The effect of insecticide synergist treatment on genome-wide gene expression in a polyphagous pest

Abstract

Synergists can counteract metabolic insecticide resistance by inhibiting detoxification enzymes or transporters. They are used in commercial formulations of insecticides, but are also frequently used in the elucidation of resistance mechanisms. However, the effect of synergists on genome-wide transcription in arthropods is poorly understood. In this study we used Illumina RNA-sequencing to investigate genome-wide transcriptional responses in an acaricide resistant strain of the spider mite Tetranychus urticae upon exposure to synergists such as S,S,S-tributyl phosphorotrithioate (DEF), diethyl maleate (DEM), piperonyl butoxide (PBO) and cyclosporin A (CsA). Exposure to PBO and DEF resulted in a broad transcriptional response and about one third of the differentially expressed genes (DEGs), including cytochrome P450 monooxygenases and UDP-glycosyltransferases, was shared between both treatments, suggesting common transcriptional regulation. Moreover, both DEF and PBO induced genes that are strongly implicated in acaricide resistance in the respective strain. In contrast, CsA treatment mainly resulted in downregulation of Major Facilitator Superfamily (MFS) genes, while DEGs of the DEM treatment were not significantly enriched for any GO-terms.

Derived esterase activity inDrosophila sechelliacontributes to evolved octanoic acid resistance

“…To investigate the possible role of common detoxification gene families in D. sechellia's evolved resistance to toxins produced by its preferred host plant M. citrifolia, we used chemical synergists to inactivate the functions of these gene families and determined if this inactivation altered resistance to the plant toxins OA and HA. We used the pesticide synergist DEM to eliminate the function of GST gene family members and tribufos to inactivate members of the EST gene family (Plapp et al, 1963;Boyland and Chasseaud, 1970;Snoeck et al, 2017). Prior research showed that members of the common detoxification gene family, the CYP genes, provide basal resistance to both OA and HA in Drosophila species but that they are not the source of D. sechellia's derived resistance to both plant toxins (Peyser et al, 2017).…”

“…Previous research has shown that tribufos acts primarily on ESTs, but can also inhibit CYP enzymatic activity, although to a smaller extent (Sanchez-Arroyo et al, 2001). Thus, it is important to also rule out CYP enzymatic activity to ensure the specificity of EST contribution when interpreting results from studies using tribufos (Snoeck et al, 2017). Importantly, in our prior study we showed that CYP enzymatic activity was not responsible for the evolved OA resistance observed in D. sechellia (Peyser et al, 2017), strengthening the conclusion that evolved EST(s) expression or function contributes to derived OA resistance in D. sechellia.…”

“…DEM works by conjugating reduced glutathione, making it unavailable in cells. This leaves the GSTs nothing to conjugate to toxins, rendering them nonfunctional in toxin resistance (Boyland and Chasseaud, 1970;Welling and De Vries, 1985;Fujioka and Casida, 2007;Snoeck et al, 2017). Tribufos is an organophosphorus compound that covalently bonds to esterase active sites and upon enzymatic cleavage of the synergist leaves the esterase inactivated by phosphorylation (Plapp et al, 1963;Snoeck et al, 2017).…”

“…This leaves the GSTs nothing to conjugate to toxins, rendering them nonfunctional in toxin resistance (Boyland and Chasseaud, 1970;Welling and De Vries, 1985;Fujioka and Casida, 2007;Snoeck et al, 2017). Tribufos is an organophosphorus compound that covalently bonds to esterase active sites and upon enzymatic cleavage of the synergist leaves the esterase inactivated by phosphorylation (Plapp et al, 1963;Snoeck et al, 2017). Insect toxin resistance mediated by GSTs (Chiang and Sun, 1993;Kostaropoulos et al, 2001;Enayati et al, 2005;Lumjuan et al, 2011;Pavlidi et al, 2015) and ESTs (Campbell et al, 1998;Farnsworth et al, 2010;Zhang et al, 2013;Feng et al, 2018) is well documented, including examples in other species of Drosophila, such as the cactophilic species Drosophila mettleri and Drosophila mojavensis (Matzkin et al, 2006;Bono et al, 2008;Hoang et al, 2015).…”

Otimização de metodologia de obtenção de pastas cimentícias contendo hidrogéis

“…Nesse sentido, pesquisas recentes destacam que a produção de compósitos de matriz cimentícia é algo inovador, principalmente ao que se refere ao controle sobre a água na tecnologia de concreto. Surgem então, alguns aditivos poliméricos que podem ser adicionados ao concreto e argamassas, tais como os hidrogéis, como uma alternativa promissora a ser adicionada aos materiais cimentícios [7].…”