전 세계적으로 RNA 간섭(RNA interference, RNAi)을 활용한 해충방제제 연구가 활발히 진행되고 있다. 대표적 으로 Monsanto의 서부 옥수수 뿌리벌레(Diabrotica virgifera virgifera) 특이적 방제용 dsRNA (DvSNF7)를 발현하 는 옥수수 종자가 상용화 되었고, 2016년 이 종자가 국내 사료 및 식품용으로 수입이 승인 되었다. 본 연구는 국내 에 서식하는 좁은가슴잎벌레(Phaedon brassicae)를 Non-target 곤충으로 사용하여, 옥수수 종자에 사용된 DvSNF7 dsRNA의 잠재적 위해성을 평가했다. P. brassicae의 SNF7 유전자와 DvSNF7 dsRNA 간 Sequence유사성 을 확인했다. 다음으로 P. brassicae가 DvSNF7 dsRNA를 섭식할 수 있는 환경을 조성하여, 치사 효과 실험과 Sequence특이적인 Knockdown효과를 확인하였다. 그 결과, DvSNF7 dsRNA는 P. brassicae생존에 영향을 미치지 않았으며, P. brassicae의 SNF7유전자를 Knockdown시키지 않음을 확인했다. 이번 연구를 통해 D. virgifera virgifera와 같은 과인 P. brassicae 는 SNF7유전자 간 Sequence유사성이 있지만, Sequence특이성이 부족하여 생존과 유전자 발현에 영향을 주지 않음으로써 위해성이 낮음을 확인했다.
The impact of transgenic Bt maize plant contained Cry1F was evaluated on the oat aphid Rhopalosiphum padi as a non-target insect species. Slightly reduced rates of survival and alata vivipar production were observed on Bt maize than on the non-Bt maize. In addition, slightly low preference to Bt maize plant was observed. Aphid fecundity, measured as the number of offspring produced for 7 days, was higher on Bt maize than on non-Bt maize but not different significantly. ELISA test using Cry1F-antibody revealed that 26% of Cry1F protein compared to the positive control was detected from the whole body of R. padi when the insects were fed Bt maize for 50 days, showing that R. padi can carry Cry1F protein to the higher trophic level when exposed to Bt maize. Taken together, the Bt maize plant is not likely to cause any negative side impacts on non-target insect R. padi but Bt toxin can be transferred to higher predators via R. padi as it carries the toxin.
Large amounts of genetically modified (GM) grains, including maize, cotton and soybean, have been imported to Korea for food, feed and processing (FFP). To evaluatethe environmental impacts, particularly on non-target insects, of FFP GM grains of unknown source, it is a prerequisite to identify Cry protein types in the test GM grains and to establish proper risk assessment protocols. Imported GM maize grains were randomly obtained and their Cry toxins were analyzed by ELISA using Cry1A, Cry1F, and Cry3A antibodies. Since all tested GM maize grains contained Cry1A, Tenebrio molitor, a non-lepidopteran species, was selected as a non-target insect species. A domestic maize strain was used as a non-GM control, which did not show any differences in major nutritional composition from the GM maize grain. Slightly increased survival rate and head capsule width of T. molitor larvae were observed when reared on GM maize powder, demonstrating no sub-chronic adverse effects of GM maize on T. molitor larvae. Head capsule width of T. molitor neonate increased steadily from hatch to 70-day-old, regardless of being fed Bt or non-Bt maize. ELISA test using Cry1A-antibody revealed that concentration of Cry1A protein slowly increased in the whole body of T. molitor from 0 to 50 post-feeding days when the insects were fed GM maize but rapidly decreased within 5 days when Bt maize-fed larvae were transferred to non-Bt maize, showing that the Cry toxin is not accumulated inside the body of T. molitor once the exposure source is removed. In addition, no Cry protein was detected in the hemolymph of the larvae reared on Bt maize, suggesting little possibility of Cry toxin exposure to higher tropic level. Taken together, the imported GM-maize grains is not likely to cause any side impacts on non-target insect T. molitor.