Department of Biology, University of Victoria, Victoria, BC, Canada
Department of Biology, University of Victoria, Victoria, BC, Canada.
Appl Environ Microbiol. 2018 Jan 31;84(4). doi: 10.1128/AEM.02299-17. Print 2018 Feb 15.
Microbial partners play important roles in the biology and ecology of animals. In insects, maternally transmitted symbionts are especially common and can have host effects ranging from reproductive manipulation to nutrient provisioning and defense against natural enemies. In this study, we report a genus-wide association of ants with the inherited bacterial symbiont We screen ants collected from the wild, including the invasive European fire ant, , and find an extraordinarily high prevalence of this symbiont-8 of 9 species, 42 of 43 colonies, and 250 of 276 individual workers harbored -only one host species was uninfected. In our screens, each host species carried a distinct strain, and none were infected with more than one strain. All symbionts belong to the clade, allied most closely with pathogenic strains of infecting corn crops and honeybees, and there is strong evidence of host-symbiont persistence across evolutionary time scales. Genome sequencing of two symbionts revealed candidate genes that may play a part in the symbiosis, a nutrient transporter absent from other strains, and a ribosome-inactivating protein previously implicated in parasite defense. These results together suggest long-term, likely mutualistic, relationships atypical of -insect associations with potential significance for broad ecological interactions with Animal-associated microbial symbionts can dramatically affect the biology of their hosts. The identification and characterization of these intimate partnerships remain an essential component of describing and predicting species interactions, especially for invasive host species. Ants perform crucial ecological functions as ecosystem engineers, scavengers, and predators, and ants in the genus can be aggressive resource competitors and reach high densities in their native and invaded habitats. In this study, a novel symbiosis is identified between ants and the facultative bacterial symbiont Broad host distribution, high frequencies of infection, and host-symbiont codivergence over evolutionary time scales, an uncommon feature of associations, suggest an important likely mutualistic interaction. Genome sequencing identified highly divergent gene candidates that may contribute to 's role as a possible defensive or nutritional partner in .
微生物伙伴在动物的生物学和生态学中发挥着重要作用。在昆虫中，母体传播的共生体尤为常见，它们对宿主的影响范围从生殖操纵到营养供应和抵御天敌。在这项研究中，我们报告了一种广泛存在于蚂蚁中的共生细菌 。我们筛选了从野外采集的蚂蚁，包括入侵的欧洲红火蚁 ，发现这种共生体的存在率非常高-9 个物种中有 8 个，43 个蚁群中有 42 个，276 个工蚁中有 250 个，只有一个宿主物种未被感染。在我们的筛选中，每个宿主物种都携带一种独特的 菌株，而且没有一种被感染超过一种菌株。所有共生体都属于 分支，与感染玉米作物和蜜蜂的致病菌株关系最为密切，并且有强有力的证据表明，在进化时间尺度上，宿主与共生体之间存在持久的共生关系。对两种 共生体的基因组测序揭示了一些可能在共生关系中发挥作用的候选基因，一种缺失于其他 菌株的营养转运蛋白，以及一种先前与寄生虫防御有关的核糖体失活蛋白。这些结果共同表明，这是一种长期的、可能是互利的关系，与 -昆虫与潜在具有重要意义的共生关系不同，与 动物相关的微生物共生体可以极大地影响宿主的生物学特性。识别和描述这些密切的伙伴关系仍然是描述和预测物种相互作用的一个基本组成部分，特别是对于入侵宿主物种。蚂蚁作为生态系统工程师、清道夫和捕食者，发挥着至关重要的生态功能，而 属中的蚂蚁则是具有侵略性的资源竞争者，并在其原生和入侵栖息地达到高密度。在这项研究中，发现了一种新型的共生关系，即在 蚂蚁和兼性细菌共生体 之间。广泛的宿主分布、高感染频率以及在进化时间尺度上的宿主与共生体的共同进化，这是 共生关系中不常见的特征，表明这是一种重要的互利相互作用。基因组测序确定了高度分化的候选基因，这些基因可能有助于 在 中作为一种可能的防御或营养伙伴。
