Genome dynamics of protective bacterial symbionts in insects

昆虫、细菌和病毒在多样性和丰度上都比地球上大多数生物多好几个数量级。本研究将研究发生在蚜虫、防御哈密尔顿菌和细菌病毒（噬菌体）之间的共生关系的进化和维持。寄生蜂通常作为一种生物防治手段来调节蚜虫对农业的危害。然而，被H. defensa和噬菌体感染的蚜虫对寄生蜂具有抗性。初步数据显示，细菌和噬菌体具有编码许多毒力因子的基因，包括在人类病原体中发现的毒素。对细菌和噬菌体基因组序列和基因表达的分析将阐明哪些毒力因子是保守的，并参与保护蚜虫。这项研究对害虫的防治具有指导意义。对H. defensa生物学的理解也将有助于提高预测利用拟寄生虫敌人进行生物控制的效果的能力。更一般地说，细菌和噬菌体传播的杀虫毒素作为生物防治作物害虫的手段可能有更广泛的用途或兴趣。此外，这项工作将继续为女性和少数民族本科生提供分子生物学和生物信息学方面的指导和培训。

Insects, bacteria and viruses outnumber most organisms on earth in both diversity and abundance by several orders of magnitude. This study will examine the evolution and maintenance of a symbiosis that occurs between aphids, the bacterium Hamiltonella defensa, and a bacterial virus (phage). Parasitoid wasps are commonly used as a biological control to mediate agricultural damage caused by aphids. However, aphids infected with H. defensa and the phage are resistant to parasitoid wasps. Preliminary data revealed that the bacteria and the phage have genes encoding many virulence factors, including toxins that have been found in human pathogens. Analyses of bacteria and phage genome sequences and of gene expression will elucidate which virulence factors are conserved and are involved in protecting aphids.This study has implications for the control of insect pests. An understanding of H. defensa biology will also help in refining the ability to predict efficacy of biological control using parasitoid enemies. More generally, bacterial and phage-borne insecticidal toxins may have broader use or interest as means of biological control of crop pests. In addition, this work will continue to provide mentorship and training in molecular biology and bioinformatics for female and minority undergraduate students.