Corn Borer Biocontrol Engineered Strains Constructed Research

Asian corn borer (Ostrinia furnacalis), heavily destruction and widely distribution, is one of the most important agricultural pest in the world. Because of its rapid production, more generation and having a stronger pesticides resistance, the chemical control on the Asian corn borer faces more and more difficulties. So, finding a high-efficient, safe and environment-friendly substitute of pesticide becomes a problem need to be resolved.In the research, by taking corn and corn borer as research objects,60 differentially expressed proteins responded to MJA treatment were identified by the means of 2D and MS based on analyzing the maize resistance respond induced by MJA. Their functions were confirmed according to the protein database corresponded. The discovered proteins play important roles in the plants defense response. Those laid a foundation on constituting bio-control engineering strain for asian corn borer. Four important plant defense regulated proteins were chosen and their anti-insect activities were analyzed. Prokaryotic expression vectors were built by the pET system, and the recombinant proteins were also induced expressed successfully. The influences of recombinant proteins'biological activities on Asian corn borer were also tested by bioassay. The recombinant proteins expressed by both pET28a-TRX and pET28a-PRP had significant effects on the development of Asian corn borer, and the inhibition rates of growth were 34.14% and 30.33% respectively. Although the recombinant protein expressed by pET28a-GRBP had no signification effect on the development of Asian corn borer, it had a signification effect on the pupa weight. Those imply that the proteins indentified maybe anti-insect proteins with high activities from Maize.Glutathione-S-transferase are important detoxifying enzymes in insect. It has an effect of metabolism toxic compounds in both the insect bodies and environment, in order to enhance the body's resistant ability. A full length GST cDNA was isolated from the midgut of Asian corn borer, named OfGST, by RT-PCR and RACE, and the bioinformatics analysis were conducted after that. Based on those, bulit the prokaryotic expression vector and performed the polyclonal antibody by the purified recombinant proteins. Western blot showed that the expression level of GST increased after the DIMBOA induced, reaching the maximum at 24h. For a further understanding GST's ability to metabolism and detoxicate secondly metabolise DIMBOA in the midgut of Asian corn borer, the RNAi vector was built. Then, the vector was constructed and expressed in HT115 to produce dsRNA. The engineering strain containing dsRNA of target gene was mixed with feed to test the interference effects. The result showed compared to the control group, the death rates of interference group were 54%. It initial prove that we have successfully constructed the GST RNAi engineering strain for Asian corn borer. It provides a new approach for bio-control of Asian corn borer in agriculture.