Insect-resistant mechanism of transgenic triploid of Chinese white poplar

Abstract

The activities of antidotal enzymes and digestive enzymes of Clostera anachoreta (Fabricius) instar larvae, feeding on leaves of three kinds of insect-resistant clones of transgenic triploid of Chinese white poplar, after 4, 12, 24, 48, 72 and 96 h, were investigated. The results showed that, feeding on clone 7, the activity of esterase, carboxylesterase, and mixed-function oxidases in the midgut of the larvae was very much decreased. Feeding on clone 10, those results were less than those of clone 7 and there were few changes on the larvae, which fed on clone 26. The changes of the amylase in the midgut of larvae were the same as those described above. However, the activities of glutathione S-transferase and proteinase were complex, increased markedly after 24 h feeding on clone 7, and then declined rapidly. The same changes were taking place on the larvae feeding on clone 10. There were many slight changes in glutathione S-transferase of the larvae, feeding on clone 26; no changes occurred in the proteinases of the midgut. Thus, the antidotal enzymes and digestive enzymes in the midgut of the larvae were inhibited. This may be the main mechanism of the transgenic triploid of Chinese white poplar.