Transgenic Cotton and Its Impact on Microbial Diversity

Abstract

Introduction of GM crops into agricultural production systems increased public concern and renewed interest in research on the possible environmental consequences of growing GM crops including human health and ecosystem functioning. Globally, Bacillus thuringiensis (Bt) cotton occupies 15 million ha which comprised 43 % of the total cotton area of 35 million ha. Bt cotton was developed by incorporating the cry gene of the soil bacterium Bacillus thuringiensis. This gene expresses the protein endotoxin (Cry) that has insecticidal activity against the common cotton lepidopteran insect pests. While the benefits of Bt cotton are well known, there is a wide spread concern about growing transgenic cotton. This stems from the fact that the Bt toxin produced in leaves, stems and roots of Bt cotton is introduced in soil which might affect general soil health. Several workers have studied the effects of transgene products and transgenic cotton on the soil biological properties. Quite a few studies assessed the risk of growing Bt cotton on flora and fauna in diverse agro-ecosystems. This chapter attempts to review the work done so far related to growing transgenic Bt cotton on the soil microbial diversity and other related soil functions.