Effects Of Bt Transgenic Cotton On Several Important Enzymes And Proteins Of Bemisia Tabaci (Gennadius)

With three Bt transgenic cotton cultivars (GK12, XM33B, and SGK321) and their non-transgenic conventional cotton cultivars (SM3,33, and SY321) as experimental materials, this study was conducted to investigate (1) protective enzymes and detoxifying enzymes activities change on the Bemisia tabaci(Gennadius) after feeding the Bt transgenic cotton;(2) midgut proteases and immune related enzymes activities change on B.tabaci after feeding the Bt transgenic cotton;(3) Bt toxic protein accumulation and eliminate on B.tabaci after feeding the Bt transgenic cotton;(4) the related protein features change on B.tabaci after feeding the Bt transgenic cotton. The main results were as follows:1. The Bt transgenic cotton had a significant effect to protective enzymes and detoxifying enzymes on B.tabaci. Compared with the B.tabaci which fed on the non-transgenic conventional otton cultivars (control), the activity of Superoxide Dismutase (SOD) on the B.tabaci which fed on transgenic cottons were significantly inhibited, with the extension of feeding time, the activities of SOD decline gradually till8h then kept in the stable state; but the activities of catalase (CAT) and peroxidase (POD) were significantly improved. The activities of Glutathione S-transferases (GSTs) and Acetylcholinesterase (AChE) were significantly inhibited compared with the control; the activity of Carboxylesterase (CarE) was significantly improved.2. The Bt transgenic cotton had a significant effect to midgut proteases and immune related enzymes. Compared with control, the activities of total protease, alkaline trypsin-like enzyme and chymotrypsin-like enzyme were significantly improved; the activities of phenoloxidase and lysozyme were significantly improved.3. The Bt toxic protein can be detected after B.tabaci fed on the Bt transgenic cotton. All the B.tabaci fed on3different transgenic cottons can detect the existence of Bt toxic protein after feeding8h, with the extension of feeding time, the content of Bt toxic protein increased gradually. The Bt toxic protein content of B.tabaci fed on GK12balanced after feeding48h, fed on XM33B and SGK321balanced after feeding24h. Through the reverse test we found that the content of Bt toxic protein declined gradually when the B.tabaci stopped feeding the Bt transgenic cotton. The Bt toxic protein in B.tabaci fed on SM3cannot detect after48h, and the B.tabaci fed on33and SY321cannot detect after36h.4. Study the protein change in B.tabaci which fed on the transgenic cotton through the two-dimensional electrophoresis, mass spectrometry. The result shows that, compared with the control, the B.tabaci fed on GK12could increase the actin expression and tropomyosin expression. The B.tabaci fed on XM33B could increase the malate dehydrogenase and acidic ribosomal protein expression. The B.tabaci fed on SGK321could increase the fatty acid binding protein, triose phosphate isomerase and glyceraldehyde3-phosphate dehydrogenase expression.