Microbial Genome Sequencing: Sequencing of Plasmids from the Bacillus Cereus Group-Mapping the Evolution of B. Anthracis Virulence Plasmids px01 and px02

本项目的目的是对蜡状芽孢杆菌菌群的大质粒的完整序列进行全面的调查，蜡状芽孢杆菌是自然土壤环境、昆虫内共生菌和动物病原体中普遍存在的成分。也许这个群体中最广为人知的成员是炭疽杆菌。在蜡样芽孢杆菌群体共有的一个主题中，编码致死毒素和聚谷氨酸胶囊的关键毒力基因，负责炭疽杆菌独特的致病特性，在大的质粒(pXO1和pXO2)上被发现。由于质粒在炭疽的生物学中起着主要作用，因此建议对多达24个蜡样芽孢杆菌组菌株中的大质粒进行调查，以回答有关与pXO1和pXO2具有和不具有已知同源性的质粒的具体问题。这些问题包括：导致pXO1和pXO2产生的进化事件能否被重建，这些质粒上的一些基因的来源能否在其他蜡样芽孢杆菌类生物中找到？复制子之间的基因交换在多大程度上发生，其机制是什么？哪些pxo基因在炭疽杆菌中是独一无二的？将从基因组DNA的脉冲场凝胶中分离出质粒，并用全基因组鸟枪法进行测序，以产生完整的、高质量的序列。该项目将大大增加关于染色体外元素如何影响这些重要微生物的关键表型的知识。这是由国家科学基金会和农业部之间的合作项目资助的基因组测序奖。

The aim of this project is to make a comprehensive survey of complete sequences of large plasmids from the Bacillus cereus group of bacteria, which are ubiquitous constituents of natural soil environments, endosymbionts of insects, and animal pathogens. Perhaps the most well known member of the group is the organism, B. anthracis. In a theme common to the B. cereus group, key virulence genes, encoding lethal toxin and poly-glutamic acid capsule, that are responsible for the unique pathogenicity profile of B. anthracis are found on large plasmids (pXO1 and pXO2). Because plasmids play a major role in the biology of anthrax, a survey of large plasmids in up to 24 B. cereus group strains is proposed to answer specific questions about plasmids with and without known homologies to pXO1 and pXO2. These questions include: can evolutionary events that led to the creation of pXO1 and pXO2 be reconstructed and can sources for some of the genes on these plasmids be found in other B. cereus group organisms? To what extent does gene exchange between replicons occur and what are the mechanisms? Which pXO genes are unique in B. anthracis? Plasmids will be isolated from pulsed-field gels of genomic DNA and sequenced by whole-genome shotgun methods to produce finished, high-quality sequence. This project will significantly add to knowledge of how extrachromsomal elements influence key phenotypes of these important microorganisms. This is a Genome Sequencing Award funded through a collaborative program between the National Science Foundation and the Department of Agriculture.