Temporal changes of symbiont density and host fitness after rifampicin treatment in a whitefly of the Bemisia tabaci species complex

Abstract

Microbial symbionts are essential or important partners to phloem-feeding insects. Antibiotics have been used to selectively eliminate symbionts from their host insects and establish host lines with or without certain symbionts for investigating functions of the symbionts. In this study, using the antibiotic rifampicin we attempted to selectively eliminate certain symbionts from a population of the Middle East-Asia Minor 1 whitefly of the Bemisia tabaci species complex, which harbors the primary symbiont "Candidatus Portiera aleyrodidarum" and two secondary symbionts "Candidatus Hamiltonella defensa" and Rickettsia. Neither the primary nor the secondary symbionts were completely depleted in the adults (F0) that fed for 48 h on a diet treated with rifampicin at concentrations of 1-100 μg/mL. However, both the primary and secondary symbionts were nearly completely depleted in the offspring (F1) of the rifampicin-treated adults. Although the F1 adults produced some eggs (F2), most of the eggs failed to hatch and none of them reached the second instar, and consequently the rifampicin-treated whitefly colony vanished at the F2 generation. Interestingly, quantitative polymerase chain reaction assays showed that in the rifampicin-treated whiteflies, the density of the primary symbiont was reduced at an obviously slower pace than the secondary symbionts. Mating experiments between rifampicin-treated and untreated adults demonstrated that the negative effects of rifampicin on host fitness were expressed when the females were treated by the antibiotic, and whether males were treated or not by the antibiotic had little contribution to the negative effects. These observations indicate that with this whitefly population it is not feasible to selectively eliminate the secondary symbionts using rifampicin without affecting the primary symbiont and establish host lines for experimental studies. However, the extinction of the whitefly colony at the second generation after rifampicin treatment indicates the potential of the antibiotic as a control agent of the whitefly pest.

Selective and stable elimination of endosymbionts from multiple‐infected whitefly Bemisia tabaci by feeding on a cotton plant cultured in antibiotic solutions

“…Meanwhile, all of the symbionts considered in our study can be removed by rifampicin treatment. But non-simultaneous reductions of the obligate and secondary symbionts were found, which was consistent with previous studies (Shan et al, 2014(Shan et al, , 2016. The reduction of facultative symbionts occurred at a much quicker pace than obligate symbiont Portiera during the rifampicin treatment.…”

“…Lysozyme injection has been less and less used recent years for the substantial odeleterious effects on host tissues (Nogge & Gerresheim, 1982;Wilkinson, 1998). Antibiotic therapy is the most widely adopted method to cure symbionts of arthropod hosts, administered either orally (via feeding chemically defined diets) or by direct injection (Shan et al, 2016). The obligate and some facultative symbionts of whitefly Bemisia tabaci (Gennadius) were depleted by feeding on a chemical diet containing rifampicin (Xue et al, 2012;Shan et al, 2016;Lv et al, 2018).…”

“…Antibiotic therapy is the most widely adopted method to cure symbionts of arthropod hosts, administered either orally (via feeding chemically defined diets) or by direct injection (Shan et al, 2016). The obligate and some facultative symbionts of whitefly Bemisia tabaci (Gennadius) were depleted by feeding on a chemical diet containing rifampicin (Xue et al, 2012;Shan et al, 2016;Lv et al, 2018). Nymphs injected with different concentrations of penicillin G selectively eliminated Cardinium from Wolbachia-Cardinium doubly infected planthopper Sogatella furcifera (Hemiptera: Delphacidae) (Zhang et al, 2012).…”

“…Wolbachia could not be completely eliminated from B. tabaci by antibiotic diet-feeding in a relatively short period of time, leading to that offspring produced by antibiotic-fed mothers also carried Wolbachia at low density (Zhong & Li, 2013). Although whitefly adults feeding on rifampicin-treated diet produced symbiont-free offspring (F1), few eggs of F1 hatched and consequently symbiont-free whitefly line failed to be established (Zhang et al, 2015;Shan et al, 2016). Comparing the performance between host lines with and without certain symbiont is the most effective way to explore the function of symbionts.…”

Thermal sensitivity of bacteriocytes constrains the persistence of intracellular bacteria in whitefly symbiosis under heat stress

“…4E and F). After depletion of symbionts by antibiotics, whiteflies also exhibit a variety of reduced performance including decrease of fecundity and occurrence of nonviable eggs (Zhang et al, 2015;Shan et al, 2016). Although high temperature or antibiotic treatment possibly exerts deleterious effects on the host directly via interrupting its metabolism, their indirect effects on the host via affecting its symbiotic bacteria are likely to be important considering the mutualistic nature between them.…”