Insect TRP channels as targets for insecticides and repellents

Salgado, Vincent L.

doi:10.1584/jpestics.d16-104

Cited by 37 publications

(28 citation statements)

References 59 publications

(81 reference statements)

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“…Remarkably, the repellency of CDIAL was comparable to DEET—the current gold standard for a repellent—despite an over 1.5-times lower molar amount of CDIAL vs. DEET used in the assays. Thus, our findings galvanize the notion suggested by others that TRPA1 agonists offer valuable potential molecules for the development of new repellents [ 31 , 34 , 40 – 43 ].…”

Section: Discussionsupporting

confidence: 84%

“…Emerging evidence in vertebrate and insect systems (including mosquitoes) suggests that electrophilic unsaturated sesquiterpene dialdehydes are agonists of Transient Receptor Potential A1 (TRPA1) channels, which are receptors that play important roles in the environmental sensing and avoidance of potentially noxious chemicals, as well as temperatures [ 31 – 39 ]. Chemical agonists of TRPA1 have been suggested as potential molecules for the development of new insect repellents [ 31 , 34 , 40 – 43 ]. Thus, we also tested the hypothesis that CDIAL’s mechanism of action in mosquitoes involved the modulation of TRPA1.…”

Section: Introductionmentioning

confidence: 99%

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A natural agonist of mosquito TRPA1 from the medicinal plant Cinnamosma fragrans that is toxic, antifeedant, and repellent to the yellow fever mosquito Aedes aegypti

et al. 2018

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Plants produce various secondary metabolites that offer a potential source of novel insecticides and repellents for the control of mosquito vectors. Plants of the genus Cinnamosma are endemic to, and widely-distributed throughout, the island of Madagascar. The barks of these species are commonly used in traditional medicines for treating a wide range of maladies. The therapeutic nature of the bark is thought to be associated with its enrichment of pungent drimane sesquiterpenes, which elicit antifeedant and toxic effects in some insects. Here we test the hypothesis that a bark extract of Cinnamosma fragrans (CINEX) and its major drimane sesquiterpenes are insecticidal, antifeedant, and repellent to Aedes aegypti, the principal mosquito vector of chikungunya, dengue, yellow fever, and Zika viruses. We demonstrate that CINEX is 1) toxic to larval and adult female mosquitoes, and 2) antifeedant and repellent to adult female mosquitoes. Moreover, we show that cinnamodial (CDIAL), a sesquiterpene dialdehyde isolated from CINEX, duplicates these bioactivities and exhibits similar toxic potency against pyrethroid-susceptible and -resistant strains of Ae. aegypti. Importantly, we show that CDIAL is an agonist of heterologously-expressed mosquito Transient Receptor Potential A1 (TRPA1) channels, and the antifeedant activity of CDIAL is dampened in a TRPA1-deficient strain of Ae. aegypti (TRPA1-/-). Intriguingly, TRPA1-/- mosquitoes do not exhibit toxic resistance to CDIAL. The data indicate that modulation of TRPA1 is required for the sensory detection and avoidance of CDIAL by mosquitoes, but not for inducing the molecule’s toxicity. Our study suggests that CDIAL may serve as a novel chemical platform for the development of natural product-based insecticides and repellents for controlling mosquito vectors.

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Section: Discussionsupporting

confidence: 84%

Section: Introductionmentioning

confidence: 99%

A natural agonist of mosquito TRPA1 from the medicinal plant Cinnamosma fragrans that is toxic, antifeedant, and repellent to the yellow fever mosquito Aedes aegypti

et al. 2018

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“…Application of the insecticide pymetrozine on the female's genitalia reduced the mechanosensory responses to tap stimulation. Pymetrozine is a pesticide that interferes with a subgroup of insect transient receptor potential channels [37,38], selectively blocking chordotonal receptors [30]. We therefore assume that besides mechanosensilla on the surface the titillator taps are also perceived by proposed internal chordotonal receptors of the female's genital fold [27].…”

Section: Discussionmentioning

confidence: 99%

Female perception of copulatory courtship by male titillators in a bushcricket

2018

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Males of the bushcricket bear paired titillators that are spiny genital structures supposedly functioning as copulatory courtship devices. During copulation, the male inserts its titillators into the female's genital chamber, where they rhythmically tap on the sensilla-covered dorsal surface of the genital fold. Here, we investigated the stimulatory function of male titillators during mating in Tracer backfills of presumptive mechanosensory sensilla at the female genital fold revealed a thick bundle of sensory axons entering the last unfused abdominal ganglion (AG-7). Electrophysiological recordings of abdominal nerves demonstrated that females sense mechanical stimulation at their genital fold. The mechanosensory responses, however, were largely reduced by the insecticide pymetrozine that selectively blocks scolopidia of internal chordotonal organs but not campaniform and hair sensilla on the outer cuticle surface. In mating experiments, the females showed resistance behaviours towards males with asymmetrically shortened titillators, but the resistance was largely reduced when mechanoreceptors at the female's genital fold were either pharmacologically silenced by pymetrozine or mechanically blocked by capping with UV-hardened glue. Our findings support the hypothesis that the male titillators in these bushcrickets may serve as copulatory courtship devices to mechanically stimulate the female genitalia to reduce resistance behaviour.

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“…Previous researches have shown that both pymetrozine and afidopyropen act by modulating TRPV channels [ 15 , 16 ], and that TRPA1 in the mosquito vector for malaria, Anopheles gambiae , is potently and directly activated by citronellal [ 17 ]. Thus, TRPs have become potential targets for insecticide development as well as for improved repellents to control insect-borne diseases [ 18 , 19 ]. Investigating the molecular characteristics of TRPs in B. dorsalis will enable a better understanding of this system in a key agricultural pest and will provide a firm foundation for future insecticide design targeting these channels.…”

Section: Introductionmentioning

confidence: 99%

Identification, characterization and expression analysis of transient receptor potential channel genes in the oriental fruit fly, Bactrocera dorsalis

Bai

Zeng

et al. 2018

BMC Genomics

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BackgroundMembers of the transient receptor potential (TRP) superfamily are proteins that are critical for insects to detect changes in environmental stimuli and also play key roles in their sensory physiology. Moreover, this family provides potential targets for the design of insecticides. In contrast to a large number of studies conducted on Drosophila melanogaster, molecular studies to characterize TRP channels in agricultural pests are lacking.ResultsIn this study, we identified 15 TRP channel genes in the genome of a notorious agricultural pest, the oriental fruit fly (Bactrocera dorsalis). Comparative analysis of the TRP channels (TRPs) in B. dorsalis with those in D. melanogaster, Glossina morsitans, Musca domestica and the closely related Ceratitis capitata, and TRPs from mosquitoes, Hymenoptera, Lepidoptera, Coleoptera and Hemiptera reveals that members of TRPA and TRPP subfamily are most diverse among insects. The results also suggest that Tephritidae family have two TRP-Polycystin 2 members even though most insects either possess just one or none. The highest expression levels of these two genes are in the testes of B. dorsalis, implying a role in regulating sperm function. We analyzed the expression profiles of the TRP channels identified in this study at different life stages using quantitative real time PCR. The results of this study demonstrate that all TRP channels are mainly expressed in adults, especially at mature stages. The one exception to this trend is BdTRPM, which is more highly expressed in the eggs of B. dorsalis, implying an important role in early development. We also detected the spatial expression of TRP channels in mature adult fruit flies by investigating expression levels within various tissues including those involved in sensory function, such as antennae, compound eyes, mouthparts, legs, and wings, as well as tissues critical for homeostasis and physiology (i.e., Malpighian tubules, the brain and gut as well as fat bodies, ovaries, and testes).ConclusionThe results of this study establish a solid foundation for future functional characterization of B. dorsalis TRP channels as well as those of other insects and will help future insecticide design targeting these channels.Electronic supplementary materialThe online version of this article (10.1186/s12864-018-5053-7) contains supplementary material, which is available to authorized users.

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Insect TRP channels as targets for insecticides and repellents

Cited by 37 publications

References 59 publications

A natural agonist of mosquito TRPA1 from the medicinal plant Cinnamosma fragrans that is toxic, antifeedant, and repellent to the yellow fever mosquito Aedes aegypti

A natural agonist of mosquito TRPA1 from the medicinal plant Cinnamosma fragrans that is toxic, antifeedant, and repellent to the yellow fever mosquito Aedes aegypti

Female perception of copulatory courtship by male titillators in a bushcricket

Identification, characterization and expression analysis of transient receptor potential channel genes in the oriental fruit fly, Bactrocera dorsalis

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