ABSTRACT
Transgenic plants that show herbicide tolerance, resistance to viral, bacterial and fungal diseases, insect resistance, improved product quality and superior agronomic properties are now widely cultivated. However, the possible impact of genetically engineered plants on human health and ecosystem functioning is of increasing concern. Micro-organisms contribute substantially to soil functions as they play an essential role in maintaining soil quality by being involved in nutrient turnover. Furthermore, plant-associated microbes may promote plant growth and health. This chapter reviews research concerning potential effects of transgenic plants on plant-associated microflora by either the synthesis of antimicrobial substances or by unintentional changes due to bacterial transformation. The possible consequences on nutrient turnover in soil due to the cultivation of genetically engineered plants are discussed. Finally, the latest findings regarding the potential for horizontal gene transfer, particularly of antibiotic resistance genes, from transgenic plants to bacteria are presented.
