Metabolic Coupling in an Obligate Insect-Bacterial Symbiosis

Angela Douglas，Georg Jander和Klaas van Wijk Proposal编号：iOS-0919765昆虫-细菌共生中的新陈代谢耦合大多数动物都有有益的细菌。这些协会中有许多是义务的：双方都是必需的。该项目将确定昆虫、豌豆蚜虫和细菌Buchnera之间的专有共生是否有共同的代谢途径支撑，这意味着动物和细菌都有助于双方所需营养的合成。在这些共享的途径中，营养物质是使用酶来制造的，其中一些由细菌基因编码，另一些由动物基因编码，中间产物在动物和细菌之间转移。该项目将确定豌豆蚜虫体内的六种必需氨基酸是否由共同的代谢途径构成。研究人员将分析共生的蛋白质互补，分离参与共享途径的候选酶，确定它们的功能，并通过稳定同位素标记来量化中间体在共享途径中的运动。关键结果将是识别有助于共同代谢途径的动物和细菌酶以及它们所介导的反应，以便可以阐明这些共同的代谢途径。这项研究将提供第一个确凿的证据，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，并将确定控制作物蚜虫的新策略的候选目标。该项目将有助于培训下一代昆虫科学、蛋白质组学和代谢生物化学方面的科学家。它将支持一名研究生的论文研究。与该项目相关的本科生暑期学生将通过已建立的本科生研究体验计划招募。

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.