Sakamoto Hironori, Ishikawa Yukio, Sasaki Tetsuhiko, Kikuyama Sakae, Tatsuki Sadahiro, Hoshizaki Sugihiko
Department of Biology, School of Education, Waseda University, Nishiwaseda, Tokyo 169-0051, Japan.
Genet Res. 2005 Jun;85(3):205-10. doi: 10.1017/S0016672305007573.
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 w Sca. In the present study, we transferred w Kue 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.
沃尔巴克氏体是节肢动物体内的一组内共生细菌，它以多种方式改变宿主的繁殖方式。一种自然感染小豆长喙天蛾Ostrinia scapulalis的沃尔巴克氏体菌株（wSca）会引发雄虫致死现象，而另一种感染地中海粉螟Ephestia kuehniella的菌株（wKue）则会在宿主中诱导细胞质不亲和性（CI）。沃尔巴克氏体的转染可能是一种强大的工具，有助于阐明沃尔巴克氏体和宿主在决定繁殖改变类型方面的相对重要性。最近研究表明，用wSca转染的E. kuehniella中会出现雄虫致死现象。在本研究中，我们通过胚胎显微注射将wKue转移到了O. scapulalis中。在被wKue转染的O. scapulalis中，出现了细胞质不亲和性，但没有出现雄虫致死现象。因此，除了wSca之外，wKue也被证明能在异源宿主中诱导与其天然宿主相同类型的改变。这些结果证明了沃尔巴克氏体基因型在决定繁殖改变类型方面的关键作用。然而，本研究也揭示了宿主因素的参与。首先，wKue在O. scapulalis中诱导的不亲和程度比在E. kuehniella中更强，这表明宿主因素会影响细胞质不亲和性的水平。其次，wKue在O. scapulalis中的垂直传播率普遍较低，这表明宿主会影响沃尔巴克氏体的传播动态。
