转Bt基因抗虫玉米根茬和根际土壤中Cry1Ab杀虫蛋白的田间降解动态

Degradation Dynamics of Cry1Ab Insecticidal Protein Within Transgenic Bacillus thuringiensis Corn Root Debris and Rhizosphere Soil in Field

【目的】研究转cry1Ab杀虫蛋白基因玉米收获后玉米根茬及其根际土壤中Cry1Ab杀虫蛋白的降解动态,比较两种Bt玉米根茬和根际土壤中Cry1Ab杀虫蛋白的降解速度。【方法】以两种表达Cry1Ab杀虫蛋白的Bt抗虫玉米MON810和Bt11为材料,采用ELISA方法测定玉米收获后根茬残体和根际土壤中Cry1Ab杀虫蛋白的田间降解动态。【结果】转Bt基因玉米根茬残体和根际土壤中杀虫蛋白是逐渐降解的,Bt玉米MON810根茬中Cry1Ab杀虫蛋白含量较高,降解的速度也较慢,收获后8个月时还不能完全降解;Bt玉米Bt11根茬中Cry1Ab杀虫蛋白含量较低,降解速度比MON810根茬中Cry1Ab杀虫蛋白降解速度快,到7个月时已检测不到Cry1Ab杀虫蛋白。Bt玉米MON810根际土壤中Cry1Ab杀虫蛋白的降解较Bt11的慢,MON810和Bt11根际土壤分别在8个月和7个月时检测不到Cry1Ab杀虫蛋白。【结论】种植过Bt11和MON810抗虫玉米的田块,在第二年春播农作物已经出土时,其根茬和根际土壤中残留的Cry1Ab杀虫蛋白尚不能完全降解,还有少量残留。

【Objective】 The field degradation dynamics of Cry1Ab insecticidal protein in transgenic Bacillus thuringiensis corn in the root debris and rhizosphere soil of corn of events MON810 and Bt11 at harvest stage were investigated and compared.【Method】 The levels of Cry1Ab protein expression in root debris and rhizosphere soil of the two transgenic Bt corns of events MON810 and Bt11were quantified by using enzyme-linked immunosorbent essay（ELISA）.【Result】 It was showed that the Cry1Ab toxin in Bt corn root debris and rhizosphere soil were gradually degraded.The content of Cry1Ab insecticidal protein in corn root debris of MON810 was higher than that of Bt11,the degradation speed was slower compared with that of Bt11.The Cry1Ab insecticidal protein in root debris could not degrade completely in 8 months after harvest.No Cry1Ab insecticidal protein was detected in root debris of Bt11 in 7 months after harvest.Degradation of Cry1Ab insecticidal protein in rhizosphere soil of event MON810 was slower than that of event Bt11,no Cry1Ab insecticidal protein was detected in the rhizosphere soil of events MON810 and Bt11 in 8 months and 7 months after harvest,respectively.【Conclusion】 The Cry1Ab insecticidal protein could not degrade completely,and some residues still remain in root debris and rhizosphere soil of events MON810 and Bt11 in the emerging stage of the spring crops in following year in field where the MON810 and Bt11 were planted.