The Impacts Of Bt-cotton On Rhizosphere Microorganism Diversity

Bt cotton is one of the most widely planted transgenic plants in the world, the impacts of the release of transgenic plant on the environment has been a hot issue to the public. In this study, the Bt-transgenic cotton, Zhongmiansuo30, a Bt-cotton developed by the Institute of Cotton, CAAS and Zhongmiansuo16, its parental non-Bt -cotton were used to study the impacts of Bt-cotton on rhizosphere microorganism diversity in greenhouse.There are mainly three parts in this study:First, The total protein and the Bt protein of the cotton were determined by using method of ELISA .The results showed that the total protein content increased from the period of 2 leaves to 5 leaves, and then decreases gradually whereafter; There is no statistic difference of total protein content between groups of different growth density; the dynamic of BT protein content was coincident with that of total protein content. As for the ratio of BT protein to total protein , there was no statistic difference between the groups in the stage of 2 leaves,, but the ratio of high growth density was much higher then that of the low growth density, especially in the season of 7 leaves.Secondly, the spatial and temporal variation of the physiological function of the soil microbial community during different period was analyzed by using the method of BIOLOG.According to the results of principle components analysis and hierarchical cluster analysis about the metabolic profiles of the microbial communities and compare means analysis about the AWCD value of the metabolic reaction of 31 carbon substrates, the metabolic ability of Bt-cotton rhizosphere soil microbial communities was higher significantly than that of non-Bt cotton soil microbial communities, However, the difference became smaller at the stage of 11 leaves.Thirdly, microbial genetic diversity was analyzed by using denaturing gradient gel electrophoresis profiles. Total soil microbial DNA was extracted, V3 region of 16sRNA gene was amplified, and then separated in the denaturing gradient gels, the denaturing gradient was from 25 % to 55 %. The results indicated: at the 2nd, 5th leave stages, a lot of microorganisms live in both rhizosphere soiland the numbers...