Variable fitness effects of Wolbachia infection in Drosophila melanogaster
Variable fitness effects of Wolbachia infection in Drosophila melanogaster
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DOI：
10.1038/sj.hdy.6800514
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发表时间：
2004-10-01
期刊：
影响因子：
3.8
通讯作者：
Rand, DM
中科院分区：
文献类型：
--
作者：
Fry, AJ;Palmer, MR;Rand, DM
母系遗传的沃尔巴克氏体细菌在昆虫中极为普遍，它们的存在通常与寄主适应性的寄生修饰有关。管状沃尔巴克氏体感染来自各大洲的黑腹果蝇种群，但尽管存在强烈的寄生效应，但它们在该物种中的持久性仍然存在。本研究对沃尔巴克氏体与黑腹d菌的共生关系进行了研究，发现沃尔巴克氏体感染对其存活和繁殖力有显著影响。与未感染的蝇相比，感染了沃尔巴克氏体的三株蝇的雌性在感染沃尔巴克氏体后表现出更高的存活率或繁殖力，其中一株对沃尔巴克氏体去除有积极的反应。我们发现受感染的雄性和未受感染的雌性的杂交在卵孵化率（细胞质不相容）上没有差异，尽管生殖力存在差异。与受感染的雌虫相比，该杂交的雌虫的产卵量始终少于受感染的雌虫，这种繁殖能力的差异可能促进了感染的传播，就像细胞质不相容一样。更令人惊讶的是，我们发现受感染的雌性与未受感染的雄性交配时，往往具有最高的繁殖力。这也可能促进沃尔巴克氏体感染的传播，尽管在沃尔巴克氏体罕见的情况下，健康的好处也有助于传播感染。我们认为，在两性中存在的可变适应度效应，以及与宿主遗传背景的强烈相互作用，可能会增加某些基因型的细胞质驱动率，并有助于解释沃尔巴克氏菌在黑腹d.s melanogaster种群中广泛存在的原因。这些相互作用可能进一步解释了为什么许多黑腹d.m anogaster种群对沃尔巴克氏体感染具有多态性。我们在宿主-共生体共同进化的背景下讨论我们的结果。
Maternally inherited Wolbachia bacteria are extremely widespread among insects and their presence is usually associated with parasitic modifications of host fitness. Wolbachia pipientis infects Drosophila melanogaster populations from all continents, but their persistence in this species occurs despite any strong parasitic effects. Here, we have investigated the symbiosis between Wolbachia and D. melanogaster and found that Wolbachia infection can have significant survival and fecundity effects. Relative to uninfected flies, infected females from three fly strains showed enhanced survival or fecundity associated with Wolbachia infection, one strain showed both and one strain responded positively to Wolbachia removal. We found no difference in egg hatch rates ( cytoplasmic incompatibility) for crosses between infected males and uninfected females, although there were fecundity differences. Females from this cross consistently produced fewer eggs than infected females and these fecundity differences could promote the spread of infection just like cytoplasmic incompatibility. More surprising, we found that infected females often had the greatest fecundity when mated to uninfected males. This could also promote the spread of Wolbachia infection, though here the fitness benefits would also help to spread infection when Wolbachia are rare. We suggest that variable fitness effects, in both sexes, and which interact strongly with the genetic background of the host, could increase cytoplasmic drive rates in some genotypes and help explain the widespread persistence of Wolbachia bacteria in D. melanogaster populations. These interactions may further explain why many D. melanogaster populations are polymorphic for Wolbachia infection. We discuss our results in the context of host - symbiont co-evolution.