Effect of cry1Ac/cpti transgenic rice on enzyme activity and nutrient availability in paddy soil

[Background]The cultivation of genetically modified (GM) plants may have the potential to alter the activity of soil enzymes or the availability of soil nutrient through root exudates and plant residues. The influence of transgenic plants on soil quality is an important aspect of the environmental risks assessments of GM crops. [Method]In this study, two lines of transgenic rice containing the cry1Ac/cpti construct (Bt toxin and cowpea trypsin inhibitor genes) (GM1 and GM2) and their parental non-transgenic rice (CK1 and CK2) were planted in the same field site for three years. Soil enzyme activity and soil nutrient availability in the field site were analyzed in the third year. [Result]The activity of acid phosphatase in soil under GM1 in heading was significantly (P0.05) higher than that of CK1. There were no other differences between GM1 and CK1 or between GM2 and CK2 in the activity leveles of acid phosphatase, alkaline phosphatase and urease in the paddy soil during the rice growth seasons. At the same time, soil pH, organic C and availability of nitrogen, phosphorus and potassium in the paddy soil under GM1 or GM2 were similar to those of CK1 or CK2. [Conclusion and significance]The cry1Ac/cpti transgenic rice did not seem to have major effects on mineralization of major soil nutrients and corresponding soil enzyme activities, and planting the cry1Ac/cpti transgenic rice did not damage the activity of soil enzyme and nutrien cycling, at least in short term.