Changes in levels, species and DNA fingerprints of soil microorganisms associated with cotton expressing the Bacillus thuringiensis var. kurstaki endotoxin
Authors: Donegan, K.K., Palm, C.J., Fieland V.J., Porteous, L.A., Ganio, L.M., Schaller, D.L., Bucao, L.Q., Seidler, R.J.
Journal, Volume, Year: Applied Soil Ecology, volume 2:111-124, 1995
The effects of leaves of three different lines of Btk-producing cotton plants and purified Btk toxin on soil microorganisms were evaluated. Two of the three Btk cotton lines caused an increase in total bacteria and fungal populations, but no effects were observed using purified Btk toxin. The authors suggest genetic manipulation of cotton plants may have produced a change in plant characteristics that could influence growth and species composition of soil microorganisms.
Two of the Btk-producing cotton lines impacted soil microbiology, but the purified Btk did not. As the authors state, these results challenge the assumption that if ecological effects of a substance have previously been evaluated, it is not necessary to re-evaluate the substance when it is produced by a transgenic plant.