Metabolic Coupling in an Obligate Insect-Bacterial Symbiosis

Angela Douglas， Georg Jander和Klaas van wij65专性昆虫-细菌共生中的代谢耦合大多数动物都有有益细菌。许多这样的关联是强制性的：双方都是必需的。该项目将确定昆虫豌豆蚜虫和细菌Buchnera之间的专性共生是否以共享的代谢途径为基础，这意味着动物和细菌都有助于合成双方所需的营养物质。在这些共享的途径中，营养物质是由酶制造的，其中一些是由细菌基因编码的，另一些是由动物基因编码的，中间产物在动物和细菌之间转移。该项目将确定豌豆蚜虫是否通过共享代谢途径产生六种必需氨基酸。研究人员将分析共生的蛋白质补体，分离参与共享途径的候选酶，确定其功能，并通过稳定同位素标记量化共享途径中中间体的运动。关键的结果将是鉴定参与共享代谢途径的动物和细菌酶及其介导的反应，从而阐明这些共享代谢途径。这项研究将提供第一个明确的证据来解释为什么双方都需要动物-细菌共生。它将作为研究自然系统中许多其他专性共生的模型，并将为控制作物蚜虫的新策略确定候选目标。该项目将有助于培养昆虫科学、蛋白质组学和代谢生物化学方面的下一代科学家。它将支持研究生的论文研究。与本项目相关的本科暑期学生将通过已建立的本科生研究经验项目招募。

Angela Douglas, Georg Jander and Klaas van WijkProposal Number: IOS-0919765Metabolic coupling in an obligate insect-bacterial symbiosisMost animals have beneficial bacteria. Many of these associations are obligate: both partners are required. This project will establish whether the obligate symbiosis between an insect, the pea aphid, and the bacterium Buchnera is underpinned by shared metabolic pathways, meaning that both animal and bacteria contribute to the synthesis of nutrients needed by both partners. In these shared pathways, the nutrients are made using enzymes, some of which are coded by bacterial genes and others by animal genes, with intermediates being transferred between the animal and bacteria. This project will establish whether six essential amino acids are made by shared metabolic pathways in the pea aphid. The investigators will analyze the protein complement of the symbiosis, isolate candidate enzymes contributing to the shared pathways, determine their function, and quantify the movement of intermediates in the shared pathways by stable isotope labeling. The key results will be the identification of animal and bacterial enzymes that contribute to the shared metabolic pathways and the reactions they mediate, so that these shared metabolic pathways can be elucidated. This research will provide the first definitive evidence explaining why an animal-bacterial symbiosis is required by both partners. It will serve as a model to investigate the many other obligate symbioses in natural systems, and it will identify candidate targets for novel strategies to control aphid pests of crops. The project will contribute to the training of the next generation of scientists in insect science, proteomics and metabolic biochemistry. It will support the thesis research of a graduate student. Undergraduate summer students affiliated with this project will be recruited through an established Research Experience for Undergraduates program.