Effects of Cotton Expressing the 'Bacillus thuringiensis' var. 'kurstaki'Endotoxin on Soil Microorganisms

摘要

Many agriculturally important plants have been engineered to produce endotoxinsfrom different subspecies of the bacterium Bacillus thuringiensis (B.t.). The endotoxin Bacillus thuringensis var. kurstake (B.t.k.) has demonstrated insecticidal activity against lepidopterans. Although high specificity has been assumed formost B.t. endotoxins, their effects on non-target organisms have not been fully evaluated. This chapter describes experiments that investigated the biological and moleuclar changes in microbial populations following the incorporation of purified B.t.k. endotoxin or B.t.k.-producing cotton into natural soils. Microbial populations were monitored for changes in the total numbers and species composition of culturable bacteria and fungi, in the substrate utilization if the bacterial community and in the total DNA content and DNA fingerprints of the eubacteria.