Adapting to life in an increasingly acid world: understanding tolerance to acidic waters in populations of trout (Salmo trutta)

适应日益酸性的世界中的生活：了解鳟鱼种群对酸性水域的耐受性（Salmo trutta）

• 批准号: 2401743
• 金额: --
• 依托单位: UNIVERSITY OF EXETER
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2401743
• 关键词: Adapting; life; increasingly; acid; world

During the freshwater phases of their lifecycles, brown trout (Salmo trutta) and Atlantic salmon (Salmo salar) inhabit a broad range of environments, ranging from acidic upland streams to neutral-alkaline chalk streams. Due primarily to the impacts of human-driven ecological perturbations, e.g. forestry clearance and acid run-off, the pH of many of these systems is now fluctuating far beyond previously recorded levels. Dartmoor National Park is a unique upland habitat in southwest England. Flowing over granite and peat, many rivers of the region are markedly acidic; nonetheless, compared to similar upland streams elsewhere in Britain and Ireland, local management activities, e.g. forestry clearance, have led to large fluctuations in pH, with readings of less than pH 4 being recorded. Despite this, most Dartmoor streams host healthy populations of trout and salmon, and molecular analysis shows trout from acid rivers to be genetically distinct.This project aims to identify the basis of tolerance to acid waters in brown trout through analysis of single nucleotide polymorphisms (SNPs) and changes in gene expression. We propose to use the complementary approaches of restriction site associated DNA sequencing (RADseq) and transcriptomics (RNA sequencing [RNAseq]) to study trout populations inhabiting acid, neutral and alkaline rivers in southern Britain. This will allow us to explore common/convergent evolutionary 'solutions' to acid tolerance. Additionally, the student will gain field experience and work with a modern conservation organisation.Our primary objective is to understand the genetic basis of acid tolerance in brown trout. We propose to use RADseq analysis of fish from rivers with low pH (Dartmoor streams), neutral rivers (other rivers in Cornwall and Devon) and more alkaline waters (chalk streams, Dorset/Hampshire). We already hold tissue samples from resident trout collected from across these regions, and the student will have the opportunity to partake in fieldwork to collect additional trout tissue samples. The sampling design includes fish from tributaries running off acid high-moor sites and neutral lowland locations (allowing us to eliminate the effects of differential genetic drift and catchment-specific selective pressures). This will allow us to identify SNPs that segregate definitively between the ecotypes and to identify regions of the trout genome associated with adaptations to living in a low pH environment. The study will provide a better understanding of the basis of acid tolerance in salmonids and addresses long-standing questions regarding persistence of this species in an otherwise species-poor (highly acid) ecosystem. It also offers the potential to reveal the mechanisms of local adaptation and the genetic architecture underlying this process. Such information will also be of value in fish conservation and aquaculture in the face of global pressures on aquatic systems, e.g. the acidifying effects of increased atmospheric CO2.Collaboration with the CASE partner, Westcountry Rivers Trust, and The Game & Wildlife Conservation Trust also provides a rare opportunity to look for changes in gene expression in relation to exposure to highly acidic conditions. Analysis by RNAseq will then characterise changes in gene expression related to acidity, identifying genes important to physiological responses in wild trout populations. By combining population genomic and gene expression approaches, this exciting studentship offers the potential to address broader questions of acid tolerance and adaptation in this fish. The team at Exeter and Bristol have extensive experience in this field and we anticipate that our research findings will be used by fisheries managers, conservationists and other stakeholders to help in monitoring at-risk environments and detecting changes in water quality that may threaten fish health and population numbers.

在其生命周期的淡水阶段，褐鳟鱼（萨尔莫trutta）和大西洋鲑鱼（萨尔莫salar）栖息在广泛的环境中，从酸性高地溪流到中性碱性白垩溪流。主要由于人为生态扰动的影响，例如森林砍伐和酸性径流，许多这些系统的pH值现在波动远远超过以前记录的水平。达特穆尔国家公园是英格兰西南部一个独特的高地栖息地。流经花岗岩和泥炭，该地区的许多河流明显呈酸性;然而，与英国和爱尔兰其他地方的类似高地溪流相比，当地的管理活动，例如森林砍伐，导致pH值大幅波动，记录的pH值低于4。尽管如此，大多数达特穆尔河都是鳟鱼和鲑鱼的健康栖息地，分子分析显示，来自酸性河流的鳟鱼在遗传上是不同的。本项目旨在通过分析单核苷酸多态性（SNP）和基因表达变化，确定褐鳟鱼对酸性沃茨耐受性的基础。我们建议使用限制性位点相关DNA测序（RADseq）和转录组学（RNA测序[RNAseq]）的互补方法来研究居住在英国南部酸性，中性和碱性河流的鳟鱼种群。这将使我们能够探索共同的/趋同的进化“解决方案”的耐酸性。此外，学生将获得实地经验，并与现代保护组织合作。我们的主要目标是了解褐鳟鱼耐酸性的遗传基础。我们建议使用RADseq分析的鱼类从河流的pH值低（达特穆尔溪流），中性河流（其他河流在康沃尔郡和德文郡）和更多的碱性沃茨（白垩流，多塞特郡/汉普郡）。我们已经持有从这些地区收集的居民鳟鱼的组织样本，学生将有机会参加实地考察，以收集更多的鳟鱼组织样本。采样设计包括从支流流出的酸性高沼地和中性低地位置的鱼类（使我们能够消除差异遗传漂变和集水区特定的选择压力的影响）。这将使我们能够确定的SNP之间的生态类型和识别区域的鳟鱼基因组与适应生活在低pH值的环境。这项研究将提供一个更好地了解鲑鱼的耐酸性的基础，并解决长期存在的问题，否则物种贫乏（高酸性）的生态系统中，这个物种的持久性。它还提供了潜在的地方适应机制和遗传结构的基础上这一过程。这些信息也将在鱼类保护和水产养殖中的价值，面对全球对水生系统的压力，例如大气CO2增加的酸化效应。与CASE合作伙伴，Westcountry Rivers Trust和The Game & Wildlife Conservation Trust的合作也提供了一个难得的机会来寻找与暴露于高酸性条件相关的基因表达变化。通过RNAseq的分析，将检测与酸度相关的基因表达的变化，识别对野生鳟鱼种群生理反应重要的基因。通过结合人口基因组和基因表达的方法，这个令人兴奋的学生提供了解决更广泛的问题，在这种鱼的耐酸性和适应的潜力。埃克塞特和布里斯托的团队在这一领域拥有丰富的经验，我们预计我们的研究结果将被渔业管理人员，自然资源保护主义者和其他利益相关者用于帮助监测风险环境和检测可能威胁鱼类健康和种群数量的水质变化。