Environmental Dynamics Of Insecticidal Proteins From Transgenic Cry1Ac Cotton And Rice

Transgenic Bt cotton NUCONT33^B and transgenic Cry1Ac/CpTI rice lines, MSA and MSB, containing a synthetic cry1Ac gene from Bacillus thuringiensis, were used to study the resistance and degradation dynamics of Bt insecticidal proteins in the tissues of Bt crops under different situations by ELISA. The results are as fellows:1. Degradation dynamics of Cry1 Ac insecticidal protein in Bt cotton tissues under differentenvironmentsThe degradation dynamics of Cry1 Ac insecticidal protein in Bt cotton with exposure to air and soil mediums under different conditions were investigated in the laboratory and field. The results showed that the degradation trends under different situations were significantly different. In general, Bt protein in cotton leaves degraded rapidly in first several days, then got slowly and entered a relative stable stage in which Bt protein content kept at a concentration of 50ngg^-1. The higher temperature and lower humidity significantly increased degradation speed of the toxin, which resulted in a short period for the content of the protein to get into stable stage. However, there were no significant differences in degradation between light and dark treatments. In natural environment, the insecticidal protein in Bt cotton degraded much rapidly in the initial period, it reached 85% in first month, and stopped during winter season, then degraded quickly in next spring until disappeared in late April.2. Detection of persistence of Bt insecticidal protein in Bt cotton fieldDetected rhizosphere-soil of the growing Bt cottons and the soil in the fields where Bt cottons have been planting for multiple years, but non-Bt-insecticidal -proteins were found. The result showed on a certain extent that to plant Bt cottons widely and repeatedly could not result in accumulations of Bt insecticidal protein in soil.3. Expressing dynamics of Cry1 Ac protein in the tissues of Bt rice.The expressing levels of Bt insecticidal proteins in the root and main stalks of Bt rice lines, MSA and MSB, at different stages were investigated by ELISA. The results showed...