No evidence of persistent effects of continuously planted transgenic insect-resistant cotton on soil microorganisms

Abstract

Transgenic insect-resistant cotton expressing the Cry1Ac and/or CpTI protein has been released into the environment for commercial cultivation for over a decade in China. In this consecutive 3-year field study (2007)(2008)(2009), we characterized the microbial populations in two different transgenic cotton fields and one non-transgenic cotton field to assess the environmental impact of long-term cultivation of transgenic insect-resistant plants in credible field conditions. We obtained samples at four different growth stages of cotton (seedling, budding, boll forming and boll opening). The results showed significant seasonal variation in the number of bacteria, fungi, azotobacter, denitrifying bacteria and ammonia-oxidizing bacteria and in diversity indices of microorganisms, but no significant difference in the number of each microbial population or diversity indices attributable to long-term cultivation of transgenic cotton.

Effect on Soil Properties ofBcWRKY1Transgenic Maize with Enhanced Salinity Tolerance

“…However, no overall consistent trends in physicochemical properties were detected in the two soil environments, over the three-year study, or in the four growth stages. This result is consistent with previous results in other plants and fields [32]. …”

“…However, no consistent trends in enzyme activity were detected in the two soil environments, over the three-year study, or in the four growth stages analyzed here. These results agree with those of previous studies in other regions and for a variety of crops [29–32]. …”

Salt tolerant SUV3 overexpressing transgenic rice plants conserve physicochemical properties and microbial communities of rhizosphere

“…The long-term cultivation of transgenic plants may or may not affect the diversity of soil microbial community (Li et al, 2011). The cultivation of transgenic maize and cotton has not shown any significant effect on rhizospheric properties as compared to wild type counterpart (Flores et al, 2005;Griffiths et al, 2006;Shen et al, 2006).…”

Populational survey of arthropods on transgenic common bean expressing therepgene fromBean golden mosaic virus

“…Priestley and Brownbridge 30 studied the impact of some Bt transgenic silage corn lines on non-target soil arthropods and reported that transgenic plants had no negative effect on any of the organisms analyzed, but there was a significant year effect on the abundance and diversity of some taxa. Li et al 31 studied the effect of Bt cotton continuously planted for many years on soil microorganisms in a three-year field experiment. These authors also reported that no significant difference in the abundance or diversity indexes could be attributable to long-term cultivation of transgenic cotton, but there was significant seasonal variation in the number of soil microorganisms collected in Bt cotton plots.…”