Wolbachia dominate Spiroplasma in the co‐infected spider mite Tetranychus truncatus

Abstract

Wolbachia and Spiroplasma are both maternally inherited endosymbionts in arthropods, and they can co‐infect the same species. However, how they interact with each other in the same host is not clear. Here we investigate a co‐infected Tetranychus truncatus spider mite strain that shares the same genetic background with singly infected and uninfected strains to detect the impacts of the two symbionts on their host. We found that Wolbachia‐infected and Spiroplasma‐infected mites can suffer significant fitness costs involving decreased fecundity, although with no effect on lifespan or development. Wolbachia induced incomplete cytoplasmic incompatibility in T. truncatus both in singly infected and doubly infected strains, resulting in female killing. In both females and males of the co‐infected spider mite strain, Wolbachia density was higher than Spiroplasma density. Transcriptome analysis of female adults showed that the most differentially expressed genes were found between the co‐infected strain and both the singly infected Spiroplasma strain and uninfected strain. The Wolbachia strain had the fewest differentially expressed genes compared with the co‐infected strain, consistent with the higher density of Wolbachia in the co‐infected strain. Wolbachia, therefore, appears to have a competitive advantage in host mites over Spiroplasma and is likely maintained in populations by cytoplasmic incompatibility despite having deleterious fitness effects.

Wolbachia affects reproduction in the spider mite Tetranychus truncatus (Acari: Tetranychidae) by regulating chorion protein S38‐like and Rop

“…5A). As in previous studies (Yang et al, 2019;Zhao et al, 2013b), Wolbachia still maintained a trend of increasing titres with adult female mites age (Fig. 5A).…”

“…The Wolbachia titres in adult female mites and eggs were monitored by comparing the Wolbachia gene wsp with the host gene Rps18. The absolute qPCR standard curve of wsp and Rps18 was conducted as described in previous studies (Xia et al, 2018;Yang et al, 2019).…”

“…CI efficiency varies from weak to strong in different geographical strains of the same spider mite species (Xie et al, 2011). In addition, Wolbachia infection changes spider mite fitness, mainly by affecting fecundity, longevity and development time (Xie et al, 2019;Yang et al, 2019). The complex infection dynamics of Wolbachia in spider mites and their influence on spider mite reproduction and fitness make spider mite a good system for studying the ubiquitous molecular mechanism between Wolbachia and its host.…”

“…Here, we studied the interaction between Wolbachia and Tetranychus truncatus at the molecular level to explain which reproduction-related genes in T. truncatus are regulated by Wolbachia. Studies on T. truncatus biology showed that Wolbachia induced weak CI and decreased fecundity (Xie et al, 2019;Yang et al, 2019). To understand the mechanism of Wolbachia-induced weak CI and fecundity decrease in T. truncatus, we compared the transcriptomes of T. truncatus infected and uninfected with Wolbachia, and found several genes that might be regulated by Wolbachia.…”

Stable Establishment ofCardiniumspp. in the Brown Planthopper Nilaparvata lugens despite Decreased Host Fitness

“…Perhaps Wolbachia does not compete successfully with Cardinium in this host background. In some doubly infected hosts, one endosymbiont sometimes has a role in regulating reproduction, while the other plays an auxiliary role (33,36,38,39). Cardinium may be able to outcompete Wolbachia in G 0 N. lugens, leaving the latter in a secondary role.…”