cry2A类Bt蛋白通过特异性地与昆虫中肠上的受体蛋白结合而发挥杀虫作用,现已广泛应用于转基因抗虫作物。本研究旨在进一步明确Cry2A类蛋白的作用机制和Cry1A受体蛋白在Cry2A发挥毒力中的作用。【方法】本研究首先提取了棉铃虫Helicoverpa armigera的BBMV,制备了钙粘蛋白(CAD)、氨肽酶N(APN)和碱性磷酸酯酶(ALP)3种受体蛋白的抗体和抗血清;然后,利用Western blot检测BBMV上这3种受体蛋白后,利用抗体封闭技术比较了敏感棉铃虫和Cry1Ac抗性棉铃虫(BtR)中3种受体蛋白的抗血清对Cry1Ac和Cry2Aa毒力的影响。【结果】对敏感品系棉铃虫,这3种已知的Cry1Ac受体蛋白抗血清显著地降低了Cry1Ac和Cry2Aa的毒力。其中APN抗血清对Cry1Ac毒力的影响最大,棉铃虫幼虫的死亡率降低了84.44%;ALP抗血清对Cry2Aa的毒力影响最大,棉铃虫幼虫死亡率比对照降低了71.04%。Cry1Ac对Cry1Ac抗性棉铃虫(BtR)的毒力显著降低,Cry2Aa的毒性也减弱。在Cry1Ac抗性棉铃虫(BtR)中,3种受体抗血清对Cry1Ac的影响比在敏感棉铃虫中的影响小,尤其是CAD和APN抗血清对Cry1Ac毒力的抑制率显著低于在敏感棉铃虫中的抑制作用;CAD和ALP抗血清对Cry2Aa毒力的影响与在敏感棉铃虫中的影响差异不显著,但APN抗血清可以显著降低Cry2Aa对Cry1Ac抗性棉铃虫(BtR)的毒力。【结论】棉铃虫CAD,APN和ALP不仅参与了Cry1Ac的杀虫过程,也对Cry2Aa毒力有一定的影响,而且这3种蛋白可能与棉铃虫对Cry1Ac和Cry2Aa产生抗性及交互抗性相关。

Effects of antiserums of cadherin,aminopeptidase N and alkaline phosphatase on the toxicities of Cry1Ac and Cry2Aa in Helicoverpa armigera (Lepidoptera: Noctuidae)

[Aim] Cry1A and Cry2A toxins play insecticidal roles by specifically binding with receptor proteins on insect midgut,and are widely used in Bt transgenic crops now.This study aims to further understand the action mechanisms of Cry2A and the roles of the functional receptor proteins of Cry1 A in the toxicity of Cry2A.[Methods] We firstly extracted brush border membrane vesicles (BBMV) of midgut,prepared antibody and antiserums of cadherin (CAD),aminopeptidase N (APN),and alkaline phosphatase (ALP) in Helicoverpa armigera.Then,after detecting the antiserums of these three receptor proteins in BBMV by Western blot,we compared the effects of antiserums of these three receptor proteins on the toxicities of Cry1Ac and Cry2Aa in the susceptible and Cry1Ac-resistant H.armigera (BtR) by the antibody blocking technology.[Results] For the susceptible H.armigera,the antiserums of these three receptor proteins not only significantly reduced the toxicity of Cry1 Ac,but also remarkably reduced the toxicity of Cry2Aa.Among them,anti-APN antiserum had the biggest impact on the toxicity of Cry1Ac,causing the mortality of H.armigera larvae to be reduced by 84.44％,and anti-ALP antiserum had the greatest effect on the toxicity of Cry2Aa,causing the larval mortality to be reduced by 71.04％ compared with the control (without treatment by antiserum).The toxicity of Cry1Ac to Cry1Ac-resistant H.armigera (BtR) was obviously reduced and the toxicity of Cry2Aa also became less to these resistant larvae.The influences of the antiserums of these three receptors on the toxicity of Cry1Ac to the Cry1Acresistant strain of H.armigera (BtR) were smaller than those to the susceptible strain.Especially,the inhibition percentage of anti-CAD and-APN antiserums to the toxicity of Cry1 Ac decreased significantly.The effects of anti-CAD and-ALP antiserums on the toxicity of Cry2Aa to the Cry1Ac-resistant strain (BtR) and the susceptible strain were not significantly different,but the anti-APN antiserum obviously reduced the toxicity of Cry2Aa to the Cry1Ac-resistant strain (BtR).[Conclusion] The midgut receptor proteins CAD,APN and ALP not only participate in the insecticidal process of Cry1Ac,but also affect the toxicity of Cry2Aa to H.armigera,and these three receptors may be related with the resistance and cross-resistance to Cry1Ac and Cry2Aa in H.armigera.