Abstract:

The larvae of Micromelalopha troglodyta were fed with leaves of transgenic poplars expressing Bt gene only and expressing Bt and CpTI genes,the activities of esterase in the midgut of larvae raised in the earlier stage,but restricted later.When the larvae were treated with leaves of transgenic poplars expressing Bt alone and expressing both genes respectively,the corresponding highest restrictive stage was 48,12 h,and the activities decreased by 15.8%,38.1%.The restrictive efficiency of the clone expressing both Bt and CpTI was superior to that expressing Bt alone.The restriction of the poplars with Bt gene to carboxylesterase in the midgut of larvae was not notable,but the plants with Bt and CpTI genes could restrain the activities of the Carboxyleterase significantly.When the larvae were fed with leaves of transgenic poplars expressing both genes for 24,36,48 h,the activities of carboxyleterase decreased by 33.4%,22.5%,29.6% respectively,which had a significant difference with CK.So it was shown that the transgenic poplars disturbed the insect regular metabolism mainly by restraining the activities of esterase and carboxyleterase in the midgut of larvae,then killed the pests.

Key words: transgenic poplars, Micromelalopha troglodyta, detoxification enzymes, esterase, carboxylesterase