HOST-PARASITE AND GENOTYPE-BY-ENVIRONMENT INTERACTIONS: TEMPERATURE MODIFIES POTENTIAL FOR SELECTION BY A STERILIZING PATHOGEN
HOST-PARASITE AND GENOTYPE-BY-ENVIRONMENT INTERACTIONS: TEMPERATURE MODIFIES POTENTIAL FOR SELECTION BY A STERILIZING PATHOGEN
复制标题
宿主-寄生虫和基因型-环境相互作用：温度改变灭菌病原体选择的潜力
DOI：
10.1554/04-526
复制
发表时间：
2005
影响因子：
11.6
通讯作者：
A. Read
中科院分区：
文献类型：
--
作者：
S. E. Mitchell;Emily S. Rogers;T. Little;A. Read
摘要寄生虫介导的选择在调节遗传多样性方面具有潜在的重要性。抗性的遗传变异是自然选择的燃料，在宿主-寄生虫相互作用中似乎很常见，但很少观察到对选择的反应。在本研究中，我们测试了环境变化是否可以介导感染并决定进化结果。温度显着改变寄生虫介导的选择在两个独立的实验室感染实验在四个温度下的潜力。细菌寄生虫，多枝巴氏杆菌，在20°C和25°C下具有极强的毒性，使其宿主大型蚤绝育，因此雌性通常不会产生一窝。然而，在10°C和15°C下，宿主-寄生虫的相互作用要良性得多，因为几乎所有的雌性都在不育之前产生育雏。毒力和温度之间的这种关联可以稳定共存，并导致多样性的维持，因为它会削弱寄生虫介导的选择在部分季节。此外，高度显着的基因型与环境的相互作用被发现，在不同温度下的感染率的克隆排名顺序的变化。我们的研究结果清楚地表明，寄生虫介导的选择在这个系统中的结果是强烈的上下文依赖。
Abstract Parasite-mediated selection is potentially of great importance in modulating genetic diversity. Genetic variation for resistance, the fuel for natural selection, appears to be common in host-parasite interactions, but responses to selection are rarely observed. In the present study, we tested whether environmental variation could mediate infection and determine evolutionary outcomes. Temperature was shown to dramatically alter the potential for parasite-mediated selection in two independent laboratory infection experiments at four temperatures. The bacterial parasite, Pasteuria ramosa, was extremely virulent at 20°C and 25°C, sterilizing its host, Daphnia magna, so that females often never produced a single brood. However, at 10°C and 15°C, the host-parasite interaction was much more benign, as nearly all females produced broods before becoming sterile. This association between virulence and temperature alone could stabilize coexistence and lead to the maintenance of diversity, because it would weaken parasite-mediated selection during parts of the season. Additionally, highly significant genotype-by-environment interactions were found, with changes in clone rank order for infection rates at different temperatures. Our results clearly show that the outcome of parasite-mediated selection in this system is strongly context dependent.