Effects Of WYMV-Nib8 Gene On Soil Microbial Ecology And Main Enzyme Activities In Rhizosphere Soil

With the development and widely application of biotechnology in nowadays, the transgenic technology has become one of the most important methods in crop breeding. With the increasing commercial cultivation area of genetically modified crops in recent years, its potential ecological security problems brought more and more concerns and discussion. Therefore, a scientific and reliable detection system is necessary for the safety evaluation of genetically modified crops.The transgenic wheat line N12-1 containing the previously developed WYMV-Nib8 gene can effectively control the wheat yellow mosaic virus (WYMV) disease. Transgenic N12-1 wheat, its parent Yangmai 158 and natural control Ningmai 9 were used in our study. N12-1 and Yangmai 158 were sowed in Luhe experimental station for transgenic crop, Jiangsu Academy of Agricultural Sciences (Luhe), in October 2013. In order to more effectively explain whether it has significantly effect, N12-1, Yangmai 158 and Ningmai 9 were sowed in Yangzhou transgenic wheat planting base (Yangzhou) at the same time. Rhizosphere soil was sampled at its six growth stages (sowing, seeding, jointing, heading, filling and mature). And the diversity of microbial communities, amount of main microbe and enzyme activity in rhizosphere soil of transgenic wheat N12-1 and the nontransgenic wheats were investigated in our study. The results are as follows:Polymerase chain reaction-denaturing gel gradient electrophoresis (PCR-DGGE) was used in this study to analyze the effect of transgenic wheat N12-1 on bacterial and fungal community diversity in rhizosphere soil. The results from comparisons using Shannon’s diversity index and an evenness index showed a significant difference in bacterial and fungal diversity in the rhizosphere soil of transgenic wheat N12-1 and the nontransgenic wheats among growth stages at both Luhe and Yangzhou. Howere, little difference was observed between N12-1 and the nontransgenic wheat.The amounts of Pseudomonas fluorescens, Fusarium graminearum and Polymyxa graminis were determined by Quantitive Real-Time PCR. The result shows that there was significant difference in the rhizosphere soil of transgenic wheat N12-1 and the nontransgenic wheats between growth stages. However, it is no significant difference between transgenic wheat N12-1 and the nontransgenic wheat.The activities of dehydrogenase, urease and sucrose in rhizosphere soil were investigated by triphenyltetrazolium chloride (TTC), phenol sodium hypochlorite colorimetry, and 3,5-dinitrosalicylic acid (DNS) colorimetry, respectively. The results showed there are some differences during the growth periods. And no significant differences were observed between N12-1 and the nontransgenic wheat at both Luhe and Yangzhou.The results of this study suggested that the transgenic wheat N12-1, which were sowed in October 2013, had no adverse impact on microbial community diversity and enzyme activity in rhizosphere soil at two different experimental locations. The study provided the basic data and technical foundation for the safety evaluation of the transgenic wheat N12-1 on soil ecosystem.