DISSERTATION RESEARCH: Multilevel Selection of the Ti Plasmid in Agrobacterium Tumefaciens

细菌病原体感染宿主的能力通常是由称为质粒的可移动遗传元件上的基因赋予的。这些遗传因素有时会在细菌种群中传播，因为它们赋予了携带它们的细菌竞争优势。当质粒的净效应为负时，其数量也会减少。该项目的一个主要目标是了解生态因素，如资源水平，如何影响致病质粒的维持。局灶质粒利用细胞间通讯协调其扩散的一个组成部分。该项目的第二个目标是深入了解许多细菌（和许多病原体）利用通信的适应性原因。这个项目将结合实验方法和数学建模来检验这些问题。质粒携带的基因参与许多重要的功能，包括发病机制和抗生素耐药性。然而，由于质粒独特的生物学特性，生物学家并不完全了解它们的种群动态。本项目的重点是了解在一种常见的植物病原体（一种常见的农业害虫）中维持毒力质粒的成本和收益。由于抗生素耐药细菌爆发时也会出现类似的种群动态，该项目还可以使人们对这一重大公共卫生问题背后的生物学有一个大致的了解。

A bacterial pathogen's ability to infect hosts is frequently conferred by genes on mobile genetic elements called plasmids. These genetic elements sometimes spread through bacterial populations because of the competitive advantages they confer to the bacteria that harbor them. Plasmids can also decline in populations when their net effects are negative. A main goal of this project is to understand how ecological factors, such as resource levels, influence the maintenance of a disease-causing plasmid. The focal plasmid employs intercellular communication to coordinate a component of its spread. A second goal of this project is to provide insight into the adaptive reasons many bacteria (and many pathogens) utilize communication. This project will combine experimental approaches with mathematical modeling to examine these issues.Plasmids carry genes involved in many important functions, including pathogenesis and antibiotic resistance. However, because of the unique biology of plasmids, biologists do not fully understand their population dynamics. This project focuses on understanding the costs and benefits associated with maintaining a virulence plasmid in a common plant pathogen that is a frequent agricultural pest. As similar population dynamics occur in outbreaks of antibiotic resistant bacteria, this project could also inform a general understanding of the biology underlying this major public health problem.