Characterizing Diverse Phage Roles in a Defensive Symbiosis

昆虫和其他动物经常感染母体遗传的共生菌，这些共生菌可以通过提供营养或宿主保护使它们的动物宿主受益。许多有益的共生体本身都感染了被称为噬菌体的病毒，这种病毒能够以关键的方式影响宿主生物学，但它们在动物-细菌共生中的作用却鲜为人知。在豌豆蚜虫Acyrthosiphon pisum中，细菌共生体汉密尔顿防御菌提供了免受寄生黄蜂攻击的保护，但只有在也存在称为APSE的噬菌体时才能提供保护。除了在保护方面的作用外，人们对类人猿对防御性粘虫和蚜虫生物学的影响知之甚少，具体包括类人猿如何促进寄生虫的死亡，以及在调节共生体丰度方面的潜在作用。该项目将使用包括基因组学和分子生物学在内的多种方法来表征APES在调节和维持保护性共生中的作用，并确定导致黄蜂死亡的特定因素。破译噬菌体-共生体的相互作用对于一般动物-微生物相互作用的研究以及对许多经济上重要的昆虫(如蚜虫)生物学的理解都是重要的。拟议的工作将为害虫种群的管理以及噬菌体在建立和维持细菌-节肢动物协会方面的作用提供具有实际意义的信息，细菌-节肢动物协会在自然界中广泛存在。这项研究的跨学科性质也非常适合作为一个平台，在共生、细胞生物学、寄生虫学和分子过程的界面上培训年轻科学家。该项目将培养高中生、本科生和研究生以及博士后研究人员。

Insects and other animals are frequently infected with maternally inherited symbiotic bacteria, which can benefit their animal hosts by providing nutrition or host protection. Many beneficial symbionts are themselves infected with viruses called bacteriophages, which have the capacity to impact host biology in critical ways, yet their roles in animal-bacterial symbioses are poorly understood. In the pea aphid, Acyrthosiphon pisum, the bacterial symbiont Hamiltonella defensa confers protection from attack by parasitic wasps, but only when bacteriophages called APSEs are also present. Aside from this role in protection, little is known about the influence of APSEs on H. defensa and aphid biology, including specifically how APSEs contribute to the demise of parasites and the potential role in the regulation of symbiont abundance. This project will use a combination of approaches, including genomics and molecular biology, to characterize the roles of APSEs in the regulation and maintenance of the protective symbiosis and to identify specific factors responsible for wasp mortality. Deciphering phage-symbiont interactions is important to the study of animal-microbial interactions generally and to understanding the biology of many economically important insects like aphids. The proposed work will yield information of practical importance for the management of pest insect populations and on the role of phages in the establishment and maintenance of bacterial-arthropod associations, which are widespread in the natural world. The interdisciplinary nature of this research is also well suited as a platform to train young scientists at the interface of symbiosis, cell biology, parasitology, and molecular processes. This project will train high school students, undergraduate and graduate students, and post-doctoral researchers.