Effect Of Pyruvate Kinase And Hexokinase Silence To Nilaparvata Lugens (Stal) Reproduction Treated By Triazophos

The brown planthopper(BPH), Nilaparvata lugens (Stal)(Homoptera:Delphacidae), is a serious pest of rice crops with long-distance migratory characteristics, its periodic outbreak brings our grain production hidden danger. When feeding or spawning, BPH would spread rice disease and resulted in a considerable reduction in production even no harvests. It is also a kind of typical pesticide- induced resurgence pest, whose outbreak is thought to be associated with the improper use of pesticides. So, the study on the mechanism of pesticide- induced BPH resurgence plays an important role in farmland medication guide. Nutrition and metabolism of insect is the material base of reproduction, meanwhile it takes part in regulate hormones involved reproduction. In this study, we explore the mechanism of fertility and the impact of pesticides on carbohydrate metabolism by proteomic analysis and RNA interference.1. Proteomic analysis of N. lugens (Stal) fat body exposed to different insecticidesMetabolism of insect plays an important role in growth, development and reproduction, and fat body plays a central role in in it. The previous investigations showed that the increase of N.lugens fecundity has closed links with its enhanced metabolism. We study the proteomics of N.lugens fat bodies after exposure to triazophos and indoxacarb, detected 685 differentially expressed proteins, and most of them are related to metabolism and biological processes.63 diff proteins related to carbohydrate metabolism are detected, accounting for 12.55% of diff proteins with pathway annotation. Meanwhile,15 carbohydrate metabolism pathways are concentrated, accounting for 6.72%. Carbohydrate metabolism-related diff proteins are mainly up-regulated after triazophos treated, but down when exposed to indoxacarb, which means that triazophos could stimulate enzymes related to metabolism, and elevate levels of carbohydrate metabolism, while indoxacarb has the opposite effect, which was consistent with what we’ve known.2. Effect of pyruvate kinase and hexokinase silence to N. lugens ReproductionIn order to further research on the molecular mechanism of fertility, we study the role of pyruvate kinase(PK) and hexokinase(HK) in reproductive based on the relationship between carbohydrate metabolism and reproduction by RNAi. We found that pyruvate kinase increased 3.66 fold after triazophos-treated, and hexokinase increased 4.92 fold, consistent with proteomics analysis.After feeding artificial diets with dsRNA, both genes are significantly down regulated. Compared with TZP- treated and TZP+dsGFP- treated, after knocking out Pyruvate kinase, the number of eggs laid decreased by 23.89% and 30.71% respectively, ovarian protein content decreased 26.46% and 20.87%. Knocking out of hexokinase decreased 16.36% and 25.40% respectively, ovarian protein content decreased 22.68% and 16.79%. It also found that the accumulation of ovarian protein is inhibited more than the fat body protein, the contant of carbohydrate metabolism is significantly decreased in ovaries while has no regularly. It suggests that Triazophos induces the expression of the two enzymes, knocking out of PK, HK can significantly inhibit the fecundity of BPH, reduce protein synthesis in the fat body and its accumulation in the ovary.