Gut symbiont enhances insecticide resistance in a significant pest, the oriental fruit fly Bactrocera dorsalis (Hendel)

Abstract

BackgroundSymbiotic bacteria affect insect physiology and ecology. They may also mediate insecticide resistance within their hosts and thereby impact pest and vector control practices. Here, we document a novel mechanism of insecticide resistance in which a gut symbiont of the tephritid pest fruit fly Bactrocera dorsalis enhances resistance to the organophosphate insecticide trichlorphon.ResultsWe demonstrated that the gut symbiont Citrobacter sp. (CF-BD) plays a key role in the degradation of trichlorphon. Based on a comparative genomics analysis with other Citrobacter species, phosphatase hydrolase genes were identified in CF-BD. These CF-BD genes had higher expression when trichlorphon was present. Bactrocera dorsalis inoculated with isolated CF-BD obtained higher trichlorphon resistance, while antibiotic-treated flies were less resistant confirming the key role of CF-BD in insecticide resistance.ConclusionsOur findings suggest that symbiont-mediated insecticide resistance can readily develop in B. dorsalis and may represent a more widely relevant insecticide resistance mechanism than previously recognized.Electronic supplementary materialThe online version of this article (doi:10.1186/s40168-017-0236-z) contains supplementary material, which is available to authorized users.

Fitness costs of infection with Serratia symbiotica are associated with greater susceptibility to insecticides in the pea aphid Acyrthosiphon pisum

“…There is growing evidence to support the involvement of insect‐associated bacterial symbionts in detoxification of chemical insecticides, e.g. the stink bug R. pedestri and its symbiont Burkholderia spp., the diamondback moth ( Plutella xylostella L.) and the symbionts Bacillus , Enterobacter and Pantoea spp., and the fruit fly ( Bactrocera dorsalis Hendel) with associated Citrobacter spp . These bacteria are mainly associated with the detoxification of organophosphates, although Bacillus spp.…”

“…These bacteria are mainly associated with the detoxification of organophosphates, although Bacillus spp. can also detoxify oxadiazine insecticides …”

Intestinal probiotics restore the ecological fitness decline of Bactrocera dorsalis by irradiation

“…Our previous studies showed that B. dorsalis adults were attracted by the metabolites of symbiotic Enterobacteriaceae (Shi, Wang, & Zhang, ). Recently, a study demonstrated that Enterobacteriaceae can degrade trichlorphon and increase the insecticide resistance of host (Cheng et al., ). The continuous presence and dominance of the Enterobacteriaceae family in the gut bacterial community of tephritidae fruit flies indicate an important functional role as symbionts in host fitness.…”

Repressed Beauveria bassiana infections in Delia antiqua due to associated microbiota

“…Current research on insect–microbe symbioses has revealed both mutualistic and antagonistic relationships between insect hosts and their microbial symbionts . In a mutualistic relationship, the microbial symbiont improves the ecological fitness of its insect host . In an antagonistic relationship, the microbial symbiont threatens the survival of the insect host.…”