Elucidating the coevolutionary dynamics in an obligate insect symbiosis

许多昆虫，包括危害作物和传播疾病的害虫物种，都依赖共生细菌生存。这种共生细菌的群落，被称为微生物组，生活在宿主的细胞和组织内，并直接从母亲传给后代。这些细菌通常使宿主受益，例如，通过产生饮食中缺少的所需营养素。但共生体也会发生对宿主有害的遗传变化。这个项目解决了共生体的有害进化是否以及如何影响它们的宿主昆虫。这里的重点是这样一个群体，蚜虫，它攻击我们的大多数农作物，需要共生细菌才能生长和繁殖。这项研究将作为基础教学生物学和遗传学的得克萨斯大学本科生，包括在一个大型的新生研究计划的参与者。此外，这些结果将进一步了解一个重要的农业害虫群体，可能有助于作物保护新方法的发展。这些实验解决了豌豆蚜虫的遗传变异如何影响其调节共生细菌的能力，以及共生细菌的遗传变异如何影响其自身在蚜虫宿主中的繁殖。研究人员测量了共生体调节的变化如何影响蚜虫的生长和繁殖。实验遗传杂交蚜虫的共生细菌的水平不同，将结合现代DNA测序方法，以确定部分蚜虫基因组影响共生体的数量。此外，共生菌株将转移蚜虫宿主之间使用显微注射，以确定不同的共生菌株如何影响主机。

Many insects, including pest species that harm crops and transmit disease, depend on symbiotic bacteria for survival. This community of symbiotic bacteria, known as the microbiome, lives inside their host's cells and tissues and is passed directly from mother to offspring. These bacteria often benefit their hosts, for example, by producing required nutrients missing from the diet. But symbionts also can undergo genetic changes detrimental to hosts. This project addresses whether and how detrimental evolution of symbionts affects their host insects. The focus here is on one such group, aphids, which attack most of our agricultural crops and require symbiotic bacteria in order to grow and reproduce. The research will be used as a basis for teaching basic biology and genetics to University of Texas undergraduate students, including participants in a large freshman research program. Also, the results will further understanding of a significant group of agricultural pests, potentially contributing to the development of new methods of crop protection.The experiments address how genetic variation of pea aphids affects their ability to regulate symbiotic bacteria and how genetic variation of the symbiotic bacteria affects their own multiplication within aphid hosts. The researchers measure how variation in symbiont regulation affects aphid growth and reproduction. Experimental genetic crosses of aphids that vary in levels of symbiotic bacteria will be combined with modern DNA sequencing methods to identify the parts of the aphid genome that affect symbiont numbers. In addition, symbiont strains will be transferred between aphid hosts using microinjection, to determine how different symbiont strains affect hosts.