Respose Of Ostrinia Furnacalis Oxidation-reduction System To DIMBOA

Ostrinia furnacalis is the most important pest on the corn. It does harms to new leaves, female ears, seeds and stems, bringing severe losses every year. DIMBOA is one important secondary metabolism substance in corn plant, which widely exists in gramineae crops and has a relationship with corps’resistance to pests and plant diseases. It has reported that DIMBOA has an impact on the life activities of Ostrinia furnacalis, and the contents of DIMBOA also relate to the resistance to Ostrinia furnacalis. There is not a report about systematical study on the impact of DIMBOA on Ostrinia furnacalis and Ostrinia furnacalis how to regulate oxidation-reduction system to resist DIMBOA defense. This thesis systematically researched the impacts of DIMBOA contents on Ostrinia furnacalis and the respose of protective enzymes and oxidation-reduction system in Ostrinia furnacalis to DIMBOA. The main results as follows:(1) Zhengdan958etiolated seedling was adopted to extract DIMBOA, detection and analysis with HPLC-MS showed that UV absorption spectrometry and HPLC-MS maps were consistent with the literature, so that the crystal material had been extracted was DIMBOA. DIMBOA contents of11corn varieties popularized in Henan province was tested with HPLC, and that DIMBOA contents varied from corn varieties. DIMBOA contents from high to low in sepuence was as following, Denghai662>Zhengdan958>Xindan33>Xundan20>Xianyu335>Xunyan158>No.9zhenghan>Jinluotuo335>Xindan36>Longyu602>No.5dedan.(2) Indoor condition, investigated the harmed degrees of11corn varieties with Ostrinia furnacalis, the index of mosaic beyond40%were No.5dedan、Longyu602、Xindan36、Jinluotuo335. With the increase of DIMBOA contents, plants’resistance to Ostrinia furnacalis gradually increased.(3) During the11corn varieties above, Denghai662, Xundan20, Longyu602were selected as the tested varieties whose DIMBOA contents were significantly different and reduced gradually. Researched the growth and development status of Ostrinia furnacalis on this3corn varieties. The results showed that:the developmental duration and total duration were significantly different among3corn varieties. Total duration on Longyu602was39.05d as the shortest one; total duration on Xundan20was43.22d as the longest one. With the decrease of DOMBOA contents, pupal weights and the eclosion rates on the3corn varieties increased gradually.(4) Ostrinia furnacalis larvae fed on Denghai662, Xundan20, Longyu602respectively, SOD、GST、POD activities and Trypsin activity on midgut were compared at24h,48h,72h,96h later. According to the results, at24h, POD activities in descending order were Denghai662, Xundan20, Longyu602, showing significant differences, this order was consistent with the DIMBOA contents. At48h,72h,96h, comparing with the contrast, POD activities increased significantly in treatment groups. In each period, GST activities increased on each corn variety with the elevation of DIMBOA contents, showing significant difference. Comparing with the contrast, SOD activities increased significantly in treatment groups, and SOD activity on the Denghai662was the highest one in every period. Basically, SOD activities increased with the rise of DIMBOA contents. Comparing with the contrast, Trypsin activities decreased significantly in treatment groups in every period, the changes among treatment groups did not have a rule.(5) Feeding on Denghai662, Xundan20, Longyu602, the expression levels of OfurGrx on fatty body and midgut were studied with the use of Real-time PCR. According to the results, at the fatty body and midgut, the expression levels of OfurGrx on Longyu602did not have a significant difference with the contrast; At fatty body, the expression levels of OfurGrx on Denghai662were inhibited at any time. At midgut, the expression level of OfurGrx on Denghai662was promoted at12h; At midgut, the expression level of OfurGrx on Xundan20was inhibited, at fatty body, it was promoted at12h and48h.(6) Artificial diets had the same DIMBOA contents with Denghai662, Xundan20, Longyu602fed Ostrinia furnacalis larvae separately, the expression levels of OfurGrx on fatty body and midgut were studied with the use of Real-time PCR. At fatty body, the expression level of OfurGrx on artificial diet was higher than that on Denghai662at12h. At midgut, the expression level on artificial was lower than that on Denghai662at12h. The result on Xundan20was totally opposited to Denghai662.