Study On Environmental Persistence Of Exogenous Protein Of Transgenic Cry1Ab/C Rice And Its Effects On The Hydrobiont

Great Progress has been made on the research of insect-resistant transgenic rice in China, two insect-resistant genetically engineered rice lines (Huahui-1and Bt-Shanyou-63) have been granted biosafety certificates by the China’s Ministry of Agriculture, But due to ecological safety concerns of genetically modified rice, it has not yet entered the stage of commercial cultivation. In this paper, we evaluated the ecological safety of transgenic crylAb/c rice by fluorescence quantitative PCR, ELIS A detection, as well as field tests.The following is the main research content and results:(A)Quantification of CrylAb/c protein and crylAb/c mRNA transcription in Transgenic Bt riceIn this study, we used enzyme-linked immunosorbent assay to analyze CrylAb/c protein levels in GM rice, the levels of expression of CrylAb/c protein changed over growth stages, the grain filling stage showed the highest level of expression of the δ-endotoxin (5.71μ.g/gfw) and lowest in brown rice seeds (2.08μg/gfw).SYBR Green real-time fluorescence quantitative method can efficiently be employed to quantify CrylAb/c protein expression levels in transgenic rice. Standard plasmid molecule, constructed by TA cloning technique, is used to established real-time fluorescence quantitative standard curves. The quantitative result shows that the target gene has expression in transgenic rice all growth period, and the grain filling stage has a bloom expression levels.(B)Bt protein residue within the water and soil in agriculture landscapeIn different growth stages of GM rice, We collected soil samples and water samples in paddy fields and2-100meters distance away from the paddy fields to detection Bt protein residues, Samples collected from transgenic rice experimental fields in Dezhou, Wuhan, Suizhou, Xiaogan and Wuxue. Research shows that Bt protein are widely distributed and persistent in transgenic rice fields and surrounding environment, and The rate of Bt-positive sites change with rice growth stages. The rate of Bt-positive samples in seeding was mild, 18(31%) of58samples had containing detectable Cry1Ab/c protein, and in flowering stage, it raised to69%. During the whole investigation period, Maximum residue levels of soil samples in Bt rice can reach1.054ng/g as well as0.306ng/L in water samples. For the rice fields outside samples, The mean concentration in water samples that were positive for Cry1Ab/c protein was0.16ng/L, with a maximum concentration of1.248ng/L, and the highest amount of residue in soil sample was1.045ng/g.(C)Evaluation of the toxicity of Bt transgenic rice with Daphnia magnaA lifespan experiment was conducted to evaluate the toxicity of Bt transgenic rice with D. magna. The results show that there are no significant differences in lifetime, body length, mortality, reproduction between D.magna fed with transgenic rice and those fed with conventional rice food. But both of rice food are different from Scenedesmus obliquus, D. magna fed rice food showed a significantly reduced fitness performance:The mortality was higher, body sizes, a lower proportion and more days (9vs15days)of females reached sexual maturation, and the overall egg production was lower compared to D. magna fed S. obliquus.(D)Effects of Bt transgenic rice on populations, species and community diversity of zooplanktonBy field survey of plankton, we analyzed the number and species of Protozoa, Rotifera, Cladocera and Cyclopoida in transgenic Bt rice field. Compared with non-transgenic rice field, there is no significant difference between the two rice paddy fields.Shannon-Wiener diversity index, Species richness, Simpson’s diversity index were used to analysis paddy zooplankton community diversity, Results shows that3years cultivation of transgenic insect-resistant rice has no significant effects on the composition and diversity of zooplankton community.