Biochemical and molecular characterisation and cross‐resistance in field and laboratory chlorpyrifos‐resistant strains of Laodelphax striatellus (Hemiptera: Delphacidae) from eastern China

Abstract

In contrast to previous reports, multiple overexpressed detoxification genes were potentially associated with chlorpyrifos resistance, as confirmed by RNAi feeding tests. Chlorpyrifos resistance exhibits cross-resistance with insecticides in the same and different classes.

Constitutive overexpression of cytochrome P450 associated with imidacloprid resistance in Laodelphax striatellus (Fallén)

“…For example, CYP314A1 conferred DDT resistance in Anopheles gambiae, 34 CYP325C1 conferred resistance to pyrethroid in A. stephensi 35 and CYP337B1 conferred deltamethrin resistance in Helicoverpa armigera. 36 Among CYP genes in L. striatellus, previous work in our laboratory showed that CYP6AY3v2, CYP306A2v2 and CYP353D1v2 were upregulated for chlorpyrifos resistance, 19 and CYP6AY3v2, CYP314A1v2, CYP6FU1, CYP353D1v2 and CYP439A1v3 were upregulated for deltamethrin resistance. 18 Thus, the identified CYP353D1v2 in the present work should be one of the multiple detoxification genes in L. striatellus.…”

Expression profiles of glutathione S‐transferase superfamily in Spodoptera litura tolerated to sublethal doses of chlorpyrifos

“…This group may play a role in CPF tolerance establishment in the 12‐generation‐CPF‐treated strain. Thus, we hypothesize that in polyphagous S. litura , some isoforms of SlGSTs can directly and quickly respond to the insecticide and detoxify it by forming nontoxic conjugates, for instance, SlGSTE1 which was responsive to CPF induction (Table ), catalyzed the conjugate of CPF and reduced glutathione (Xu et al ., ); while other isoforms, especially microsomal GSTs that have peroxidase activity, may respond to the oxidative stress generated by CPF and detoxify it through peroxidase activity. This finding is similar to reports in other species.…”

“…This compound binds to the active site of the cholinesterase (ChE), resulting in accumulation of acetylcholine in the synaptic cleft (Karanth & Pope, ). Three kinds of detoxification enzymes have been reported to be involved in CPF resistance in insects, for example, cytochrome P450 enzymes and esterases in Laodelphax striatellus (Xu et al ., ) and glutathione S ‐transferase MlGSTu1 in migratory locust (Qin et al ., ). Detoxification enzymes can detoxify not only CPF, but also toxic oxidative products derived from CPF.…”

Viral infection induces different detoxification enzyme activities in insecticide-resistant and -susceptible brown planthopper <i>Nilaparvata lugens</i> strains

“…Several studies have indicated decreasing susceptibility to various insecticides, including pyrethroids, organophosphates, carbamates, and neonicotinoids, [9][10][11][12][13] which is caused largely by the induction and activation of detoxification enzymes 14) such as carboxylesterase (CE) 15) and cytochrome-P450-monooxygenase (P450) against organophosphates and carbamates, 16) glutathione S-transferase (GST) against pyrethroids, [17][18][19] and P450 against neonicotinoid insecticides.…”

“…Insecticide-selected BPH individuals overexpress cytochrome P450 (CYP) genes encoding P450 enzymes [24][25][26][27][28] and also show promoter polymorphism, 29) wherein the CYP and CE genes are overexpressed in response to the organophosphate chlorpyrifos. 16) On the other hand, BPH acquires and transmits rice ragged stunt virus (RRSV; Reoviridae, Fijivirus) [30][31][32][33] and rice grassy stunt virus (RGSV; Tenuivirus) 33,34) by feeding on infected plants, accelerating the severe damage on growing rice plants. Although the role of detoxification enzymes in insecticide resistance has been clarified, the effects of virus infection on the activities of key detoxification enzymes such as CE, GST, and P450 in vector insects remain undescribed.…”