Dermauw W

References (18)

Title : Incidence and molecular mechanisms of insecticide resistance in Frankliniella occidentalis, Thrips tabaci and other economically important thrips species - Mocchetti_2023_Entomol.Gen_43_587
Author(s) : Mocchetti A , Dermauw W , Van Leeuwen T
Ref : Entomol Gen , 43 :587 , 2023
Abstract : Thrips species (Thysanoptera) damage plants by direct feeding and transmitting plant viruses and are considered one of the most harmful insect pests on crops worldwide. Their control mainly relies on the use of insecticides, but due to their frequent use and several biological aspects of thrips, insecticide resistance has arisen. However, despite its economic impact, the molecular mechanisms of thrips resistance have been poorly investigated. Resistance mutations in genes encoding the target-sites of insecticides have been infrequently reported for only five target-site genes. As an illustration of the lack of knowledge, analysis of publicly available sequencing data revealed the presence of acetylcholine esterase resistance mutations A201S and F290V, which had not yet been reported from the field. Next, we also summarize the importance of metabolic resistance, historically inferred mainly from data from enzyme activity assays and synergism studies. As these only suggest main routes of detoxification without providing details on underlying genetic mechanisms, the rapidly changing availability of genomic data provides an impetus to dissect causal genes. As not all main detoxification families were annotated in the main species, we took advantage of recently published thrips genomes to annotate and compare the glutathione-S-transferase (GST) family of Frankliniella occidentalis and found a relatively higher number of sigma GSTs. A broader understanding of the molecular mechanisms of resistance and especially the identification of resistance mutations and key detoxification enzyme genes will drive the development of molecular diagnostic tools that can be used for monitoring insecticide resistance in thrips.
ESTHER : Mocchetti_2023_Entomol.Gen_43_587
PubMedSearch : Mocchetti_2023_Entomol.Gen_43_587

Title : Biochemical and molecular mechanisms of acaricide resistance in Dermanyssus gallinae populations from Turkey - Koc_2022_Pestic.Biochem.Physiol_180_104985
Author(s) : Koc N , Inak E , Nalbantoglu S , Alpkent YN , Dermauw W , Van Leeuwen T
Ref : Pestic Biochem Physiol , 180 :104985 , 2022
Abstract : The poultry red mite, Dermanyssus gallinae, is the most important blood sucking ectoparasite of egg laying hens and causes economic losses in poultry farms worldwide. Although various management methods exist, the control of poultry red mites (PRMs) mainly relies on acaricides such as pyrethroids and organophosphates (OPs) in many regions of the world. However, repeated use of these synthetic chemicals has resulted in resistance development causing control failure of PRM. In this study, we investigated acaricide resistance mechanisms of Turkish PRM populations. First, we obtained the COI sequence from 30 PRM populations from different regions in Turkey and identified four different COI haplotypes. Toxicity assays showed that four field-collected PRM populations were highly resistant to the pyrethroid alpha-cypermethrin, with resistance ratios (RRs) varying between 100- and 400-fold, while two of these populations had a RR of more than 24-fold against the OP acaricide phoxim. Biochemical assays showed a relatively higher activity of glutathione-S-transferases and carboxyl-cholinesterases, two well-known classes of detoxification enzymes, in one of these resistant populations. In addition, we also screened for mutations in the gene encoding the voltage-gated sodium channel (vgsc) and acetylcholinesterase 1 (ace-1), the target-site of pyrethroids and OPs, respectively. In all but two PRM populations, at least one vgsc mutation was detected. A total of four target-site mutations, previously associated with pyrethroid resistance, M918T, T929I, F1534L, F1538L were found in domain II and III of the VGSC. The T929I mutation was present in the vgsc of almost all PRM populations, while the other mutations were only found at low frequency. The G119S/A mutation in ace-1, previously associated with OP resistance, was found in PRM for the first time and present in fourteen populations. Last, both alive and dead PRMs were genotyped after pesticide exposure and supported the possible role of target-site mutations, T929I and G119S, in alpha-cypermethrin and phoxim resistance, respectively. To conclude, our study provides a current overview of resistance levels and resistance mutations in Turkish PRM populations and might aid in the design of an effective resistance management program of PRM in Turkey.
ESTHER : Koc_2022_Pestic.Biochem.Physiol_180_104985
PubMedSearch : Koc_2022_Pestic.Biochem.Physiol_180_104985
PubMedID: 34955178

Title : High-Resolution Genetic Mapping Combined with Transcriptome Profiling Reveals That Both Target-Site Resistance and Increased Detoxification Confer Resistance to the Pyrethroid Bifenthrin in the Spider Mite Tetranychus urticae - De Beer_2022_Biology.(Basel)_11_
Author(s) : De Beer B , Vandenhole M , Njiru C , Spanoghe P , Dermauw W , Van Leeuwen T
Ref : Biology (Basel) , 11 : , 2022
Abstract : Pyrethroids are widely applied insecticides in agriculture, but their frequent use has provoked many cases of resistance, in which mutations in the voltage-gated sodium channel (VGSC), the pyrethroid target-site, were shown to play a major role. However, for the spider mite Tetranychus urticae, it has also been shown that increased detoxification contributes to resistance against the pyrethroid bifenthrin. Here, we performed QTL-mapping to identify the genomic loci underlying bifenthrin resistance in T. urticae. Two loci on chromosome 1 were identified, with the VGSC gene being located near the second QTL and harboring the well-known L1024V mutation. In addition, the presence of an L925M mutation in the VGSC of a highly bifenthrin-resistant strain and its loss in its derived, susceptible, inbred line indicated the importance of target-site mutations in bifenthrin resistance. Further, RNAseq experiments revealed that genes encoding detoxification enzymes, including carboxyl/choline esterases (CCEs), cytochrome P450 monooxygenases and UDP-glycosyl transferases (UGTs), were overexpressed in resistant strains. Toxicity bioassays with bifenthrin (ester pyrethroid) and etofenprox (non-ester pyrethroid) also indicated a possible role for CCEs in bifenthrin resistance. A selection of CCEs and UGTs were therefore functionally expressed, and CCEinc18 was shown to metabolize bifenthrin, while teturUGT10 could glycosylate bifenthrin-alcohol. To conclude, our findings suggest that both target-site and metabolic mechanisms underlie bifenthrin resistance in T. urticae, and these might synergize high levels of resistance.
ESTHER : De Beer_2022_Biology.(Basel)_11_
PubMedSearch : De Beer_2022_Biology.(Basel)_11_
PubMedID: 36358331

Title : Long-term survey and characterization of cyflumetofen resistance in Tetranychus urticae populations from Turkey - Inak_2022_Pestic.Biochem.Physiol_188_105235
Author(s) : Inak E , Alpkent YN , Saalwaechter C , Albayrak T , Inak A , Dermauw W , Geibel S , Van Leeuwen T
Ref : Pestic Biochem Physiol , 188 :105235 , 2022
Abstract : The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is the most economically important mite pest in agricultural areas and chemical acaricides are widely used to control T. urticae populations. Cyflumetofen is a recently introduced acaricide that inhibits the mitochondrial electron transport chain at complex II (succinate dehydrogenase, SDH), which represents the most recently developed mode of action for mite control worldwide. In the present study, started upon the launch of cyflumetofen in Turkey, a five-year survey was performed to monitor cyflumetofen susceptibility in 28sT. urticae populations collected from agricultural fields across the country. The first resistance case that might cause control failure in practical field conditions was uncovered in 2019, three years after the registration of cyflumetofen. In addition, an extremely resistant population (1722-fold resistance) was also detected towards the end of 2019. Cyflumetofen resistance did not decrease in the laboratory after relaxation of selection pressure for over one year in field-collected populations, suggesting the absence of a fitness cost associated with resistance in these populations. Next to phenotypic resistance, metabolic and physiological mechanisms underlying the decreased susceptibility were also investigated. Synergism assays showed the involvement of P450 monooxygenases in cyflumetofen resistance. Downregulation of carboxylesterases as resistance mechanism, is underpinned by the fact that pre-treatment with esterase inhibitor DEF decreased cyflumetofen toxicity in field-collected strains. Furthermore, a novel H258L substitution in the subunit B of complex II was uncovered in a field population. In silico modeling of the new mutation suggested that the mutation might indeed influence toxicity to complex II inhibitors cyenopyrafen and pyflubumide, but most likely not cyflumetofen. However, further studies are needed to uncover the exact role of this mutation in resistance to this new class of complex II inhibitors.
ESTHER : Inak_2022_Pestic.Biochem.Physiol_188_105235
PubMedSearch : Inak_2022_Pestic.Biochem.Physiol_188_105235
PubMedID: 36464352

Title : Variation of diazinon and amitraz susceptibility of Hyalomma marginatum (Acari: Ixodidae) in the Rabat-Sale-Kenitra region of Morocco - Elhachimi_2021_Ticks.Tick.Borne.Dis_13_101883
Author(s) : Elhachimi L , Van Leeuwen T , Dermauw W , Rogiers C , Valcarcel F , Olmeda AS , Khatat SE , Daminet S , Sahibi H , Duchateau L
Ref : Ticks Tick Borne Dis , 13 :101883 , 2021
Abstract : In the present study, the acaricide susceptibility status of Hyalomma marginatum in Morocco was investigated in the Rabat-Sale-Kenitra region using the Larval Packet Test. The overall LC(50) value for diazinon and amitraz was 115 ppm (95% CI: [104; 125]) and 22 ppm (95% CI: [21; 23]), respectively. The LC(50) values varied significantly between the nine sampled locations (P<0.001) ranging from 75 ppm (95% CI: [65; 84]) in Ouelmes to 179 ppm (95% CI: [139; 201]) in Jorf El Melha for diazinon and from 18 ppm (95% CI: [15; 21]) in Skhirat to 28 ppm (95% CI: [24; 31]) in Ouelmes for amitraz. Sequencing of the target-site of diazinon, acetylcholinesterase 1 (AChE1), indicated that previously reported resistance mutations in AChE1 were absent in ticks from Jorf El Melha surviving 500 ppm diazinon. This study is the first report on the H. marginatum susceptibilty status to the most frequently used acaricides in Morocco and indicates that acaricide tick resistance is emerging.
ESTHER : Elhachimi_2021_Ticks.Tick.Borne.Dis_13_101883
PubMedSearch : Elhachimi_2021_Ticks.Tick.Borne.Dis_13_101883
PubMedID: 34894524
Gene_locus related to this paper: 9acar-MT743247

Title : Identification and characterization of striking multiple-insecticide resistance in a Tetranychus urticae field population from Greece - Papapostolou_2021_Pest.Manag.Sci_77_666
Author(s) : Papapostolou KM , Riga M , Charamis J , Skoufa E , Souchlas V , Ilias A , Dermauw W , Ioannidis P , Van Leeuwen T , Vontas J
Ref : Pest Manag Sci , 77 :666 , 2021
Abstract : BACKGROUND: Tetranychus urticae is a notorious crop pest with world-wide distribution that has developed resistance to a wide range of acaricides. Here, we investigated the resistance levels of a T. urticae population collected from an ornamental greenhouse in Peloponnese, Greece, and analyzed its resistance mechanisms at the molecular level. RESULTS: Toxicological assays showed resistance levels against compounds with different mode of action, with resistance ratios scaling at: 89-fold for abamectin, >1000-fold for clofentezine, >5000-fold etoxazole, 27-fold for fenpyroximate and pyridaben, 20- and 36-fold for spirodiclofen and spirotetramat, respectively and 116- and >500-fold for cyenopyrafen and cyflumetofen, respectively. Bioassays with synergists indicated the involvement of detoxification enzymes in resistance to abamectin but not to cyflumetofen and spirodiclofen. RNAseq analysis showed significant over-expression of several genes encoding detoxification enzymes such as cytochrome P450 monooxygenases and UDP-glycosyltransferases, which have been previously associated with acaricide resistance. Known target-site resistance mutations were identified in acetyl-choline esterase, chitin synthase 1 and NDUFS7/psst, but also discovered putative novel resistance mutations in targets such as the glutamate-gated chloride channel subunit 3. Interestingly, target site resistance mutations against pyrethroids or bifenazate were not identified possibly indicating a recent reduced selection pressure in Greece, as well as a possible opportunity to rotate these chemistries. CONCLUSION: We identified and characterized a striking case of multiple acaricide resistance in a field population of T. urticae. Exceptionally strong resistance phenotypes, with accumulation of multiple resistance mutations and over-expression of P450s and other detoxification genes in the same field population is reported. This article is protected by copyright. All rights reserved.
ESTHER : Papapostolou_2021_Pest.Manag.Sci_77_666
PubMedSearch : Papapostolou_2021_Pest.Manag.Sci_77_666
PubMedID: 33051974
Gene_locus related to this paper: tetur-ACHE

Title : Overexpression of an alternative allele of carboxyl\/choline esterase 4 (CCE04) of Tetranychus urticae is associated with high levels of resistance to the keto-enol acaricide spirodiclofen - Wei_2020_Pest.Manag.Sci_76_1142
Author(s) : Wei P , Demaeght P , De Schutter K , Grigoraki L , Labropoulou V , Riga M , Vontas J , Nauen R , Dermauw W , Van Leeuwen T
Ref : Pest Manag Sci , 76 :1142 , 2020
Abstract : BACKGROUND: Spirodiclofen is an acaricide that targets lipid biosynthesis by inhibiting acetyl-coenzyme A carboxylase. Spirodiclofen resistance in spider mites has been previously documented and was associated with overexpression of CYP392E10, a cytochrome P450 mono-oxygenase that metabolizes spirodiclofen. However, additional mechanisms have been suggested in several studies and a carboxyl/choline esterase gene, CCE04, was shown to be overexpressed in two genetically different strains, SR-VP and SR-TK, both exhibiting high spirodiclofen resistance levels. RESULTS: We identified two different CCE04 alleles in both resistant strains, CCE04(SR-VP) and CCE04(London) , with CCE04(SR-VP) being highly overexpressed. Isoelectric focusing analysis confirmed the overexpression of a single esterase isozyme, while copy number and random fragment length polymorphism analysis revealed that CCE04(SR-VP) overexpression was more likely due to selection for the CCE04(SR-VP) allele rather than gene amplification. Both CCE04 alleles were functionally expressed using the Pichia expression system. Functional enzyme assays revealed only limited kinetic differences between CCE04 isoforms for model substrates. In addition, inhibition/competition experiments with spirodiclofen suggested a similar interaction with both enzymes, whereas its active metabolite, spirodiclofen enol, did not inhibit enzyme activity. CONCLUSION: Our study suggests that selection with spirodiclofen results in enrichment of a specific allele of CCE04 (CCE04(SR-VP) ) in two genetically independent strains, which is highly overexpressed. Based on kinetic enzyme data, however, quantitative rather than qualitative differences between CCE04(SR-VP) and CCE04(London) seem more likely to be involved in resistance. Our findings are discussed in the light of a possible spirodiclofen resistance mechanism, with sequestration of spirodiclofen by CCE04(SR-VP) being a likely hypothesis.
ESTHER : Wei_2020_Pest.Manag.Sci_76_1142
PubMedSearch : Wei_2020_Pest.Manag.Sci_76_1142
PubMedID: 31583806
Gene_locus related to this paper: tetur-t1jsj6 , tetur-t1jth6

Title : Acaricide resistance status and identification of resistance mutations in populations of the two-spotted spider mite Tetranychus urticae from Ethiopia - Simma_2020_Exp.Appl.Acarol_82_475
Author(s) : Simma EA , Hailu B , Jonckheere W , Rogiers C , Duchateau L , Dermauw W , Van Leeuwen T
Ref : Exp Appl Acarol , 82 :475 , 2020
Abstract : The intensive use of pesticides is a common practice for the management of the two-spotted spider mite, Tetranychus urticae, in greenhouses and field farms of Ethiopia. However, incidence of resistance and possible resistance mechanisms in T. urticae populations from Ethiopia have not yet been studied. Here, we assessed the toxicity of various acaricides-bifenazate, abamectin, emamectin benzoate, profenofos, fenbutatin oxide, fenpyroximate, amitraz and chlorfenapyr-on T. urticae populations sampled from six flower greenhouse farms, three strawberry greenhouse farms, one field-grown vegetable farm and two wild populations. In parallel, all populations were screened for known target-site mutations. All tested populations were fully susceptible to bifenazate, abamectin, emamectin benzoate and profenofos, but resistant against fenbutatin oxide and fenpyroximate. Four populations showed considerable levels of resistance against amitraz and one population was resistant to chlorfenapyr. Several target-site mutations were identified in the tested populations, including G119S, A201S, T280A, G328A and F331W/C/Y in acetylcholinesterase and the F1538I and L1024V mutation in the voltage-gated sodium channel. The F1538I mutation was found in eight out of 12 populations, whereas the L1024V mutation was only found in two populations. The H92R mutation in the PSST subunit of complex I and the I1017F mutation in chitin synthase 1 was detected in half of the tested populations. The G326E and I321T mutations in the glutamate-gated chloride channel 3 were also detected, but more rarely, whereas mitochondrial cytochrome b mutations were not detected. The current study revealed multiple resistance patterns in Ethiopian T. urticae populations and together with the wide presence of target-site mutations, calls for the wise use of acaricides in the management of T. urticae in Ethiopia.
ESTHER : Simma_2020_Exp.Appl.Acarol_82_475
PubMedSearch : Simma_2020_Exp.Appl.Acarol_82_475
PubMedID: 33174613
Gene_locus related to this paper: tetur-ACHE

Title : Molecular characterization of pyrethroid resistance in the olive fruit fly Bactrocera oleae - Pavlidi_2018_Pestic.Biochem.Physiol_148_1
Author(s) : Pavlidi N , Kampouraki A , Tseliou V , Wybouw N , Dermauw W , Roditakis E , Nauen R , Van Leeuwen T , Vontas J
Ref : Pestic Biochem Physiol , 148 :1 , 2018
Abstract : Alpha reduction of pyrethroid efficacy has been recently recorded in Bactrocera oleae, the most destructive insect of olives. The resistance levels of field populations collected from Crete-Greece scaled up to 22-folds, compared to reference laboratory strains. Sequence analysis of the IIS4-IIS6 region of para sodium channel gene in a large number of resistant flies indicated that resistance may not be associated with target site mutations, in line with previous studies in other Tephritidae species. We analyzed the transcriptomic differences between two resistant populations versus an almost susceptible field population and two laboratory strains. A large number of genes was found to be significantly differentially transcribed across the pairwise comparisons. Interestingly, gene set analysis revealed that genes of the 'electron carrier activity' GO group were enriched in one specific comparison, which might suggest a P450-mediated resistance mechanism. The up-regulation of several transcripts encoding detoxification enzymes was qPCR validated, focusing on transcripts coding for P450s. Of note, the expression of contig00436 and contig02103, encoding CYP6 P450s, was significantly higher in all resistant populations, compared to susceptible ones. These results suggest that an increase in the amount of the CYP6 P450s might be an important mechanism of pyrethroid resistance in B. oleae.
ESTHER : Pavlidi_2018_Pestic.Biochem.Physiol_148_1
PubMedSearch : Pavlidi_2018_Pestic.Biochem.Physiol_148_1
PubMedID: 29891359

Title : The relative contribution of target-site mutations in complex acaricide resistant phenotypes as assessed by marker assisted backcrossing in Tetranychus urticae - Riga_2017_Sci.Rep_7_9202
Author(s) : Riga M , Bajda S , Themistokleous C , Papadaki S , Palzewicz M , Dermauw W , Vontas J , Leeuwen TV
Ref : Sci Rep , 7 :9202 , 2017
Abstract : The mechanisms underlying insecticide and acaricide resistance in insects and mites are often complex, including additive effects of target-site insensitivity, increased metabolism and transport. The extent to which target-site resistance mutations contribute to the resistance phenotype is, however, not well studied. Here, we used marker-assisted backcrossing to create 30 congenic lines carrying nine mutations (alone, or in combination in a few cases) associated with resistance to avermectins, pyrethroids, mite growth inhibitors and mitochondrial complex III inhibitors (QoI) in a polyphagous arthropod pest, the spider mite Tetranychus urticae. Toxicity tests revealed that mutations in the voltage-gated sodium channel, chitin synthase 1 and cytochrome b confer high levels of resistance and, when fixed in a population, these mutations alone can result in field failure of acaricide treatment. In contrast, although we confirmed the implication of mutations in glutamate-gated chloride channels in abamectin and milbemectin insensitivity, these mutations do not lead to the high resistance levels that are often reported in abamectin resistant strains of T. urticae. Overall, this study functionally validates reported target-site resistance mutations in T. urticae, by uncoupling them from additional mechanisms, allowing to finally investigate the strength of the conferred phenotype in vivo.
ESTHER : Riga_2017_Sci.Rep_7_9202
PubMedSearch : Riga_2017_Sci.Rep_7_9202
PubMedID: 28835683

Title : The Molecular Evolution of Xenobiotic Metabolism and Resistance in Chelicerate Mites - Van Leeuwen_2016_Annu.Rev.Entomol_61_475
Author(s) : Van Leeuwen T , Dermauw W
Ref : Annual Review of Entomology , 61 :475 , 2016
Abstract : Chelicerate mites diverged from other arthropod lineages more than 400 million years ago and subsequently developed specific and remarkable xenobiotic adaptations. The study of the two-spotted spider mite, Tetranychus urticae, for which a high-quality Sanger-sequenced genome was first available, revealed expansions and radiations in all major detoxification gene families, including P450 monooxygenases, carboxyl/cholinesterases, glutathione-S-transferases, and ATP-binding cassette transporters. Novel gene families that are not well studied in other arthropods, such as major facilitator family transporters and lipocalins, also reflect the evolution of xenobiotic adaptation. The acquisition of genes by horizontal gene transfer provided new routes to handle toxins, for example, the beta-cyanoalanine synthase enzyme that metabolizes cyanide. The availability of genomic resources for other mite species has allowed researchers to study the lineage specificity of these gene family expansions and the distinct evolution of genes involved in xenobiotic metabolism in mites. Genome-based tools have been crucial in supporting the idiosyncrasies of mite detoxification and will further support the expanding field of mite-plant interactions.
ESTHER : Van Leeuwen_2016_Annu.Rev.Entomol_61_475
PubMedSearch : Van Leeuwen_2016_Annu.Rev.Entomol_61_475
PubMedID: 26982444

Title : Molecular analysis of cyenopyrafen resistance in the two-spotted spider mite Tetranychus urticae - Khalighi_2016_Pest.Manag.Sci_72_103
Author(s) : Khalighi M , Dermauw W , Wybouw N , Bajda S , Osakabe M , Tirry L , Van Leeuwen T
Ref : Pest Manag Sci , 72 :103 , 2016
Abstract : BACKGROUND: Cyenopyrafen is a recently developed acaricide with a new mode of action as a complex II inhibitor. However, it was recently shown that cross-resistance to cyenopyrafen can occur in resistant field strains of Tetranychus urticae, which might be linked to the previous use of classical METI acaricides. Here, we selected for cyenopyrafen resistance and studied the molecular mechanisms that underlie resistance. RESULTS: Selection for cyenopyrafen resistance confers cross-resistance to the complex II inhibitor cyflumetofen, but also to pyridaben, a frequently used complex I inhibitor. Cyenopyrafen resistance is highly synergised by piperonyl butoxide, and a 15-fold higher P450 activity was detected in the resistant strain. Target-site resistance was not detected. Genome-wide gene expression data, followed by a meta-analysis of previously obtained gene expression data, revealed the overexpression specifically of CYP392A11 and CYP392A12. CONCLUSIONS: Cyenopyrafen resistance is strongly linked to the overexpression of two P450s, which probably explains the observed cross-resistance. This information is highly valuable, as the novel complex II inhibitors cyenopyrafen and cyflumetofen are in the process of worldwide registration. The role of both CYP392A11 and CYP392A12 should be further supported by functional expression, but they are very promising candidates as molecular diagnostic markers for monitoring cyenopyrafen susceptibility in the field.
ESTHER : Khalighi_2016_Pest.Manag.Sci_72_103
PubMedSearch : Khalighi_2016_Pest.Manag.Sci_72_103
PubMedID: 26118668

Title : Transcriptome profiling of a spirodiclofen susceptible and resistant strain of the European red mite Panonychus ulmi using strand-specific RNA-seq - Bajda_2015_BMC.Genomics_16_974
Author(s) : Bajda S , Dermauw W , Greenhalgh R , Nauen R , Tirry L , Clark RM , Van Leeuwen T
Ref : BMC Genomics , 16 :974 , 2015
Abstract : BACKGROUND: The European red mite, Panonychus ulmi, is among the most important mite pests in fruit orchards, where it is controlled primarily by acaricide application. However, the species rapidly develops pesticide resistance, and the elucidation of resistance mechanisms for P. ulmi has not kept pace with insects or with the closely related spider mite Tetranychus urticae. The main reason for this lack of knowledge has been the absence of genomic resources needed to investigate the molecular biology of resistance mechanisms. RESULTS: Here, we provide a comprehensive strand-specific RNA-seq based transcriptome resource for P. ulmi derived from strains susceptible and resistant to the widely used acaricide spirodiclofen. From a de novo assembly of the P. ulmi transcriptome, we manually annotated detoxification enzyme families, target-sites of commonly used acaricides, and horizontally transferred genes implicated in plant-mite interactions and pesticide resistance. In a comparative analysis that incorporated sequences available for Panonychus citri, T. urticae, and insects, we identified radiations for detoxification gene families following the divergence of Panonychus and Tetranychus genera. Finally, we used the replicated RNA-seq data from the spirodiclofen susceptible and resistant strains to describe gene expression changes associated with resistance. A cytochrome P450 monooxygenase, as well as multiple carboxylcholinesterases, were differentially expressed between the susceptible and resistant strains, and provide a molecular entry point for understanding resistance to spirodiclofen, widely used to control P. ulmi populations. CONCLUSIONS: The new genomic resources and data that we present in this study for P. ulmi will substantially facilitate molecular studies of underlying mechanisms involved in acaricide resistance.
ESTHER : Bajda_2015_BMC.Genomics_16_974
PubMedSearch : Bajda_2015_BMC.Genomics_16_974
PubMedID: 26581334

Title : Genotype to phenotype, the molecular and physiological dimensions of resistance in arthropods - Feyereisen_2015_Pestic.Biochem.Physiol_121_61
Author(s) : Feyereisen R , Dermauw W , Van Leeuwen T
Ref : Pestic Biochem Physiol , 121 :61 , 2015
Abstract : The recent accumulation of molecular studies on mutations in insects, ticks and mites conferring resistance to insecticides, acaricides and biopesticides is reviewed. Resistance is traditionally classified by physiological and biochemical criteria, such as target-site insensitivity and metabolic resistance. However, mutations are discrete molecular changes that differ in their intrinsic frequency, effects on gene dosage and fitness consequences. These attributes in turn impact the population genetics of resistance and resistance management strategies, thus calling for a molecular genetic classification. Mutations in structural genes remain the most abundantly described, mostly in genes coding for target proteins. These provide the most compelling examples of parallel mutations in response to selection. Mutations causing upregulation and downregulation of genes, both in cis (in the gene itself) and in trans (in regulatory processes) remain difficult to characterize precisely. Gene duplications and gene disruption are increasingly reported. Gene disruption appears prevalent in the case of multiple, hetero-oligomeric or redundant targets.
ESTHER : Feyereisen_2015_Pestic.Biochem.Physiol_121_61
PubMedSearch : Feyereisen_2015_Pestic.Biochem.Physiol_121_61
PubMedID: 26047113

Title : Genome sequence of the Asian Tiger mosquito, Aedes albopictus, reveals insights into its biology, genetics, and evolution - Chen_2015_Proc.Natl.Acad.Sci.U.S.A_112_E5907
Author(s) : Chen XG , Jiang X , Gu J , Xu M , Wu Y , Deng Y , Zhang C , Bonizzoni M , Dermauw W , Vontas J , Armbruster P , Huang X , Yang Y , Zhang H , He W , Peng H , Liu Y , Wu K , Chen J , Lirakis M , Topalis P , Van Leeuwen T , Hall AB , Thorpe C , Mueller RL , Sun C , Waterhouse RM , Yan G , Tu ZJ , Fang X , James AA
Ref : Proc Natl Acad Sci U S A , 112 :E5907 , 2015
Abstract : The Asian tiger mosquito, Aedes albopictus, is a highly successful invasive species that transmits a number of human viral diseases, including dengue and Chikungunya fevers. This species has a large genome with significant population-based size variation. The complete genome sequence was determined for the Foshan strain, an established laboratory colony derived from wild mosquitoes from southeastern China, a region within the historical range of the origin of the species. The genome comprises 1,967 Mb, the largest mosquito genome sequenced to date, and its size results principally from an abundance of repetitive DNA classes. In addition, expansions of the numbers of members in gene families involved in insecticide-resistance mechanisms, diapause, sex determination, immunity, and olfaction also contribute to the larger size. Portions of integrated flavivirus-like genomes support a shared evolutionary history of association of these viruses with their vector. The large genome repertory may contribute to the adaptability and success of Ae. albopictus as an invasive species.
ESTHER : Chen_2015_Proc.Natl.Acad.Sci.U.S.A_112_E5907
PubMedSearch : Chen_2015_Proc.Natl.Acad.Sci.U.S.A_112_E5907
PubMedID: 26483478
Gene_locus related to this paper: aedae-q177c7 , aedal-a0a182gwe3 , aedal-a0a182gwt8 , aedal-a0a023eq67

Title : Molecular analysis of resistance to acaricidal spirocyclic tetronic acids in Tetranychus urticae: CYP392E10 metabolizes spirodiclofen, but not its corresponding enol - Demaeght_2013_Insect.Biochem.Mol.Biol_43_544
Author(s) : Demaeght P , Dermauw W , Tsakireli D , Khajehali J , Nauen R , Tirry L , Vontas J , Lummen P , Van Leeuwen T
Ref : Insect Biochemistry & Molecular Biology , 43 :544 , 2013
Abstract : Spirodiclofen is one of the most recently developed acaricides and belongs to the new family of spirocyclic tetronic acids (ketoenols). This new acaricidal family is an important chemical tool in resistance management strategies providing sustainable control of spider mites such as Tetranychus urticae. Spirodiclofen targets lipid biosynthesis mediated by direct inhibition of acetyl coenzyme A carboxylase (ACCase). In this study, we investigated two genetically distant spider mite strains with high resistance to spirodiclofen. Despite the strong resistance levels to spirodiclofen (up to 680-fold), only limited cross-resistance with other members of this group such as spiromesifen and spirotetramat could be detected. Amplification and sequencing of the ACCase gene from resistant and susceptible strains did not reveal common non-synonymous mutations, and expression levels of ACCase were similar in both resistant and susceptible strains, indicating the absence of target-site resistance. Furthermore, we collected genome-wide expression data of susceptible and resistant T. urticae strains using microarray technology. Analysis of differentially expressed genes revealed a broad response, but within the overlap of two resistant strains, several cytochrome P450s were prominent. Quantitative PCR confirmed the constitutive over-expression of CYP392E7 and CYP392E10 in resistant strains, and CYP392E10 expression was highly induced by spirodiclofen. Furthermore, stage specific expression profiling revealed that expression levels were not significantly different between developing stages, but very low in eggs, matching the age-dependent resistance pattern previously observed. Functional expression of CYP392E7 and CYP392E10 confirmed that CYP392E10 (but not CYP392E7) metabolizes spirodiclofen by hydroxylation as identified by LC-MS/MS, and revealed cooperative substrate binding and a Km of 43 muM spirodiclofen. CYP392E10 also metabolizes spiromesifen, but not spirotetramat. Surprisingly, no metabolism of the hydrolyzed spirodiclofen-enol metabolite could be detected. These findings are discussed in the light of a likely resistance mechanism.
ESTHER : Demaeght_2013_Insect.Biochem.Mol.Biol_43_544
PubMedSearch : Demaeght_2013_Insect.Biochem.Mol.Biol_43_544
PubMedID: 23523619

Title : The genome of Tetranychus urticae reveals herbivorous pest adaptations - Grbic_2011_Nature_479_487
Author(s) : Grbic M , Van Leeuwen T , Clark RM , Rombauts S , Rouze P , Grbic V , Osborne EJ , Dermauw W , Ngoc PC , Ortego F , Hernandez-Crespo P , Diaz I , Martinez M , Navajas M , Sucena E , Magalhaes S , Nagy L , Pace RM , Djuranovic S , Smagghe G , Iga M , Christiaens O , Veenstra JA , Ewer J , Villalobos RM , Hutter JL , Hudson SD , Velez M , Yi SV , Zeng J , Pires-daSilva A , Roch F , Cazaux M , Navarro M , Zhurov V , Acevedo G , Bjelica A , Fawcett JA , Bonnet E , Martens C , Baele G , Wissler L , Sanchez-Rodriguez A , Tirry L , Blais C , Demeestere K , Henz SR , Gregory TR , Mathieu J , Verdon L , Farinelli L , Schmutz J , Lindquist E , Feyereisen R , Van de Peer Y
Ref : Nature , 479 :487 , 2011
Abstract : The spider mite Tetranychus urticae is a cosmopolitan agricultural pest with an extensive host plant range and an extreme record of pesticide resistance. Here we present the completely sequenced and annotated spider mite genome, representing the first complete chelicerate genome. At 90 megabases T. urticae has the smallest sequenced arthropod genome. Compared with other arthropods, the spider mite genome shows unique changes in the hormonal environment and organization of the Hox complex, and also reveals evolutionary innovation of silk production. We find strong signatures of polyphagy and detoxification in gene families associated with feeding on different hosts and in new gene families acquired by lateral gene transfer. Deep transcriptome analysis of mites feeding on different plants shows how this pest responds to a changing host environment. The T. urticae genome thus offers new insights into arthropod evolution and plant-herbivore interactions, and provides unique opportunities for developing novel plant protection strategies.
ESTHER : Grbic_2011_Nature_479_487
PubMedSearch : Grbic_2011_Nature_479_487
PubMedID: 22113690
Gene_locus related to this paper: tetur-ACHE

Title : Acaricide resistance mechanisms in the two-spotted spider mite Tetranychus urticae and other important Acari: a review - Van Leeuwen_2010_Insect.Biochem.Mol.Biol_40_563
Author(s) : Van Leeuwen T , Vontas J , Tsagkarakou A , Dermauw W , Tirry L
Ref : Insect Biochemistry & Molecular Biology , 40 :563 , 2010
Abstract : The two-spotted spider mite Tetranychus urticae Koch is one of the economically most important pests in a wide range of outdoor and protected crops worldwide. Its control has been and still is largely based on the use of insecticides and acaricides. However, due to its short life cycle, abundant progeny and arrhenotokous reproduction, it is able to develop resistance to these compounds very rapidly. As a consequence, it has the dubious reputation to be the"most resistant species" in terms of the total number of pesticides to which populations have become resistant, and its control has become problematic in many areas worldwide. Insecticide and acaricide resistance has also been reported in the ectoparasite Sarcoptes scabiei, the causative organism of scabies, and other economically important Acari, such as the Southern cattle tick Rhipicephalus microplus, one of the biggest arthropod threats to livestock, and the parasitic mite Varroa destructor, a major economic burden for beekeepers worldwide. Although resistance research in Acari has not kept pace with that in insects, a number of studies on the molecular mechanisms responsible for the resistant phenotype has been conducted recently. In this review, state-of-the-art information on T. urticae resistance, supplemented with data on other important Acari has been brought together. Considerable attention is given to the underlying resistance mechanisms that have been elucidated at the molecular level. The incidence of bifenazate resistance in T. urticae is expanded as an insecticide resistance evolutionary paradigm in arthropods.
ESTHER : Van Leeuwen_2010_Insect.Biochem.Mol.Biol_40_563
PubMedSearch : Van Leeuwen_2010_Insect.Biochem.Mol.Biol_40_563
PubMedID: 20685616