title: Evidence for a recent horizontal transmission and spatial spread of Wolbachia from endemic Rhagoletis cerasi (Diptera: Tephritidae) to invasive Rhagoletis cingulata in Europe.
abstract: The widespread occurrence of Wolbachia in arthropods and nematodes suggests that this intracellular, maternally inherited endosymbiont has the ability to cross species boundaries. However, direct evidence for such a horizontal transmission of Wolbachia in nature is scarce. Here, we compare the well-characterized Wolbachia infection of the European cherry fruit fly, Rhagoletis cerasi, with that of the North American eastern cherry fruit fly, Rhagoletis cingulata, recently introduced to Europe. Molecular genetic analysis of Wolbachia based on multilocus sequence typing and the Wolbachia surface protein wsp showed that all R. cingulata individuals are infected with wCin2 identical to wCer2 in R. cerasi. In contrast, wCin1, a strain identical to wCer1 in R. cerasi, was present in several European populations of R. cingulata, but not in any individual from the United States. Surveys of R. cingulata from Germany and Hungary indicated that in some populations, the frequency of wCin1 increased significantly in just a few years with at least two independent horizontal transmission events. This is corroborated by the analysis of the mitochondrial cytochrome oxidase II gene that showed association of wCin1 with two distinct haplotypes in Germany, one of which is also infected with wCin1 in Hungary. In summary, our study provides strong evidence for a very recent inter-specific Wolbachia transmission with a subsequent spatial spread in field populations.
authors.affiliation: Department of Forest and Soil Sciences, Institute of Forest Entomology, Forest Pathology and Forest Protection, Boku, University of Natural Resources and Life Sciences, Hasenauerstr, 38, 1190, Vienna, Austria. hannes.schuler@boku.ac.at
authors.forename: Hannes
authors.initials: H
authors.lastname: Schuler
authors.forename: Coralie
authors.initials: C
authors.lastname: Bertheau
authors.forename: Scott P
authors.initials: SP
authors.lastname: Egan
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Feder
authors.forename: Markus
authors.initials: M
authors.lastname: Riegler
authors.forename: Birgit C
authors.initials: BC
authors.lastname: Schlick-Steiner
authors.forename: Florian M
authors.initials: FM
authors.lastname: Steiner
authors.forename: Jes
authors.initials: J
authors.lastname: Johannesen
authors.forename: Peter
authors.initials: P
authors.lastname: Kern
authors.forename: Katalin
authors.initials: K
authors.lastname: Tuba
authors.forename: Ferenc
authors.initials: F
authors.lastname: Lakatos
authors.forename: Kirsten
authors.initials: K
authors.lastname: Köppler
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Arthofer
authors.forename: Christian
authors.initials: C
authors.lastname: Stauffer
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics*; D018562:Disease Transmission, Infectious; D003576:Electron Transport Complex IV / Q000235:genetics*; D014644:Genetic Variation; D005838:Genotype; D058885:Multilocus Sequence Typing; D033621:Tephritidae / Q000382:microbiology*; D020577:Wolbachia / Q000145:classification / Q000235:genetics*
chemical_list: D001425:Bacterial Outer Membrane Proteins; C112171:Wsp protein, Wolbachia; D003576:Electron Transport Complex IV
keywords: Rhagoletis cerasi; Rhagoletis cingulata; Wolbachia; horizontal transmission; invasive species; multilocus sequence typing