Transinfection reveals the crucial importance of Wolbachia genotypes in determining the type of reproductive alteration in the host
Wolbachia, a group of endosymbiotic bacteria in arthropods, alter the reproduction of their hosts in various ways. A Wolbachia strain (wSca) naturally infecting the adzuki bean borer moth Ostrinia scapulalis induces male killing, while another strain (wKue) infecting the Mediterranean flour moth Ephestia kuehniella induces cytoplasmic incompatibility (CI) in the resident host. Transinfection of Wolbachia can be a powerful tool to elucidate the relative importance of Wolbachia and the host in determining the type of reproductive alterations. Recently, male killing was shown to occur in E. kuehniella transinfected with wSca. In the present study, we transferred wKue to O. scapulalis by embryonic microinjection. In the O. scapulalis transinfected with wKue, CI, but not male killing occurred. Thus, in addition to wSca, wKue was shown to induce the same type of alteration in a foreign host as in its natural host. These results demonstrate the crucial role of the Wolbachia genotype in determining the type of reproductive alteration. However, the present study also revealed the involvement of host factors. First, the degree of incompatibility induced by wKue in O. scapulalis was stronger than that in E. kuehniella, indicating that host factors can affect the level of CI. Second, the vertical transmission rate of wKue in O. scapulalis was generally low, suggesting that the host affects the dynamics of Wolbachia transmission.(Received November 1 2004)
(Revised April 18 2005)
c1 Corresponding author.
p1 Current address: Laboratory of Applied Entomology, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Yayoi, Tokyo 113-8657, Japan. Tel: +81 3 58415093. Fax: +81 3 58415060. e-mail: email@example.com