AUTHOR=Liu Yuan , He Zi-Qi , Wen Qin , Peng Jing , Zhou Yu-Tong , Mandour Nasser , McKenzie Cindy L. , Ahmed Muhammad Z. , Qiu Bao-Li 

TITLE=Parasitoid-mediated horizontal transmission of Rickettsia between whiteflies

JOURNAL=Frontiers in Cellular and Infection Microbiology

VOLUME=12

YEAR=2023

URL=https://www.frontiersin.org/journals/cellular-and-infection-microbiology/articles/10.3389/fcimb.2022.1077494

DOI=10.3389/fcimb.2022.1077494

ISSN=2235-2988

ABSTRACT=<p>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 <italic>Encarsia formosa</italic>-mediated horizontal transmission of the endosymbiont <italic>Rickettsia</italic> between different populations of whitefly <italic>Bemisia tabaci</italic> MEAM1. <italic>Rickettsia</italic> was successfully transmitted from the positive MEAM1 nymphs (<italic>R</italic><sup>+</sup>) into <italic>E. formosa</italic> and retained at least for 48 h in <italic>E. formosa</italic> adults. Fluorescence <italic>in situ</italic> hybridization (FISH) visualization results revealed that the ovipositors, mouthparts, and digestive tract of parasitoid adults get contaminated with <italic>Rickettsia</italic>. Random non-lethal probing of <italic>Rickettisia-</italic>negative (<italic>R<sup>−</sup></italic>) MEAM1 nymphs by these <italic>Rickettsia-</italic>carrying <italic>E. formosa</italic> resulted in newly infected MEAM1 nymphs, and the vertical transmission of <italic>Rickettsia</italic> within the recipient females can remain at least up to F3 generation. Further phylogenetic analyses revealed that <italic>Rickettsia</italic> had high fidelity during the horizontal transmission in whiteflies and parasitoids. Our findings may help to explain why <italic>Rickettsia</italic> bacteria are so abundant in arthropods and suggest that, in some insect species that shared the same parasitoids, <italic>Rickettsia</italic> may be maintained in populations by horizontal transmission.</p>