关键词: 棉铃虫, Vip3Aa, Cry1Ac, 中肠组织, 病理变化

Abstract: The pathological changes in midgut tissues of larvae of the cotton bollworm, Helicoverpa armigera (Hübner), 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 Cry1Ac. 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 Cry1Ac, however, appeared at 2 h after Cry1Ac treatment. This study may enrich the theoretical basis for better using Vip3Aa as new toxin strategy in IPM of the cotton bollworm.

Key words: Helicoverpa armigera, Vip3Aa, Cry1Ac, midgut tissues, pathological changes