Collaborative Research: Evolutionary Dynamics of Endosymbiont-Borne Adaptation in Aphids

9627879鲍曼蚜虫和许多其他以植物为食的昆虫依赖于称为内共生体的特殊细菌，这些细菌生活在细胞内，并从母亲昆虫传播给她的后代。蚜虫内共生体的最佳记录功能是提供必需营养素色氨酸。因为蚜虫在它们的食物中不摄取色氨酸，它们依赖于它们的内共生体来提供这种营养。因此，细菌基因的基础色氨酸生产是至关重要的生长和繁殖的昆虫宿主。本研究探讨了蚜虫内共生体色氨酸生产相关基因的进化。 以前的工作表明，这些基因在某些蚜虫物种的内共生体中显示出不寻常的加速进化模式。该项目使用分子生物学方法来测试对该基因进化速率变化的解释。 由于内共生体是许多作物害虫的重要组成部分，包括蚜虫，粉虱和介壳虫等群体，这项研究将有助于基础知识，最终可能导致害虫管理的进展。 农业昆虫学家认为，影响昆虫表现的内共生体性状的短期进化在害虫新品种的起源中很重要。这项研究将是第一个直接研究内共生体基因进化的研究，这些基因对昆虫的生存和繁殖至关重要。

9627879 BAUMANN Aphids and many other plant-feeding insects are dependent on specialized bacteria, called endosymbionts, that live within cells and that are transmitted from the mother insect to her offspring. The best documented function of endosymbionts within aphids is the provision of the essential nutrient, tryptophan. Because aphids do not ingest tryptophan in their diets, they depend on their endosymbionts to provide this nutrient. Thus the bacterial genes that underlie tryptophan production are critical to the growth and reproduction of the insect host. This study examines the evolution of the endosymbiont genes underlying tryptophan production in aphids. Previous work has indicated that these genes show an unusual pattern of accelerated evolution in the endosymbionts of certain aphid species. This project uses methods of molecular biology to test explanations for the variation in evolutionary rates in this gene. Because endosymbionts are an essential component of many crop pests, including such groups as aphids, whiteflies, and scale insects, this study will contribute to fundamental knowledge that could ultimately lead to progress in pest management. Agricultural entomologists have suggested that the short-term evolution of endosymbiont traits that affect insect performance is important in the origin of new strains of pest species. This study will be one of the first to directly examine evolution within endosymbiont genes that are critical to insect survival and reproduction.