Understanding the breakneck spread of a Rickettsia symbiont in an invasive whitefly: Mechanisms and conditional effects

许多昆虫都有细菌共生体，它们生活在细胞内，并在卵中从母亲传给后代。该项目研究了这种涉及细菌共生体立克次体的共生关系在适应入侵的甘薯粉虱烟粉虱（Bemisia tabaci）宿主中的作用，烟粉虱是一种重要的农业害虫。在亚利桑那州，这种共生体的数量急剧增加，在短短六年内，从1%增加到97%的粉虱个体感染。研究小组将整合观察，实验和分子方法来理解为什么共生体如此有效地传播。这项研究将提高对共生体传播的理解，对共生体对宿主的影响，以及这些影响如何随遗传和环境特征而变化。细胞内共生体与宿主的相互作用是快速和长期适应的重要来源。共生体的获得实际上代表了宿主昆虫的即时适应。由于细菌是遗传的，它们成为昆虫宿主扩展基因组的一部分，昆虫生物学可能会永久改变，例如使甘薯粉虱等严重的农业害虫更具侵略性。这项研究所获得的知识可用于改善害虫管理或开发支持益虫的技术。 该项目还将为中学课堂开发和实施共生和昆虫生物学课程补充，包括本科生研究机会。

Many insects have bacterial symbionts that live within their cells and are transmitted from mother to offspring in the egg. This project studies the role of such a symbiosis involving a bacterial symbiont, Rickettsia, in adaptation of a host, the invasive sweetpotato whitefly Bemisia tabaci, which is an important agricultural pest. The symbiont has increased dramatically in Arizona, from 1% to 97% of whitefly individuals infected, over just six years. The research team will integrate observational, experimental and molecular approaches to understand why the symbiont spread so effectively. The research will improve understanding of how the spread of the symbiont occurred, of the consequences to the host of having the symbiont, and of how these consequences vary with genetic and environmental characteristics. The interactions of intracellular symbionts and their hosts are potentially important as sources of rapid and long-term adaptation. Acquisition of a symbiont represents a virtually instant adaptation of the host insects. Because the bacteria are inherited, they become a part of the extended genome of their insect hosts, and the insect biology may be permanently altered, for example making a serious agricultural pest like the sweetpotato whitefly more invasive. The knowledge gained by this research may be used to improve pest management or to develop techniques that support beneficial insects. This project also will develop and implement a curriculum supplement on symbiosis and insect biology for middle school classrooms and includes undergraduate research opportunities.