Assessment of the Influence of Transgenic Cotton on Beneficial Soil Rhizosphere Microbes

Abstract

In this study the impact of Bt cotton has been accessed on the population of beneficial microbes in the rhizosphere of transgenic Bt cotton line (RCH-2 BG II) and its counterpart (a non-Bt cotton line). The Bacillus thuringiensis (Bt) proteins i.e., Cry1Ac and Cry2Ab were released from root exudates of Bt cotton (RCH-2 BG II) was confirmed by qualitative Enzyme-Linked Immunosorbent Assay (ELISA). Rhizosphere soil samples were collected in fifteen days interval i.e., 15, 30, 45 and 60 days after sowing (DAS). Azospirillum brasilense, Bacillus megaterium, Pseudomonas fluorescens population was more on 15th day in non Bt rhizosphere than Bt except Trichoderma viride, where as in 45th and 60th day all four microbes were more in Bt cotton (RCH-2 BG II) rhizosphere than its counterpart RCH-2. The statistical analysis of the data obtained from the pot cuture showed no significant differences in the numbers of CFU of Azospirillum brasilense, Bacillus megaterium (biofertilizer), Pseudomonas fluorescens and Trichoderma viride (biocontrol agents) between  rhizosphere soil of Bt and non-Bt cotton. Restriction enzyme analysis of 16S rRNA of Azospirillum brasilense, Bacillus megaterium (biofertilizer), Pseudomonas fluorescens and ITS region of Trichoderma viride obtained from Bt and non Bt cotton rhizosphere in different intervals showed similar banding pattern between them.