From specialist to generalist: biotic and abiotic and reservoirs of fungal pathogens

许多真菌病原体具有广泛的寄主范围、长期的环境阶段和腐坏生长的潜力。这种类型的病原体需要新的模型，以提高我们理解这种独特的、多样化的、丰富的病原体群体的动态和影响的能力。该项目的总体目标是扩大我们对新兴真菌病原体在其宿主之间和外部的动态的理解。利用两栖壶菌Batrachochytrium dendroatidis （Bd）作为主要模型系统，将进行实验室和实地实验以及实地调查，以开发和拟合疾病模型。最近的证据表明，Bd可以感染多种生物（除了两栖动物），并且Bd具有形成生物膜的能力（这可能增强其环境持久性的潜力），使其成为该项目的理想模型系统。将开发和参数化真菌疾病模型，包括多面手病原体、外部病原体库（包括将病原体纳入生物膜的可能性）和腐坏性病原体生长的潜力。这些模型将用于探索真菌病原体的这些特征对目标宿主物种的病原体患病率和疾病严重程度的影响，包括两栖动物/Bd系统和其他新兴的真菌病原体系统。具体而言，研究团队将(1)深入分析Bd可能在宿主外持续存在的替代宿主和环境宿主；(2)实验测试这些替代宿主和环境宿主对Bd的生存和繁殖、Bd在环境中的持久性以及病原体向两栖动物传播的作用；(3)测试Bd生物膜的形成如何影响Bd的持久性和繁殖。(4)利用新方法（宏基因组学、元转录组学、元蛋白质组学）探索双歧杆菌生物膜如何在极端环境（即温度）中持续存在，以及这是否会影响双歧杆菌的传染性；(5)改进基于真菌的疾病模型，包括以生态系统为中心的方法，以双歧杆菌为例研究；(6)创建新兴真菌数据库，进行meta分析，并将我们的疾病模型与其他新兴真菌疾病相匹配。

Many fungal pathogens have broad host ranges, long-lived environmental stages, and the potential for saprotrophic growth. New models are needed for this type of pathogen, in order to improve our ability to understand the dynamics and impacts of this unique, diverse, and abundant group of pathogens. The overall aim of this project is to expand our understanding of the dynamics of emerging fungal pathogens both amongst and outside of their hosts. Laboratory and field experiments and field surveys will be conducted to develop and fit disease models, utilizing the amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), as the primary model system. Recent evidence that Bd can infect a wide diversity of organisms (in addition to amphibians), and that Bd has the ability to form biofilms (which may enhance its potential for environmental persistence), makes this an ideal model system for this project. Fungal disease models will be developed and parameterized, including generalist pathogens, external pathogen reservoirs (including the possibility of incorporation of the pathogen into biofilms), and the potential for saprotrophic pathogen growth. The models will be used to explore the implications of these features of fungal pathogens on pathogen prevalence and disease severity in target host species, in the both the amphibian/Bd system and in other emerging fungal pathogen systems. Specifically, the research team will (1) perform an in-depth analysis of alternative hosts and environmental reservoirs where Bd may persist outside of the host, (2) test experimentally the role of these alternative hosts and environmental reservoirs on survival and reproduction of Bd, persistence of Bd in the environment, and in transmission of the pathogen to amphibians, (3) test how Bd biofilm formation affects Bd persistence and reproduction, (4) explore how Bd biofilms persist in extreme environments (i.e. temperatures) and if this affects the infectiousness of Bd using novel approaches (metagenomics, meta-transcriptomics, meta-proteomics), (5) improve the fungal-based disease model to include an ecosystem-centric approach using Bd as a case study, and (6) create an emerging fungal database, conduct a metanalysis, and fit our disease models to other emerging fungal diseases.