种植Bt水稻后的土壤对赤子爱胜蚓生长发育及酶活性的影响

Effect of soil planted with Bt rice on the development and enzyme activities of Eisenia foetida

【背景】转基因作物种植的安全问题一直备受关注。关于Bt蛋白对地下非靶标生物影响的研究是转基因作物安全评价的重要内容。【方法】在转Bt基因水稻收割后的稻田里分别种植豌豆、紫云英和油菜作为后茬作物。分别于2013年1、3和6月3次采集不同后茬作物田中的土壤作为材料,于室内饲养赤子爱胜蚓,4周和7周后,测定蚯蚓的生长发育指标、存活率以及体内酶活性的变化情况。此外,还测定了不同深度土壤中Bt蛋白的含量以及用Bt蛋白直接饲喂的赤子爱胜蚓的存活率。【结果】与种植过非转基因水稻MH63的土壤相比,分别种植过含cry2A和cry1C基因水稻后的土壤对赤子爱胜蚓的生长发育、存活率及体内酶活性无显著影响。1月份和3月份转cry2A基因水稻田以及1月份转cry1C基因水稻田采集的表层土样中的Bt蛋白含量显著高于地下10 cm和地下20 cm土壤中的含量,地下2层土样中的Cry2A蛋白含量之间无差异。3月份转cry1C基因水稻田以及6月份转cry2A和转cry1C基因水稻田的土壤中Bt蛋白的含量均不受土壤深度的影响。种植的后茬作物对土壤中的Bt蛋白无显著消解作用。室内模拟土壤最高Bt蛋白浓度的条件下,Cry2A蛋白处理的蚯蚓存活率为96.7%,Cry1C蛋白处理的蚯蚓存活率为95.0%,两者与对照相比无显著差异。【结论与意义】转cry2A和cry1C基因Bt水稻的种植对蚯蚓的生长发育和体内酶活性无显著影响。本研究为转基因水稻的安全评价提供了一定的依据。

[Background] The safety associated with planting transgenic crops remains a concern for the public. Study on the effect of Bt proteins on the underground non-target organisms is an important part for the safety evaluation of transgenic crops.[Method] In this study, pea, alfalfa, and rape were planted as after-reap crops in the experimental field, where transgenic Bt rice was previously grown. In the field, soil samples were collected in January, March, and June of 2013 and used to cultivate Eisenia foetida in labora-tory conditions. At weeks 4 and 7, we determined the development and enzymatic activities of E.foetida. The contents of Bt protein in soil samples at different depths were determined and the survival rate of E. foetida feeding with Bt protein directly was evaluated.[Result] The soil samples collected from the plotd planted with transgenic Bt rice T1C-19 and T2A-1 had no significant effects on the development, survival rate and enzymatic activities of E.foetida compared with soil samples collected from plots planted with the non-transgenic Bt rice MH63. Samples of the surface soil showed significantly higher levels of Cry2A protein in in January and March and of Cry1C protein in January than soil collected in deeper. There were no significant differences in the amounts of Cry2A Bt pro-tein in 10 cm and 20 cm as well as soils collected from T1C-19 plot in March and June and T2A-1 plot in June. Dynamics of Bt pro-tein were not affected by the after-reap crop in this study. The survival rates of E.foetida directly fed with Cry2A and Cry1C proteins were 96.7% and 95.0%, and did not significantly differ from the control. [Conclusion and significance] Our results indicated that＆amp;nbsp;the planting of transgenic cry2A and cry1C Bt rice had no significant difference on the development and enzyme activities of E.foeti-da. Our study provides some basic protocol for evaluating the safety of transgenic rice.