Impact of Environmental Stress-Tolerant Transgenic Potato on Genotypic Diversity of Microbial Communities and Soil Enzyme Activities under Stress Conditions.

Transgenic crops able to tolerate environmental stress are being developed throughout the world. However, little data is available on the impact of environmental stress-tolerant transgenic crops on soil microorganisms and biochemistry. Recently developed transgenic potato plants carrying an environmental stress-related gene, DREB1A, with a stress-inducible promoter, are being evaluated for growth performance in greenhouses. In this study, we investigated microbial diversity and soil function to assess potential environmental risks of these transgenic potato lines. Genotypic diversity of the 16S-23S rRNA intergenic spacer region and activity levels of four enzymes were used as indicators of microbial genetic diversity and soil function, respectively. Salinity had a major effect on both bacterial (88-93%) and fungal (54-55%) diversity, while the transgene had a relatively small effect on genotypic structure (0-5%) based on the analysis of variance. However, a few genotypes appeared only in soils planted with the transgenic lines. Some enzyme activities were found to differ significantly between the transgenic and non-transgenic lines, although the results were not repeatable in the second trial. These results suggest that abiotic growth environments had a stronger impact on soil microorganisms and biochemistry than did plant genotypes.