Functional transitions in an insect-bacteria symbiosis

昆虫-细菌共生中的功能转变

• 批准号: 1256680
• 负责人: John McCutcheon
• 金额: $ 53.9万
• 依托单位: University of Montana
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-06-15 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1256680&HistoricalAwards=false
• 关键词: Functional; transitions; insect; bacteria; symbiosis

Insects are ideal model systems for studying associations between animals and microorganisms because of the diversity of interactions formed between them. These interactions, or symbioses, span a wide continuum of types, from those that are pathogenic and short-lived to those that are beneficial and stable over extremely long periods of time. Sap-feeding insects in particular have been shown to form intimate and stable symbioses with bacteria that live exclusively within insect cells. This strict intracellular lifestyle has profound effects on the symbiotic bacteria, effects that are dramatically manifest in their highly reduced genomes. This project will investigate a symbiosis involving a cicada that lives in the southwestern United States and its dual bacterial symbionts. One of these symbionts, named Hodgkinia, has a remarkably small genome encoding many fewer genes than was thought possible for an autonomous organism. The investigators will use both genetic and molecular techniques to uncover the mechanistic changes that have allowed Hodgkinia's extreme genome reduction. It is expected that adaptations in both the host insect and symbiont will be found that enable such dramatic gene loss. This work has broad-reaching consequences for the way we understand genome reduction in bacteria, the integration of organisms in the context of intimate symbioses, and the formation of cellular organelles such as mitochondria. The broader impacts of this project will involve the training of several undergraduate students, one graduate student, one postdoctoral fellow, and several K-12 teachers and students through collaboration with the Missoula County Public Schools and College of Education and Human Sciences at the University of Montana.

昆虫是研究动物和微生物之间相互作用的理想模型系统，因为它们之间形成了多样性的相互作用。这些相互作用或共生体跨越了广泛的类型连续体，从致病的和短暂的，到有益的和在极长时间内稳定的。特别是以树液为食的昆虫已被证明与仅生活在昆虫细胞内的细菌形成亲密而稳定的共生。这种严格的细胞内生活方式对共生细菌产生了深远的影响，这种影响在它们高度减少的基因组中表现得非常明显。这个项目将调查一种生活在美国西南部的蝉及其双重细菌共生体的共生关系。其中一种名为Hodgkinia的共生体的基因组非常小，编码的基因比人们认为的自主有机体可能编码的基因要少得多。研究人员将同时使用遗传和分子技术来揭示导致霍奇基尼亚病毒基因组极度减少的机械性变化。预计将在寄主昆虫和共生体中发现使这种戏剧性基因丢失的适应。这项工作对我们理解细菌基因组减少、紧密共生背景下有机体的整合以及线粒体等细胞器的形成具有广泛的影响。该项目的更广泛影响将包括通过与密苏拉县公立学校和蒙大拿大学教育与人文科学学院合作，对几名本科生、一名研究生、一名博士后研究员以及几名K-12教师和学生进行培训。