Degradation of Bt Protein in Stored Transgenic Rice and its Effect on the Activity of Three Protective Enzymes in Indian Meal Moth, Plodia interpunctella(Hübner)

Transgenic cry1Ab/cry1Ac rice (Huahui 1) is able to control the stored pest Plodia interpunctella.Our previous study confirmed that the enzymatic activities of three major antioxidases, including POD, CAT,and SOD, could be significantly changed after short-term stressed with these Bt containing rice. This study focused on the characteristics of rice during storage, the results showed that the Bt protein content in rice husk and brown rice was 5.534 μg/g and 1.003 μg/g respectively, and after 270 days at 25 ℃, the degradation rate was 67.3% and 27.7%, respectively. Moreover, the enzymatic activities of three antioxidases in P.interpunctella long-term fed with transgenic cry1Ab/cry1Ac rice powder would be addressed by enzymatic detection assays. Our data showed that the SOD activities could be significantly inhibited by the Bt containing rice after fed with Bt-rice powder for 12 days or 5 months, However, the enzymatic activities of POD and CAT significantly increase with the concentrations of Bt toxins. In addition, the change trend of protective enzyme activity in the Indian Meal Moth fed with transgenic rice flour for 5 months was consistent with that after 12 days of feeding. Our researches find that there are differences in the trend of increase and decrease of the three major protective enzymes after fed with Bt containing rice powder for a long time,which indicates that the expression mechanisms of the three protective enzymes might be different. Our results provide a theoretical basis for the study of toxicology and related resistance mechanism of transgenic Bt crops.