Microbial Genome Sequencing: Comparative Genomics of Chemosynthetic Symbionts

哈佛大学的Colleen Cavanaugh博士与基因组研究所（TIGR）的Jonathan Eisen博士合作，获得了一项资助，对两种与海洋无脊椎动物共生的具有代表性的化学合成细菌的基因组进行测序。像植物中的叶绿体（产糖细胞器）一样，化学合成共生体利用硫化物代替阳光作为能量来源，为宿主提供内部营养来源。化学合成细菌作为海洋无脊椎动物的共生体广泛存在，尚未被培养，也是海洋环境中硫和碳循环的重要组成部分，包括深海热液喷口。获得这些共生体基因组序列将允许与相关的自由生活细菌和其他内共生体的基因组进行比较，从而快速了解化学合成共生体的遗传学，代谢潜力和进化。这些动物-细菌共生在进化上具有重要意义，有效地创造了“吃硫动物”，并作为理解动物细胞器的细菌起源和进化的模型，并且在生态上，作为富硫化物环境中的初级生产者。基因组分析将回答有关微生物共生、生理学、遗传学、生态学和进化的问题。此外，这些基因组的比较将促进我们对细菌如何在宿主代之间传递以及共生共生体与病原体感染机制之间的异同的理解。与该项目相关的外联工作将包括通过TIGR网站提供基因组序列。该项目的网站www.endosymbiont.org包含了与出版物、其他基因组、研究人员、该领域新闻和教育材料相关的链接。本科生、研究生和博士后将有充分的机会参与共生基因组的分析。关于内共生体基因组学的信息将通过从小学课堂到国际研究会议等各种场所的讲座向科学和普通观众传播。

A grant has been awarded to Dr. Colleen Cavanaugh of Harvard University, in collaboration with Dr. Jonathan Eisen of The Institute for Genome Research (TIGR), to sequence the genomes of two representative chemosynthetic bacteria which live in symbiotic associations with marine invertebrates. Like chloroplasts in plants (the sugar-producing organelles), chemosynthetic symbionts provide their host an internal source of nutrition, using sulfide instead of sunlight as an energy source. Chemosynthetic bacteria are widespread as symbionts of marine invertebrates, as-yet-uncultured, and substantial components of sulfur and carbon cycling in marine environments, including deep-sea hydrothermal vents. Obtaining these symbiont genome sequences will allow comparison with the genomes of related free-living bacteria and other endosymbionts, providing rapid insights into the genetics, metabolic potential, and evolution of chemosynthetic symbioses. These animal-bacteria symbioses are significant evolutionarily, effectively creating "sulfur-eating animals" and as models for understanding the bacterial origin and evolution of animal cellular organelles, and, ecologically, as primary producers in sulfide-rich environments. Genome analyses will answer questions regarding microbial symbiosis, physiology, genetics, ecology, and evolution. Further, comparison of these genomes will advance our understanding of how the bacteria are passed between host generations and the similarities and differences between infection mechanisms of mutualistic symbionts vs. pathogens. Outreach efforts associated with the project will include the availability of the genome sequences via the TIGR website. The project website, www.endosymbiont.org, contains relevant links to publications, other genomes, researchers, news in the field, and educational materials. Undergraduates, graduate students, and postdoctoral fellows will have ample opportunity to participate in analyses of the symbiont genomes. Information on endosymbiont genomics will be disseminated to scientific and general audiences by lectures at venues ranging from elementary school classes through international research meetings.