PIRE: U.S.-East Africa Research and Education Partnership: Cassava mosaic disease - A paradigm for the evolution of insect-transmitted plant virus pathosystems

该项目在美国和东非的科学家和学生之间建立了一种研究和培训伙伴关系，以研究植物DNA病毒如何随时间变化。植物DNA病毒已经成为威胁全球农作物的主要病原体。这些研究将集中在木薯花叶病上，这是非洲特有的疾病，严重限制了木薯的生产，木薯是整个非洲大陆的主要粮食作物。由于非洲是世界上增长最快的地区之一，预计到2050年人口将翻一番，达到24亿人，因此在那里生产足够数量的高质量、营养丰富的食物是一项挑战。农业正日益成为一项全球性的事业，寻找粮食安全问题的解决方案将取决于像这样的研究伙伴关系，它探索植物DNA病毒如何进化的基础科学，以及是什么限制了它们随着时间的推移而适应的能力。这样的基础知识可以被其他人用来制定合理的、持久的策略来控制这些重要的植物病原体。该项目依靠美国和非洲参与者的综合专业知识和资源，为培训美国学生发展科学技能和在全球社区工作以帮助确保发展中国家和发达国家未来的安全提供了一个极好的框架。植物病毒的分子进化是通过病毒基因组成分的突变、重组和重配而发生的，从而导致高度变异。在复杂的病原体-宿主系统中，进化结果受到许多生态因素的影响，包括农业实践、昆虫媒介种群、作物与水库植物之间的相互作用以及气候。我们对病毒进化的大部分知识都是基于现场收集的样本，这些样本只能提供特定时间和地点病毒多样性的快照。为了研究植物DNA病毒的全部进化潜力和限制其进化的瓶颈，我们建议在严格控制的实验条件下对病毒遗传多样性、出现、持续和传播的驱动因素进行全面分析。我们将重点研究导致木薯花叶病的DNA病毒，使用NexGen测序来比较它们在营养传播和白蝇传播、混合感染和作为宿主的野生植物中的多样性。我们将询问通过寄主植物和/或昆虫媒介传播是否成为限制病毒多样性的瓶颈。我们对导致木薯花叶病的进化潜力和因素的研究是变革性的，因为它将提供一个全面的框架，使用准确反映现实世界条件的作物和接种方法来检查病毒与宿主，昆虫媒介和环境的关系。我们的综合方法还将作为审查病毒进化的模型，并将为制定对植物、动物和人类健康产生负面影响的其他昆虫传播病毒的控制战略提供信息。博士后研究人员、研究生和本科生将由一个强大的国际研究团队指导，该团队包括病毒种群遗传学、昆虫媒介传播和种群动力学、病毒/媒介/植物相互作用以及STEM教育方面的专家。该研究的多学科性质将为受训者提供实验室和实地研究以及生物信息学方面的经验。这将使他们成为全球参与的独立科学家，在一系列研究方法和环境方面拥有坚实的基础，并在国际和多学科合作方面拥有第一手经验。

This PIRE project establishes a research and training partnership between scientists and students in the United States and East Africa to study how plant DNA viruses change over time. Plant DNA viruses have emerged as leading pathogens that threaten crops worldwide. These studies will focus on Cassava mosaic disease, which is endemic to Africa and severely limits the production of cassava, a major food crop across the continent. Because Africa is one of the fastest growing regions in the world, with a population projected to double to 2.4 billion people by 2050, producing sufficient quantities of high quality, nutritious food is a challenge there. Agriculture is increasingly a global enterprise and finding solutions to food security problems will depend on research partnerships such as this one that explores the basic science of how plant DNA viruses evolve and what limits their ability to adapt over time. Such fundamental knowledge can then be used by others to develop rational, durable strategies to control these important plant pathogens. The project, which relies on the combined expertise and resources of U.S. and African participants, provides an excellent framework for training U.S. students to develop their scientific skills and to work in a global community to help ensure the future security of the developing and developed world.Molecular evolution of plant viruses occurs through mutation, recombination and reassortment of viral genome components, resulting in a high degree of variation. In complex pathogen-host systems, the evolutionary outcomes are influenced by many ecological factors including agricultural practices, insect vector populations, interactions between crops and reservoir plants, and climate. Most of our knowledge of viral evolution is based on field-collected samples, which only provide snapshots of viral diversity at specific times and locations. To examine the full evolutionary potential of plant DNA viruses and the bottlenecks that constrain their evolution, we propose a comprehensive analysis of the drivers of viral genetic diversity, emergence, persistence and spread under tightly controlled experimental conditions. We will focus on the DNA viruses that cause Cassava mosaic disease using NexGen sequencing to compare their diversity during vegetative and whitefly transmission, in mixed infections, and in wild plants that serve as reservoir hosts. We will ask if movement through the host plant and/or transmission by insect vectors serve as bottlenecks that limit viral diversity. Our study of the evolutionary potential and factors that contribute to Cassava mosaic disease is transformative in that it will provide a comprehensive framework for examining viral evolution in relationship to the host, the insect vector and the environment using a crop and inoculation methods that accurately reflect real world conditions. Our integrated approach will also serve as a model for examining viral evolution and will inform the development of control strategies for other insect-transmitted viruses that negatively impact plant, animal and human health. Postdoctoral researchers, graduate students and undergraduates will be mentored by a strong international research team, which includes experts on viral population genetics, insect vector transmission and population dynamics, virus/vector/plant interactions, and STEM education. The multidisciplinary nature of the research will provide trainees experience in laboratory and field-based research as well as bioinformatics. This will prepare them to become globally engaged, independent scientists with a solid foundation in a range of research methodologies and environments and first-hand experience in international and multidisciplinary collaborations.