Ecological drivers of evolutionary transitions in mutualistic symbioses

互利共生进化转变的生态驱动因素

基本信息

批准号：
NE/K011774/2
负责人：
Michael Brockhurst
金额：
$ 3.02万
依托单位：
University of Sheffield
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2017
资助国家：
英国
起止时间：
2017 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=NE%2FK011774%2F2
关键词：
Ecological drivers evolutionary transitions mutualistic

项目摘要

Intimate and prolonged associations between different organisms - symbioses - are widespread and important in the natural environment. A key form of symbiosis are associations involving photosynthetic organisms which provide their hosts with energy from sunlight: so called photosymbioses. Examples of photosymbioses include lichens, where a fungus hosts an green alga, and corals, where a cnidaria hosts a zooxanthellae alga. Through photosymbiosis pairs of organisms can survive in environments where neither would alone, therefore photosymbioses increase biodiversity and underpin the functioning of ecosystems. An important feature of photosymbiosis is that the benefits to hosts of carrying symbionts depend upon the environmental conditions: for instance in well-lit habitats symbionts are highly beneficial to hosts whereas in dark environments symbionts may be costly for hosts to maintain. Here, we want to understand how environmental variation in light intensity shapes the long-term evolution of photosymbioses.Despite their widespread importance, little is known about the evolutionary origins of photosymbioses. Possible reasons for this are that lichens and corals are ancient associations and are very slow growing and hard to cultivate in the lab. Our approach is to observe the real-time evolution of a photosymbiosis created by us in the lab between a single-celled eukaryote host (Paramecium) and a photosynthetic cyanobacteria symbiont (Synechocystis). Although many Paramecium-alga symbioses exist in nature, by using a 'synthetic' symbiosis we will capture the entire evolutionary history of the symbiosis from the moment of its inception. We will exploit the short generation times, and large population sizes of Paramecium to observe evolution in real time for 100s of generations. We will discover and contrast the adaptations of both hosts and symbionts that occur as they co-evolve across a gradient of light intensity from near dark to bright light. To fully understand the physiological, biochemical and genetic bases of adaptations we will employ cutting edge cell-imaging, mass spectrometry and genome sequencing technologies. - Our study is novel because we will, for the first time, study the evolution of a photosymbiosis from inception for 100s of generations in real time- Our study is relevant to the natural environment because we test the effect of environmental variation of a crucial ecological variable affecting photosymbioses: light intensity. Moreover, our findings will help to predict responses of natural photosymbioses to changing environments - Our study is powerful because we will use an experimental approach to study evolution in real time.- Our study is timely because we will exploit the latest technologies in DNA sequencing, biochemistry and cell-imaging to directly observe evolution of genetic, physiological and biochemical adaptations.

不同生物体之间密切且长期的联系——共生——在自然环境中广泛且重要。共生的一种关键形式是涉及光合生物的关联，这些生物为其宿主提供来自阳光的能量：所谓的光共生。光共生的例子包括地衣（真菌寄生绿藻）和珊瑚（刺胞动物寄生虫黄藻）。通过光共生，成对的生物体可以在任何一方都无法单独生存的环境中生存，因此光共生增加了生物多样性并支撑了生态系统的功能。光共生的一个重要特征是，携带共生体对宿主的好处取决于环境条件：例如，在光线充足的栖息地中，共生体对宿主非常有益，而在黑暗环境中，共生体的维持成本可能会很高。在这里，我们想要了解光强度的环境变化如何影响光共生的长期进化。尽管光共生具有广泛的重要性，但人们对光共生的进化起源知之甚少。造成这种情况的可能原因是地衣和珊瑚是古老的组合，生长非常缓慢，很难在实验室中培养。我们的方法是观察我们在实验室中创建的单细胞真核生物宿主（草履虫）和光合蓝藻共生体（集胞藻）之间光共生的实时演化。尽管自然界中存在许多草履虫-藻类共生体，但通过使用“合成”共生体，我们将捕获共生体从其诞生那一刻起的整个进化历史。我们将利用草履虫较短的世代时间和较大的种群规模来实时观察数百代的进化。我们将发现并对比宿主和共生体在从近暗到亮光的光强度梯度上共同进化时发生的适应。为了充分了解适应的生理、生化和遗传基础，我们将采用尖端的细胞成像、质谱和基因组测序技术。 - 我们的研究很新颖，因为我们将首次实时研究光共生从开始到数百代的演化过程 - 我们的研究与自然环境相关，因为我们测试了一个关键生态系统的环境变化的影响影响光共生的变量：光强度。此外，我们的研究结果将有助于预测自然光共生对不断变化的环境的反应 - 我们的研究是强大的，因为我们将使用实验方法来实时研究进化。 - 我们的研究是及时的，因为我们将利用最新的 DNA 测序技术，生物化学和细胞成像直接观察遗传、生理和生化适应的进化。