The Studies On The Impaction Of Transgenic Cotton To Rhizosphere Soil Micoorganism

In recent years, with the generalize and ampliative growing area of transgenic cotton, the important social and economic benefits have being appeared, it is developing rapidly. At the same time, it bring negative impact which have arisen the concerns of scientists around the world. Thus, it is necessary that transgenic cotton must be assessed on ecological safety before the stages of trial and commercialization. Soil microorganism is an important component of soil, the ecological safety assessment that transgenic cotton impact soil microorganism communities which is an important element of the evaluation. Because of the special nature of soil microorganism, there are some difficulties in research methods in recent years, molecular biology techniques have provided new powerful tools for the soil microorganism study. The soil microorganism research of root system for transgenic cotton has important theoretical and practical significance.In addition, Verticillium dahliae and Fusarium oxysponmf.sp.cubense are serious harmful to cotton production, a large number of unreasonable use of chemical pesticides in the traditional plant protection impact the environment and human,which is not consistent with the requirements of sustainable agricultural development, and biological prevention approach with the characteristics of security, economic and non-pollution the environment has provided a new hope and technological base for sustainable agricultural development strategy. Preventing microbial applications is one of the important means for biological prevention,the selection and application of antagonistic microbes has played an important role in agricultural production.The main researchs of the paper include total DNA in soil microorganism PCR-DGGE testing technology, screened antagonistic microbes against Verticillium dahliae and Fusarium oxysponmf.sp.cubense of cotton and tested their antagonistic activity.1. Total DNA extraction from soil microorganism has been acquired, the DNA can be good for the overall PCR-DGGE technology.2.PCR method was optimized,it show that, the finial concentration of PCR system was 2.5³mmol/L dNTP,0.2μmol/L primer,2².5μmol/ Mg²⁺ L,2.5U/μL Taq E,the result is best. The denaturants concentration change from 35%⁵5% in (DGGE) method agent concentration, there are the best separate result, the soil microorganism in transgenic cotton is less than ordinary cotton soil microorganism, the conclusions added new contents for the safety evaluation of transgenic cotton.3. 41 strains antagonistic microbes selected from the soil of transgenic cotton and ordinary cotton which include 34 strains are against cotton Verticillium dahliae, and 7 stains are against cotton Fusarium oxysponmf.sp.cubense. The 27 strains antagonistic microbes selected from transgenic cotton soil account for 66% of the total bacteria.4. Selected 6 strains antagonistic microbes which has bigger inhibition radius test their inhibition activity,3 strains show good activity.