Experimental host-parasite coevolution in a changing environment

不断变化的环境中实验性宿主-寄生虫协同进化

• 批准号: 129443528
• 负责人: Professor Dr. Thomas U. Berendonk
• 金额: --
• 依托单位: Institut für Hydrobiologie
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2014-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/129443528?language=en
• 关键词: Experimental; host; parasite; coevolution; changing

Theory predicts that stressors can have multiple effects on a host-parasite interaction either by increasing the number of hosts with decreased resistance or by reducing host abundance and consequently the transmission rate of the parasite. Likewise, stress can promote an increase or decrease of parasite virulence or pathogenicity. The so-called killer trait of the Paramecium / Caedibacter host-parasite system will be used to investigate these open questions. This killer trait of Paramecium tetraurelia is mediated by the vertically transmitted bacterial parasite Caedibacter taeniospiralis, which offers a selective competition advantage to its host. Infected paramecia release low amounts of their parasite into the medium. After ingestion by a parasite-free Paramecium, the bacterial killer-toxin kills the susceptible competitor of the host. Consequently, in this system the parasite can evolve towards increased or decreased pathogenicity. We propose to analyse the outcome of a long-term experimental co-evolution under heat stress. Particularly, we will investigate the hypothesis that stress increases parasite pathogenicity, which concomitantly fosters the evolution of a killer-toxin resistance in Paramecium. Further, we will test the hypothesis that the rapid evolution of the host is based on epigenetic changes and that the killer-toxin resistance is genotype specific. Combined experimental and molecular approaches will be used to understand the evolution of Paramecium’s killer-toxin resistance at a genomic level as well as the functional background of parasite pathogenicity.

理论预测，压力源可以通过增加抗性降低的宿主数量或减少宿主丰度从而降低寄生虫的传播率来对宿主-寄生虫相互作用产生多重影响。同样，压力可以促进寄生虫毒力或致病性的增加或减少。草履虫/ Caedibacter宿主-寄生虫系统的所谓杀手性状将被用来调查这些开放的问题。四脲草履虫的这一杀手性状是由垂直传播的细菌寄生虫带螺旋Caedibacter taeniospiralis介导的，它为其宿主提供了选择性竞争优势。被感染的副寄生虫释放少量的寄生虫到培养基中。在被无寄生虫的草履虫摄入后，细菌性寄生虫毒素杀死宿主的敏感竞争者。因此，在这个系统中，寄生虫可以朝着增加或减少致病性的方向进化。我们建议在热应力下分析长期实验共同进化的结果。特别是，我们将调查的假设，压力增加寄生虫的致病性，这伴随着促进草履虫的细菌毒素抗性的演变。此外，我们将测试的假设，即宿主的快速进化是基于表观遗传的变化和细菌毒素抗性是基因型特异性的。结合实验和分子生物学的方法将被用来了解草履虫的毒素抗性在基因组水平的进化，以及寄生虫致病性的功能背景。