Effects Of Different Soil Conditions On The Degradation Of Bt Protenin

Using genetic engineering technology obtains transgenic Bt gene resistant maize,which effectively alleviates the harm caused by insect pests to crop production,and increased crop yield and reduced the use of chemical pesticides.However,the large-scale commercialization of Bt transgenic maize still has potential ecological risk,and the degradation dynamics of Bt protein in soil has also been widely concerned by scholars at home and abroad.Under indoor controlled conditions,an artificial climate box was used to simulate the state of the natural environment to conduct a 96-day experiment to investigate the degradation of Bt protein in soil.Using mG2-aroA and cry1 Ah transferred exogenous gene corn OG1161 as experimental materials,the effects of different temperature and humidity(simulate the relative water capacity of field soil)on the degradation of Cry1 Ah protein in the soil of 4 regions in Gongzhuling,Ji'nan,Beijing and Zhengzhou,and the effects of animals and microbes on the degradation of Cry1 Ah protein in the soil of Gongzhuling were studied.Using mG2-aroA and cry1 Ah transferred exogenous gene corn OG1161 as well as cry1 Ab and cp4-epsps transferred exogenous gene corn C0030.3.5 as experimental materials,the effects of soil on the degradation of two Bt proteins of Cry1 Ah and Cry1 Ab in 4 regions of Gongzhuling,Ji'nan,Beijing and Zhengzhou were studied respectively,and analyzing the degradation situation of two kinds of Bt protein in the same regional soil.It uses first-order kinetic model to match the half-life period that Bt protein degrades in soil and the 90% subduction period.The results of the research show as the follows:Under the circumstance of humidity and different temperature in the same field soil,Cry1 Ah protein are showing basically the same degradation trends in 4 regional soils.During the process of degradation,there is a protein accumulation on average.However,the accumulation time of 15? appears later than 35? and 25?.The accumulation time at 15 ? is 20 h,and the accumulation time at 25? and 35? is 16 h.With the increase of temperature,the half-life of Cry1 Ah protein in soil gradually decreased.The results show that the high temperature promotes Bt protein's degradation in soil.Under the circumstance of different humidity in field soil and same temperature,Cry1 Ah protein are showing basically the same degradation trends in 4 regional soils.There is a protein accumulation on average during the sampling stage.The half-life of Cry1 Ah protein in soil did not decrease with the increase of humidity.The optimum humidity in soil in 4 regions was different.The results showed that humidity had no significant effect on the degradation of Cry1 Ah protein in soil.Under the circumstance of temperature 35? and 50% humidity in field soil,the degradation trend of Cry1 Ah protein was basically consistent in situ soil,soil animal soil,soil animals and microbial soil.There was a protein accumulation phenomenon,with the accumulation time of 16 h.The experimental results show that the microorganism Bt insecticidal protein promotes the degradation in soil,but the soil animals impact a little on it.Under the circumstance of temperature 35? and 50% humidity in field soil,Cry1 Ah protein are showing significant different degradation trends in 4 kinds of soil treatments.The degradation trends of Cry1 Ah protein in Zhengzhou and Gongzhuling soil is extremely similar,the degradation trends 0-7d of soil in Beijing and Jinan region is obviously different,while the later period of degradation trend is extremely the same.The test results show that there was effect of different soil sources on the degradation of Cry1 Ah protein in soil.Under the circumstance of temperature 35? and 50% humidity in field soil,Cry1 Ab protein are showing basically the same degradation trends in 4 regions,but it still shows obvious difference in some same sampling time.The test results show that there was effect of different soil sources on the degradation of Cry1 Ab protein in soil.Two kinds of Bt protein have a certain difference on degradation trends in the same regional soil,the degradation trends of two Bt protein in Gongzhuling and Zhengzhou regional soil differs obviously,while it differs slightly in Beijing and Jinan regional soils.It shows that different Bt protein types affect the degradation of Bt protein in soil.In summary,the results of this study show that temperature,soil microorganism,soil source and Bt transgenic crop types all affect the degradation rate of Bt protein.Humidity and soil animals had no significant effect on the degradation rate of Bt protein in soil.This experiment can provide basic data for environmental safety assessment of transgenic maize.