| Drosophila melanogaster is an important model organism. Based on its clear genetic background and convenient genetic manipulation, it has been widely used in the fields of developmental biology, molecular biology, biochemistry and so on.Deltamethrin (DM) has been widely used to control pest for its strong toxicity, high efficacy and few environmental remaining. Unfortunately, long-term widespread and improper use has induced the development of insecticide resistance, which presents a difficult obstacle for pest control, so studies on the molecular mechanisms of insecticide resistance have received extensive attention. With the development of molecular biology and insect genomics, the past few years have witnessed increasing knowledge of the molecular mechanism of insect resistance, and it is generally believed that the formation of resistance includes three kinds of mechanism:gene amplification, gene differential expression and changes of gene structure at the gene level, some target genes have been cloned and verified. However, insecticide resistance is highly complex and associated with a number of genes, so identification and characterization of new target genes associated with insecticide resistance will contribute to clarify the mechanism of insecticide resistance and provide theoretical basis for the prevention and control of pests in production practice.In our previous study, differential expression of the ubiquitin and proteasome alpha6 (prosalpha6) were reported between Plutella xylostella strains that are resistant or susceptible to DM, ubiquitin and prosalpha6 were up-regulated in DM-resistant (DR) strain of Plutella xylostella, which were identified by two-dimensional electrophoresis (2-DE) and tandem mass spectrometry (TOFMS-MALDI). Moreover, ubiquitin has been proved to be a candidate gene that may confer insecticide resistance through RNA interference in DR strain and overexpression in Drosophila Kc cells. However, whether prosalpha6 participates in DM stress response requires further study. To better understand the contribution of prosalpha6 in DM stress response, RNA interference, heterologous expression, and a proteasome inhibitor (MG-132) were used, the results are as follows:(1) dsRNA was designed to block the function of prosalpha6, Drosophila Kc cells were treated with DM at the different concentrations, and CCK-8 Reagent kit was used to measure the cell viability at 24 h of DM exposure, normal Kc cell was regarded as the control group. The result shows that prosalpha6 knockdown increased the Drosophila cells sensitivity to DM;(2) pIB/prosalpha6 plasmid was constructed and transfected into Drosophila Kc cells which were then treated with various concentrations. After 24 h treatment, CCK-8 was used to determine the cell viability, the result shows that the survival rate of transfected cells was significantly higher than that of the control group;(3) Drosophila Kc cells were treated with MG-132 for 6 h prior to DM treatment, the percentage of cell survival upon DM treatment was measured using the CCK-8 reagent kit, the result shows that MG-132 treatment made the Drosophila cells more susceptible to DM compared to the DM-treated alone cells;(4) DM-resistant (DR) strain of Plutella xylostella were treated with MG-132 for 24 h prior to deltamethrin toxicity, the result shows that the LC50 of DR strain to deltamethrin significantly down regulated.The results indicated that prosalpha6 is related to DM stress response and overexpression of prosalpha6 would protect Drosophila cells from DM damage. However, the mechanisms underlying DM stress remain to be further studied. |
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