| The brown planthopper(BPH), Nilaparvata lugens (Stal)(Hemiptera:Delphacidae), is a typical pesticide-induced resurgent pest. Insecticide-induced stimulation of reproduction is one of causes of BPH resurgence occurrence. In most insects, Vg is synthesised in the fat body and secreted into the hemolymph where it is absorbed by the developing oocytes in the ovary. These proteins synthesized in the fat body are secreted into the hemolymph, and specifically absorbed by the mature follicle as a nutrient source for embryo development. The previous investigations on N. lugensa fecundity have mainly focused on the ovaries, and the researches on fat bodies are concentrated in model insects, such as Bombyx mory, Drosophila melanogaster, and Aedes aegypti. In this paper, we conducted a study on relationship between changes of insecticide-induced gene expression of the fat body and stimulation of reproduction of BPH.1. Proteomic analysis of insecticide-treated N. lugensa fat bodyIn order to understand the role of fat body in N. lugensa resurgence mechanisms, we study the proteomics of N. lugensa fat bodies after exposure to triazophos and indoxacarb by iTRAQ. The results showed that the 3431 proteins were detected in our samples, of which 685 are significantly difference compared to the control. By functional analysis, these different expressed proteins could be divided into 12 categories based on molecular function, while in view of biological process, there are 22 categories.502 diffentially proteins are distributed throughout 223 pathways, which catalogied to many aspects, for metabolism, immunity, signal, development, and reproduction. Two pathways are directly related to the oocytes, namely oocyte meiosis and progesterone-mediated oocyte maturation.2. The effect of small G protein Ras knockout on BPH reproduction and biochemical substances of the fat bodyIt is well known that triazophos(TZP) is a typical insecticidewhich induced BPH resurgence. Proteomics analysis showed that TZP significantly changed the expression of Ras in fat bodies. RNA interference(RNAi) by feeding dsRNA is used to knockout BPH NIRas to examine effect on BPH reproduction and biochemical substances. The relative excpression level of NlRas exposed to TZP increased by 78.64%, the number of eggs laid (NEL) significantly increased 41.29%, the protein content of ovary and fat body were increased 54.78% and 12.77%, soluble sugar content significantly increased by 47.40%and 94.12%, respectively, compared to control. No significant differences on NEL and geen expression level between TZP+dsRas BPH and TZP BPH were observed. But protein contents in ovary and fat body of TZP+dsRas BPH decreased by 36.71% and 20.24%,21.79% and 24.41%, respectively, compared to the control and dsGfp. No significant difference on soluble sugar content in ovaryof TZP+dsRas BPH was observed. However, there was significant difference on soluble sugar content in fat body, decrasing by 23.03%, compared to TZP BPH.3. The effect of cAMP-dependent protein kinase 1(Pka) knockout on BPH reproduction and biochemical substances of the fat bodyPka regulates follicular cells intake of vitellogenin(Vg). Proteomic analysis showed that indoxacarb-treated BPH decreased Pka expression in fat body. In this study, we carried out RNAi by feeding dsRNA to knockout NIPka to examine effect on BPH reproduction and biochemical substances. The relative excpression level of NIRas exposed toindoxacarb (IDC) increased by significantly decreased by 55.67%, but no significant differences on NEL and protein content in ovary were observed, but there was a significant difference on protein content in fat body, decreasing by 31.41%, compared to control. Soluble sugar content in ovary of IDC-treated BPH significantly was lower than that of control, decreasing by 32.76%, but no significant difference on soluble sugar content in fat body was observed. The relative expression level of NlPka of IDC+dsPka BPH significantly was lower than that of dsGfp and control BPHs, decreasing by 51.60% and 50.67%, respectively, NEL decreasing by 26.21% and 27.14%. protein content in fat body of IDC+dsPka BPH was lower than that of dsGfp and control, decrasing by 35.54% and 28.39%, but soluble sugar contents in ovary and fat body significantly were higher than that of dsGfp and control, increasing by 43.55% and 54.56%, and 43.82% and 62.46%, respectively. |
PDF Full Text Request