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、长寿命的环境阶段和腐生型生长的潜力。为了提高我们理解这类独特、多样和丰富的病原体的动态和影响的能力，需要针对这种类型的病原体建立新的模型。这个项目的总体目标是扩大我们对宿主内部和外部新出现的真菌病原体动态的了解。将进行实验室和田间实验和田间调查，以开发和适应疾病模型，使用两栖菊科真菌Batrachochytrium endrobatidis(Bd)作为主要模型系统。最近的证据表明，Bd可以感染各种各样的生物(除了两栖动物之外)，并且Bd具有形成生物膜的能力(这可能会增强其环境持久性的潜力)，这使其成为该项目的理想模型系统。真菌疾病模型将被开发和参数化，包括通用病原体、外部病原体储存库(包括将病原体合并到生物膜中的可能性)和腐生型病原体生长的潜力。这些模型将被用来探索真菌病原体的这些特征对目标寄主物种中病原体流行和疾病严重性的影响，在两栖动物/Bd系统和其他新兴的真菌病原体系统中都是如此。具体地说，研究小组将(1)深入分析Bd可能存在于宿主外的替代宿主和环境水库，(2)通过实验测试这些替代宿主和环境水库对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的持续和繁殖，(4)利用新的方法(元基因组学、元转录组学、元蛋白质组学)探索Bd生物膜如何在极端环境(即温度)中持续存在，以及这是否影响Bd的传染性，(5)改进基于真菌的疾病模型，以BD为案例研究纳入以生态系统为中心的方法，以及(6)创建一个新兴真菌数据库，进行荟萃分析，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.