Reduced insecticide susceptibility of the wheat aphid Sitobion miscanthi after infection by the secondary bacterial symbiont Hamiltonella defensa

Abstract

BACKGROUND Bacterial symbionts in insects, especially aphids, have a major influence on host adaptation. We previously showed that infection with the secondary symbiont Hamiltonella defensa increases the fitness of the wheat aphid Sitobion miscanthi, yielding increases in fitness parameters such as adult weight and offspring number. However, whether H. defensa affects the sensitivity of host aphids to insecticides remains unknown. RESULTS We tested the effects of H. defensa on host aphid susceptibility to the insecticides chlorpyrifos methyl, imidacloprid, cyantraniliprole and acetamiprid. Our results showed that compared with Hamiltonella‐free aphid clones, Hamiltonella‐infected aphid clones exhibited lower sensitivity to most of the tested insecticides at low concentrations. Quantitative polymerase chain reaction showed that the density of H. defensa in the infected clones was slightly decreased at 24 h but then sharply increased until the late stage after treatment with the different insecticides. H. defensa in the host aphids was detected by fluorescence in situ hybridization and was localized to the aphid hindgut. Levels of the detoxification enzymes acetylcholinesterase, glutathione transferase and carboxylesterase were significantly higher in Hamiltonella‐infected clones than in Hamiltonella‐free clones. CONCLUSIONS The findings indicated that infection with H. defensa reduced aphid susceptibility to the investigated insecticides at low concentrations, potentially by increasing detoxification enzyme activity in the host. Therefore, symbiont‐mediated insecticide resistance should be taken into account when performing resistance‐monitoring studies. Studies of symbiont‐mediated insecticide resistance may enhance our understanding of the emergence of insecticide resistance in agricultural systems. © 2020 Society of Chemical Industry

Molecular basis of mutual benefits between Cucurbit chlorotic yellows virus (CCYV) transmission and imidacloprid resistance in Bemisia tabaci

“…There have also been reports of microbe-mediated insecticide sensitivity. For example, the symbiotic bacteria or gut microbiota of wheat aphid Sitobion miscanthi and Rhagoletis pomonella are reportedly associated with detoxification (Li et al, 2021;Lauzon et al, 2003). This has raised the question whether insect vector-borne viruses and insect vectors exist in a mutually beneficial relationship over the long term.…”

Common facultative endosymbionts do not influence sensitivity of cereal aphids to pyrethroids

“…Intra-species diversity in cereal aphids is associated with genetic diversity and the composition of endosymbiont communities (Alkhedir et al ., 2013; Malloch et al ., 2016; Guo et al ., 2019; Leybourne et al ., 2020a). This intra-species diversity can affect the aphid phenotype, and there is evidence that this could include heightened aphid susceptibility to insecticides (Li et al ., 2021). In order to examine whether natural occurrence of facultative endosymbionts influences aphid sensitivity to pyrethroids, we characterised the facultative endosymbiont community of the 32 aphid populations and related this to the results of the dose-response assays.…”

Symbiotic microbial studies in diverse populations of Aphis gossypii, existing on altered host plants in different localities during different times

“…gossypii by enhancing its performance (Ayoubi et al., 2020 ). Recent research shows Hamiltonella also can have an effect on insecticide resistance of aphids (Li et al., 2020 ) or can alter the dynamics of host metabolic interactions with co‐occurring microorganisms (Blow et al., 2020 ). Costs and benefits of coinfection have influenced within‐host interactions between these symbionts, resulting in coinfection dynamic changes within natural populations (Russell et al., 2013 ).…”