LTREB : Collaborative Research: Long-term dynamics of amphibian populations following disease-driven declines

LTREB：合作研究：疾病驱动的下降后两栖动物种群的长期动态

• 批准号: 1556494
• 负责人: Erica Rosenblum
• 金额: $ 22.4万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-01 至 2021-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1556494&HistoricalAwards=false
• 关键词: LTREB; Collaborative; Research; Long; term

Outbreaks of emerging infectious diseases are increasingly recognized as major threats to wildlife populations. The initial invasion of a novel pathogen into a susceptible host population can cause a disease outbreak resulting in high levels of mortality and declines in population size. When this happens, natural selection can occur on both the host and pathogen populations during the disease outbreak. This can result in evolutionary changes in the host's susceptibility and tolerance to infection by the pathogen. It can also change the pathogen's ability to damage the host (virulence). These changes can in turn determine whether the host population can persist and recover from the disease. Understanding these evolutionary processes is crucial in development of conservation strategies for threatened species. This project will examine these processes for the case of a fungal pathogen that causes the disease Chytridiomycosis in frogs and salamanders. This disease has had catastrophic effects on amphibians worldwide, with numerous species extinctions documented in recent decades and many more species at risk. The researchers will investigate the patterns of evolutionary change in both the pathogen and the host (mountain yellow-legged frogs), following the invasion of the disease into hundreds of high elevation lakes in the California Sierra Nevada. This project will contribute to the understanding of the role of infectious diseases, such as Chytridiomycosis, as agents of evolutionary change in natural populations. It will provide critical information to state and federal agencies. It will also train and educate numerous, undergraduates and graduate students as well as the general public. This research builds on data from a long-term study of the population dynamics of mountain yellow-legged frogs (Rana sierrae and Rana muscosa) in the complex landscape of the California Sierra Nevada, and the impacts of Batrachochytrium dendrobatidis (Bd), as it has invaded and spread through hundreds of frog populations. In most cases, invasion of Bd results in outbreaks of the disease Chytridiomycosis, rapid frog population declines, and local extinctions. In some cases however long-term persistence of frog populations occurs with Bd in an enzootic state in which the impact of the pathogen is greatly reduced. The research will make use of recent advances in molecular approaches, and the extensive dataset and archive of samples from the R. sierrae/R. muscosa - Bd system, to investigate how populations of both host and pathogen change during the transition from pre-pathogen arrival, to disease outbreak, to enzootic disease, to potential recovery of the pre-disease host population abundances. This dataset will be used to investigate the genetic basis for differences in host resistance/tolerance and pathogen virulence. Cutting-edge genomic analysis of existing swab samples will be combined with continued surveys of field populations to identify new disease outbreaks and describe the transition from outbreak to enzootic state, collection of Bd cultures and frog mucosal samples from field populations, and laboratory experiments on Bd virulence and frog

人们越来越认识到新出现的传染病的爆发是对野生动物种群的主要威胁。新型病原体最初入侵易感宿主群体可能会导致疾病爆发，导致高死亡率和种群规模下降。当这种情况发生时，在疾病爆发期间，宿主和病原体种群都会发生自然选择。这可能导致宿主对病原体感染的易感性和耐受性发生进化变化。它还可以改变病原体损害宿主的能力（毒力）。这些变化反过来可以决定宿主群体是否能够持续患病并从疾病中恢复。 了解这些进化过程对于制定受威胁物种的保护策略至关重要。该项目将检查这些过程中是否存在引起青蛙和蝾螈壶菌病的真菌病原体。这种疾病对全世界的两栖动物造成了灾难性影响，近几十年来记录了许多物种灭绝，还有更多物种面临危险。研究人员将研究该疾病入侵加利福尼亚州内华达山脉数百个高海拔湖泊后，病原体和宿主（山黄腿蛙）的进化变化模式。该项目将有助于了解壶菌病等传染病作为自然种群进化变化的推动者的作用。它将向州和联邦机构提供关键信息。它还将培训和教育众多本科生、研究生以及公众。这项研究建立在对加州内华达山脉复杂景观中山地黄腿蛙（Rana sierrae 和 Rana muscosa）种群动态以及 Batrachochytrium dendrobatidis (Bd) 影响的长期研究数据的基础上，因为它已入侵并在数百个青蛙种群中传播。在大多数情况下，Bd 的入侵会导致壶菌病的爆发、青蛙数量的迅速下降和局部灭绝。然而，在某些情况下，青蛙种群会长期存在 Bd，处于地方性动物流行状态，其中病原体的影响大大减少。该研究将利用分子方法的最新进展以及来自 R. sierrae/R. 的广泛数据集和样本档案。 muscosa - Bd 系统，研究宿主和病原体的种群在从病原体到达前到疾病爆发、到地方性动物疾病、到疾病前宿主种群丰度的潜在恢复的过渡过程中如何变化。该数据集将用于研究宿主抗性/耐受性和病原体毒力差异的遗传基础。对现有拭子样本的尖端基因组分析将与对野外种群的持续调查相结合，以确定新的疾病暴发并描述从暴发到地方性动物流行状态的转变，从野外种群中收集 Bd 培养物和青蛙粘膜样本，以及 Bd 的实验室实验毒力和青蛙