Influence of aging on cytoplasmic incompatibility, sperm modification and Wolbachia density in Culex pipiens mosquitoes
Influence of aging on cytoplasmic incompatibility, sperm modification and Wolbachia density in Culex pipiens mosquitoes
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DOI：
10.1038/sj.hdy.6800948
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发表时间：
2007-06-01
期刊：
影响因子：
3.8
通讯作者：
Weill, M.
中科院分区：
文献类型：
--
作者：
Duron, O.;Fort, P.;Weill, M.
沃尔巴克氏体是母系遗传的细胞内细菌，广泛存在于无脊椎动物中，能够改变宿主繁殖的几个方面。胞质不相容性（CI）是节肢动物中常见的现象，它能导致感染沃尔巴克氏体的雄性和未感染的雌性（或被不相容菌株感染的雌性）杂交产生的卵孵化失败。几个因素，如细菌和宿主基因型或细菌密度有助于CI强度，它已被提出，主要是从果蝇的数据，老年男性有一个较低的沃尔巴克氏体负载在睾丸中，因此，诱导较轻的CI。在这里，我们挑战这一假设，使用不同的不兼容库蚊株，并表明CI持续在整个蚊子寿命相同的强度。从不兼容的杂交胚胎显示，随着时间的推移，甚至分布的败育表型，这表明主机老化不减少精子修饰诱导沃尔巴克氏体。CI保持恒定时，精子被放置在受精囊的不兼容的女性，表明精子的修改也是稳定的，随着时间的推移。感染女性抢救CI的能力与年龄无关。最后，整个睾丸中的沃尔巴克氏体密度具有高度的应变依赖性，并随着年龄的增长而显着增加。总之，这些数据强调了C。pipiens/Wolbachia相互作用，并建议在这种关联的情况下，细菌剂量模型应被拒绝。
Wolbachia are maternally inherited endocellular bacteria, widespread in invertebrates and capable of altering several aspects of host reproduction. Cytoplasmic incompatibility (CI) is commonly found in arthropods and induces hatching failure of eggs from crosses between Wolbachia-infected males and uninfected females (or females infected by incompatible strains). Several factors such as bacterial and host genotypes or bacterial density contribute to CI strength and it has been proposed, mostly from Drosophila data, that older males have a lower Wolbachia load in testes which, thus, induces a lighter CI. Here, we challenge this hypothesis using different incompatible Culex pipiens mosquito strains and show that CI persists at the same intensity throughout the mosquito life span. Embryos from incompatible crosses showed even distributions of abortive phenotypes over time, suggesting that host ageing does not reduce the sperm-modification induced by Wolbachia. CI remained constant when sperm was placed in the spermathecae of incompatible females, indicating that sperm modification is also stable over time. The capacity of infected females to rescue CI was independent of age. Last, the density of Wolbachia in whole testes was highly strain-dependent and increased dramatically with age. Taken together, these data stress the peculiarity of the C. pipiens/Wolbachia interaction and suggest that the bacterial dosage model should be rejected in the case of this association.