Microecological Risk Study On Transgenic Paulownia

Ceoropins is a kind of broadly antibacterial polypeptide excreted by insect, due to its actively antibacterial capacity, had been transfered into several kinds of plants which all showed the antibacterial capacity .transgenic Paulownia had been acquired in Wuhan Institute of Virology(WHIOV) China Academic of Sciences(CAS) ,which showed the active antibacteria capacity to Paulownia witches broom. The thesis focused on the microecological risk rtudy on transgenic Paulownia, which would provide enough information about microecological risk before transgenic Paulownia released ; it included designing methods and applying them on microecological risk study systemically. Five different methods were designed and used for DNA extraction from soil. All the methods were demonstrated to be able to generate DNA with more than 15 kb in size, although the yield of DNA varied from method to method. The extracted DNAs were used for PCR using primers corresponding to 16S rRNA gene and Shiva-1 gene, respectively.Method 5 is more suitable for DNA extraction from a small amount of soil sample as it produce a good yield of DNA in high integrity with reliable reproducibility. Additionally,a study was applied on analyses of bacteria classification relationship by PCR-DGGE, a method combining PCR and denture gradient gel electrophoresis. DGGE profiles of 16sRNA gene and rpo5 gene fragments from eight bacterium strains reflected their classification relationship; these data were also consistent with the homologous analyses of 16S rRNA gene sequences. Findings in the current study indicate that PCR- DGGE is a straight forward and efficient strategy to determine the relationship between bacteria.Meanwhile, evaluating the potential influence on culturable bacteria by transgenic paulownia. and the possible effects on rhizophere bacterium community caused by transgenic paulownia were proceeded .The dominant bacterium communities from the soil of transgenic and none transgenic paulownia were collected, cultured and identified. Both bacterium communities were composed of bacteria belonging to bacillus and pseudomonas sp group. Following one-year observation, no significant difference was found between transgenic and non-transgenic paulownia in terms of bacterium numbers. It alo included a study on the influence of transgenic paulownia on two agriculturalbacteria: Bacillus thringiensis and Sinohizobium melilot. After half year, the bacteria were collected from soils and quantified. Although the absolute numbers of these two bacteria largely decreased, no significant difference was found between transgenicand non-transgenic paulownia- growing soils in terms of bacterium killing. In year one, rhizophere bacteria were collected from transgenic paulownia- and none transgenic paulowni- growing soils. Total DNAs were extracted for PCR to amplify 16S rRNA and rpo5 gene, and subsequently analyzed by DGGE. No significant difference was found between rhizophere bacteria isolated from transgenic paulownia and none transgenic paulowni growing soils.