Tuesday, April 29, 2008

As a continuation of studies in the lab. and a plant-growth room, a field study was conducted at the Rosemount Expt. Station of the University of Minnesota.

Three Bt corn varieties that express the Cry1Ab protein, which is toxic to the European corn borer (Ostrinia nubilalis Hubner), and one Btcorn variety that expresses the Cry3Bb1 protein, which is toxic to the corn rootworm complex (Diabrotica spp.), and their near-isogenic non-Bt varieties were evaluated for their effects on microbial diversity by classical diln. plating and mol. (polymerase chain reaction-denaturing gradient gel electrophoresis) techniques and for the activities of some enzymes (arylsulfatases, acid and alk. phosphatases, dehydrogenases, and proteases) involved in the degrdn. of plant biomass.

After 4 consecutive years of corn cultivation (2003-2006), there were, in general, no consistent statistically significant differences in the nos. of different groups of microorganisms, the activities of the enzymes, and the pH between soils planted with Bt and non-Bt corn. Nos. and types of microorganisms and enzyme activities differed with season and with the varieties of corn, but these differences were not related to the presence of the Cry proteins in soil. The Cry1Ab protein of Bt corn (events Btl1 and MON810) was detected in most soils during the 4 yr, whereas the Cry3Bb1 protein was not detected in soils of Bt corn (event MON863) expressing the cry3Bb1 gene.

Reference
Icoz, I., Saxena, D., Andow, D. A., Zwahlen, C., Stotzky, G. (2008). Microbial Populations and Enzyme Activities in Soil in Situ Under Transgenic Corn Expressing Cry Proteins from Bacillus Thuringiensis. Journal of Environmental Quality37(2): 647-662.

Copyright © 2008 Journal of Environmental Quality