Quantification and Persistence of Recombinant DNA of Roundup Ready Corn and Soybean in Rotation

Abstract

The presence of the recombinant cp4 epsps gene from Roundup Ready (RR) corn and RR soybean was quantified using real-time PCR in soil samples from a field experiment growing RR and conventional corn and soybean in rotation. RR corn and RR soybean cp4 epsps persisted in soil for up to 1 year after seeding. The concentration of recombinant DNA in soil peaked in July and August in RR corn and RR soybean plots, respectively. A small fraction of soil samples from plots seeded with conventional crops contained recombinant DNA, suggesting transgene dispersal by means of natural process or agricultural practices. This research will aid in the understanding of the persistence of recombinant DNA in agricultural cropping systems.

Development of real time PCR assays for detection and quantification of transgene DNA of a Bacillus thuringiensis (Bt) corn hybrid in soil samples

“…leaves buried in soil did not persist for more than 4 months. Lerat et al (2007) reported that transgene DNA of GM corn and soybean was detected 7 months after the crop had been harvested but transgene DNA was not detectable after one growing season with conventional soybean in the same plots. However, Gebhard and Smalla (1999) detected transgene DNA from transgenic sugar beet (Beta vulgaris L.) in soil samples even 2 years after their introduction in a disposal site.…”

“…Little information is available about the potential of gene transfer in soil and the effect of indigenous bacteria carrying the transgenes on the structure and function of the soil microbial community (Dunfield and Germida 2004;Heinemann and Traavik 2004;Nielsen and Townsend 2004). As a prerequisite to addressing this issue, data on the persistence of transgene DNA in soil through continuous cultivation of GM crops need to be generated (Lerat et al , 2007.…”

“…Over the last decade, molecular methods have been developed for detecting and quantifying transgene DNA of GM plants in soil, including PCR (Widmer et al 1996), real time PCR (Lerat et al , 2007, and bacterial natural transformation (also called marker rescue system) (de Vries and Wackernagel 1998;Gebhard and Smalla 1998;Nielsen et al 2000a, b). Among them, PCR usually provides data on the presence or absence of transgene DNA, whereas real time PCR can quantify its copy number.…”

“…To investigate the possibility of horizontal gene transfer from GM crops to soil bacteria and potential ecological consequences, knowledge of the availability and accessibility of transgene DNA in soil is required (Lerat et al 2007). The objectives of this study were (1) to develop real time PCR assays to quantify the transgene DNA containing a neomycin phosphotransferase (nptII) gene in a commercially released Bt corn (Zea mays L.) hybrid DKC42-23 (derived from event MON863) and (2) to investigate the presence and persistence of transgene DNA in a field experiment with DKC42-23 for 3 years using real time PCR and bacterial natural transformation.…”

In‐field detection and quantification of extracellular DNA

“…Furthermore, if plant-to-bacteria gene transfer occurs in field soil, it would be expected to occur during the growing season, as bacterial-populations peak, when soil temperatures and nutrient supply are optimal (Lerat et al, 2007).…”