The Transmission And Location Of Cry1A Protein In The Food Chain From Transgenic Cotton To Pests Resistant Helicoverpa Armigera And Its Natural Enemy Microplitis Mediator Haliday

Transgenic Bt cotton have obviously lethiferous effect on the target insects.The quantity and the quality of the target insects may directly affect the quantity and the quality of natural enemy, and furthermore have influence on the tritrophic structure of the food chain/web—Plant-Pest-Natural enemy.This paper figured out the motivity and accumulation of CrylA protein between the parasitoid and its host insect in the food chain: transgenic crylA cotton/CrylAc protein diet-Resistant Helicoverpa armigera- Microplitis mediator Haliday by using the method of ELISA and immunocytochemistry techniques. At the same time, the biological effects of CrylAc protein on the parasitoid, Microplitis mediator Haliday and the location of the CrylAc protein in different organs were studied. This study provided the evidence for the assessment of the genetically modified crops (GMCs).The main results were as follows:Prokaryotic expression vector pGEX/cry1Ac-GFP was constructed, and the 114kD green fluorescent protein was expressed.When fed on the leaves of transgenic cotton Nuctn 33B carrying cry1Ac gone and transgenic cotton sGk321 carrying cryAc+CpTI, the growth of Helicoverpa armigera was inhibited. The parasitoid offspring developed more slowly, pupal rate and the adult longevity reduced when the parasitized host larvae fed on the Bt cotton leaves compared with those for the non-Bt treatment. At the same time, there were prominent difference in offspring development, pupal weight, pupal rate and adult longevity between the two treatments of transgenic cotton. The adult longevity of the parasitoid was reduced when the parasitized host larvae fed on diet containing 4ug/g CrylAc protein. The parasitoid offspring developed more slowly, pupal rate and pupal weight reduced, adult longevity, adult eclosion rate and adult weight also reduced when the parasitized host larvae fed on diet containing 40ug/g Cry1Ac protein.The trace Cry1Ac protein was detected in the five larve instars from the four treatments: 33B cotton diet, sGk321 diet, 20.0 Cry lAc protein dietcontaining 4ug/g Cry1Ac protein and Cry1Ac protein diet containing 40ug/g Cry1Ac protein. The great mass of Cry1Ac protein was excreted. There were trace Cry1Ac protein in the mid gut and mid gut content of the 5^th stage of resistant H. armigera. The concentration of Cry1Ac protein in bloodlymph of the 5^th stage of resistant H. armigera fed on 33B cotton leaves and Cry1Ac diet were: fresh weight 10.52±0.39ng/g and13.86±1.12ng/g respectively. The concentration of Cry1Ac protein in mature larvae of the parasitoid when the parasitized host larvae fed on the 33B cotton leaves and Cry1Ac diet were: fresh weight 10.46±0.53ng/g and 10.52±0.68ng/g respectively. The concentration of total dissoluble protein in the larvae of H. armigera were measured. The result indicated that the concentration of total dissoluble protein of the Cry1Ac protein diet was less than th the non-Cry1Ac protein diet. The Cry1Ac protein in propotion to the total dissoluble protein was different between the 33B line and sGK321 line. The Cry1Ac protein in propotion to the total dissoluble protein was similiar between the two Cry1Ac protein diets, and the ratio decreased from the fast instar to the fifth instar. The binding site of the Cry1Ac protein in the H. armigera was Brush Border Membrane Vesicles (BBMV) in the mid gut.This study provides the basis for searching after the transmission and the location of the thransgenic protein in the tritrophic interactions, and provides support for the effect of transgenic cotton on the insect food chain/food web.