Influences Of Atg6 On Reproduction Of Helicoverpa Armigera And Its Role In Autophagy Of Lepidopetera Insect Cells

Autophagy is an intracellular bulk phagocytosis and degradation phenomenon of a lysosomal-mediated that is found ubiquitously in eukaryotes. It is not only the mechanism of self-protection but also the programmed cell death (Programmed cell death, PCD) type II which is different with apoptosis. Hence, autophagy has a very important biological function in the development of the individual, the occurrence of disease, aging and cell differentiation. Meanwhile, autophagy plays a pivotal role in preventing against environmental stress and pathogenic microorganisms. Atg6 (Autophagy-related-gene-6) is a vitally important cell-regulatory molecule during autophagy, which is called as a gatekeeper, and Atg6 has a very important biological function in mammalian cell. Autophagy related gene 8 is located in the membrane of autophagosome. During autophagy, Atg8 and autophagosomes are subsequently fused with vacuole where their contents are degraded. So Atg8 is an essential landmark protein of autophagy. Helicoverpa armigera, belonging to lepidoptera noctuidae, is an important pest in our country, and it can cause serious harm to agricultural crops. However, the research of Atg6 on the regulation of autophagy and the influence of H. armigera Atg6 on its growth and development are still not reported.In our research, silencing Atg6 expression by RNAi is established to explore the impact of Atg6 gene on larval growth and development of H. armigera. Firstly the specific dsRNA of H. armigera Atg6 gene is chemically synthesized and injected into abdomen of larvae. The effect of the Atg6 dsRNA is confirmed by detection of Atg6 mRNA using qRT-PCR. The impact of silenced Atg6 expression on larval growth and reproduction of the insect is assessed by weighing larva and counting egg production and hatching rate. In addition, we have studied the optimal dose through qRT-PCR during the process which Atg6 of H. armigera was silenced. The results demonstrated that Atg6 expression in the midgut tissue of larva 48h post injection of dsRNA reduced as compared with control larva whose Atg6 expression was not interfered. And the optimal dose of silencing Atg6 expression in H. armigera was 2μg. Detection of larval growth and reproduction of the insects demonstrated that no difference of body weight between dsRNA-treated group and control group were observed, but egg production and hatching rate significantly decreased in dsRNA-treated group compared with control.In addition, this article also conducted a series of research on the regulation of Atg6 on autophagy in insect cells. Firstly, the influence of Atg8 protein expression after silencing Atg6 expression in TH and TnH5 cells was studied; then, it was the change of autophagy activity when Atg6 was over-expressed in TH. In our study, western blot and qRT-PCR technique are used to detect Atg8 protein expression.The results show that autophagy related genes 6 in the process of autophagy plays a crucial role in insect cells, and has significant impact on the reproduction of H. armigera, indicating that the Atg6 e is likely a potential target for development of new pesticide and the article can provide an important reference for the research of insect physiology and pest management.