Project description:Piperonyl butoxide (PBO) is an insecticide synergist known to inhibit the activity of cytochrome P450 enzymes. PBO is currently used in many insecticide formulations, and has also been suggested as a pre-treatment in some pesticide applications. Little is known about how insects respond to PBO exposure at the gene transcription level. We have characterised the transcriptional response of the Drosophila melanogaster genome after PBO treatment, using both a custom designed “detox” microarray containing cytochrome P450 (P450), glutathione S-transferase (GST) and esterase genes, and a full genome microarray. We identify a subset of P450 and GST genes, along with additional metabolic genes, that are highly induced by PBO. The gene set is an extremely similar gene set to that induced by phenobarbital, a compound for which pre-treatment is known to confer tolerance to a range of insecticide compounds. The implications of the induction of gene families known to metabolise insecticides and the use of PBO in pest management programs are discussed. Keywords: Induction response after treatment by PBO
Project description:To screen for xenobiotic-metabolizing-enzyme genes (XME) induced by caffeine exposure, a microarray experiment (performed with a Drosophila pangenomic array (Agilent 4 X 44K) was carried out between control and individuals exposed to caffeine (18mM ). Among 23401 genes consistantly found in the three biological replicates, 13108 showed a significant variation. 749 genes were over-expressed whereas 1518 were under-expressed. Interestingly, several genes belonging to all major classes of detoxification enzymes including XME were among the most highly induced such as CYP12d1, CYP6a8 and CYP6d5.
Project description:We performed expression quantitative trait locus (eQTL) mapping between two strains of Tetranychus urticae (the two-spotted spider mite), a generalist herbivore known for its rapid evolution of acaricide resistance. For parents, we used the inbred strain MR-VPi that is highly resistant to multiple acaricides in different classes, and the inbred strain ROS-ITi that is comparatively susceptible to many acaricides. The eQTL mapping experiment was performed with F3 samples, and thousands of trans and cis eQTL were identified, including for genes in families known (or suspected) to be involved in the metabolism of xenobiotics (plant produced secondary compounds and acaricides). One trans eQTL hotspot was identified that strongly impacted the expression of many detoxification genes in different gene families. Follow up studies using derived near isogenic lines validated the trans eQTL hotspot, and RNA interference (RNAi) knockdown of tandemly duplicated genes encoding products with homology to the ligand binding domains of nuclear hormone receptor 96 genes impacted many of the same detoxification genes controlled by the hotspot.
Project description:The goal of this study is to proactively assess the risk of insecticide resistance development by determining susceptibility of field-collected D. suzukii and their response to insecticide treatment at the transcriptome level using next-generation sequencing technology. Methods:LC50 values were calculated for zeta-cypermethrin, spinosad, malathion treated D. suzukii field-collected and lab-reared populations. LC50 dosage survived and untreated (10 individuals per replicate) field-collected and lab reared D.suzukii transcript profiles were generated by RNA sequencing, in triplicate, using Illumina NextSeq 500. The 24 samples (paired-end reads, including replicates) were independently mapped onto the D. suzukii genome (SpottedWingFlybase v.1) by using TopHat followed by Cufflinks to estimate the expression values of the transcripts in FPKM (Fragments Per Kilobase per Million mapped reads) with the Cuffdiff 2 default geometric normalization. Differentially expressed genes (FDR < 0.05 after Benjamini-Hochberg correction for multiple-testing) were identified for insecticide-treated or untreated control for either (1) lab-reared populations or (2) field-collected populations. Results: As an approach to proactively assess the risk of insecticide resistance development, we determined the LC50 (lethal concentration, 50%) values of commonly used insecticides zeta-cypermethrin, spinosad, and malathion against laboratory-reared and field-collected D. suzukii populations. The LC50 values were significantly higher in field-collected populations when compared to lab-reared populations, indicating that field populations are less susceptible to these insecticides. Furthermore, we used RNA sequencing to analyze the response of D. suzukii at the transcriptome level upon treatment with the same three insecticide classes that are used in our bioassays. We identified differentially expressed genes (DEGs) in D. suzukii that survived LD50 doses of zeta-cypermethrin, spinosad, and malathion and gene classes that are overrepresented in DEGs. We observed that a high number of significantly DEGs are involved in detoxification and reduced cuticular penetration, especially in field population, thus providing potential molecular mechanisms for the higher LC50 values for field-collected population. Conclusion: Our study identified a high number of metabolic detoxification genes that are induced in field-collected D. suzukii upon insecticide treatment and a high degree of overlap when examining the lists of genes that are induced when D. suzukii is treated with three commonly used insecticides. Based on our results, we conclude that there is a substantial risk of insecticide resistance and cross-resistance development in D. suzukii in the field.
Project description:Survival of insects on a substrate containing toxic substances such as plant secondary metabolites or insecticides is dependent on the metabolism or excretion of those xenobiotics. The primary sites of xenobiotic metabolism are the midgut, Malpighian tubules and fat body. In general, these organs are treated as single tissues by online databases, but several studies have shown that gene expression within subsections of the midgut is compartmentalized. In this article, RNA sequencing analysis was used to investigate whole-genome expression in subsections of the third-instar larval midgut. The results support functional diversification in subsections of the midgut. Analysis of the expression of gene families that are implicated in the metabolism of xenobiotics suggests that metabolism may not be uniform along the midgut. These data provide a starting point for investigating gene expression and xenobiotic metabolism in the larval midgut.
Project description:Survival of insects on a substrate containing toxic substances such as plant secondary metabolites or insecticides is dependent on the metabolism or excretion of those xenobiotics. The primary sites of xenobiotic metabolism are the midgut, Malpighian tubules and fat body. In general, these organs are treated as single tissues by online databases, but several studies have shown that gene expression within subsections of the midgut is compartmentalized. In this article, RNA sequencing analysis was used to investigate whole-genome expression in subsections of the third-instar larval midgut. The results support functional diversification in subsections of the midgut. Analysis of the expression of gene families that are implicated in the metabolism of xenobiotics suggests that metabolism may not be uniform along the midgut. These data provide a starting point for investigating gene expression and xenobiotic metabolism in the larval midgut. Examination of expression in eight samples corresponding to compartments of gene expression in the midgut
Project description: In order to clarify the molecular mechanism of metabolic detoxification in Spodoptera frugiperda, the enzyme activity assay and transcriptome sequencing analysis were used to screen and identify the relevant genes related to metabolic detoxification after induced by insecticides at LC50 dose.
Project description:The fall armyworm (FAW) Spodoptera frugiperda is one of the most severe economic pests of multiple crops globally. Control of this pest is often achieved using insecticides; however, over time, S. frugiperda has developed resistance to new mode of action compounds, including diamides. Previous studies have indicated diamide resistance is a complex developmental process involving multiple detoxification genes. Still, the mechanism underlying the possible involvement of microRNAs in post-transcriptional regulation of resistance has not yet been elucidated. In this study, a global screen of microRNAs (miRNAs) revealed 109 known and 63 novel miRNAs. Nine miRNAs (four known and five novel) were differentially expressed between insecticide-resistant and -susceptible strains. Gene Ontology analysis predicted putative target transcripts of the differentially expressed miRNAs encoding significant genes belonging to detoxification pathways. Additionally, miRNAs are involved in response to diamide exposure, indicating they are probably associated with the detoxification pathway. Thus, this study provides comprehensive evidence for the link between repressed miRNA expression and induced target transcripts that possibly mediate diamide resistance through post-transcriptional regulation. These findings highlight important clues for further research to unravel the roles and mechanisms of miRNAs in conferring diamide resistance.
Project description:To screen for xenobiotic-metabolizing-enzyme genes (XME) induced by caffeine exposure, a microarray experiment (performed with a Drosophila pangenomic array (Agilent 4 X 44K) was carried out between control and individuals exposed to caffeine (18mM ). Among 23401 genes consistantly found in the three biological replicates, 13108 showed a significant variation. 749 genes were over-expressed whereas 1518 were under-expressed. Interestingly, several genes belonging to all major classes of detoxification enzymes including XME were among the most highly induced such as CYP12d1, CYP6a8 and CYP6d5. Caffeine ingestion induced gene expression in Drosophila melanogaster male thorax and abdomen was mesured at 12h after exposure to doses of 0, 18mM of caffeine. Three independant experiments were performed at each dose using different drosophila for each experiment.
Project description:modENCODE_submission_754 This submission comes from a modENCODE project of Eric Lai. For full list of modENCODE projects, see http://www.genome.gov/26524648 Project Goal: We plan to generate a comprehensive catalog of expressed and functional microRNAs, and generate biological evidence for their regulatory activity. We plan also to delineate the primary transcription units of microRNA genes. Finally, we plan to annotate other classes of non-miRNA expressed small RNAs, as least some of which may define novel classes of small RNA genes. For data usage terms and conditions, please refer to http://www.genome.gov/27528022 and http://www.genome.gov/Pages/Research/ENCODE/ENCODEDataReleasePolicyFinal2008.pdf