Abstract: By using three-room rhizobox method, this paper studied the distribution features of the recombinant DNA of transgenic insect-resistant cotton in different zones of the cotton soil. A semi-quantitative PCR technology for detecting the recombinant DNA in soil was developed to
investigate the distribution patterns of reference phosphofructokinase gene fragments and of 35S-Cry1A and 35S-NPTII construct-specific fragments in different soil zones at the three growth stages (40th, 50th, and 60th day after sowing) of the cotton. The phosphofructokinase gene fragments were detected in all rhizoplane, rhizosphere soil, and one non-rhizosphere soil at the 40th and 50th day after sowing, and in all soil samples at the 60th day. The 35S-Cry1A construct-specific fragments were detected in two rhizoplane and one rhizosphere soil at the 40th and 50th day, respectively, but none in non-rhizosphere soil, and detected in all rhizoplane, rhizosphere soil, and one non-rhizosphere soil at the 60th day. The relative amount of 35S-Cry1A construct-specific fragments had nearly the same variation trend as that of the phosphofructokinase gene fragments. The 35S-NPTII construct-specific fragments were detected in all rhizoplane at the 40th, 50th, and 60th day, and in all rhizosphere soil and two of the other soil samples at the 60th day. The variation trend of the relative amount of 35S-NPTII construct-specific fragments was basically the same as that of the 35S-Cry1A construct-specific fragments. Similar to the distribution of phosphofructokinase gene fragments, the 35S-Cry1A and 35S-NPTII construct-specific fragments mainly located in rhizoplane and rhizosphere soil, and the distribution areas of the recombinant DNA expanded gradually with the growth of the cotton.

Key words: species diversity, edge effect, ground beetle, spider, alfalfa mowing., alfalfa-wheat interface