Table_1_Wolbachia Horizontal Transmission Events in Ants: What Do We Know and What Can We Learn?.pdf

While strict vertical transmission insures the durability of intracellular symbioses, phylogenetic incongruences between hosts and endosymbionts suggest horizontal transmission must also occur. These horizontal acquisitions can have important implications for the biology of the host. Wolbachia is one of the most ecologically successful prokaryotes in arthropods, infecting an estimated 50–70% of all insect species. Much of this success is likely due to the fact that, in arthropods, Wolbachia is notorious for manipulating host reproduction to favor transmission through the female germline. However, its natural potential for horizontal transmission remains poorly understood. Here we evaluate the fundamental prerequisites for successful horizontal transfer, including necessary environmental conditions, genetic potential of bacterial strains, and means of mediating transfers. Furthermore, we revisit the relatedness of Wolbachia strains infecting the Panamanian leaf-cutting ant, Acromyrmex echinatior, and its inquiline social parasite, Acromyrmex insinuator, and compare our results to a study published more than 15 years ago by Van Borm et al. (2003). The results of this pilot study prompt us to reevaluate previous notions that obligate social parasitism reliably facilitates horizontal transfer and suggest that not all Wolbachia strains associated with ants have the same genetic potential for horizontal transmission.

尽管严格的垂直传播可保障细胞内共生关系的稳定性，但宿主与内共生体之间的系统发育不一致现象表明，水平传播必然也会发生。这类水平获得事件可对宿主的生物学特性产生重要影响。沃尔巴克氏体（Wolbachia）是节肢动物中生态适应性最为成功的原核生物之一，据估计其可感染50%至70%的昆虫物种。该菌的这种高侵染成功率，很大程度上可能源于其在节肢动物中臭名昭著的特性：通过操控宿主生殖过程，以利于自身经雌性生殖系进行传播。然而，人们对其自然状态下的水平传播潜力仍知之甚少。本研究旨在评估成功实现水平传播的各项基本前提，包括必需的环境条件、细菌菌株的遗传潜力，以及介导传播的具体途径。此外，我们重新分析了感染巴拿马切叶蚁（Acromyrmex echinatior）及其寄居性社会寄生者（Acromyrmex insinuator）的沃尔巴克氏体菌株的亲缘关系，并将本研究结果与Van Borm等人于2003年发表的一项距今已超15年的研究进行了对比。本预研究的结果促使我们重新审视此前的观点：专性社会寄生可稳定促进水平传播；同时研究结果还表明，并非所有与蚂蚁相关的沃尔巴克氏体菌株都具备相同的水平传播遗传潜力。