The pathological changes in midgut tissues of larvae of the cotton bollworm, Helicoverpa armigera (H(u)bner) , fed on artificial diet containing Vip3Aa protein were observed using transmission electron microscope, and the changes induced by Cry1Ac were also investigated in order to ascertain the action mechanism of Vip3Aa. The results showed that the goblet cells changed gradually after H. armigera larvae fed on artificial diet containing Vip3Aa protein, and the major symptoms included: microvilli swelled and dropped off, the boundaries of karyotheca in cell nucleus blurred and the chromatins unevenly distributed, the numbers of mitochondria and endoplasmic reticulum reduced, the inner cristae of mitochondria blurred, and the endoplasmic reticulum mixed disorderly. The pathological changes of goblet cells in the midgut of H. armigera larvae induced by Vip3Aa were slower than that by CrylAc. The obvious pathological changes were detected at 12 h after feeding Vip3Aa, and the pathological changes became more and more evident with extension of feeding time. The obvious pathological changes of H. armigera induced by CrylAc, however, appeared at 2 h after CrylAc treatment. This study may enrich the theoretical basis for better using Vip3Aa as new toxin strategy in IPM of the cotton bollworm.%为了进一步明确Vip3Aa的作用机制,利用透射电镜观察了棉铃虫4龄幼虫取食含Vip3Aa蛋白饲料后中肠杯状细胞的病理变化,并比较了其病变与取食含Cry1Ac饲料后棉铃虫组织病变的差异.取食含Vip3Aa饲料后,棉铃虫幼虫的中肠杯状细胞逐渐发生病变,主要表现为:微绒毛肿胀、脱落；细胞核核膜界限不清晰,染色质分布不均匀；线粒体变形、数量减少,内脊不清晰；内质网杂乱不规则、数量减少.与取食Cry1 Ac的棉铃虫相比,取食Vip3Aa的棉铃虫中肠杯状细胞发生病变较为缓慢,在取食12 h后才发现明显病变,随着取食时间的增加病变越来越明显；而取食Cry1 Ac的棉铃虫2h后中肠杯状细胞就出现明显病变.本研究可为Vip3Aa作为新毒素策略的重要蛋白在棉铃虫Helicoverpa armigera综合防治中更好地发挥作用提供理论依据.
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