Parasitoid-mediated horizontal transmission of Rickettsia between whiteflies

Abstract

Intracellular bacterial endosymbionts of arthropods are mainly transmitted vertically from mother to offspring, but phylogenetically distant insect hosts often harbor identical endosymbionts, indicating that horizontal transmission from one species to another occurs in nature. Here, we investigated the parasitoid Encarsia formosa-mediated horizontal transmission of the endosymbiont Rickettsia between different populations of whitefly Bemisia tabaci MEAM1. Rickettsia was successfully transmitted from the positive MEAM1 nymphs (R+) into E. formosa and retained at least for 48 h in E. formosa adults. Fluorescence in situ hybridization (FISH) visualization results revealed that the ovipositors, mouthparts, and digestive tract of parasitoid adults get contaminated with Rickettsia. Random non-lethal probing of Rickettisia-negative (R−) MEAM1 nymphs by these Rickettsia-carrying E. formosa resulted in newly infected MEAM1 nymphs, and the vertical transmission of Rickettsia within the recipient females can remain at least up to F3 generation. Further phylogenetic analyses revealed that Rickettsia had high fidelity during the horizontal transmission in whiteflies and parasitoids. Our findings may help to explain why Rickettsia bacteria are so abundant in arthropods and suggest that, in some insect species that shared the same parasitoids, Rickettsia may be maintained in populations by horizontal transmission.

The phylogeny and distribution of Wolbachia in two pathogen vector insects, Asian citrus psyllid and Longan psyllid

“…and C. sinica in the current study were clustered into one branch of Con subgroup in the supergroup B, which can assist in predicting the roles of Wolbachia in D. citri and C. sinica. Wolbachia can also be horizontally transmitted between intraspecies of insect hosts (Ahmed et al, 2013;Chu et al, 2016;Li Y. H et al, 2017;Liu et al, 2023). For example, by comparing the phylogeny of different Bemisia species and their endophytes, Ahmed et al (2013) revealed the discordance of Wolbachia with their whitefly hosts and testified that Wolbachia can achieve host transfer through horizontal transmission.…”

“…Wolbachia can also be horizontally transmitted between intraspecies of insect hosts ( Ahmed et al., 2013 ; Chu et al., 2016 ; Li S. J et al., 2017 ; Li Y. H et al., 2017 ; Liu et al., 2023 ). For example, by comparing the phylogeny of different Bemisia species and their endophytes, Ahmed et al.…”