Safety Assessment Of Cry1C Protein On Habrobracon Hebtor

Transgenic Bt insect-resistant plants are highly resistant to most lepidopteran pests.However,Bt insecticidal proteins may be transmitted to their natural enemies by parasitism to the host.After lepidoptera hosts feed transgenic Bt insect-resistant crops,those growth and development are usually significantly adversely affected,and then it will result in "quasi-prey quality-mediated effect",that is,the bad developmental condition of hosts have the negative impact on the growth of its natural enemy,Therefore,it is very difficult to accurately evaluate potential risk assessment of exogenous insecticidal protein on its natural enemies by directly parasizing(or preying)the host.In this study,we choose Lepidoptera stockpile pest Indian meal moth(Plodia interpunctella)and its parasitic natural enemy wheat moths parasites(Habrobracon hebetor)as the research objects.Bt protein was injected microscopically into hemolymph of Indian meal moth mature larvae,and these larva were used as Bt protein carriers to rear the parasite.Using this method,we developped a new Tier-1 risk assessment system for parasitoid and succussfuly avoided "quasi-prey quality-mediated effect".The results were as follows:(1)The content of Cry1 C protein in the hemolymph of Indian meal moth mature larvae decreased rapidly at the beginning and slowly later after the injection.At the 0h after the injection,the content of Cry1 C protein in the hemolymph collected at the end of abdominal segment was higher than ones at the head,however,there were not any different between these two treatments beyond 0.5h after injection.The dynamics of Cry1 C protein in the hemolymph of Indian meal moth mature larvae parasited or not parasited by wasp had the significant difference during 7 days' observation.In the parasited larva,the content of Cry1 C protein almost didn't changed during 7 days,and it was all more than 10 times of 1.72 ng/g which is the dose in the hemolymph of larva fed by T1C-19 rice grain.Meanwhile,the results of the bioassay indicate indicated that the injected Cry1 C protein had its bioactivity.In the non-parasited larva,the content of Cry1 C protein decreased quickly by time.(2)The injected Cry1 C have no any negative impact on H.hebetoron's egg hatching rate,the development duration,weight of pupa,sex ratio,adults weight(male and female),adult longevity,survival curvea and reproduction.For the positive control(the injected GNA)show significant negative impact H.hebetoron's egghatching rate,adults weight(male and female),adult longevity,survival curvea and reproduction.(3)Cry1C protein could transfer into the parasitoid by Indian meal moth mature larvae.Cry1 C protein could accumulate in larvae of H.hebetor,and reach the highest in mature larvae;the content of Cry1 C in H.hebetor pupa,female and male lower than one in H.hebetor larve and mature larvae.Besides,the content of Cry1 C in H.hebetor each development stage significantly lower than one in the hemolymph of Indian meal moth mature larvae.However,the content of Cry1 C in H.hebetor adults could not be detected by ELISA method.