En-Gen: Mutation in Genomes of Obligate Symbionts and Impacts on the Ecological Tolerances and Distributions of Hosts: Buchnera and Pea Aphids

大多数动植物的健康和生存依赖于特殊的共生微生物，主要是细菌。共生体可以影响宿主对环境因素的耐受性，如热、寄生虫或营养压力。在许多情况下，共生体在出生前从母亲转移到后代，母体传播在昆虫中尤其常见。本项目主要研究影响共生体基因组的突变，以及这些突变如何影响宿主的功能和环境耐受性。将对蚜虫的细菌共生体Buchnera进行全基因组重测序，Buchnera是共生研究最好的例子之一。这些数据将揭示共生体基因组中突变的总体频率，以及影响宿主重要功能的突变频率，如必需营养物质的产生或耐热性。为了量化这些突变对宿主的影响，将对含有不同共生基因型的活昆虫进行实验室实验。初步证据表明，即使是共生体DNA序列的一个单一变化，也会对蚜虫在高温下生存的能力产生巨大影响。新的结果将显示这种突变在整个共生体基因组中的程度。这一结果将有助于了解决定一大类作物害虫（蚜虫）分布的基本过程，并将对在许多其他害虫中发现的类似共生系统产生影响。这项研究对预测生物如何应对气候变化具有直接意义。教育成分，从高中到研究生水平，被纳入研究。研究生和本科生将进行主要研究的重要部分。此外，高中生将通过主要研究者和一所大型城市高中的生物教师之间的持续合作参与，其中大多数学生来自科学和大学中代表性不足的群体。

The health and survival of most animals and plants depends on specialized symbiotic microorganisms, mostly bacteria. Symbionts can affect the tolerances of hosts to environmental factors such as heat, parasites or nutritional stress. In many cases, symbionts are transferred from mother to offspring before birth, with maternal transmission especially common in insects. This project focuses on mutations affecting symbiont genomes and on how these mutations impact the functioning and environmental tolerances of hosts. Full genome resequencing will be carried out for Buchnera, the bacterial symbionts of aphids and one of the best studied examples of symbiosis. These data will reveal the overall frequency of mutations in the symbiont genome and the frequency of mutations that affect functions important to hosts, such as production of essential nutrients or tolerance to heat. To quantify the effects of these mutations on hosts, lab experiments with live insects containing different symbiont genotypes will be conducted. Preliminary evidence indicates that even a single change in the symbiont DNA sequence can have a massive effect on the aphid's ability to survive heat exposure. The new results will show the extent of such mutations across the entire symbiont genome. The results will add to understanding of fundamental processes determining the distribution of a major group of crop pests (aphids) and will have implications for similar symbiotic systems found in many other insect pests. The study has direct implications for predicting how organisms respond to climate change. Educational components, from the high school to graduate level, are integrated into the research. Graduate and undergraduate students will conduct significant portions of the primary research. In addition, high school students will participate through a sustained collaboration between the main investigator and a biology teacher at a large urban high school with a majority of students from groups underrepresented in science and in the university.