Resistance Selection To CrylAc Toxin And Research Of Resistance Mechanism Of Plodia Interpunctella

In this study, the larvae of Plodia interpunctella was fed on artificial feed with CrylAc toxin. Then the larval mortality, larval development period, pupation rate, eclosion rate and total development period of Plodia interpunctella was record. The changes in activities of the important protective enzyme, the detoxifying enzymes and the protease of midgut was determinated. In addition, the resistance lines to Cryl Ac toxin of Plodia interpunctella was selected in the laboratory at the same time. The main results were as follows:1. Effect of CrylAc toxic protein on growth development of Plodia interpunctella.After the larve of Plodia interpunctella fed on the artificial feed with CrylAc toxin24h later, the CrylAc toxin started to work. The larval mortality greatly higher than the control when the the concentrations of CrylAc toxin was higher than1.22μg/g, at a very significance level. The larval mortality was higher along with the increased of CrylAc toxin, and reached the extremely significant difference between each other. There was no significant influnce to Plodia interpunctella when CrylAc toxin was0.3μg/g. Compared with the control, the pupa rate and eclosion rate of Plodia interpunctella which fed on the artificial feed with CrylAc toxin were significantly decreased, the larvae development period and the total development period extended obviously, and with the higher of Bt toxin concentration, the more significant difference.2. Resistance selection of Plodia interpunctella to CrylAc toxinFed Plodia interpunctella on the artificial feed with CrylAc toxin, after6generations of selection, the resistance increased to268times of the original, but the resistance was in a low level still. Compared with the control, the pupa rate and eclosion rate of Plodia interpunctella which fed on the artificial feed with CrylAc toxin were significantly decreased, but the larval development period and the total development period were extended obviously. The growth development was significantly inhibited, the pupa weight significantly lower than the control, but average pupa weight is stable in the generations, there was no obvious difference.3. Effect of CrylAc toxin on the activities of the important protective enzyme in the larvae of Plodia interpunctella The activities of POD and SOD were greatly inhibited after Plodia interpunctella fed on the artificial feed with different CrylAc toxin12days later, which increased along with rised of the concentration of CrylAc toxin, but there were no significantly difference between each other. Compared with the control, The activities of POD of Plodia interpunctella which fed on the artificial feed with CrylAc toxin were lower, which reached the very significantly difference at48h and72h. The activities of SOD were lower than the concorl except12h, there was the very significantly difference after48h and72h later.4. Effect of CrylAc toxin on the activities of the important detoxifying enzyme in the larvae of Plodia interpunctellaAfter Plodia interpunctella fed on the artificial feed with different CrylAc toxin12days later, the activities of AChE increased with the CrylAc toxin concentration rised, on the contrary, the activities of ALP decreased, but the activities were hihger than the control. The the activities of AChE were rised, which were greatly higher than the control at24h and reached the very significantly difference. Compare the control, the the activities of ALP were increased, which were greatly higher at24h and72h and reached the very significantly difference.5. Effect of CrylAc toxin on the activities of the important protease of midgut in the larvae of Plodia interpunctellaThe activities of weak alkaline trypsin-like enzyme and chymotrypsin-like enzyme were greatly inhibited after Plodia interpunctella fed on the artificial feed with different CrylAc toxin12days later, which icreased with rised of CrylAc toxin concentration. Compare with the control, Weak alkaline trypsin-like enzyme activities were higher at12h, then the activities drops rapidly, which were highly significantly lower at36h,and72h. Chymotrypsin-like enzyme activities were lower than the control, where the enzyme activities were highly significantly difference for48h.